The present invention is a fertilizer feedstock steel slag, a method of producing a fertilizer feedstock steel slag, a manufacturing method and fertilization methods fertilizer.
BACKGROUND
[0002]
As an essential element for plant growth, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), oxygen (O), in hydrogen (H), carbon (C), magnesium (Mg), sulfur (S), iron (Fe), manganese (Mn), boron (B), zinc (Zn), nickel (Ni), molybdenum (Mo), copper (Cu), chlorine (Cl) are known.
[0003]
　Among the above elements, nitrogen (N), phosphorus (P), potassium (K) is referred to as three elements of fertilizer, it is known that the plant is an element to large amounts needed. Further, calcium (Ca), magnesium (Mg), sulfur (S) are called secondary element, it is said that elements required by the plant next to the above three factors. Furthermore, iron (Fe), manganese (Mn), boron (B), zinc (Zn), molybdenum (Mo), copper (Cu), chlorine (Cl), because the plant requires trace, and trace elements being called.
[0004]
　Further, boron (B) of the above elements, in recent years, it is an element necessary for the formation of the cell wall of the cells of the roots of the plant are being found. In addition, rice, wheat, the major food crops of the world's population, such as corn, in addition to the above elements, and require large amounts of the silicon (Si), which is a silicate crops.
[0005]
　Ca, P, Si, Mg, Fe, Mn, B, each element of S, the one way to feed to the plant, there is a foliar. In foliar application, for each element, for example the following substances are used.
　　Ca: Calcium chloride
　　P: potassium primary phosphate
　　Mg: Magnesium sulfate
　　Fe: ferrous sulfate
　　Mn: manganese sulfate
　　B:
　　borate, Si: potassium
　　silicate, S: calcium sulfate (gypsum), magnesium sulfate, first sulfuric acid iron, manganese sulfate
[0006]
　However, since foliar is a method of time-consuming to work, a method capable of roots absorb the elements as described above regardless of the foliar is desired.
[0007]
　On the other hand, steel slag obtained by hot metal pretreatment and decarburization treatment of the steel industry, because it contains various minerals as its constituents, as disclosed in Patent Documents 1 to 9 below, fertilizers and soil It has been used as materials.
[0008]
　For example, Patent Document 1 below, the raw material for silicic acid phosphate fertilizer recovered in dephosphorization process during the hot metal pretreatment of blast furnace hot metal in the steelmaking process, the method for producing the silicic acid phosphate fertilizer raw materials, It has been reported.
[0009]
　Patent Document 2 below, a method of producing a slag phosphate fertilizer steelmaking slag obtained from the hot metal pretreatment process steelmaking process as a raw material have been reported.
[0010]
　Patent Document 3 below, there are sales effect of rice slag grains consisting of steel slag of steelmaking process, it has been reported that some inhibitory effect of greenhouse gases.
[0011]
　Patent Document 4 and Patent Document 5 below, using one of the converter type refining furnace, have been reported hot metal pretreatment method for implementing the desiliconization treatment and dephosphorization process is sequentially, Patent Document 6 below, method of producing a siliceous fertilizers have been reported in the hot metal pretreatment step of steelmaking process.
[0012]
　In the following Patent Document 7, a coal ash containing only silicate not dissolution, by mixing with slag stainless steel molten state, been reported enabled silicic acid fertilizer elution silicic acid there.
[0013]
　In the following Patent Document 8, a manufacturing method of fertilizer phosphoric acid containing slag has been reported, the following Patent Document 9, the manufacturing method of the phosphate fertilizer material resulting from steelmaking processes have been reported.
CITATION
Patent Document
[0014]
Patent Document 1: Japanese Patent No. 5105322
Patent Document 2: Patent No. 6040064 Patent
Patent Document 3: Patent No. 5881286 Patent
Patent Document 4: Japanese Patent No. 5983900 Patent
Patent Document 5: JP 2016-29206 JP
Patent Document 6: Japanese Patent No. 4246782 No.
Patent Document 7: Japanese Patent No. 4040542 Patent
Patent Document 8: Japanese Patent No. 6119361
Patent Document 9: Japanese Patent No. 6011556
Summary of the Invention
Problems that the Invention is to Solve
[0015]
　P, Fe, Mn, Zn, Si, Ca, Mg, B, be applied at a rate of many types of materials including the elements, such as S, it can be expected fertilizer effect of each element, costly and labor. In the case of applying a material containing each element in the soil, because the specific gravity for each material is different, specific gravity smaller material, may in the soil area flooding often of high rainfall areas and rivers resulting in erosion is there. As a result, in the period of one work that the plant is cultivated, there is a concern that will have to grow plants in conditions that lacks the balance of each element. Rainwater, to carbon dioxide in the air dissolves shows weak acidity of about pH 5.6. In addition, in recent years, under the influence of the exhaust gas containing sulfur oxides and nitrogen oxides, in the Southeast Asia region it has also become a problem that falls is pH4 units of acid rain. In high rainfall areas and there are many areas of soil flooding of the river by the rain water, the effect of prolonged exposure to rain water of such acid, possible Fe from the soil, Mn, elements such as B is insufficient to runoff there is sex.
[0016]
　In soil flooding of large areas of high rainfall regions and rivers, rice, wheat, that can be stably grown silicic acid plants such as corn, it is very important from the point of view of stable food supply.
[0017]
　Also, of the secondary elements, Ca, Mg is an element necessary for the growth and photosynthesis of plant roots. Further, such a Ca, Mg are lime, shows alkalinity as magnesia, is a major constituent element of the alkali content measured by fertilizer analysis, etc., tend to be acidic under the influence of prolonged exposure to acidic rain against soil, to increase the pH of the soil is also an element has the effect of improving to pH suitable for the cultivation of plants.
[0018]
　In addition, one of the secondary element, S is an essential element in the biosynthesis of sulfur-containing amino acid, garlic, onion, the cultivation of Amaryllidaceae or Liliaceae plants such as green onion is particularly necessary element. However, S is, after addition to the soil, is oxidized or acidified soil becomes sulfuric acid, or may or causing the root rot become hydrogen sulfide is reduced by the action of sulphate-reducing bacteria element it is.
[0019]
　In addition, Si is, rice, wheat, is an element necessary to grow in a stable silicic acid plants such as corn, is very important from the point of view of stable food supply.
[0020]
　In this way, P, Fe, Mn, Si, Ca, Mg, S, many kinds of elements of B, even in the soil of the region flooding in many of the high rainfall areas and rivers, without erosion by water flow easily and at low cost, which can be supplied as a fertilizer plant, it is the current state of development of the fertilizer and fertilizing methods are required.
[0021]
　Accordingly, the present invention has been made in view of the above problems, it is an object of the present invention, even in the soil of the region flooding in many of the high rainfall areas and rivers, without erosion by water flow easily and at low cost, many kinds of elements can be supplied as a fertilizer plant, it is to provide a fertilizer feedstock steel slag, a method of producing a fertilizer feedstock steel slag, a manufacturing method and fertilization methods fertilizer.
Means for Solving the Problems
[0022]
　The present inventors have, as a result of intensive studies in view of the above problems, P, Fe, Mn, Si, Ca, Mg, B, to supply many kinds of elements of S, specifically for fertilizer raw steel and slag and a manufacturing method thereof, each of these elements to develop a manufacturing method and fertilization methods fertilizers can be supplied, and have completed the present invention.
　The gist of the present invention is as follows.
[0023]
[1] in terms of mass% P 2 O 5 : 2% to 8% or less, MnO: 10% 3% or more or less, boron: less than 0.005% 0.05% total iron: 15% or more than 30% , CaO: less 29% than 38% SiO 2 : below 16% to 22%, sulfur: 0.1% to 0.6% or less, MgO: 8% 4% to less, Al 2 O 3 : 0.5 % to 3% or less, containing the P 2 O 5 soluble P in 2 O 5 ratio of, is 50% or more, the proportion of Ku-soluble MnO in the MnO is at least 80%, ( CaO content / SiO 2 slag basicity represented by the content) is 1.5 exceed 2.2, bulk specific gravity is 2.3 or more than 3.2, fertilizers steelmaking slag. [2]
2CaO · SiO 2 -3CaO · P 2 O 5 solid solution, and, FeO-MnO-CaO-SiO 2 containing solid solution, respectively, fertilizer feedstock steel slag according to [1].
[3] the percentage of Ku-soluble boron in the boron, less than 95%, [1] or [2] fertilizer feedstock steel slag according to.
[4] particle size less than 5mm as a whole, and the mass ratio of those particle size is less than 600μm is 60% or more with respect to the total mass, one any one of [1] to [3] fertilizer raw materials for steelmaking slag as claimed in One.
[5] [1] to [4] it is any one method for producing a fertilizer raw material for steelmaking slag according to the respect converter type pan, corresponding to a length to hot metal liquid surface from (throat free void ratio expressed in a furnace height) of the board / throat corresponding to the length up to the furnace bottom so that 0.5 to 0.9, and injected blast furnace hot metal, said converter to with respect to the blast furnace hot metal in the mold pan, manganese ore, manganese-containing decarburization slag, and, by adding at least one of ferromanganese, the particle size is less quicklime 30 mm, and / or the blast furnace hot metal calcium carbonate after having added to the from the lance inserted into the blast furnace hot metal, blowing oxygen to the blast furnace hot metal, slag performed by forming dephosphorization treatment at 1300 ° C. or higher 1400 ° C. or less, (CaO content / SiO 2 slag base represented by content) Degrees becomes a 1.5 excess 2.2 or less and is prepared as MnO content of the slag is 3 mass% to 10 mass%, the production method of the fertilizer feedstock steel slag.
[6] The molten slag after dephosphorization treatment was poured into the dish-shaped heat-resistant container and solidified by rapid cooling method fertilizer feedstock steel slag according to [5].
[7] watering by performing rapidly cooling the molten slag after the dephosphorization process, the manufacturing method of the fertilizer feedstock steel slag according to [6].
[8] By tilting the converter type pot, after the molten slag after the dephosphorization process was devoted to the slag pot, the molten slag in said slag pot, to tilt possible first heat-resistant container and devote a, the molten slag by performing water spray in the first heat-resistant container after having solidified upon rapid cooling, crushing the solidified slag, to tilt the first heat-resistant container Te, crushed by dropping sliding the solidified the slag in the second heat-resistant vessel, [5] - method of manufacturing a fertilizer feedstock steel slag according to any one of [7].
[9] by rapid cooling, 2CaO · SiO 2 -3CaO · P 2 O 5 solid solution, and, FeO-MnO-CaO-SiO 2 solid solution to be formed, respectively, in any one of [5] to [8] manufacturing method of fertilizer raw materials for steelmaking slag described.
[10] the particle diameter is less than 5mm as a whole, and the mass ratio of those particle size is less than 600μm is such that 60% or more with respect to the total mass, grinding the slag, [5] - [ method for producing a fertilizer feedstock steel slag according to any one of 9].
[11] [5] to powdering fertilizer feedstock steel slag fertilizer feedstock steel slag produced by the method according to any one of - [10] The method of manufacturing a fertilizer.
[12] After the addition of fertilizers for steelmaking slag for a given binding agent after powdering, granulation, method for producing a fertilizer according to [11].
[13] The obtained fertilizer, further mixing the organics [11] A process for producing a fertilizer according to [12].
[14] The organic material, livestock manure, plant residues, and is at least one of the resulting compost from fish, method for producing a fertilizer according to [13].
[15] [1] ~ fertilizer feedstock steel slag according to any one of [4], produced by the production method of the fertilizer feedstock steel slag according to any one of [5] to [10] fertilizer feedstock steel slag, or [11] to [14] the fertilizer with fertilizer which is manufactured by the manufacturing method of fertilizer according to any one of, pH (H 2 O) is 5.6 or higher 7 .5 or less, and the effective phosphate in the following 5 mg / 100 g dry soil, and / or manganese content of less 50 mg / 100 g dry soil, and / or boron content of 0.05 mg / 100 g dry soil to fertilizer for the soil is less than or equal to, fertilization method.
[16] the application rates of the fertilizer, as said fertilizer feedstock steel slag, or less 0.05 t / ha or more 2t / ha, fertilization method according to [15].
[17] the fertilizer before planting seed or seedlings, or sprinkled plow layer surface, or is mixed with the plow layer, fertilization method according to [15] or [16].
[18] the fertilizer or sprinkled plow layer surface in the vicinity of the plant to be cultivated, or are mixed to the plow layer, fertilization method according to [15] or [16].
The invention's effect
[0024]
　According to the present invention described above, even in the soil area flooding often of high rainfall areas and rivers, easily and inexpensively without erosion by water, many kinds of elements as a fertilizer plant it is possible to supply.
DESCRIPTION OF THE INVENTION
[0025]
　The following describes in detail preferred embodiments of the present invention.
[0026]
(Present invention will consider what have conducted)
　Prior to describing the embodiments of the present invention, the present inventors have carried out, the examination results about the demand for fertilizers and fertilizer application methods as described prior, in detail explain.
[0027]

with respect to requested such as prior described, feedstock silicate phosphate fertilizer disclosed in Patent Document 1, (CaO content / SiO 2 at a content) basicity represented is of 1.0 to 1.4, since a lower basicity, hardly out effective acidic soils. Further, the raw material for silicic acid phosphate fertilizer disclosed in Patent Document 1, the content of soluble CaO is as low as 30 wt% or less, because basicity weaker still difficult out effective acidic soils.
[0028]
　Furthermore, in Patent Document 1, Al 2 O 3 The content has been described that 10 mass% or less, referring to Examples, Al 2 O 3 content of 4.84 wt% or more 6 and at .33% by weight or less, it has a high value exceeding 4% by weight. Al is easily combined with phosphate ions, and, because it is a substance that causes interfere with phosphorus absorption of plants, lower Al 2 O 3 content is desired.
[0029]
　Further, in Patent Document 1, description of content of boron, and not present description of the fertilizer effect of boron.
[0030]

　In the above Patent Document 2, a steel slag obtained from the hot metal pretreatment process steelmaking process as a raw material, a method of producing a slag phosphate fertilizer is disclosed, wherein a method for manufacturing a steel slag as a raw material for slag phosphate fertilizer is not present. Also, from Examples of Patent Document 2, Ku-soluble phosphate content of steelmaking slag as the raw material is not more than 2.56 mass% to 2.62 mass%, the slag phosphate fertilizer standard "V it can be seen that no not satisfy the condition that soluble phosphate content of 3 mass% or more. " The aforementioned Patent Document 2, description of content of boron and manganese, and, there is no description of a fertilizer effect of boron and manganese.
[0031]

　In Patent Document 3, that the content of the phosphoric acid is 5 wt% or less than 1.5 wt% have been described, of which, how much ratio can act effectively to plants, to whether a soluble phosphoric acid (phosphoric acid, eluting with ammonium page ether Man citrate solution), wherein is absent.
[0032]
　In Patent Document 3, that the content of CaO is less than 50% by weight to 20% by weight are described. The reason for such content, in the steel process, CaO content of less than 20% by weight, or have shown that steel slag of more than 50 mass% hardly occurs.
[0033]
　In Patent Document 3, the slag grains consisting of steelmaking slag, SiO 2 that contains the following 30 to 10 mass% is described. In Patent Document 3, as because, SiO 2 when it is less than 10 wt%, the amount of variable supply status silicate eluting decreases the ability photosynthesis by generating oxygen in the soil surface of paddy filled with water It has been shown to not be expected the effect of promoting the growth of diatoms having. In Patent Document 3, in steelmaking process SiO 2 for steel slag such as those containing more than 30 mass% hardly occurs, it is shown that difficult to obtain.
[0034]
　Such patent document 3, the slag basicity (= CaO / SiO 2 for the description of) the absence, as described above, the content of CaO is 50 wt% or less than 20 wt%, and, SiO 2 content becomes possible may not more than 10 wt% to 30 wt%, basicity of the slag, 0.67 (CaO: 20 wt%, SiO 2 : 30 wt%) from 5 (CaO: 50 wt% , SiO 2 : can take a value of a very wide range of up to 10% by weight). Basicity of the slag, phosphorus, iron, because strongly related to the dissolution of the fertilizer active ingredients such as manganese, basicity of the settings suitable for the elution of these fertilizers effective element is considered necessary.
[0035]
　Further, in Patent Document 3, the slag grains consisting of steelmaking slag, it is described that contains more than 10 wt% 3.5 wt% or more of MnO. In Patent Document 3, as because, when the content of MnO is less than 3.5 mass%, may dissolution does not occur in sufficient multivalent manganese to raise the redox potential of the paddy soil it has been shown that there is. Here, the stated rate of application in Patent Document 3 is 0.5 t / ha or more 5t / ha, in application rate of this range, sufficient polyvalent manganese to raise the redox potential of the paddy soil it is contemplated that the elution occurs. When the amount of application is smaller than the above range is considered to be necessary to consider a more efficient conditions for manganese is eluted.
[0036]
　As described above, in Patent Document 3, since the description of the slag basicity absent, CaO content and SiO in Patent Document 3 2 in the range of basicity 0.67 to 5 estimated from the content, phosphorus Ya the basicity suitable for efficient elution of manganese, not been studied at all.
[0037]
　In Patent Document 3, description of the boron is not present, from any tissue of slag, even absent according to whether the phosphate, calcium, silicon, manganese and the like are eluted. In addition, has a 0.5 t / ha or more 5t / ha with regard application rates, requires a larger amount of application, costly regarding exertion for sow and cost of the fertilizer it is disadvantageous.
[0038]

　The hot metal pretreatment methods disclosed in Patent Documents 4 and 5, using one of the converter type refining furnace, desiliconization treatment and by performing the dephosphorization process in order, and slag containing an effective silicate fertilizer, and slag containing phosphoric acid will be recovered separately. However, as the fertilizer, it is preferable that the silicic acid and phosphoric acid is contained together. Further, by performing the desiliconization treatment and dephosphorization process separately, from the viewpoint of obtaining a slag as a fertilizer raw material, it takes time and cost. Further, Patent Document 4 and Patent Document 5, the composition of dephosphorization slag produced is not disclosed at all, nor is there description of a fertilizer. Thus, for whether these Patent Documents 4 and slag disclosed in Patent Document 5 is suitable for fertilizer, it is impossible to determine.
[0039]
　Further, in order to appropriately control the composition of the slag to be produced, the present inventors, as described in detail below freeboard (i.e., the length from the throat to the hot metal liquid surface in the converter type pot ) it is considered to be one of the important conditions. However, Patent Document 4, using one of the converter type refining furnace, the freeboard when performing desiliconization treatment and dephosphorization treatment in order not disclosed at all. In Patent Document 5, only for desiliconization treatment there is a description of the ratio of freeboard, the dephosphorization process, there is no description of the freeboard.
[0040]

　Patent Document 6, and a method for producing a siliceous fertilizers are disclosed in the hot metal pretreatment step of steel production process, Ku converter slag caused by hot metal pretreatment soluble by adding phosphoric acid, it is described that the Ku-soluble phosphoric acid 5 mass% or more. In Patent Document 6, the phosphoric acid content of the original slag, have been described that is less than 4 mass% to 1 mass%. In addition, Patent Document 6, containing boron, and, for the fertilizer effect of boron, not described at all. In Patent Document 6, there is no description about the freeboard during slag production, even absent described for collection and cooling process according Haikasu slag.
[0041]

　Patent Document 7, a coal ash containing only silicate not dissolution, by mixing with slag stainless steel melted state, the dissolution of the silicate Enabling silicic acid fertilizer is disclosed. However, such siliceous fertilizers, in order to be slag stainless steel, a high content of chromium. For this reason, or large amount of application of the fertilizer to such slag as a raw material, and a long period of time or applied, there is concern that the higher the chromium content of the soil. Moreover, since it is necessary to mix the coal ash becomes a factor of increase in cost due to increase in operation.
[0042]

　Patent Document 8, a manufacturing method of fertilizer phosphoric acid containing slag is disclosed, phosphoric acid content of such fertilizer phosphoric acid containing slag, 18.32 there is a mass% or more. However, such phosphate content is significant deviation phosphate content manufacturable steelmaking slag in the hot metal pretreatment and decarburization of a normal steelmaking process, molten iron pretreatment or decarburization conventional steelmaking process in the process, it is impossible to manufacture. Therefore, special steps in order to prepare such slag is required, which causes a cost increase.
[0043]

　in Patent Document 9, the manufacturing method of the phosphate fertilizer material resulting from steel production process is disclosed, phosphate slag to be according phosphate fertilizer material content is 15 mass% or more. However, such phosphate content is significant deviation phosphate content manufacturable steelmaking slag in the hot metal pretreatment and decarburization of a normal steelmaking process, molten iron pretreatment or decarburization conventional steelmaking process in the process, it is impossible to manufacture. Therefore, special steps in order to prepare such slag is required, which causes a cost increase.
[0044]
　As described above in detail, the steel slag steelmaking process for producing a fertilizer feedstock, or, when used as a fertilizer raw material capable of supplying a variety of minerals steelmaking slag steelmaking process, various problems to be solved It exists.
[0045]
　The present inventors, as a result of intensive investigations for the above problems, P, Fe, Mn, Si, Ca, Mg, B, to supply many kinds of elements of S, steelmaking slag specializing in fertilizer raw materials and a manufacturing method thereof, these respective elements to develop a manufacturing method and fertilization methods fertilizers can be supplied in a more easy and low cost, many kinds of elements fertilizer raw materials which can be supplied as a fertilizer plant it was possible to obtain a steel slag of use. Hereinafter, embodiments of the present invention will be described in detail.
[0046]
(Embodiment)

　Before describing in detail the fertilizer feedstock steel slag according to an embodiment of the present invention, for comparison, the general steelmaking slag be briefly described.
[0047]
　Commonly steel slag used in fertilizers, for example, is a type of steel slag by-produced in hot metal pretreatment step of steelmaking process, mention may be made of dephosphorization slag. Note that the dephosphorization slag, lime, iron oxide was added as a dephosphorization agent into molten iron to remove phosphorus contained in molten pig iron, by-product is by blowing gas such as oxygen, it is a slag containing phosphorus , which is a kind of steel slag.
[0048]
　In the iron and steel slag Association, has published the composition of a typical steel slag (BOF slag) (http://www.slg.jp/character.html), its typical composition is as follows .
　　CaO: 45.8, SiO 2 : 11.0, total
　　iron: 17.4, MgO: 6.5, Al 2 O 3 : 1.9, S: 0.06, P 2 O 5 : 1.7, MnO: 5.3 (each mass%)
[0049]
　Described in detail below, fertilizer feedstock steel slag according to an embodiment of the present invention is a kind of dephosphorization slag, as detailed below, when compared to the composition of a typical steel slag as described above , P 2 O 5 and SiO 2 high content of, it is characterized by a low content of CaO. Also, fertilizer feedstock steel slag according to the present embodiment, for the content of the Ku-soluble boron, compared with the composition of a typical steel slag as described above, it is high it is characterized.
[0050]

　Hereinafter, a fertilizer feedstock steel slag according to the present embodiment will be described in detail.
　Fertilizer feedstock steel slag according to the present embodiment, contain predetermined amounts of the components, a steel slag obtained by performing dephosphorization process on a blast furnace hot metal, Ca, P, Si, Mg, Fe , Mn, B, S, various elements such as Al or the like, and contains a predetermined amount.
[0051]
　More particularly, the fertilizer feedstock steel slag according to the present embodiment, by mass%, P 2 O 5 : 8% 2% or more or less, MnO: 10% 3% or more or less, boron: less than 0.005% 0 less than .05%, total iron: 15% or more than 30%, CaO: less 29% than 38%, SiO 2 : below 16% to 22%, sulfur: 0.1% to 0.6% or less, MgO: 4 % or more and 8% or less, Al 2 O 3 : containing 0.5% to 3% or less. Also, fertilizer feedstock steel slag according to the present embodiment, in addition to the above components, sometimes contain a variety of impurities.
　Hereinafter, each component contained in the fertilizer feedstock steel slag according to the present embodiment will be described in detail.
[0052]
[CaO: less than 29 mass% or more 38 wt%]
　First, Ca will be described.
　Ca is an essential fertilizer elements in the plant. In fertilizers, steel slag, when denoted the content of Ca, since the amount contained in terms of CaO in the oxide is denoted in the following, represents the content of Ca as CaO.
[0053]
　CaO is a compound showing alkalinity, have an effect on improvement of long-term acidic tend soil under the influence of exposure to acidic rain. The content of CaO contained in the fertilizer feedstock steel slag according to the present embodiment, as less than 29 wt% or more 38 wt%, 45.8 wt% of CaO contained in the steelmaking slag typical composition as described above compared with, much lower. This, in manufacturing the steel slag and reducing the amount of CaO to be added to molten pig iron, there is a merit to reduce the cost of CaO. However, the fertilizer feedstock steel slag according to the present embodiment, when the content of CaO is less than 29 wt%, the alkali resistance is weak, a fertilizer with fertilizer feedstock steel slag according to the present embodiment application also, it can not be sufficiently carried out the improvement of tend to soil acidification in the impact of a long period of time are exposed to acidic rainwater.
[0054]
　Further, the fertilizer feedstock steel slag according to the present embodiment, P is 2CaO · SiO 2 -3CaO · P 2 O 5 to be mainly present as a solid solution, the present P is in this embodiment, a sufficient amount presence of CaO is essential. When CaO content of the fertilizer feedstock steel slag according to the present embodiment is less than 29 wt%, present in the fertilizer in the above embodiment, a fertilizer raw material which gradually elutable P in soil, according to the present embodiment it may become impossible held in fertilizers containing steelmaking slag.
[0055]
　On the other hand, if the CaO content of the fertilizer feedstock steel slag according to the present embodiment is 38% or more by mass, the cost by reducing the amount of CaO to be added to molten iron for manufacturing as described above, the steel slag reduction is not obtained as compared with conventional steel slag production cost. Further, in view from the perspective of a fertilizer material, when the content of CaO is 38 wt% or more, by applying the fertilizer raw material for steelmaking slag of the present invention, excessive alkalinization pH of soil to be applied is possibility that there is, which is not preferable.
[0056]
　From such a viewpoint, the content of CaO fertilizer feedstock steel slag according to the present embodiment, and less than 29 wt% or more 38 wt%. The content of CaO is preferably at most 37 mass% to 30 mass%, more preferably is 36 wt% or less 31% by mass or more.
[0057]
　The content of such CaO, for example, can be measured by X-ray fluorescence analysis.
　Specifically, the content of CaO is a known measurement sample, a plurality prepared while changing the content, measuring the fluorescent X-ray intensities obtained from Ca measurement sample prepared by the fluorescent X-ray analyzer. The resulting a fluorescent X-ray intensity from Ca was using, and the content of CaO, advance a calibration curve showing the relationship between the content and the fluorescent X-ray intensity of CaO. Thereafter, the sample content is unknown CaO of interest, a fluorescent X-ray intensity from Ca was measured by a fluorescent X-ray analyzer, using a fluorescent X-ray intensities obtained, the calibration curve, the, of CaO it is possible to identify the content.
[0058]
　Here, the sample of interest is, in terms of samples were taken as follows to prepare the following procedure to measure the fluorescent X-ray intensity measured under the following conditions.
　That is, the analytical sample was set in a vibration mill (manufactured by Kawasaki Heavy Industries T-100 Model Co., Ltd.), the analytical sample is crushed into powder (instrument conditions: milling time 30 sec, 1000 rpm). The ground samples, using a sieve having a mesh opening 212 m, to implement the distribution. Subsequently, the platinum dish was charged with a sample 0.3 g, lithium iodide (separation material) ear spoon 2 cups about that passed through the sieve of lithium tetraborate (flux) 6 g, the mesh opening (212 m), the bead 1,150 ° C. × 10 minutes × at samplers 3-4 times melted performed to produce a glass bead. Similarly, processing performed in a glass bead also standard. A calibration curve with fluorescent X-ray analyzer (Rigaku Denki Kogyo ZSX PrimusII), carrying out the check analysis by quantitative and standards of the sample passed through the sieve of the mesh opening (212 m). This analysis method is based on JIS standard "JIS M 8205".
[0059]
[SiO 2 : 16 mass% or more and less than 22 wt%
　Then, Si is described.
　Si, although not an essential element of the plant, rice, wheat, such as corn, rice for the family of silicic acid plant, is a very important element. About 5% of the dry weight of the plants rice silicate (SiO 2 occupied) is. In fertilizers, steel slag, when notation Si content, SiO oxide 2 for the amount contained in terms of is denoted hereinafter, SiO 2 represents the content of Si as.
[0060]
　Fertilizer feedstock steel slag according to the present embodiment, as prior mentioned, compared to the composition of a typical steel slag, SiO 2 contains much. Fertilizer feedstock steel slag according to the present embodiment, since it contains many valid variable supply condition silicate plants, to supply Si against grasses like, are effective.
[0061]
　While reducing the cost of CaO reduces the amount of CaO to be added to the hot metal, when manufacturing a fertilizer feedstock steel slag according to the present embodiment in a converter furnace process such as described in detail or less, Si is, Ca 2 SiO 4 , CaSiO 3 , CaFeSiO 4 compounds of Ca, such like, or, 2CaO · SiO 2 as a solid solution or the like, will be present in the steelmaking slag. The fertilizer feedstock steel slag according to the present embodiment, the result of reducing the amount of CaO to be added to the molten iron to reduce costs, but the content of Ca in the steel slag is lowered, to satisfy the basicity conditions as described below to, along with lowering the Ca content, Si content must also be low.
[0062]
　As described above, under conditions to reduce the amount of CaO to be added to molten pig iron, when producing the fertilizer feedstock steel slag according to the present embodiment, SiO 2 by a content of less than 22 wt%, Si fertilizer not only effective, it is possible to obtain Ca is another element, P, Mn, Fe, Mg , B, S , etc. and good balance cooperatively fertilizer effect. Therefore, in the manure feedstock steel slag according to the present embodiment, in order to actively implement such fertilizer effect, SiO 2 content of a less than 22% by weight. On the other hand, SiO fertilizer feedstock steel slag according to the present embodiment 2 when the content of is less than 16 mass%, the fertilizer effect of Si is hardly exerted. Thus, the fertilizer feedstock steel slag according to the present embodiment, SiO 2 is the content of the 16 mass% or more. SiO 2 content of preferably not more than 17 wt% or more 21 wt%, more preferably 20 mass% or less 18% by mass or more.
[0063]
　Incidentally, such SiO 2 content is, for example, can be measured by X-ray fluorescence analysis.
　Specifically, SiO 2 content of a known measurement sample, a plurality prepared while changing the content, measuring the fluorescent X-ray intensity from Si measurement sample prepared by the fluorescent X-ray analyzer. The resulting a fluorescent X-ray intensity from Si were, SiO 2 and the content of, using, SiO 2 in advance a calibration curve showing the relationship between the content of the fluorescent X-ray intensity. Then, SiO attention 2 for the unknown content of the sample, the fluorescent X-ray intensity from Si measured by a fluorescent X-ray analyzer, using a fluorescent X-ray intensities obtained, the calibration curve, the, SiO 2 can identify the content of.
[0064]
　Here, the measuring conditions of preparation method and fluorescent X-ray intensity of the sample of interest is the same as in the case of CaO.
[0065]
[Basicity (CaO content / SiO 2 content): 1.5 Excess 2.2]
　fertilizer feedstock steel slag according to the present embodiment, CaO content and SiO as the 2 conditions on content both satisfied, and, (CaO content / SiO 2 basicity represented by content), a 1.5 excess 2.2 or less.
[0066]
　In the fertilizer feedstock steel slag according to the present embodiment, the content of CaO is from less than 29 wt% or more 38 wt%, SiO 2 content of in the case of basicity as described below, as follows as defined in.
　　If basicity of 2.3: 12 wt% to 16 wt% or less
　　when basicity of 2.2: 13 wt% to 17 wt% or less
　　when basicity of 2.1: 14 wt% to 18 wt% the following
　　case basicity of 1.8: 16 wt% to 21 wt% or less
　　when basicity of 1.5: 19 wt% to 25 wt% or less
　　when basicity of 1.4: 21 wt% or more 27 wt %Less than
[0067]
　Basicity of 1.5 or less, or, in the case where the 2.2 exceeded, SiO fertilizer feedstock steel slag according to the present embodiment 2 content of, and within the range of less than 16 wt% to 22 wt% no longer become. Therefore, the basicity of the fertilizer feedstock steel slag according to the present embodiment, a 1.5 excess 2.2 or less.
[0068]
　Properties characterize most characteristic properties of slag are basic. CaO is a component which is a major cause of basic slag. Further, in actual steel process, many of the basicity of the steel slag obtained by dephosphorization process of hot metal pretreatment, is about 1.5-1.8, it is easy to obtain. Moreover, silicic acid, phosphoric acid, manganese, that the slag basicity that can achieve good further balance the dissolution of fertilizer active ingredient, such as boron is in the vicinity of 1.5-1.8, we test study It was found as a result. Therefore, the basicity of the fertilizer feedstock steel slag according to the present embodiment is preferably 1.5 exceed 1.8.
[0069]
　In the fertilizer feedstock steel slag according to the present embodiment, when the basicity is 1.5 or less, considering from the viewpoint of a fertilizer raw material, SiO 2 for CaO respect is relatively small, will be described later · SiO 2CaO 2 -3CaO · P 2 O 5 is not preferred because the solid solution is difficult to form. On the other hand, the fertilizer feedstock steel slag according to the present embodiment, when the basicity exceeds 2.2, From the viewpoint of fertilizer raw material, tend to be acidic under the influence of prolonged exposure to acidic rain against soil, might fertilizer an excessive CaO than CaO necessary for improvement of the soil, is not preferable because it causes the increase in cost of lime added as CaO source. Thus, the fertilizer feedstock steel slag according to the present embodiment, basicity is was a 1.5 excess 2.2 or less. The basicity With 1.5 exceeded 2.2, in terms of for fertilizers, soil improving effect and CaO content relative to long-term acidic tend soil under the influence of exposure to acidic rain it is possible to suppress the cost of the lime is added in order to increase the. Basicity, preferably, 1.6 or more 2.1 or less, more preferably 1.6 to 2.0.
[0070]
　Further, by adjusting the basicity to 1.5 excess 2.2 or less, the steelmaking slag produced, 2CaO · SiO 2 -3CaO · P 2 O 5 solid solution, and, FeO-MnO-CaO-SiO 2 based solid solution is likely to be formed together. Further, as described in detail below, in the manufacturing process of the steel slag, by quenching in solidifying the slag, two solid solution as described above is more likely to be more formed. These solid solutions, as described in detail below, in addition to silicic acid, in order to promote the elution of phosphoric acid and manganese and boron, as a steel slag for fertilizers, to have a solid solution thereof together preferable.
[0071]
[P 2 O 5 : 2 wt% or more and 8 mass% or less, soluble P 2 O 5 ratio of: 50%
　will be described below P.
　P is an essential element of N, along with the K plant. P is the energy metabolites, such as DNA or RNA, ATP is a gene, an element necessary such as constituents of cell membranes. In addition, P acts on the growing point of the root, it is an element that is effective in the growth of roots. If P is insufficient, root growth is suppressed.
[0072]
　In fertilizers, steel slag, when notation P content, P oxide 2 O 5 for the amount contained in terms of is denoted in the following, P 2 O 5 content of P as represent.
[0073]
　It is acidic, and, in the Al and Fe is finally developed condition ionized soils, P is aluminum phosphate (AlPO 4 ) and iron phosphate (FePO 4 will be insolubilized as), plant roots P phosphate ions (PO containing 4 3 could not be absorbed). Fertilizer feedstock steel slag according to the present embodiment, contains CaO and MgO, and, because it is alkaline, while preventing Al and Fe from the soil to improve the acid soil to elute ionized, and, the P, phosphate ions (PO 4 3- can be gradually eluted as).
[0074]
　In the fertilizer feedstock steel slag according to the present embodiment, P is, Ca 2 SiO 4 -Ca 3 (PO 4 ) 2 is present primarily in the composition. In soil, the fertilizer with fertilizer feedstock steel slag according to the present embodiment, Ca, together with Si, P is, PO 4 3- gradually elutes as. Accordingly, in the long term several months level falls one work crops such as rice, without being insolubilized by Al and Fe, to plants, it is possible to gradually supply the P.
[0075]
　In the fertilizer feedstock steel slag according to the present embodiment, P 2 O 5 content is if it is less than 2 mass%, it is impossible to reliably achieve the above effects. Therefore, the fertilizer feedstock steel slag according to the present embodiment, P 2 O 5 content of, and 2 mass% or more.
[0076]
　On the other hand, the fertilizer feedstock steel slag according to the present embodiment, P 2 O 5 in the case where the content of more than 8% by weight, in view from the perspective of a fertilizer feedstock, P soil 2 O 5 is another might be supplied excessively lacks balance between nitrogen and potassium fertilizers three elements, which is not preferable. Thus, the fertilizer feedstock steel slag according to the present embodiment, P 2 O 5 content of is 8 mass% or less.
[0077]
　Incidentally, in the fertilizer feedstock steel slag according to the present embodiment, P 2 O 5 content of preferably not more than 3 mass% or more and 8 wt%, more preferably 3 mass% or more 6 wt% or less is there.
[0078]
　The Fertilizer Control Act, as tailings phosphate fertilizer, Ku-soluble P 2 O 5 defines the content of 3 mass% or more. Fertilizer feedstock steel slag according to the present embodiment, but not necessarily those meeting the specifications of tailings phosphate fertilizer, for the reasons mentioned above, can be expected fertilizer effect of P. In the fertilizer feedstock steel slag according to the present embodiment, P 2 O 5 that content is 2 mass% or more, Ku-soluble P 2 O 5 content of corresponds to approximately 1.0 wt% .
[0079]
　On the other hand, rather than soluble P eluting with 2% aqueous citric acid 2 O 5 from the soluble P eluted with citric acid aqueous solution of ammonium neutral (page ether Man ammonium citrate solution) 2 O 5 towards is actually plant P can be absorbed from roots 2 O 5 with respect, is known to be a more appropriate value. Fertilizer feedstock steel slag according to the present embodiment, the microstructure control the composition of the slag, P contained in the slag 2 O 5 of the soluble P 2 O 5 the percentage of which was succeeded in raising more than 50% is there. That is, with reference to the method of manufacturing a fertilizer feedstock steel slag as described in detail below, by the production of fertilizers for steelmaking slag, P contained in the slag 2 O 5 soluble P in 2 O 5 mass proportions may be 50% or more. P contained in slag 2 O 5 soluble P in 2 O 5 the upper limit of the mass ratio of, not particularly defined, but the higher the better, can not be 100% in view of the results of the analysis by making a number of actually steel slag samples, the upper limit is about 85%. P contained in slag 2 O 5 soluble P in 2 O 5 mass ratio of preferably not less than 50%, more preferably 60% or more.
[0080]
　Incidentally, P 2 O 5 content of, for example, can be measured by X-ray fluorescence analysis.
　Specifically, the content of P is a known measurement sample, a plurality prepared while changing the content, measuring the fluorescent X-ray intensities obtained from P measurement sample prepared by the fluorescent X-ray analyzer. And the fluorescent X-ray intensity from P obtained, P was calculated from the content of P 2 O 5 equivalent amount and, using, P 2 O 5 the relationship between the equivalent amount and the fluorescent X-ray intensity of you create a calibration curve shown in advance. Thereafter, the sample content is unknown P of interest, to measure the fluorescent X-ray intensity from P by a fluorescent X-ray analyzer, using a fluorescent X-ray intensities obtained, the calibration curve, the, P 2 O 5 content of can be identified.
[0081]
　Here, the measuring conditions of preparation method and fluorescent X-ray intensity of the sample of interest is the same as in the case of CaO.
[0082]
　Further, soluble P 2 O 5 content were used page ether Man ammonium citrate solution, it can be measured by banner de ammonium molybdate absorptiometry. Measured P 2 O 5 content and soluble P of 2 O 5 with a content of, P 2 O 5 soluble P in 2 O 5 can be calculated by mass ratio.
[0083]
: [MgO 4% by mass or more and 8 wt% or less]
　Subsequently, a description will be given Mg.
　Mg is a necessary element for plants, there is a secondary element.
[0084]
　Generally, MgO content of steel slag is a much lower value than the CaO content. Mg contained in the steel slag is attributable to Mg to mainly elute from the furnace wall refractory brick added and BOF in the sintering process. In fertilizers, steel slag, when denoted the content of Mg is, since the amount contained in terms of MgO oxide is denoted hereinafter, represents the content of Mg as MgO.
[0085]
　MgO is alkaline, with CaO, have an effect on the improvement of long-term acidic to tend to the soil under the influence, which is exposed to acidic rainwater. In the fertilizer feedstock steel slag according to the present embodiment, since the content of CaO is less than CaO content in general steel slag, when the content of MgO is less than 4 wt%, the supply amount of Mg is reduced, fertilizer effect of Mg can not be expected. On the other hand, if the content of MgO exceeds 8 mass%, unless also be added by adding a Mg source in actual steel production process, to ensure that more than 8 wt% of MgO content difficult is there. Thus, the fertilizer feedstock steel slag according to the present embodiment, MgO content is 8 wt% or less than 4 wt%. The content of MgO is preferably not more than 4 mass% to 7 mass%, and more preferably is 6% or less 4% by mass or more.
[0086]
　The content of MgO is, for example, can be measured by X-ray fluorescence analysis.
　Specifically, the content of Mg is a known measurement sample, a plurality prepared while changing the content, measuring the fluorescent X-ray intensities obtained from Mg measurement sample prepared by the fluorescent X-ray analyzer. And the fluorescent X-ray intensity from Mg obtained, with a conversion of MgO calculated from the content of Mg, advance a calibration curve showing the relationship between the equivalent amount and the fluorescent X-ray intensity of MgO keep. Thereafter, the sample content is unknown Mg of interest, a fluorescent X-ray intensity from Mg measured by a fluorescent X-ray analyzer, using a fluorescent X-ray intensities obtained, the calibration curve, the, of MgO it is possible to identify the content.
[0087]
　Here, the measuring conditions of preparation method and fluorescent X-ray intensity of the sample of interest is the same as in the case of CaO.
[0088]
: Total iron 15% by weight to 30% by weight]
　Subsequently, a description will be given Fe.
　Fe is a trace elements necessary for plants, and iron-containing material is used as a special fertilizer. However, in soils of acidic, Fe is due to the possibility of generating iron overload in plants, is also an element may become harmful to plants.
[0089]
　Fertilizer feedstock steel slag according to the present embodiment contains the CaO is less than 29 mass% or more 38 wt%, and, MgO since containing 4 mass% or more and 8 mass% or less, is alkaline. However, a composition of a typical steel slag as described above, CaO content: 45.8 wt%, MgO content: Compared to 6.5 wt%, it can be said that the alkaline is steel slag weakening. Fertilizer feedstock steel slag according to the present embodiment, to include in the total iron of 30 mass% or less and high content of more than 15 wt% of the fertilizer comprising the fertilizer feedstock steel slag according to the present embodiment, iron overload is it is preferable to use the soil other than soil has occurred.
[0090]
　Further, as a feature of the fertilizer with fertilizer feedstock steel slag according to the present embodiment, without erosion by rainwater because bulk density is large, a feature that can be eluted elements each with a long-term fertilizer effect remains is there. Fe, in order to increase the bulk density of the fertilizer with fertilizer feedstock steel slag according to the present embodiment is also an important element.
[0091]
　Therefore, from the viewpoint of erosion prevention, bulk density is high, i.e., so that more high total Fe content of steelmaking slag are preferred. In the fertilizer feedstock steel slag according to the present embodiment, when the content of total iron is more than 30 mass%, the contribution to iron overload with iron eluted from the fertilizer is concerned.
[0092]
　Further, the fertilizer feedstock steel slag according to the present embodiment, when obtaining the manufacturing method as described in detail below, to a high temperature and short time processing is performed, the content of total iron steelmaking slag produced , there is a relatively higher tendency, the entire iron content becomes 15 mass% or more. Accordingly, the content of total iron fertilizer feedstock steel slag according to the present embodiment, the above 15 wt% 30 wt% or less. The content of total iron is preferably not more than 16 wt% or more 28 wt%, more preferably is 26 wt% or less 17% by mass or more.
[0093]
　When the fertilizer feedstock steel slag according to the present embodiment is analyzed by X-ray diffraction apparatus, FeO-CaO-SiO 2 peaks minerals attributable to system is observed. On the other hand, electron microprobe tissue fertilizer feedstock steel slag according to the present embodiment after immersion long time in water: when observed by (Electron Probe Micro Analyzer EPMA), concentration moieties present overlap Fe and Mn traces of decline can be seen. Therefore, FeO-MnO-CaO-SiO to MnO and FeO are each other dissolved 2 the solid solution is formed, is considered elution of Mn into the soil along with the Fe is further promoted. The oxidation state of such Fe, in line with the manufacturing method of the fertilizer feedstock steel slag as described in detail below, by the production of fertilizers for steelmaking slag, it is realized. Incidentally, the name of a solid solution in the present embodiment is was clearly the major chemical components, their nature may also include components not explicitly. For example, FeO-MnO-CaO-SiO 2 in the solid solution, also include those of MgO solid solution.
[0094]
　The content of total iron, for example, can be measured by X-ray fluorescence analysis.
　Specifically, the content of total iron is a known measurement sample, a plurality prepared while changing the content, measuring the fluorescent X-ray intensities obtained from Fe measurement sample prepared by the fluorescent X-ray analyzer. The resulting a fluorescent X-ray intensity from Fe were, and the content of total iron, with the advance a calibration curve showing the relationship between the content and the fluorescent X-ray intensity of the total iron. Thereafter, the sample content is unknown total iron of interest, a fluorescent X-ray intensity from Fe measured by a fluorescent X-ray analyzer, using a fluorescent X-ray intensities obtained, the calibration curve, the total it is possible to identify the content of iron.
[0095]
　Here, the measuring conditions of preparation method and fluorescent X-ray intensity of the sample of interest is the same as in the case of CaO.
[0096]
[MnO: 3 mass% to 10 mass%, Ku proportion of soluble manganese: 80%]
　following describes Mn.
　Mn is also an element that there is a fertilizer effect on the plant as a trace element. In fertilizers, steel slag, when denoted Mn content, since the amount contained in terms of MnO oxide is denoted hereinafter, represents the content of Mn as MnO.
[0097]
　In the fertilizer feedstock steel slag according to the present embodiment, when the content of MnO is less than 3% by mass, due to the low content of MnO, from fertilizers containing fertilizers for steelmaking slag according to the present embodiment elution of Mn is not sufficient, fertilizer effect of Mn can not be exhibited. On the other hand, if the content of MnO is more than 10 mass%, particularly in acidic soils, since would cause manganese hyperkinesia plants, unfavorable. Thus, the fertilizer feedstock steel slag according to the present embodiment, the content of MnO is 10 mass% or less than 3 wt%. The content of MnO is preferably not more than 4 mass% to 9 mass%, and more preferably, it is 8 wt% or less than 5 wt%.
[0098]
　Further, the fertilizer in the raw material for steelmaking slag according to the present embodiment, 2CaO · SiO 2 -3CaO · P 2 O 5 solid solution, and, FeO-MnO-CaO-SiO 2 by forming both solid solution, as described above in addition to the elution of such Mn is further promoted, it becomes possible to facilitate the dissolution of the silicate and phosphate and boron.
[0099]
　Plants has been known to roots secrete organic acids, the soluble manganese walking manganese eluting 2% aqueous citric acid, be regarded as a plant available manganese, and an index. Fertilizer feedstock steel slag according to the present embodiment, the composition and structure control, among MnO contained in the steel slag, has been successful in a soluble MnO to rather more than 80%. That is, with reference to the method of manufacturing a fertilizer feedstock steel slag as described in detail below, by the production of fertilizers for steel slag, a Ku weight ratio of soluble MnO in MnO contained in the slag, 80% it can be equal to or greater than. The upper limit of the mass ratio of the Ku-soluble MnO in MnO contained in the slag are not intended to be particularly limited, but preferably as high as possible, 100% and in view of the results of the analysis by making a number of actually steel slag can not be, the upper limit is about 95%. Weight ratio of Ku-soluble MnO in MnO contained in the slag is preferably 85% or more, more preferably 90% or more.
[0100]
　The content of MnO is, for example, can be measured by X-ray fluorescence analysis.
　Specifically, the content of Mn is a known measurement sample, a plurality prepared while changing the content, measuring the fluorescent X-ray intensities obtained from Mn measurement sample prepared by the fluorescent X-ray analyzer. Previously prepared and the fluorescent X-ray intensity from Mn obtained, and in terms of MnO calculated from the content of Mn, with the calibration curve showing the relationship between the equivalent amount and the fluorescent X-ray intensity of MnO keep. Thereafter, the sample content is unknown Mn of interest, a fluorescent X-ray intensity from Mn measured by a fluorescent X-ray analyzer, using a fluorescent X-ray intensities obtained, the calibration curve, the, the MnO it is possible to identify the content.
[0101]
　Here, the measuring conditions of preparation method and fluorescent X-ray intensity of the sample of interest is the same as in the case of CaO.
[0102]
　The content of Ku-soluble MnO is such that 2% elution and flame atomic absorption spectrometry using a citric acid solution, National Institute for Food Quality, Labeling and Consumer Safety Technology Center (Food and Agricultural Materials Inspection Center: FAMIC) defined by by using the method described in fertilizer test method (2016), it can be measured. Using the content of the content and Ku-soluble MnO of the measured MnO, it is possible to calculate the Ku mass percentage of soluble MnO in MnO.
[0103]
[Boron: Less than 0.005 wt% 0.05 wt%, the proportion of Ku-soluble boron: 95%]
　following describes boron.
　Boron is a trace element necessary for the plant, and boron deficiency, it is known that boron deficiency occurs in the plant. Boron is an element necessary for the synthesis of the plant cell wall.
[0104]
　On the other hand, if the boron content of the soil is more than 5 mg / kg, it is known that there is a possibility that the boron overload disorder occurs plants. Boron content of 5 mg / kg is very low. As a fertilizer containing boron, which is commercially available, for example, borate fertilizers (Ku-soluble boron 35% or higher), 熔成 boron fertilizers (Ku-soluble boron about 24%), 熔成 trace elements compound fertilizer (FTE) (Ku there are soluble boron 5-9%), to include any amounts of boron, be boron hyperkinesia occurs is concerned by the excessive use of these fertilizers. These commercial fertilizer applied to the soil to the boron content of the soil below 5 mg / kg is not easy.
[0105]
　For example, when applying the boron content of 5% fertilizer to the soil 1 kg, as the boron has not been contained in the soil, a small amount of fertilizer hereinafter 100mg to the boron content of the soil than 5 mg / kg uniform It was mixed with soil so that there is a need to apply. Therefore, in general application rates, a large concern that boron is excessively applied. Although in order to uniformly applied using a small amount of fertilizer that contains these amounts of boron may be considered to apply by dissolving or dispersing in water, in the conventional fertilizer by rainwater, it is considered that easy erosion. Therefore, in order to supply a boron optimally in soil, the boron content is low and the type of fertilizer without erosion is considered preferable.
[0106]
　In the fertilizer feedstock steel slag according to the present embodiment, when the content of boron is less than 0.005 mass% (= 50mg / kg), fertilizer with fertilizer feedstock steel slag according to the present embodiment with respect to the soil even if the application of, for supplying the amount of boron is small, it can not exhibit the fertilizer effect of boron to the plant. On the other hand, steel slag, such as the content of boron is 0.05 mass% or more is not obtained in normal steelmaking process, adding dare add boron source such as borax in order to increase the boron content It is not preferable because the cost increase factor. Also, fertilizer feedstock steel slag according to the present embodiment, since the ratio of the Ku-soluble boron in containing boron is very high as compared with the conventional boron fertilizers, the boron content is less than 0.05 wt% also, there is a boron supply capacity comparable to conventional boron fertilizers. Thus, the fertilizer feedstock steel slag according to the present embodiment, the boron content is less than 0.005 mass% 0.05 mass% or more. The content of boron, preferably not more than 0.05 mass% to 0.01 mass%, more preferably 0.05 wt% or less than 0.02 mass%.
[0107]
　As described above, plants are known to roots secrete organic acids, the soluble boron walking boron eluting 2% aqueous citric acid, it is regarded as boron available plants, one One of the indicators. Fertilizer feedstock steel slag according to the present embodiment, CaO and SiO 2 basicity which is the ratio of the content of a 1.5 excess 2.2 or less, and a method of cooling when the temperature and the slag solidifies when molten slag produced performed tissue control by devising a boron for example, SiO 2 SiO in the compound of 2 the portion of the B 2 O 3 that is generated as such compounds substituted with, including boron easily soluble form in soil succeeded in, 95% or more of boron contained in the steel slag, could be a Ku-soluble boron. That is, with reference to the method of manufacturing a fertilizer feedstock steel slag as described in detail below, by the production of fertilizers for steel slag, a weight ratio of Ku-soluble boron in the boron contained in the slag, 95% it can be equal to or greater than. Ku by a high proportion of soluble boron, despite the low content of boron contained in the fertilizer feedstock steel slag, it is possible to obtain high fertilization.
[0108]
　The content of boron, for example, can be measured by ICP emission spectrometry.
　Specifically, the sample 0.5g reagent (sodium carbonate 2g, sodium peroxide 3g) to be had to the Ni crucible, carrying out the alkali fusion (burner heating). Put Ni crucible after alkali fusion in a beaker, water and hydrochloric acid (1: 9) When Ni crucible contents are melted put, removed Ni crucible, dissolving the sample by heating the beaker. Resulting lysate sample inductively coupled plasma: introducing into (apparatus by Hitachi High-Tech Science SPS3100), light emission by boron as measured at a wavelength 249.753Nm, to quantify the boron. This analysis method is a method based on JIS A 5011-3 Annex A.
[0109]
　Further, Ku content of soluble boron, of 2% citric acid aqueous solution elution and azomethine H method using, National Institute for Food Quality, Labeling and Consumer Safety Technology Center (Food and Agricultural Materials Inspection Center: FAMIC) fertilizer defined by such method described in test method (2016) the use of a measurable. Using the content of the content and Ku-soluble boron measured boron, it is possible to calculate the mass ratio of the Ku-soluble boron in the boron.
[0110]
: Sulfur 0.1 wt% to 0.6 wt%]
　Subsequently, a description will be given of sulfur.
　Sulfur, cysteine, methionine, such as the biosynthesis of sulfur-containing amino acid, and further is an element required for the biosynthesis of proteins, leeks, onions, is in growth, such as garlic is an indispensable element.
[0111]
　If the sulfur content of fertilizers feedstock steel slag according to the present embodiment is less than 0.1 wt%, even if application of the fertilizer with fertilizer feedstock steel slag according to the present embodiment in the soil, the supply of sulfur for small amount, it may not be exhibited fertilizer effect of sulfur on plants. On the other hand, if the sulfur content of the fertilizer feedstock steel slag according to the present embodiment is more than 0.6 mass%, sulfur is supplied from the manure causes hydrogen sulfide occurs in the soil, such as rot roots there is a possibility that the problem arises. Therefore, the sulfur content of the fertilizer feedstock steel slag according to the present embodiment, 0.6 mass% 0.1 mass% or more. The content of sulfur is preferably not more than 0.2 mass% to 0.6 mass%, more preferably 0.6 wt% or less than 0.3 wt%.
[0112]
　The content of such sulfur is, for example, be measured by alkali fusion and ICP emission spectrometry.
　Specifically, the sample 0.5g reagent (sodium carbonate 2g, sodium peroxide 3g) to be had to the Ni crucible, carrying out the alkali fusion (burner heating). Put Ni crucible after alkali fusion in a beaker, water and hydrochloric acid (1: 9) When Ni crucible contents are melted put, removed Ni crucible, heating the beaker to dissolve the sample. Resulting lysate sample is introduced into a high-frequency inductively coupled plasma (apparatus by Hitachi High-Tech Science SPS3100), the light emission by sulfur as measured at a wavelength 182.036Nm, to quantify the sulfur. This analysis method is a method based on JIS A 5011-3 Annex A.
[0113]
[Al 2 O 3 : 0.5 wt% to 3 wt% or less]
　The following describes Al.
　In fertilizers, steel slag, when denoted the content of Al is, Al oxide 2 O 3 for the amount contained in terms of is denoted hereinafter, Al 2 O 3 represents the content of Al as .
[0114]
　Al is aluminum ion Al in acidic soil 3+ , and the phosphate ion PO 4 3- for become bonded to, there is effect of suppressing the plant roots to absorb P. Therefore, Al in the fertilizer feedstock steel slag according to the present embodiment 2 O 3 content of is preferably as low as possible.
[0115]
　Al fertilizer feedstock steel slag according to the present embodiment 2 O 3 in the case where the content of more than 3% by weight, for the reason set forth above, from fertilizers containing fertilizers for steelmaking slag according to the present embodiment thereby suppressing the P elution. On the other hand, when subjected to dephosphorization process on a blast furnace hot metal, the slag Al 2 O 3 will have to inevitably mixed, Al 2 O 3 is difficult to the content of 0.5 mass% or less it is. Thus, the fertilizer feedstock steel slag according to the present embodiment, Al 2 O 3 content of, and 3 wt% or less than 0.5 wt%. Al 2 O 3 content of, preferably not more than 0.5 mass% to 2.5 mass%, more preferably 2% by mass or less than 0.5 wt%.
[0116]
　Incidentally, Al 2 O 3 content of, for example, can be measured by X-ray fluorescence analysis.
　Specifically, the content of Al is a known measurement sample, a plurality prepared while changing the content, measuring the fluorescent X-ray intensities obtained from Al measurement sample prepared by the fluorescent X-ray analyzer. And the fluorescent X-ray intensity from Al obtained, Al was calculated from the content of Al 2 O 3 and in terms of using, Al 2 O 3 the relation between the equivalent amount and the fluorescent X-ray intensity of you create a calibration curve shown in advance. Thereafter, the sample content is unknown Al of interest, a fluorescent X-ray intensity from Al measured by a fluorescent X-ray analyzer, using a fluorescent X-ray intensities obtained, the calibration curve, the, Al 2 O 3 content of can be identified.
[0117]
　Here, the measuring conditions of preparation method and fluorescent X-ray intensity of the sample of interest is the same as in the case of CaO.
[0118]
[Bulk density: 2.3 or more 3.2 or less]
　fertilizer feedstock steel slag according to the present embodiment, by having the above composition (more specifically, the bulk density loosen) the bulk specific gravity of 2 a .3 more than 3.2 or less. If the bulk specific gravity is less than 2.3, since the large amount of rainfall, may fertilizer to erosion occurs, undesirable. On the other hand, if the bulk density exceeds 3.2, the fertilizer becomes heavy with fertilizer feedstock steel slag according to the present embodiment, since the causes that require excessive effort for transportation and spraying fertilizers, undesirable . Bulk density fertilizer feedstock steel slag according to the present embodiment, preferably, 2.4 to 3.0, more preferably 2.4 or more 2.8 or less.
[0119]
　Incidentally, the bulk specific gravity of the fertilizer feedstock steel slag, for example, can be measured by the following method. That is, the mass was filled lightly in a certain volume, as divided by the volume, it is possible to determine the bulk density (bulk specific gravity loosening). Here, slag used for measurement, the MS-25 equivalent particle size defined in JIS A5015, measures the unit volume mass (= bulk specific gravity) in compliance with JIS A 1104.
[0120]
Organization for fertilizer feedstock steel slag]
　fertilizer feedstock steel slag according to the present embodiment, as a tissue, 2CaO · SiO 2 -3CaO · P 2 O 5 solid solution, and, FeO-MnO-CaO-SiO 2 system preferably it contains both a solid solution. These solid solutions, as described below, when producing the fertilizer raw material for steelmaking slag, when solidifying slag in a molten state, by quenching the slag, can be more efficiently formed Become.
[0121]
　In soil, 2CaO · SiO 2 -3CaO · P 2 O 5 from the solid solution, in addition to calcium and silicate, phosphate more efficiently eluted. Further, in the soil, FeO-MnO-CaO-SiO 2 from solid solution, iron and manganese are more efficient elution. Thus, the fertilizer feedstock steel slag according to the present embodiment, as a tissue, by containing these solid solutions together, more efficiently, calcium in the soil, silicic acid, phosphoric acid, iron, fertilizer effects such manganese those elements that have, it is possible to elute. Further, the fertilizer feedstock steel slag is produced through a production method as described below, although the reason is not clear, SiO these in solid solution 2 of a portion B 2 O 3 and is easily substituted with, these solid solutions by containing both, it is possible to also eluted for boron.
[0122]
　The above · SiO 2CaO 2 -3CaO · P 2 O 5 solid solution, and, FeO-MnO-CaO-SiO 2 solid solution by methods described below, it is possible to confirm the presence.
[0123]
　For example, in terms of the fertilizer feedstock steel slag according to the present embodiment is a powder, by a general X-ray diffraction apparatus (e.g. manufactured by Rigaku X-ray diffractometer SmartLab), X-ray source Co-Kα (λ = 1. 7902A) and then, X-rays source load power (tube voltage / tube current) was set to 5.4kW (40kV / 135mA), the detector is a scintillation counter, at a scan rate 1.5 ° / min, the focusing method (theta-2 [theta] measurement ) by and by X-ray diffractometry, 2CaO · SiO 2 crystal and FeO · CaO · SiO 2 confirms crystallization and the like. Further, after the manure feedstock steel slag according to the present embodiment is embedded into a known resin such as an epoxy resin, ground and polished to expose the smoothed cross-section of such a fertilizer feedstock steel slag, General EPMA device (e.g. JEOL JXA-8100 type) is used to map each element distribution of slag tissue to be observed on the cross section at an acceleration voltage 15kV. Further, Ca focuses the measurement region having a diameter of 100 [mu] m, Si, O, P slag tissue to be observed together, and, Fe, Mn, Ca, Si, at O slag tissue being observed together with EPMA of the elements count analyzed by ZAF method, by semi-quantitative, 2CaO · SiO 2 -3CaO · P 2 O 5 solid solution, or, FeO-MnO-CaO-SiO 2 can be confirmed that the solid solution is present.
[0124]
[Fertilizer the particle size of the raw material for steelmaking slag]
　In this embodiment, more fertilizer feedstock steel slag as described by adjusting to an appropriate particle size by milling or the like, it can be suitably used as a raw material for fertilizers it is. The grinding of such fertilizer feedstock steel slag, for example, a jaw crusher, a hammer crusher can be used a rod mill, a ball mill, a roll mill, a known means such as a roller mill.
[0125]
　The grinding method as described above, the fertilizer feedstock steel slag is preferably less than the particle size 5 mm, particle size is more preferably less than 600 .mu.m. Note that these particle sizes, using a defined sieve JIS Z8801, a particle size by sieving method. If the particle size of the fertilizer feedstock steel slag is equal to or greater than 5mm, the specific surface area of ​​the manure feedstock steel slag becomes too small, the elution efficiency of each fertilizer effect element can be low. In addition, the particle size of the fertilizer feedstock steel slag is less than 600 .mu.m, the specific surface area of ​​the manure feedstock steel slag becomes more large, it becomes possible to increase the elution efficiency of each fertilizer effect element.
[0126]
　Further, the fertilizer feedstock steel slag according to the present embodiment, the mass ratio of those having a particle size is less than 600μm, it is preferable to be 60% or more with respect to the total mass. Particle size that mass ratio of those less than 600μm is less than 60%, it is possible to further increase the dissolution efficiency of each fertilizer effect element. Weight ratio of those having a particle size is less than 600μm, more preferably 80% or more.
[0127]
　Although the manure feedstock steel slag according to the present embodiment has been described in detail.
[0128]

　Next, a method of manufacturing a fertilizer feedstock steel slag according to the present embodiment will be described in detail. Fertilizer feedstock steel slag according to the present embodiment is different from the blast furnace hot metal, by performing a specific dephosphorization process, as described below, is manufactured.
[0129]
　As described above, fertilizers feedstock steel slag according to the present embodiment, (1) to the converter type pan, the furnace from the freeboard / furnace opening corresponding to the length to the hot metal liquid surface from (throat as the void ratio expressed in a furnace height) corresponding to the length to the bottom is 0.5 to 0.9, and injected blast furnace hot metal, (2) to the blast furnace hot metal in the BOF type pot in contrast, manganese ore, manganese-containing decarburization slag, and, by adding at least one of ferromanganese, (3) particle size below quicklime 30 mm, and / or calcium carbonate in terms of added to blast furnace hot metal, from the lance was inserted into the blast furnace hot metal, blowing oxygen with respect to the blast furnace hot metal is produced by performing dephosphorization process by forming a slag at 1300 ° C. or higher 1400 ° C. or less. At this time, (CaO content / SiO 2 and the content) slag basicity represented by becomes the 1.5 exceeded 2.2 or less and more than 10 wt% MnO content of 3 mass% or more in the slag It is manufactured to be.
[0130]
[1: blast furnace hot metal injection process]
　(1) a blast furnace hot metal injection step shown in the generated blast furnace hot metal is a step of injecting into the converter type pan. The blast furnace hot metal, when injected into the converter type pot, when the void ratio is expressed by (freeboard / furnace height) is less than 0.5 as a result of the freeboard too small, hot metal liquid surface since voids present above becomes too narrowed, it is difficult to sufficiently forming the blast furnace hot metal, sufficiently undesirably becomes impossible to proceed dephosphorization reaction. On the other hand, if the void ratio expressed by (freeboard / furnace height) exceeds 0.9, undesirably the amount of molten iron to dephosphorization becomes less and less inefficient, also, of the converter-type pot to become the little blast furnace hot metal is not injected into the productivity reduces the operating efficiency decreases. Void ratio expressed by (freeboard / furnace height) is preferably not less than 0.5 and not more than 0.8, more preferably 0.6 to 0.8.
[0131]
: [2 additive adding step]
　additive adding step shown in the above (2), to the blast furnace hot metal in the BOF type pan, manganese ore, manganese-containing decarburization slag, and, at least one of ferromanganese and the desired MnO content in the slag (i.e., less than 10 wt% in MnO content of 3 mass% or more slag) step of introducing such that. Here, among the above additives, for either turning which additive material in what amounts, is not particularly limited, depending on the desired MnO content in the slag, it may be suitably determined.
[0132]
: [3 dephosphorization process]
　dephosphorization process step shown in the above (3), to the blast furnace hot metal MnO content is adjusted, after supplying the calcium source, blowing oxygen, at a predetermined temperature be to forming the slag is a step of performing dephosphorization process of the blast furnace hot metal.
[0133]
　Examples of the calcium source used in the dephosphorization process, the particle size is less quicklime 30 mm, and uses at least one of calcium carbonate. The particle diameter 30mm following quicklime and calcium carbonate can be obtained using an industrial sieve defined in JIS Z8801. The average particle diameter as a calcium source may be used following quicklime 1 mm. The average particle diameter of quicklime, cumulative mass% value in the particle size distribution passing through the industrial sieve defined in JIS Z8801 is meant a particle size of 50%. The addition amount of such a calcium source, a desired basicity at the end of the dephosphorization process (i.e., 1.5 exceeded 2.2 or less) become such an amount.
[0134]
　The temperature of the slag at the time of forming is, to 1300 ° C. or higher 1400 ° C. or less. When the temperature of the slag is lower than 1300 ° C. is not preferable because the dephosphorization reaction does not proceed. On the other hand, when the temperature of the slag is higher than 1400 ° C. is not preferable because of the possibility of recovery of phosphorus with phosphorus back dissolved in the molten steel. Temperature of the slag at the time of forming is preferably not 1390 ° C. or less 1310 ° C. or more, more preferably 1380 ° C. or less 1320 ° C. or higher. The temperature of the slag can be measured using a thermocouple or optical pyrometer.
[0135]
　Dephosphorization treatment described above, the slag basicity, is 1.5 exceeded 2.2, and is implemented as MnO content of the slag is 3 mass% to 10 mass%, slag bases when the degrees and MnO content falls within the above range, dephosphorization process ends.
[0136]
　By dephosphorization process described above is carried out, components of the produced steel slag, takes on the characteristics as described prior, the specific gravity, falls within the aforementioned range.
[0137]
　Or after the dephosphorization process steps described, and such (4) slag solidification step as described below, (5) and the slag grinding process, it is carried out preferably.
[0138]
[4: slag solidification step]
　slag solidification step shown in the above (4) is a step of solidifying the molten slag after dephosphorization process by a predetermined method.
[0139]
　Such slag solidification step, for example, the molten slag after dephosphorization treatment was poured into the dish-shaped heat-resistant container may be a step of solidifying by rapid cooling. At this time, in order to cool more efficiently molten slag, molten slag, thin it is preferable to spread the dish-shaped heat-resistant vessel, also by performing a water spray against thin widened molten slag it is preferable that the rapid cooling (quenching) the molten slag.
[0140]
　Also, In addition to the above-mentioned methods, the slag solidifying step, it is also possible to adopt the following method.
　In other words, to (a) by tilting the converter type pot, after the molten slag after dephosphorization treatment was devoted to the slag pot, the molten slag in the slag pot, the first heat-resistant container capable tilt was devoted, (b) by performing a water spray in the first heat-resistant container, after solidified by rapid cooling to approximately the molten slag example 600 ° C., and crushed solidified slag, (c) first of the heat resistant container is tilted, crushed by dropping sliding the solidified slag to a second heat-resistant container.
[0141]
　In either of the two types of slag solidification step as described above also, by performing water spray or the like when solidifying the molten slag, it is preferable to rapidly cool the molten slag. By rapidly cooling the molten slag, 2CaO · SiO 2 -3CaO · P 2 O 5 solid solution, and, FeO-MnO-CaO-SiO 2 both solid solution, more reliably and can be formed in the slag Become.
[0142]
[5. Slag grinding process]
　slag pulverizing step shown in the above (5), a steel slag which solidified as described above, a step of milling to a desired particle size.
[0143]
　In such a slag milling process, for example, a jaw crusher, hammer crusher, rod mill, ball mill, roll mill, using a known method such as a roller mill, crushing / grinding to the steelmaking slag in a solid state to a desired particle size. Here, the particle size of the steel slag, as prior mentioned, the overall particle size is less than 5 mm, and, as a mass ratio of those particle size of less than 600μm becomes 60% or more relative to the total weight , it is preferable to crush / grinding.
[0144]
　By performing the process as described above, fertilizers feedstock steel slag according to the present embodiment is manufactured.
[0145]

　Next, a method of manufacturing a fertilizer with fertilizer feedstock steel slag according to the present embodiment will be briefly described.
　Fertilizer feedstock steel slag according to the present embodiment as described above, the particle size within a predetermined range (e.g., all approximately less than 600 .mu.m) by adjusting the, can be directly used as a fertilizer. That is, the manufacturing method of the fertilizer according to the present embodiment, the fertilizer feedstock steel slag fertilizer feedstock steel slag produced by the production method of the above is for powdering by known means.
[0146]
　Also, fertilizer feedstock steel slag after powdering, although it can be used directly as a fertilizer as described above, after adding a predetermined coupling agent, may also be granulated. Here, the binder used in the granulation is not particularly limited, for example, it can be used molasses, lignin, lignin sulfonic acid metal salt, starch, polyvinyl alcohol, carboxymethyl cellulose and the like.
[0147]
　Furthermore, with respect to the fertilizer obtained by the method as described above, it may be further mixed organics. Such organic material, for example, cattle dung, pig dung, manure livestock chicken droppings and the like, can be mentioned plant residues, and, at least one of compost derived from fish. Such organics by further mixing, it is possible to further improve the fertilizer effect of the fertilizer with fertilizer feedstock steel slag according to the present embodiment.
[0148]
　As described above, the fertilizer according to this embodiment, phosphorus (P), iron (Fe), manganese (Mn), silicon (Si), calcium (Ca), magnesium (Mg), boron (B), sulfur many kinds of each element of (S), it is possible to more effectively supplied.
[0149]

　The following describes fertilization method of fertilizer with fertilizer feedstock steel slag according to the present embodiment.
　More fertilizer, including fertilizer raw materials for steelmaking slag as described, even in the soil of the region flooding in many of the high rainfall areas and rivers, easily and at low cost without erosion by water, many kinds of element it can be supplied as a fertilizer plant. More particularly, in a manner described below, by fertilization with respect to long-term acidic tend soil under the influence of exposure to acidic rain, achieving the suppression of soil acidification and growth the plant to be, the more effectively many kinds of elements can be supplied as a fertilizer.
[0150]
　That is, in the fertilization method according to the present embodiment, the fertilizer with fertilizer feedstock steel slag or fertilizers as above, pH (H 2 O) is 5.6 to 7.5, (i) valid state phosphate or less 5 mg / 100 g dry soil, and / or, (ii) manganese content is less 50 mg / 100 g dry soil, and / or, (iii) soil boron content is less than 0.05 mg / 100 g dry soil to fertilization against.
[0151]
　Here, pH (H 2 O) is meant the pH of the suspension obtained by adding water at a predetermined ratio with respect to the soil, H are dissolved in the soil moisture + represents the concentration of there. pH (H 2 O) is said to exhibit strength of soil acidic directly related to the growth of plant roots (the active acidic). The pH (H soil 2 and O) is 5.6 to 7.5 indicates that a neutral soil from weakly acidic, is generally considered a pH suitable for the growth of plants.
[0152]
　The above pH (H 2 O), pH (KCl), after shaking placed in shaking 100ml bottles Kazeinuido 20g, vibration by adding 50ml distilled water or 1N KCl solution 50ml 30 minutes, pH of the pH of the aqueous solution It can be measured by measuring with a glass electrode. The effective state phosphoric acid content can be measured by Toruogu method.
[0153]
　Fertilizer according to this embodiment, in the areas prone to missing the fertilizer effect elements and erosion by rainfall, as described above, phosphoric acid, manganese, and at least one of boron is insufficient, long rainwater acidic period to acidic to tend to the soil under the influence, which is exposed, exhibits an excellent fertilizer effect.
[0154]
　If valid phosphoric acid shown in the above (i) is less than 5 mg / 100 g dry soil, there is a possibility of running out of phosphoric acid fed from the soil to the plant. Also, if the manganese content shown in the above (ii) is not more than 50 mg / 100 g dry soil, there is a possibility of running out of manganese supplied from the soil to the plant. Also, if the boron content shown in (iii) above is less than 0.05 mg / 100 g dry soil, there is a possibility of insufficient boron supplied from the soil to the plant. Therefore, by applying the fertilizer to the fertilizer feedstock slag according to the present embodiment as a raw material, phosphoric acid, manganese, boron also becomes possible to absorb the plant.
[0155]
　Here, the application rates of the fertilizer according to the present embodiment, as a fertilizer feedstock steel slag is preferably less 0.05 t / ha or more 2t / ha. When the amount of application is less than 0.05 t / ha, the application rate is too small, the effect of the fertilizer according to the present embodiment includes a plurality of fertilizer effect element, there may not be clearly exhibited. On the other hand, if the rate of application of more than 2t / ha, the cost increases by a large amount using the fertilizer of the present embodiment. More preferred application rate is less than 0.1 t / ha or more 1t / ha.
[0156]
　The fertilization method according to the present embodiment, a fertilizer according to the present embodiment as described above, prior to planting seed or seedlings, or sprinkled plow layer surface, or may be mixed with the plow layer. Moreover, the fertilizer according to the present embodiment as described above, or sprinkled plow layer surface in the vicinity of the plant to be cultivated, or may be mixed to the plow layer.
[0157]
　The target crop fertilizer according to the present embodiment as described above, for example, grasses, Cyperaceae plants, cucurbits, legumes, Amaryllidaceae plants, Liliaceae, Solanaceae, Brassicaceae, Rosaceae plant, Musaceae plant, palm family plant, grape family plant, Araceae plants, orchids, Convolvulaceae plant of the family, Asteraceae, pedaliaceae plant, Labiatae plant, poppy family plant, Rutaceae plants, Umbelliferae mention may be made of the plant, pepper plant of the family, Rubiaceae plant, a plant, such as belonging to any of the nettle family. Fertilizer feedstock steel slag according to the present embodiment, three elements of fertilizer, which easily emit secondary elements and trace elements, fertilizers using such fertilizers for steelmaking slag, as shown in the following examples typical for Gramineae effect rice is a plant has been demonstrated, for the plant as described above except Gramineae, it is expected that the effect is obtained. Moreover, even for plants other than the above, it fertilizer according to the present embodiment is applicable, of course.
[0158]
　Although the fertilization method according to the present embodiment has been briefly described.
Example
[0159]
　Hereinafter, while showing Examples and Comparative Examples, the fertilizer feedstock steel slag according to the present invention, the fertilizers and fertilizer method using such a steel slag, specifically described. Incidentally, embodiments described below, merely only one example, the present invention is not limited to the examples shown below.
[0160]
(Example 1)
　by the method described below, to produce a fertilizer raw material for steelmaking slag.
　That is, the average particle size (freeboard / furnace height) void ratio which is expressed by in a converter is 0.8, MnO-containing blast furnace hot metal to the general blast furnace hot metal obtained by placing the manganese ore was charged with the following calcium carbonate 30 mm, oxygen an average particle size 1mm below quicklime added blowing from the lance, the dephosphorization treatment was carried out while forming at 1350 ° C.. After tapping was carried out two cooling processing for the generated slag. One is, after the slag produced from the converter to devote to the slag pot, to devote to tiltable heat resistant container and quenched and solidified to 600 ° C. by performing watering in this vessel. The heat-resistant container is tilted and dropped sliding slag solidified to the following heat-resistant vessel were crushed slag was further quenched slag to 300 ° C. and sprinkled with such a heat-resistant vessel. Then, stop watering, was the room temperature. Another, after the slag produced from the converter to devote to slag pot, after 30 minutes, and left to discharge again the slag by tilting the slag pot exhaust Sai field, slowly cooled to room temperature.
[0161]
　Obtained above, quenched with steelmaking slag and slowly cooled steel slag was ground respectively, becomes less than the whole of the particle size 5 mm, and a mass ratio of those having a particle size of less than 600μm was set to be 60%. With reference to the prior described method, performs analysis of the resulting steel slag, the analysis of quenched steel slag are shown in Table 1 below. X-ray fluorescence spectrometer used in the analysis is a Rigaku Denki Kogyo Co., Ltd. ZSX PrimusII, ICP emission spectrometer used for the analysis, a Shimadzu ICPS-8100.
[0162]
　The chemical components of the quenched steel slag and gradually cooled steel slag was identical to each other. Soluble P steelmaking slag slowly cooled 2 O 5 weight ratio, Ku weight ratio of soluble MnO, and the mass ratio of the Ku-soluble boron, 60% respectively, 65%, was 75%.
[0163]
　Here, in Table 1 below, basicity and units of items other than specific gravity, the mass%, soluble P 2 O 5 , Ku values of soluble MnO and Ku-soluble boron is obtained by converting the content. In Table 1 below, the alkalinity, which represents the ability that the fertilizer to neutralize the acidity of the soil, National Institute for Food Quality, Labeling and Consumer Safety Technology Center (Food and Agricultural Materials Inspection Center: fertilizer test method specified by FAMIC) (indicates a value measured by ethylenediaminetetraacetic acid salt method described in 2016).
[0164]
　From Table 1, below, quenched steel slag is soluble P 2 O 5 weight ratio of a 76%, a Ku mass fraction of 87% of the soluble MnO, 100% weight ratio of Ku-soluble boron. Further, the obtained steel slag, CaO, P 2 O 5 , SiO 2 , MgO, Al 2 O 3 , total iron, MnO, boron, and the total content of sulfur is 92.61 wt%, the remainder was impurities.

WE claims

[Requested item 1]

　　Mass% P 2 O 5 : 2% to 8% or
　　less, MnO: 10% 3% or more or less,
　　boron: less than 0.005% 0.05%
　　total iron: 15% or more than
　　30%, CaO: less 29% than
　　38% SiO 2 : below 16% to 22%,
　　sulfur: 0.1% to 0.6% or
　　less, MgO: 4% to 8% or
　　less, Al 2 O 3 : 0.5% or more 3 % or less,
containing,
　the P 2 O 5 soluble P in 2 O 5 ratio of, is 50% or more,
　the proportion of Ku-soluble MnO in the MnO is at least
　80%, (CaO content / SiO 2Slag basicity represented by the content) is 1.5 exceed 2.2,
　bulk specific gravity is 2.3 or more than 3.2, fertilizers steelmaking slag.
[Requested item 2]
· SiO 　2CaO 2 -3CaO · P 2 O 5 solid solution, and, FeO-MnO-CaO-SiO 2 containing solid solution, respectively, fertilizer feedstock steel slag according to claim 1.
[Requested item 3]
　Proportion of Ku-soluble boron in the boron is 95% or more, fertilizer feedstock steel slag according to claim 1 or 2.
[Requested item 4]
　Particle size less than 5mm as a whole, and the mass ratio of those particle size is less than 600μm is 60% or more relative to the total weight, according to any one of claims 1 to 3 Fertilizer raw materials for steelmaking slag.
[Requested item 5]
　A method of manufacturing a fertilizer feedstock steel slag according to any one of claims 1 to 4,
　with respect to the converter type pan, freeboard / furnace corresponding to the length to the hot metal liquid surface from (throat as the void ratio expressed in a furnace height) corresponding to the length from the mouth to the furnace bottom is 0.5 to 0.9, and injected blast furnace hot metal,
　said in the converter type pot against blast furnace hot metal, manganese ore, manganese-containing decarburization slag, and, by adding at least one of ferromanganese,
　the particle size is less quicklime 30 mm, and / or, the calcium carbonate in terms of added to the blast furnace hot metal , from said inserted lance blast furnace hot metal, the blowing oxygen with respect to the blast furnace hot metal,
　slag subjected to dephosphorization process by forming at 1300 ° C. or higher 1400 ° C. or less,
　(CaO content / SiO 2 at a content) slag basicity represented is, Becomes .5 exceeded 2.2, and is prepared as MnO content of the slag is 3 mass% to 10 mass%, the production method of the fertilizer feedstock steel slag.
[Requested item 6]
　The molten slag after dephosphorization treatment was poured into the dish-shaped heat-resistant container and solidified by rapid cooling method fertilizer feedstock steel slag according to claim 5.
[Requested item 7]
　Watering by performing rapidly cooling the molten slag after the dephosphorization process, the manufacturing method of the fertilizer feedstock steel slag according to claim 6.
[Requested item 8]
　By tilting the converter type pot, the molten slag after the dephosphorization process was devoted to the slag pot, the molten slag in said slag pot, to devote to the first heat-resistant container capable tilt ,
　wherein the molten slag by performing water spray in the first heat-resistant container after having solidified upon rapid cooling, crushing the solidified slag,
　by tilting the first heat-resistant container, solidifies the slag is crushed by dropping sliding in the second heat-resistant container, a manufacturing method of a fertilizer feedstock steel slag according to any one of claims 5-7 that.
[Requested item 9]
　By rapid cooling, 2CaO · SiO 2 -3CaO · P 2 O 5 solid solution, and, FeO-MnO-CaO-SiO 2 solid solution, respectively to form, for fertilizers according to any one of claims 5-8 manufacturing method of steelmaking slag.
[Requested item 10]
　Particle size less than 5mm as a whole, and, as a mass ratio of those particle size is less than 600μm is less than 60% relative to the total mass, grinding the slag, claim 5-9 method for producing a fertilizer feedstock steel slag according to item 1.
[Requested item 11]
　To powdering fertilizer feedstock steel slag produced by the production method of the fertilizer feedstock steel slag according to any one of claims 5-10, a manufacturing method of the fertilizer.
[Requested item 12]
　After the addition of fertilizers for steelmaking slag for a given binding agent after powdering, granulation, method for producing a fertilizer according to claim 11.
[Requested item 13]
　The obtained fertilizer, further mixing the organic substance, method for producing a fertilizer according to claim 11 or 12.
[Requested item 14]
　The organic material, livestock manure, plant residues, and is at least one of the resulting compost from fish, method for producing a fertilizer according to claim 13.
[Requested item 15]
　Fertilizer feedstock steel slag according to any one of claims 1 to 4, claims 5-10 any one fertilizer feedstock steel slag fertilizer feedstock steel slag produced by the method according to, Alternatively, the fertilizer with fertilizer which is manufactured by the manufacturing method of fertilizer according to any one of claims 11 to claim
　14, pH (H 2 O) is 5.6 to 7.5, and , effective phosphate in the following 5 mg / 100 g dry soil, and / or manganese content of less 50 mg / 100 g dry soil, and / or for soil boron content is less than 0.05 mg / 100 g dry soil fertilization to, fertilization method.
[Requested item 16]
　Application rate of the fertilizer, as said fertilizer feedstock steel slag, or less 0.05 t / ha or more 2t / ha, fertilization method according to claim 15.
[Requested item 17]
　The fertilizer, before planting seed or seedlings, or sprinkled plow layer surface, or is mixed with the plow layer, fertilization method according to claim 15 or 16.
[Requested item 18]
　The fertilizer or sprinkled plow layer surface in the vicinity of the plant to be cultivated, or are mixed to the plow layer, fertilization method according to claim 15 or 16.