Description:FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

1 TITLE OF THE INVENTION :
A PORTLAND CEMENT CLINKER COMPOSITION INCLUDING ALUMINA SUPPLEMENTING STEEL SLAGS AND PROCESS FOR SUCH CLINKER MAKING.



2 APPLICANT (S)

Name : JSW CEMENT LIMITED.

Nationality : An Indian Company incorporated under the Companies Act, 1956.

Address : JSW CENTRE,
BANDRA KURLA COMPLEX,
BANDRA(EAST),
MUMBAI-400051,
MAHARASHTRA,INDIA.




3 PREAMBLE TO THE DESCRIPTION

COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to a cement clinker composition utilizing iron and steel slags. More particularly, the present invention providesa Portland cement clinker composition including alumina supplementing steel slags. Ladle refining furnace slag (LRF Slag) is a kind of steel making slag. In this present invention, LRF slag along with other two slags (Blast Furnace Slag and Basic Oxygen Furnace Slag) have been explored as a potential alumina supplementing raw material for clinker making. This invention has also explored a new pathway to recycle an industrial by-product to produce a consumable material in a sustainable manner.

BACKGROUND OF THE INVENTION
The cement is the principal binder material in civil construction and one of the most consumed material. Clinker is the main hydraulic component of conventional Portland cement. Conventionally clinker is produced by pyro-treatment of limestone and other supplementary raw materials. Apart from lime stone, other raw materials are used in raw-mix of clinker to achieve a desired chemical composition.
On the other hand, iron and steel industries have a huge production line, starting from mining to production of different grades of steels. A large number of solid waste and by-products are being generated from this sector. Slag is one of the principal by-product of iron and steel sector.
Cement, being one of the most consumable material, is the principal binder for building construction. Considering the gradually increasing population and civilization, the consumption of cement may increase by 3 to 4 times than the current consumption. The conventional cement is composed of Portland Clinker and Gypsum. The main raw material to make clinker is limestone. Calcium carbonate is the main component for limestone. Apart from that silica, alumina, iron oxide, magnesia etc. are the other components of limestone. A good quality clinker is composed of tri calcium silicate - alite (C3S), di calcium silicates- belite (C2S), tri calcium aluminate - aluminate (C3A), and tetra calcium alumina ferrite – ferrite (C4AF) with a certain proportion of each. The well-defined clinker chemistry is usually being achieved by proper chemical composition of raw-mix and kiln operation for clinkerization.
Hence to achieve clinker with desired proportion of mineral phases, the raw-mix must have a well-defined chemical composition with certain percentages of different oxides (e.g. CaO, SiO2, Al2O3, MgO, Fe2O3etc). At the temperature of ~1450 °C these oxides react with each other to make the clinker phases (e.g. alite, belite, aluminite and ferrite). But the chemical composition of limestone varies from mines to mines. Hence to achieve the desired chemical composition often some supplementary raw materials are blended with limestone to make a proper raw-mix for clinker making.
Al2O3 and Fe2O3 are two important components in clinker making. Those play some vital role in clinker chemistry as well as kiln operation. While Al2O3 and Fe2O3are not present in required quantity of limestone, those are required to be supplemented by other different raw materials, which are rich in Al2O3 and Fe2O3. There are few examples of those supplementary raw material like forAl2O3 : Bauxite, for Fe2O3 : iron ore, for Fe2O3 + Al2O3 : Alumina laterite etc. Normally alumina rich materials are comparatively expensive. Hence addition of those increases the cost of production. So finding an alternate material from the industrial by-products will be economically viable as well as a sustainable approach.
Iron and steel making slagsare by-product of iron and steel industries. Slags generate by the high temperature reaction of existing impurities in molten metal (silica, alumina etc) and the added flux (lime stone, calcined lime, dolomite etc.).Slags come out of the molten metal in the form of different silicates aluminates etc. Although the iron making slag (blast furnace slag or BF slag) is being used for cement making, the steel slags are almost remaining unused due to some shortcomingslike high metallic content and poor grinability. Hence in spite of being mineralogically rich, steel making slags are being dumped or used for land filling.
Ladle refinery furnace is a secondary steel making furnace. To remove dissolved oxygen present in the molten metal, metallic aluminium usually been added to the furnace.Aluminium, being more susceptible to oxidation, reacts faster with oxygen to make alumina. Consequently, the slag generated from this process is alumina rich. Hence the ladle refining furnace slag (LRF Slag) may be a good supplementary raw material for alumina supplement.Similarly, BOF Slag and AOD slags are the by-product from the basic oxygen furnace process of primary steel refining and Argon Oxygen Decarburization process of stainless steel making.
This current invention has explored a new scope of application of LRF slag as an alumina rich supplementary raw material for clinker making.This work offers a potential scope of utilization of an industrial by product to make value added high-volume consumable material like cement. Moreover the LRF slag, being a calcined material, consumes less energy during calcination of raw-mix of clinker and provides better energy efficiency. Hence overall the present inventionoffers a sustainable approach to recycle an industrial by-product like LRF slag towards circular economy.
STATE OF PRIOR ART:
Slag is a by-product of iron and steel industries. The impurities (primarily silica and alumina) present in molten metal usually been eliminated by reaction with externally added flux materials (mostly lime stone, dolomite etc.). This reaction leads to formation of comparatively low melting silicates or aluminates, which are termed as slag. Although the steel slags and Portland clinker are having many common phases, still these materials don’t have any significant usage. This current invention has explored LRF slag along with other two slags (BF Slag, LD Slag)as a potential alumina supplementing raw material for clinker making. Few relevant existing literatures have been discussed following.
Russian Patent RU2674048C2 has disclosed a combined method of steel and clinker making where the chemistry of the molten slag has been adjusted by saturation with lime to get the clinker chemistry and followed by rapid cooling of discharged slag to produce clinker. This work has explored a combined method where simultaneously steel and clinker may be produced.
South Korean Patent KR20120116896A has disclosed the preparation of Calcium sulphoaluminate type clinker from 40-80 % electric reduction slag, 10-40 % thermos electric power station coal and 5-25 % gypsum. The sintering temperature is 1200 ºC.
Chinese patent CN109928653A has disclosed a method of production of clinker direct from molten blast furnace slag. Here the direct molten slag was discharged vortex induction heating type high temperature reduction furnace followed by addition of calcareous material to achieve the chemical composition of clinker.
South Korean patent KR101088183B1 has disclosed a method of Portland cement clinker making by mixing molten blast furnace slag with other supplementary materials like limestone, waste lime, cement kiln dust, steelmaking slag and iron ore etc.
Tsakiridiset al. reported production of Portland cement clinker by addition of 10.5 % of steel slag along with the other raw materials and found the obtained quality of the clinker was good.
Hence from all the above literature it is clear that iron and steel making slag have potential to be a raw material for clinker making and there is no negative effect of those slags in quality of clinker of the chemical composition of clinker is maintained properly in clinkerization process. Moreover all those existing literatures have utilized the iron and steel making slags a common raw material for clinker and based on the chemical composition of slags the other raw materials has been designed. But none of them has used as a special kind of supplementary raw material like alumina supplementing raw material, iron oxide supplementing raw material etc.
Herein the current invention has explored LRF Slag and a composition of iron and steel slags (BF Slag, LRF Slag and LD Slag) as potential alumina supplementing raw materials. This work offers the replacement (partial/complete) of a high cost raw material (from natural resources) like alumina laterite.
OBJECTIVES OF INVENTION
The objectives of the present invention are as follows:
• The basic object is to provide a portland cement clinker composition utilizing iron and steel slags including Ladle Refining Furnace(LRF) slag as an alumina supplementing raw material for clinker making.
• Replacement of conventionally used natural alumina supplementary raw material like alumina laterite with industrial by product like iron and steel making slags.
• Detail chemical analysis of some iron and steel making slag to find out their applicability as a supplementary raw material for clinker making.
• Optimize a certain dosage of iron and steel slag for clinker mix-design with all property analysis.
• Utilization of iron and steel slag with clinker mix-design without affecting the kiln operation as well as the pyro process.
• Utilization of steel industry by-product to make a value added product like cement.
• Conservation of natural resources (raw material) by recycling industrial by-product.
• The utilization of steel industry by product as a potential raw material to develop a superior quality clinker with improve compressive.
• Utilization of pre-calcined and LOI free (loss on ignition) industrial by product to achieve thermal efficiency and higher mass yield for clinkerization.
SUMMARY OF THE INVENTION
The basic aspect of the present invention is directed to a Portland cement clinker composition including alumina supplementing steel slags comprising :
clinker mix composition selected from limestone 89.3 to 93.7 % by wt , Flue dust 0.5 to 1.5 %, red mud 0 to 1 % by wt and sweetner 0 to 5 % by wt including alumina supplementing steel slag as pre-calcined and LOI free steel slag selected from BF Slag: 0-1.0%,LRF Slag: 2.8-4.5%, and LD Slag: 0-4.0%, favouring higher clinker yield with said alumina supplemented steel slag vis a vis only alumina and cost effective, fuel efficient and environment friendly clinker generation.

A further aspect of the present invention is directed to said portland cement clinker composition wherein said clinker mix composition comprises

Raw Materials Chemical Composition (%)
LOI SiO2 Al2O3 Fe2O3 CaO MgO SO3 Na2O K2O TiO2
Iron and Steel Slags
BF Slag 0.10 34.80 20.00 0.60 35.80 6.00 0.32 0.4 0.4 0.5
LRF Slag 1.26 7.21 32.82 3.94 50.95 2.26 0.0 0.09 0.21 0.4
LD Slag 5.00 15.00 3.50 26.0 43.5 4.5 0.15 0.12 0.3 0.05
Other Raw Materials
Lime Stone 35.64 13.38 1.81 0.88 46.02 0.47 0.11 0.15 0.14 0.0
Sweetner 40 4.37 0.65 0.8 51.47 1.41 0.13 0.13 0.38 0.0
Al. Laterite 20.5 9.53 33.98 30.25 0.58 0.1 0.11 0.23 0.32 2.0
Flue Dust 18.00 12.00 8.00 57.00 3.50 0.50 0.05 0.10 0.20 0.10
Red Mud 11.98 12.02 21.04 38.0 1.00 0.40 0.30 7.00 0.50 7.00

A still further aspect of the present invention is directed to said portland cement clinker composition including said alumina source supplemented include bauxite and aluminium laterite and said steel industry flue dust as supplement of iron oxide, said lime stone (sweetener) supplement of calcium oxide, said red-mud supplements of iron oxide as well as alkali metals.
A still further aspect of the present invention is directed to said portland cement clinker composition wherein said alumina supplementing steel slag completely supplement the alumina source of alumina laterite and include a combination of 1 % of BF Slag, 4 % LD Slag and 4.5 % LRF slag.
A still further aspect of the present invention is directed to said portland cement climker composition wherein said alumina supplemented steel slag include LRF Slag (2.8 %) to partially supplement alumina laterite (4.2 % to 2 %).
Another aspect of the present invention is directed to said portland cement clinker composition wherein said clinker mix selected to attain Raw-mix lime saturation factor (LSF) : 100-106 %, Silica Modulus (SM) : 2-2.5 %, Alumina Modulus (AM) : 1.1-1.5 % and Liquid in clinker: > 28 %.
Yet another aspect of the present invention is directed to said portland cement clinker composition wherein said clinker mix provide for generation of clinker having phases comprising tri calcium silicate (alite, C3S), : 50-55 %, di calcium silicate (belite, C2S): 19-23 %, tri calcium aluminate (C3A): 7-10 %, tetra calcium alumino ferrite (C4AF): 11-13 %,
A further aspect of the present invention is directed to a process to produce clinker from the clinker composition as described above comprising
(i) Involving clinker mix composition selected from limestone 89.3 to 93.7 % by wt , Flue dust 0.5 to 1.5 %, red mud 0 to 1 % by wt and sweetner 0 to 5 % by wt including alumina supplementing steel slag as pre-calcined and LOI free steel slag selected from BF Slag: 0-1.0%,LRF Slag: 2.8-4.5%, and LD Slag: 0-4.0%
(ii) producing small nodules from the said clinker mix with selective proportion of iron and steel slags as supplemented alumina source ;
(iii) subjecting the nodules to pyro-treatment in a static muffle furnace where the materials are soaked at 1350 ºC to 1450 ºC preferably about 1450 ºC for 45 min to 1 h 15 min, preferably about 1 h, followed by immediate removal from the furnace and instant cooling by compressed air flow; and finally,
(iv) storing the clinkers thus obtained in an air-tight container for further use.

A further aspect of the present invention is directed to said process involving said clinker raw mix composition favoured achieving required quality of clinker having phases comprising tri calcium silicate (alite, C3S), : 50-55 %, di calcium silicate (belite, C2S): 19-23 %, tri calcium aluminate (C3A): 7-10 %, tetra calcium alumino ferrite (C4AF): 11-13 %, wherein composition of clinker from the available raw materials and available fuel (coal) the process factors have been set in a certain range like Raw-mix lime saturation factor (LSF) : 100-106 %, Silica Modulus (SM) : 2-2.5 %, Alumina Modulus (AM) : 1.1-1.5 % and Liquid in clinker: > 28 %.
A further aspect of the present invention is directed to said process where portland cement clinker produced with use of iron and steel making slag in raw material mix yields high amount of clinker where 9.5 % of iron and steel making slag led to raw-mix : clinker ratio = 1.47; and 2.8 % of LRF Slag led to raw-mix : clinker ratio = 1.52, while no usage of iron and steel making slag led to raw-mix : clinker ratio = 1.54.
A still further aspect of the present invention is directed to said process wherein use of pre-calcined and loss on ignition (LOI) free steel slag as industrial by product utilized in raw material mix helps to achieve thermal efficiency and higher mass yield for clinkerization and offers higher fuel efficiency during calcination as well as consequently lower CO2 emission.
A further aspect of the present invention is directed to saidOridinary Portland Cement(OPC) produced using the clinker obtained by the process by grinding developed clinkers with 5 % mineral gypsum to make Ordinary Portland Cement having Fineness of OPC maintained at 340±10 M2/Kg.
A further aspect of the present invention is directed to said OPC having properties comprising Specific Surface-345 to 351 M2/Kg, initial setting time 75-85minutes, final setting time 155-160minutes, soundness tested by Auto Clave 0.004 to 0.012%, Normal Consistency more than 28%, superior compressive strength.
A still further aspect of the present invention is directed to saide OPC when produced using LRF slag (2.8 %) as partial replacement of alumina laterite (2.2 %) in mix yields clinker with superior quality of 28 Days compressive strength 93.5 Mpa for OPC, and when using complete replacement of alumina laterite by combination of iron and steel slags (1 % of BF Slag, 4 % LD Slag and 4.5 % LRF slag) yields a superior clinker with 28 days compressive strength 82.9 Mpa for OPC.
Another aspect of the present invention is directed to aCement clinker obtained of the clinker mix as described above having phases comprising tri calcium silicate (alite, C3S), : 50-55 %, di calcium silicate (belite, C2S): 19-23 %, tri calcium aluminate (C3A): 7-10 %, tetra calcium alumino ferrite (C4AF): 11-13 %,
Yet anotheraspect of the present invention is directed to aCement composition comprising of cement clinker composition including alumina supplementing steel slags in amounts of 0 to 9.5 % bywt and mineral gypsum in amounts of 0 to 5 % by wt. having setting time in the range of 75 to 85 min (initial setting time) and 155-160 min (final setting time); compressive strength (28 Days) in the range of 71.5 to 93.5 MPa comparable to the Cement including clinker with alumina sources free of any supplemented alumina with steel slag.
The above and other aspects and advantages of the present invention are described hereunder in greater details with reference to following non limiting illustrative drawings.
BRIEF DESCRIPTION OF ACCOMPANIED DRAWING
Fig. 1: demonstrates the digital images of green nodules (before pyro-process) made with three different raw mix (1-3) and corresponding clinkers made by lab scale burnability study.
Fig. 2:demonstrates theX-Ray diffractogram of Clinker 1 and quantitative phase analysis data.
Fig. 3: demonstrates theX-Ray diffractogram of Clinker 2 and quantitative phase analysis data.
Fig. 4: demonstrates theX-Ray diffractogram of Clinker 3 and quantitative phase analysis data.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO ACCOMPNAYING DRAWINGS AND EXAMPLES
The principal component of conventional Portland Cement is clinker. Clinker is being produced by the pyro-process of limestone with a desired chemical composition. As the chemical composition of lime stone defers from mines to mines, some supplementary raw materials are often blended with required quantity with limestone for making desired raw mix of clinker. Among the different supplementary raw materials, the alumina supplementing raw materials are quite higher priced. Bauxite, alumina laterite are two common examples of alumina rich raw material.
On the other hand, the waste management is common cause of concern of any industry. Steel industry generates around 300-400 Kg of steel slags per ton of steel production. In spite of being mineralogically rich, these materials are not being recycled or reused for making any value added product. These materials are being dumped or used for land filling, which demands huge land space as well as causes environment pollution.
The present invention has addressed these above two concerns. Herein different iron and steel making slags (BF Slag, LRF slag, LD Slag) have been explored as potential supplementary raw material to supplement alumina in clinker raw mix and replacement (complete/partial) of existing alumina supplementing raw material.
The clinkerization unit of JSW Cement Ltd. at Nandyal, AP, India uses alumina laterite as a source of alumina in clinker. The chemical analysis of different raw materials for clinker making has been done to find the suitability of different steel making slags. Consequently, lab scale burnability study has been performed with different raw mix design to assess the quality of the clinker. Then cement has been made with the developed clinker and the properties of the cement has been assessed to find out the optimized raw mix design with maximum replacement alumina laterite with steel making slag.
Portland clinker usually been formed by the high temperature (1400-1450 ºC) treatment of limestone powder (with a certain chemical composition). To achieve the desired chemical composition supplementary raw materials are used often on plant process. The supplementary raw materials are rich in one or multiple minerals, those it supplements in clinker. For example, steel industry flue dust supplements iron oxide, high grade lime stone (sweetener) supplements calcium oxide, bauxite and aluminium laterite supplements alumina, red-mud supplements iron oxide as well as alkali metals etc.
The present invention discloses the utilization of steel making slags as a potential alumina supplementary raw material for clinker making. In this work not only the steel industries by-product (slag) has been recycled for making a value added product, but also replace the natural raw material like alumina laterite/bauxite. This work promotes sustainable production of clinker by conserving natural resources.
Four kinds of iron and steel making slag samples (BF Slag, LD Slag, AOD Slag and LRF slag) has been collected from JSW Steel Ltd., Vijayanagar Works, Karnataka-583123. Other raw materials (limestone, blast furnace slag, alumina laterite, red mud, sweetner) has been collected from Clinkerization unit of JSW Cement Ltd., Nandyal, Andhra Pradesh. BF Slag and AOD slag was received with the small particle sizes (Particle size < 4 mm) with no metallic content. Whereas LD and LRF Slag were received in the form of lumps (Lumps < 20 mm). These slags lumps were crushed down to 4 mm particle size with Jaw-Crusher followed by removal of metallic content. Then all the slags were finely ground in a ball mill. Wet chemical analysis of all the raw material has been performed to determine the chemical compositions of the raw materials. The iron making slag (BF Slag) contains 20 % of alumina, 34.8 % silica and 35.8 % of lime. Although the silica content is quite high, still this material has been used for further raw-mix design, considering the alumina content (20 %). Among the steel slags LRF slag contents significantly high amount of alumina and lime (32.82 % and 50.95 % respectively). Hence this slag has been used further for raw-mix design of lab scale clinker making. Although LD slag don’t have a significant amount of alumina (3.5 %), it is rich in iron oxide (26 %) and lime (43.5 %), so this has also been used further for raw-mix design of lab scale clinker making. But the derived chemical composition of AOD Slag has exhibited higher amount of(9.8 %) of magnesia. As magnesia is not desirable for cement, AOD slag has been rejected from further analyses (clinker makings). The details of chemical compositions of these steel slag materials and other raw materials have been demonstrated in following example section.
Based on the chemical analysis of all the raw materials different mix-designs of clinker have been made. The mix-designs were intended to replace the alumina laterite by steel slags without affecting the clinker quality. For comparison, a mix design without any steel making slag has been taken from the previous plant process of clinkerization. This composition has been considered as control (Raw-mix Design 1) and it used 4.2 % of alumina laterite. Whereas the Raw-mix Design 2has been made by complete replacement of alumina laterite (0 % alumina laterite + 4 % LD slag + 4.5 % LRF slag). The Raw-mix Design 3 has been made by partial replacement of alumina laterite (2 % alumina laterite + 2.8 % LRF slag).Burnability study has been conducted with all the prepared raw-mix designs.
Physical and chemical parameters of the developed clinkers were analysed according to IS 4031 and IS 4032.
Examples
The experiments conducted by way of this invention are described as following.
Example 1 : Chemical analysis of steel slags and other raw materials
To find out the applicability as well as the raw-mix composition for clinker making, the wet chemical analysis of the received steel slags (LD Slag, LRF Slag, AOD Slag) and other raw materials were done according to IS 4032. The results have been demonstrated in Table 1.

Table 1. Chemical analysis of the raw materials
Raw Materials Chemical Composition (%)
LOI SiO2 Al2O3 Fe2O3 CaO MgO SO3 Na2O K2O TiO2
Iron and Steel Slags
BF Slag 0.10 34.80 20.00 0.60 35.80 6.00 0.32 0.4 0.4 0.5
LRF Slag 1.26 7.21 32.82 3.94 50.95 2.26 0.0 0.09 0.21 0.4
LD Slag 5.00 15.00 3.50 26.0 43.5 4.5 0.15 0.12 0.3 0.05
AOD Slag 3.30 37.00 3.00 0.9 39.5 9.8 0.1 0.12 0.9 0.4
BF Slag 0.10 34.80 20.00 0.60 35.80 6.00 0.32 0.4 0.4 0.5
Other Raw Materials
Lime Stone 35.64 13.38 1.81 0.88 46.02 0.47 0.11 0.15 0.14 0.0
Sweetner 40 4.37 0.65 0.8 51.47 1.41 0.13 0.13 0.38 0.0
Al. Laterite 20.5 9.53 33.98 30.25 0.58 0.1 0.11 0.23 0.32 2.0
Flue Dust 18.00 12.00 8.00 57.00 3.50 0.50 0.05 0.10 0.20 0.10
Red Mud 11.98 12.02 21.04 38.0 1.00 0.40 0.30 7.00 0.50 7.00

From the above wet chemical analysis results, it has been found that all the slag samples possess very low loss on ignition (LOI, 0.1 – 5 %). This indicates that the materials are pre-calcined as these are coming out from the pyro-metallurgical process. Utilization of these materials will offer better energy efficiency and higher yield of clinker production. The iron making slag (BF Slag) contains 20 % of alumina, 34.8 % silica and 35.8 % of lime. The iron making slag (BF Slag) contains 20 % of alumina, 34.8 % silica and 35.8 % of lime. Although the silica content is quite high, still this material has been used for further raw-mix design, considering the alumina content (20 %). Among the steel slags LRF slag contents significant amount of alumina and lime (32.82 % and 50.95 % respectively). Hence this slag has been used further for raw-mix design of lab scale clinker making. Although LD slag don’t have a significant amount of alumina (3.5 %), it is rich in iron oxide (26 %) and lime (43.5 %), so this has also been used further for raw-mix design of lab scale clinker making. But the derived chemical composition of AOD Slag has exhibited higher amount of (9.8 %) of magnesia. As magnesia is not desirable for cement, AOD slag has been rejected from further analyses (clinker makings).
Based on the chemical composition of all the raw materials, mix designs for clinkers have been prepared with the objective of partial/complete replacement of alumina laterite as alumina supplementary raw-materials by iron and steel making slags.
Example 2: Raw-mix designs of clinkers and burnability studies
Raw-mix design of clinker has a great influence in clinker quality as well as pyro-process of clinker making. To get an optimum composition of raw-mix design, there are some parameters to be maintained in certain ranges, e.g. lime saturation factor (LSF), Silica Modulus (SM), Alumina Modulus (AM) and % Liquid. The projected quality of clinker like C3S : 50-55 %, C2S : 19-23 %, C3A : 7-10 %, C4AF : 11-13 %. To achieve this composition of clinker from the available raw materials and available fuel (coal) the process factors have been set in a certain range like Raw-mix LSF : 100-106 %, SM : 2-2.5 %, AM : 1.1-1.5 % and Liquid : > 28 %.
Based on the above criteria the burnability study of three raw-mix were conducted. The compositions of the raw-mix’s have been demonstrated at following table (Table 2).
Table 2. Raw-mix designs for burnability study
Parameters Ram-mix 1 Raw-mix 2 Raw-mix 3
Composition
Present Raw materials Lime Stone 89.30 89.50 93.70
Sweetner 5.00 0.00 0.00
Al. Laterite 4.20 0.00 2.00
Flue Dust 0.50 1.00 1.50
Red Mud 1.00 0.00 0.00
Iron-Steel Making Slags BF Slag 0 1.00 0.00
LRF Slag 0 4.50 2.80
LD Slag 0 4.00 0.00
Process and Raw-Mix parameters
LSF (%) 105.43 105.32 105.35
SM 2.09 2.2 2.26
AM 1.21 1.36 1.43
Liquid in Clinker (%) 29.55 28.99 28.26
Theoretical Clinker Quality Parameters (From Bogue’s Formula)
C3S 52.05 51.85 52.34
C2S 20.56 21.19 21.23
C3A 8.63 9.51 9.79
C4AF 13.42 12.14 11.61
Clinker Yield
Raw-mix:Clinker Ratio 1.54 1.47 1.52

For lab-scale burnability study, small nodules were made with the above three raw-mix designs. Then the nodules were treated at 1450 ºC in a static muffle furnace. The materials were soaked at 1450 ºC for 1 h followed by immediate removal from the furnace and instant cooling by compressed air flow. The obtained clinkers (Raw-mix 1 : Clinker 1; Raw-mix 2 : Clinker 2; Raw-mix 3 : Clinker 3) were stored in an air-tight container for further studies. Digital images of all the green nodules (before pyro-treatment) and after pyro-treatment (clinkers) has been demonstrated in Figure 1.
Iron and steel making slags, being a pre-calcined material, a very negligible weight loss occurs during the clinkerization process. Hence utilization of these slags offers higher clinker yield. More the amount of clinker obtained from a certain amount of raw-mix, the Raw-mix:Clinker ratio will be less. From the above table it is observed that yield of clinker is higher (less Raw-mix:Clinker ratio) for Raw Mix 2 and 3 than Raw Mix 1. Maximum amount of iron and steel making slag has been used in Raw-Mix 2 (9.5 %), and consequently it has demonstrated highest clinker yield (lowest Raw-mix : Clinker ratio = 1.47).
Example 3: Quality analysis (chemical and physical properties) of developed clinkers
Chemical composition of the prepared three clinkers were evaluated by wet chemical analysis (according to IS 4032). Results of the evaluation of chemical properties of prepared clinkers have been demonstrated in Table 3.Quantitative presence of different clinker phases in three clinkers has been theoretically calculated by Bogue’s formula. The results have been demonstrated in Table 3.
Parameter Clinker 1 Clinker 2 Clinker 3

Chemical Composition LOI (%) 0.09 0.13 0.11
SiO2 (%) 21.0 21.1 21.23
Al2O3 (%) 6.2 6.1 6.13
Fe2O3 (%) 4.4 4.0 3.82
CaO (%) 65.3 65.5 66.13
MgO (%) 1.1 1.2 1.00
SO3 (%) 1.2 1.2 1.10
Na2O (%) 0.34 0.22 0.25
K2O(%) 0.28 0.25 0.23
F/CaO 0.97 1.00 0.90
Theoretical % of different phases in clinker from Bogue’s Formula C3S 49.38 51.85 52.34
C2S 22.88 21.19 21.23
C3A 8.98 9.51 9.79
C4AF 13.38 12.14 11.61

The results of the chemical analysis of developed clinkers (Table 3) have shown that there is no significant difference in developed clinkers. The utilization iron and steel slags (Clinker 2 and 3) has led to develop clinkers with comparable chemical composition with control sample (Clinker 1 : clinker without iron and steel slag).
Then the developed clinkers were ground with 5 % mineral gypsum to make Ordinary Portland Cement (Clinker 1 : OPC 1; Clinker 2 : OPC 2; Clinker 3 : OPC 3). Fineness of OPC were maintained at 340±10 M2/Kg. Comparative analysis of physical parameters of developed OPC cements have been conducted with a commercially available OPC (from JSW Cement Ltd.). The physical parameters were evaluated according to IS 4031. The results have been demonstrated in Table 3.
Physical Parameter Unit Plant OPC OPC 1 OPC 2 OPC 3
SP.SURFACE M2 / Kg 335 349 345 351
SETTTING TIME
Initial Minutes 90 85 75 85
Final Minutes 170 155 155 160
SOUNDNESS
By Le Chatelier mm 0 0 0 0
By Auto Clave % 0.006 0.012 0.011 0.004
Normal Consistency % 29 28 28.5 28.5
COMP.STRENGTH
1 DAY MPa 22 24 23 25.1
3 DAYS MPa 36 43.1 40.0 38.8
7 DAYS MPa 47 56.8 65.8 62.0
28 DAYS MPa 68 71.5 82.9 93.5

Now from the evaluated physical parameters of the prepared OPCs, it is clear that the setting time and soundness behaviours of OPC 2 and OPC 3 are comparable with OPC 1 (control) and the commercially available OPC. Moreover, the compressive strengths OPC 2 and OPC 3 is better than OPC 1 and commercially available OPC. This indicates that iron and steel making slags are potential sources of alumina clinker for clinker making. Comparing the compressive strength of OPC 2 and OPC 3, it has been found that OPC 3 has higher compressive strength. This indicates that the partial replacement of alumina laterite (2.2 %) by only LRF slag (2.8 %) has produced superior clinker than complete replacement of alumina laterite (4.2 %) by usage of all three iron and steel making slags (1 % BF Slag + 4.5 % LRF slag + 4 % LD Slag). From this experimental investigation it has been found that iron and steel making slags can be used as potential supplementary raw material for Portland clinker making. Among the investigated 3 types of slags (BF Slag, LRF Slag, LD Slag) LRF Slag has better properties to be an alumina supplementing raw material. LRF slag has highest alumina content (32 %)compare to the other two slags and this is very close to the conventionally used alumina laterite (alumina content: 33.98 %).

Phase analysis of developed clinkers by X-Ray diffraction
Portland cement clinker is composed of different mineral phases; those are developed during the pyro process. The major phases present in the clinkers are tri calcium silicate (alite, C3S), di calcium silicate (belite, C2S), tri calcium aluminate (C3A) and tetra calcium alumino ferrite (C4AF). X-Ray diffraction study was performed for qualitative as well as quantitative analysis of clinker using X-Ray diffractometer (Made: Panalytical). The phase identification has been done using ICDD PDF 2 data base and quantification was performed by Reitveld analysis. X-Ray diffractogram along with quantified phases has been demonstrated in Figure 2-4. For all the three clinkers the pattern of X-Ray diffractogram are similar in nature and showing crystalline behaviour of the developed clinkers. Figure 2 has demonstrated the diffractogram of Clinker 1. The quantitative phase analysis suggests that the clinker 1 is composed of 54.1% of C3S, 25.15% of C2S, 6.1% of C3A, 12.4 % of C4AF, 0.95% of free lime and 1.3% of periclase.Figure 3 has diffractogram of Clinker 2. The quantitative phase analysis suggests that the clinker 2 is composed of 52.5% of C3S, 26.6% of C2S, 7.3% of C3A, 11.5 % of C4AF, 1.0% of free lime and 1.1% of periclase. Figure 4 has diffractogram of Clinker 3. The quantitative phase analysis suggests that the clinker 3 is composed of 56.6% of C3S, 22.4% of C2S, 7.5% of C3A, 12.3 % of C4AF, 0.7% of free lime and 0.5% of periclase. The compositions of the developed clinkers evaluated from XRD analysis is closely resemble with those data available form chemical analysis of raw mix design (Table 2) and clinkers (Table 2). Moreover form the phase distribution of the developed clinkers supports the applicability of iron and steel making slags as potential raw material for clinker making.

References:
Non Patent Citation
1. P.E. Tsakiridis, G.D. Papadimitriou, S. Tsivilis, C. Koroneos, Utilization of steel slag for Portland cement clinker production, Journal of Hazardous Materials 152 (2008) 805–811.
Patent Citations
1. RU2674048C2, Method for production of steel and portland cement in single process and technological chamber for implementing method.
2. KR20120116896A, Composition of calcium sulfoaluminate type clinker, cement comprising the same and method of preparing the same.
3. CN109928653A, A method of utilizing the direct cement of molten state blast furnace slag.
4. KR101088183B1, Synthetic method of portland cement by using the heat and elements of the fused blast furnace slag and portland cement manufactured with this.
, Claims:We Claim:

1. A Portland cement clinker composition including alumina supplementing steel slags comprising :
Clinker mix composition selected from limestone 89.3 to 93.7 % by wt , Flue dust 0.5 to 1.5 %, red mud 0 to 1 % by wt and sweetner 0 to 5 % by wt including alumina supplementing steel slag as pre-calcined and LOI free steel slag selected from BF Slag: 0-1.0%,LRF Slag: 2.8-4.5%, and LD Slag: 0-4.0%, favouring higher clinker yield with said alumina supplemented steel slag vis a vis only alumina and cost effective,fuel efficient and environment friendly clinker generation.

2. The portland cement clinker composition as claimed in claim 1 wherein said clinker mix composition comprises

Raw Materials Chemical Composition (%)
LOI SiO2 Al2O3 Fe2O3 CaO MgO SO3 Na2O K2O TiO2
Iron and Steel Slags
BF Slag 0.10 34.80 20.00 0.60 35.80 6.00 0.32 0.4 0.4 0.5
LRF Slag 1.26 7.21 32.82 3.94 50.95 2.26 0.0 0.09 0.21 0.4
LD Slag 5.00 15.00 3.50 26.0 43.5 4.5 0.15 0.12 0.3 0.05
Other Raw Materials
Lime Stone 35.64 13.38 1.81 0.88 46.02 0.47 0.11 0.15 0.14 0.0
Sweetner 40 4.37 0.65 0.8 51.47 1.41 0.13 0.13 0.38 0.0
Al. Laterite 20.5 9.53 33.98 30.25 0.58 0.1 0.11 0.23 0.32 2.0
Flue Dust 18.00 12.00 8.00 57.00 3.50 0.50 0.05 0.10 0.20 0.10
Red Mud 11.98 12.02 21.04 38.0 1.00 0.40 0.30 7.00 0.50 7.00

3. The portland cement clinker composition as claimed in claims 1 or 2 including said alumina source supplemented include bauxite and aluminium laterite and said steel industry flue dust as supplement of iron oxide, said lime stone (sweetener) supplement of calcium oxide, said red-mud supplements of iron oxide as well as alkali metals.
4. The portland cement clinker composition as claimed anyone of claims 1 to 3 wherein said alumina supplementing steel slag completely supplement the alumina source of alumina laterite and include a combination of 1 % of BF Slag, 4 % LD Slag and 4.5 % LRF slag.
5. The portland cement climker composition as claimed in anyone of claims 1 to 4 wherein said alumina supplemented steel slag include LRF Slag (2.8 %) to partially supplement alumina laterite (4.2 % to 2 %).
6. The portland cement clinker composition as claimed in anyone of claims 1 to 5 wherein said clinker mix selected to attain Raw-mix lime saturation factor (LSF) : 100-106 %, Silica Modulus (SM) : 2-2.5 %, Alumina Modulus (AM) : 1.1-1.5 % and Liquid in clinker: > 28 %.
7. The portland cement clinker composition as claimed in anyone of claims 1 to 6 wherein said clinker mix provide for generation of clinker having phases comprisingtri calcium silicate (alite, C3S), : 50-55 %, di calcium silicate (belite, C2S): 19-23 %, tri calcium aluminate (C3A): 7-10 %, tetra calcium alumino ferrite (C4AF): 11-13 %,
8. A process to produce clinker from the clinker composition as claimed in claims 1 to 7 comprising

(i) Involving clinker mix composition selected from limestone 89.3 to 93.7 % by wt , Flue dust 0.5 to 1.5 %, red mud 0 to 1 % by wt and sweetner 0 to 5 % by wtincluding alumina supplementing steel slag as pre-calcined and LOI free steel slag selected from BF Slag: 0-1.0%,LRF Slag: 2.8-4.5%, and LD Slag: 0-4.0%.
(ii) producing small nodules from the said clinker mix with selective proportion of iron and steel slags as supplemented alumina source ;
(iii) subjecting the nodules to pyro-treatment in a static muffle furnace where the materials are soaked at 1350 ºC to 1450 ºC preferably about 1450 ºC for 45 min to 1 h 15 min, preferably about 1 h, followed by immediate removal from the furnace and instant cooling by compressed air flow; and finally,
(iv) storing the clinkers thus obtained in an air-tight container for further use.

9. The process as claimed in claim 8 involving said clinker raw mix composition favoured achieving required quality of clinker having phases comprising tri calcium silicate (alite, C3S), : 50-55 %, di calcium silicate (belite, C2S): 19-23 %, tri calcium aluminate (C3A): 7-10 %, tetra calcium alumino ferrite (C4AF): 11-13 %, wherein composition of clinker from the available raw materials and available fuel (coal) the process factors have been set in a certain range like Raw-mix lime saturation factor (LSF) : 100-106 %, Silica Modulus (SM) : 2-2.5 %, Alumina Modulus (AM) : 1.1-1.5 % and Liquid in clinker: > 28 %.
10. The process as claimed in claims 8 or 9 where portland cement clinker produced with use of iron and steel making slag in raw materia mix yields high amount of clinker where 9.5 % of iron and steel making slag led to raw-mix : clinker ratio = 1.47; and 2.8 % of LRF Slag led to raw-mix : clinker ratio = 1.52, while no usage of iron and steel making slag led to raw-mix : clinker ratio = 1.54.
11. The process as claimed in anyone of claims 8 to 10 wherein use of pre-calcined and loss on ignition (LOI) free steel slag as industrial by product utilized in raw material mix helps to achieve thermal efficiency and higher mass yield for clinkerization and offers higher fuel efficiency during calcination as well as consequently lower CO2 emission.
12. Oridinary Portland Cement(OPC) produced using the clinker obtained by the process as claimed in claims 8 to 11 by grinding developed clinkers with 5 % mineral gypsum to make Ordinary Portland Cement having Fineness of OPC maintained at 340±10 M2/Kg.
13. The OPC of claim 10 having properties comprising Specific Surface-345 to 351 M2/Kg, initial setting time 75-85minutes, final setting time 155-160minutes, soundness tested by Auto Clave 0.004 to 0.012%, Normal Consistency more than 28%, superior compressive strength.
14. The OPC of claim 10 when produced using LRF slag (2.8 %) as partial replacement of alumina laterite (2.2 %) in mix yields clinker with superior quality of 28 Days compressive strength 93.5 Mpa for OPC, and when using complete replacement of alumina laterite by combination of iron and steel slags (1 % of BF Slag, 4 % LD Slag and 4.5 % LRF slag) yields a superior clinker with 28 days compressive strength 82.9 Mpa for OPC.
15. Cement clinker obtained of the clinker mix as claimed in anyone of claims 1 to 7 having phases comprisingtri calcium silicate (alite, C3S), : 50-55 %, di calcium silicate (belite, C2S): 19-23 %, tri calcium aluminate (C3A): 7-10 %, tetra calcium alumino ferrite (C4AF): 11-13 %,
16. Cement composition comprising of cement clinker composition including alumina supplementing steel slags as claimed in claim 1 in amounts of 0 to 9.5 % bywt and mineral gypsum in amounts of 0 to 5 % by wt. having setting time in the range of 75 to 85 min (initial setting time) and 155-160 min (final setting time); compressive strength (28 Days) in the range of 71.5 to 93.5 MPa comparable to the Cement including clinker with alumina sources free of any supplemented alumina with steel slag.

Dated this the 8th day of February, 2024
Anjan Sen
Of Anjan Sen & Associates
(Applicant’s Agent)
IN/PA-199