Claims:WE Claim:
1. A process for preparing silica-iron oxide nanocomposite from iron ore slime, said process comprises:
- digesting the iron ore slime, followed by filtering to obtain residue;
- mixing the residue with solvent to obtain a solution, followed by sonication;
- mixing the solution with alkali, followed by stirring and heating; and
- cooling the solution, followed by washing and drying to obtain the silica-iron oxide nanocomposite.

2. The process as claimed in claim 1, wherein the iron ore slime is digested by mixing the iron ore slime in acid, followed by heating.

3. The process as claimed in claim 2, wherein the acid is selected from a group comprising hydrochloric acid and sulphuric acid; and wherein concentration of the acid is ranging from about 25% to 35 %.

4. The process as claimed in claim 2, wherein the heating is carried out at a temperature ranging from about 80 ? to 90 ?, for a duration ranging from about 30 minutes to 45 minutes.

5. The process as claimed in claim 1, wherein the sonication is carried out for a duration ranging from about 2 hours to 3 hours.

6. The process as claimed in claim 1, wherein the solvent is deionized water.

7. The process as claimed in claim 1, wherein the mixing with alkali comprises- adding the alkali to the solution with continuous stirring to obtain a homogenous solution.

8. The process as claimed in claim 1, wherein the alkali is selected from a group comprising sodium hydroxide and potassium hydroxide; and wherein concentration of the alkali is ranging from about 0.05 M to 0.1 M.

9. The process as claimed in claim 1, wherein the stirring is carried out at a speed ranging from about 500 rpm to 600 rpm, for a duration ranging from about 3 hours to 4 hours; and at a temperature ranging from about 20 ? to 40 ?.
10. The process as claimed in claim 1, wherein the heating is carried out at a temperature ranging from about 80 ? to 90 ?, for a duration ranging from about 3 to 4 hours.

11. The process as claimed in claim 1, wherein the cooling is carried out naturally to a temperature ranging from about 20 ? to 40 ?.

12. The process as claimed in claim 1, wherein the washing is carried out with solvent for about 2 to 4 times; and wherein the solvent is water.

13. The process as claimed in claim 1, wherein the drying is carried out at a temperature ranging from about 70 ? to 80 ?, for a duration ranging from about 8 to 12 hours.

14. The process as claimed in claim 1, wherein the iron ore slime comprises- about 30% to 50% of iron; about 5% to 8% of silicon; and about 6% to 10% of aluminium.

15. The process as claimed in claim 1, wherein the iron ore slime comprises components having size ranging from about 20 µm to 40 µm.

16. The process as claimed in claim 1, wherein the silica-iron oxide nanocomposite comprises silica having size ranging from about 7 nm to 15 nm and iron oxide having size ranging from about 50 nm to 70 nm.

, Description:TECHNICAL FIELD
The present disclosure relates to field of metallurgy and material sciences. The present disclosure particularly relates to method of preparing silica-iron oxide nanocomposite from iron ore slime. The disclosure more particularly relates to effective usage of iron ore slime (discard/waste) for preparing silica-iron oxide nanocomposite.

BACKGROUND OF THE DISCLOSURE
Iron is one of the important components for the growth of various industries such as steel, automotive, construction and transportation. The high grade and stable iron oxide from (hematite) have been widely utilized for steel manufacturing. During the production of iron rod or steel, a waste of iron containing compounds, such as slime is obtained as a waste. During iron ore mining, it is noted that generally 15% to 25% ore is utilized, and the rest is discarded as slime. It has been estimated that 49% to 65% of iron will be in slime along with other gangue materials such as Al2O3, SiO2, CaO and MgO.

Though slime generated during the production of iron materials and steel contains high amount of iron element, slime cannot be used directly because of poor iron quality that will choke the furnace feeder during the feeding process in blast furnace.

Various techniques are available for recovering or recycling of iron ore from slime, such as physicochemical process, magnetic separation, gravity separation and flotation. However, it is noted that, said techniques do not yield complete recovery or extraction of iron ore. In other words, after extraction of iron ore from said techniques, there seems to be huge leftovers containing iron oxide along with silica. Thus, it is noted that there is still scope for improving extraction of iron ore from iron ore slime generated during beneficiation of iron ore.

The present disclosure describes an improved method for efficient extraction of iron ore from iron ore slime that overcomes the drawback noted in the available techniques.

STATEMENT OF THE DISCLOSURE
Accordingly, the present disclosure describes a process for preparing silica-iron oxide nanocomposite from iron ore slime, said process comprises- digesting the iron ore slime, followed by filtering to obtain residue, mixing the residue with solvent to obtain a solution, followed by sonication, mixing the solution with alkali, followed by stirring and heating; and cooling the solution, followed by washing and drying to obtain the silica-iron oxide nanocomposite.

The process of the present disclosure is an improved and efficient process for effective utilization of iron ore slime for recovering iron ore by preparing silica-iron oxide nanocomposite. In other words, the efficient recovery of iron ore from the iron ore slime is obtained in the form of silica-iron oxide nanocomposite with nil or negligible leftovers of iron ore in the slime.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
In order that the present disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, where:

Figure 1 illustrates a schematic representation of preparation of silica-iron oxide nanocomposite from iron ore slime according to the process of the present disclosure.

Figure 2 illustrates Powder X-ray Diffraction (PXRD) plot of iron ore slime showing presence of hematite and maghemite.

Figure 3a illustrates scanning electron microscope (SEM) image depicting morphology of iron ore slime.

Figure 3b illustrates Energy Dispersive X-ray Spectroscopy (EDX) analysis plot of iron ore slime.

Figure 4 illustrates Powder X-ray Diffraction (PXRD) plot of the silica-iron oxide nanocomposite prepared in the present disclosure.

Figure 5 illustrates Transmission electron microscopy (TEM) image of silica-iron oxide nanocomposite prepared in the present disclosure.

Figure 6 illustrates Energy Dispersive X-ray Spectroscopy (EDX) analysis plot of silica-iron oxide nanocomposite.

Figure 7 illustrates Powder X-ray Diffraction (PXRD) plot of the silica-iron oxide nanocomposite prepared in the present disclosure.

Figure 8 illustrates Energy Dispersive X-ray Spectroscopy (EDX) analysis plot of silica-iron oxide nanocomposite.

DETAILED DESCRIPTION OF THE DISCLOSURE
Unless otherwise defined, all terms used in the disclosure, including technical and scientific terms, have meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. By means of further guidance, term definitions are included for better understanding of the present disclosure.

As used herein, the singular forms ‘a’, ‘an’ and ‘the’ include both singular and plural referents unless the context clearly dictates otherwise.

The term ‘comprising’, ‘comprises’ or ‘comprised of’ as used herein are synonymous with ‘including’, ‘includes’, ‘containing’ or ‘contains’ and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps.

The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within the respective ranges, as well as the recited endpoints.

The term ‘about’ as used herein when referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of ±10% or less, preferably ±5% or less, more preferably ±1% or less and still more preferably ±0.1% or less of and from the specified value, insofar such variations are appropriate to perform the present disclosure. It is to be understood that the value to which the modifier ‘about’ refers is itself also specifically, and preferably disclosed.

Reference throughout this specification to ‘some embodiments’, ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. thus, the appearances of the phrases ‘in some embodiments’, ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification may not necessarily all refer to the same embodiment. It is appreciated that certain features of the disclosure, which are for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The present disclosure relates to improved and efficient process for recovering/extracting iron ore from iron ore slime.

In an embodiment, the recovering of the iron ore from the iron ore slime is achieved by preparing silica-iron oxide from iron ore slime. The inventors have particularly identified that preparing silica-iron oxide from iron ore slime provides for nil or negligible leftovers of the iron ore in the slime.

In some embodiments of the present disclosure, the process of preparing silica-iron oxide from iron ore slime, comprises:
- digesting the iron ore slime, followed by filtering to obtain residue;
- mixing the residue with solvent to obtain a solution, followed by sonication;
- mixing the solution with alkali, followed by stirring and heating; and
- cooling the solution, followed by washing and drying to obtain the silica-iron oxide nanocomposite.

In some embodiments of the present disclosure, the digesting of the iron ore slime is carried out by mixing the iron ore slime in acid and heating.

In some embodiments of the present disclosure, the acid employed for digesting of the iron ore slime includes but it is not limited to hydrochloric acid and sulphuric acid. In an embodiment, the acid is employed in an amount ranging from about 25% to 35%, including all the values in the range, for instance, 25.1%, 25.2%, 25.3%, 25.4% and so on and so forth. In an embodiment, the acid is having concentration ranging from about 5 M to 10 M, including all the values in the range, for instance, 5.1 M, 5.2 M, 5.3 M, 5.4 M and so on and so forth.

In some embodiments of the present disclosure, during the digesting, the heating is carried out at a temperature ranging from about 80 ? to 90 ?, including all the values in the range, for instance, 80.1 ?, 80.2 ?¸80.3?, 80.4 ? and so on and so forth. In an embodiment, the heating is carried out for a duration ranging from about 30 minutes to 45 minutes, including all the values in the range, for instance, 31 minutes, 32 minutes, 33 minutes, 34 minutes and so on and so forth.

In some embodiments of the present disclosure, the digested residue is subjected to filtration to obtain a residue. The obtained residue is mixed with solvent including but it is not limited to deionized water, to obtain a solution.

In some embodiments of the present disclosure, the obtained solution is subjected to sonication for a duration ranging from about 2 hours to 3 hours, including all the values in the range, for instance, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours and so on and so forth.

In some embodiments of the present disclosure, the mixing with the alkali comprises adding the alkali to the solution with continuous stirring to obtain a homogenous solution. In an embodiment, the alkali includes but it is not limited to sodium hydroxide and potassium hydroxide. In an embodiment, the alkali is having concentration ranging from about 0.05 M to 0.1 M, including all the values in the range, for instance, 0.06 M, 0.07 M, 0.08 M, 0.09 M and so on and so forth. In an embodiment, the alkali is added in an amount ranging from about 25 ml to 30 ml.

In an embodiment, upon adding the alkali to the solution, the stirring is carried out at a speed ranging from about 500 rpm to 600 rpm, including all the values in the range, for instance, about 501 rpm, 502 rpm, 503 rpm, 504 rpm. In an embodiment, the stirring is carried out for a duration ranging from about 3 hours to 4 hours, including all the values in the range, for instance, 3.1 hours, 3.2 hours, 3.3 hours, 3.4 hours and so on and so forth. In an embodiment, the stirring is carried out at a temperature ranging from about 20 ? to 40 ?, including all the values in the range, for instance, 20.1 ?, 20.2 ?, 20.3 ?, 20.4? and so on and so forth.

In some embodiments of the present disclosure, upon stirring the solution, the solution is subjected to heating at a temperature ranging from about 80 ? to 90 ?, including all the values in the range, for instance, 80.1 ?, 80.2 ?, 80.3 ?, 80.4 ? and so on and so forth. In an embodiment, the heating is carried out for a duration ranging from about 3 hours to 4 hours, including all the values in the range, for instance, 3.1 hours, 3.2 hours, 3.3 hours, 3.4 hours and so on and so forth.

In some embodiments of the present disclosure, the cooling is carried out naturally to a temperature ranging from about 20 ? to 40 ?, including all the values in the range, for instance, 20.1 ?, 20.2 ?, 20.3 ?, 20.4 ? and so on and so forth.

In some embodiments of the present disclosure, the washing is carried out with solvent including but it is not limited to water, for about 2 times to 4 times. In an embodiment, the washing is carried out for about 2 times, about 3 times or about 4 times.

In some embodiments of the present disclosure, the drying is carried out at a temperature ranging from about 70 ? to 80 ?, including all the values in the range, for instance, 70.1 ?, 70.2 ?, 70.3 ?, 70.4 ? and so on and so forth. In an embodiment, the drying is carried out for a duration ranging from about 8 hours to 12 hours, including all the values in the range, for instance, 8.1 hours, 8.2 hours, 8.3 hours, 8.4 hours and so on and so forth.

In an exemplary embodiment, the drying can be carried out in oven at a temperature ranging from about 70 ? to 80 ?, for a duration ranging from about 8 hours to 12 hours.

In an exemplary embodiment of the present disclosure, the process of preparing the silica-iron oxide nanocomposite from iron ore slime, comprises:
- digesting the iron ore slime in the acid and heating at a temperature ranging from about 80 ? to 90 ? for a duration ranging from about 30 minutes to 45 minutes;
- filtering the digested iron ore slime to obtain residue;
- mixing the residue with solvent to obtain a solution, followed by sonication for a duration ranging from about 2 hours to 3 hours;
- mixing the sonicated solution with the alkali until homogenous solution is obtained, followed by stirring at a speed ranging from about 500 rpm to 600 rpm for a duration ranging from about 3 hours to 4 hours;
- heating the stirred solution at a temperature ranging from about 80 ? to 90 ? for a duration ranging from about 3 hours to 4 hours;
- cooling the solution naturally to a temperature ranging from about 20 ? to 40 ?;
- washing for about 2 times to 4 times and drying at a temperature ranging from about 70 ? to 80 ? for a duration ranging from about 8 hours to 12 hours to obtain silica-iron oxide.

In some embodiments of the present disclosure, the silica-iron oxide nanocomposite comprises silica particles having size ranging from about 7 nm to 15 nm, including all the values in the range, for instance, 7.1 nm, 7.2 nm, 7.3 nm, 7.4 nm and so on and so forth.

In some embodiments, of the present disclosure, the silica-iron oxide nanocomposite comprises iron oxide having size ranging from about 50 nm to 70 nm, including all the values in the range, for instance, 50.1 nm, 50.2 nm, 50.3 nm, 50.4 nm and so on and so forth.

In some embodiments of the present disclosure, in the silica-iron oxide nanocomposite, the silica particles are distributed on the iron oxide. The iron oxide is rod like structure having rod width ranging from about 10 nm to 15 nm, including all the values in the range, for instance, 10.1 nm, 10.2 nm, 10.3 nm, 10.4 nm and so on and so forth.

The Figure 1 provides a schematic representation of the preparation of the silica-iron oxide according to the process described above. The inventors in the present disclosure have particularly identified that employing combination of steps involving digesting the iron ore slime with the acid and treating the solution with the alkali provides for silica-iron oxide nanocomposite. Thus, leading to effective recovery/extraction of iron ore from iron ore slime with nil or negligible leftovers of the iron ore in the iron ore slime.

The figures 4 and 7 describes Powder X-ray Diffraction (PXRD) analysis of the silica-iron oxide nanocomposite, wherein the plot describes presence of SiO2 peak in the nanocomposite.

The Figure 5 provides a Transmission electron microscopy (TEM) micrograph of silica-iron oxide nanocomposite, wherein the particles are of silicon of size of about 10 nm and rod-like structure is iron oxide of size about 50 nm to 70 nm, with width of the rods are about 10 nm to 15 nm. The distribution of the silicon particles on the iron oxide confirms the formation of the silica-iron oxide nanocomposite. Further, the Figures 6 and 8 provides Energy Dispersive X-Ray Analysis (EDX) plot of the silica-iron oxide nanocomposite. The EDX analysis verifies the homogenous distribution of Si on iron oxide surface. The EDX analysis describes presence of Si, Fe, Al and O at the points confirming homogenous distribution of Si in the nanocomposite.

In some embodiments of the present disclosure, the iron ore slime employed comprises about 30% to 50% of iron, about 5% to 8% silicon and about 6% to 10% of aluminium.

In some embodiments of the present disclosure, the iron ore slime employed comprises components having size ranging from about 20 µm to 40 µm, including all the values in the range, for instance, 21 µm, 22 µm, 23 µm, 24 µm and so on and so forth.

Figure 2 describes the Powder X-ray Diffraction (PXRD) analysis of the iron ore slime employed in the above described proves. The PXRD analysis shows that the iron ore slime has hematite (Fe2O3, Rhombo H axes, R-3c) and maghemite-C (Fe2O3, cubic, P4132) phase.

Figure 3a describes Scanning Electron Microscopy (SEM) image of the iron ore slime employed in the process. The SEM analysis describes that the iron ore slime is composed of particles having size ranging from about 20 µm to 40 µm.
Figure 3b describes Energy Dispersive X-ray Spectroscopy (EDX) analysis plot of the iron ore slime. The insert of the Figure 3b describes elemental percentage of iron ore slime.

It is to be understood that the foregoing description is illustrative not a limitation. While considerable emphasis has been placed herein on particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. Those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein. Similarly, additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based upon description provided herein.

Descriptions of well-known/conventional methods/steps and techniques are omitted so as to not unnecessarily obscure the embodiments herein. Further, the disclosure herein provides for examples illustrating the above-described embodiments, and in order to illustrate the embodiments of the present disclosure, certain aspects have been employed. The examples used herein for such illustration are intended merely to facilitate an understanding of ways in which the embodiments may be practiced and to further enable those of skill in the art to practice the embodiments. Accordingly, following examples should not be construed as limiting the scope of the embodiments herein.

EXAMPLES
Example 1: Preparation of the silica-iron oxide nanocomposite.
About 3 g of iron ore slime was digested with about 80 ml HCl and the solution was boiled for about 30 minutes and cooled naturally and subjected to filtration. After filtration the obtained residue was transferred into about 25 ml Deionized water and sonicated for about 2 hours. The pH of the solution was about 1.2. After sonication, about 0.1 M NaOH solution (about 25 ml) was added into the sonicated solution with continuous stirring. The mixture was stirred at about 600 rpm for about 3 hours at room temperature after that the solution was heated at about 80 °C for about 4 hours. After the reaction, the solution was naturally cooled to room temperature. The obtained solution was washed with water several times (at least 2 times) and dried in oven at about 70 ? to obtain silica-iron oxide nanocomposite.

The phase identification of the silica-iron oxide was carried out using PXRD. The diffraction patterns matched with ICDD card no. 33-0664 of Fe2O3 of space group R-3c (167) (see Figure 4). A small peak of silica present was matched with ICDD no 00-046-1045 hexagonal P3121. Apart from that, the hump in PXRD was due to amorphous silica. The confirmation of presence of silica was carried out using TEM-EDX. The TEM micrograph indicates two types of microstructures, wherein the particles are of silicon having size of about 10 nm and iron oxide in the form of rod-like structure having size of about 50 nm to 70 nm with width of rods of about 10 nm to 15 nm. It was noted that Si particles are distributed on the Fe2O3 which confirms the formation of heterostructure nanocomposite (see Figure 5). To verify the local homogeneous distribution of Si on Fe2O3 surface STEM-EDX studies was carried out. Figure 6 shows the point EDX of all the SiO2-Fe2O3 heterostructure nanocomposites for points A1, A2, A3, A4. The point EDX studies indicate the presence of Si, Fe, Al and O at all the points in the obtained nanocomposite which confirms the homogeneous distribution of Si in the nanocomposite.

Example 2: Preparation of the silica-iron oxide nanocomposite.
About 3 gm of slime was digested with about 40 ml HCl and the solution was boiled for about 30 minutes and cooled naturally and subjected to filtration. After filtration the obtained residue was transferred into about 25 ml deionized water and sonicated for about 2 hours. The Ph of the solution was about 1.2. After sonication, about 0.1 M NaOH solution (about 25 ml) was added into the sonicated solution with continuous stirring. The mixture was stirred at about 600 rpm for 3 hours at room temperature after that the solution was heated at about 80 °C for about 4 hours. After the reaction, the solution was naturally cooled to room temperature. The obtained solution was washed with water several times (at least 2 times) and dried in an oven at about 70 ? to obtain silica-iron oxide nanocomposite.

The phase identification of the silica-iron oxide was carried out using PXRD. The diffraction patterns matched with ICDD card no. 33-0664 of Fe2O3 of space group R-3c (167) (see Figure 7). A small peak of silica present was matched with ICDD no 00-046-1045 hexagonal P3121 (see Figure 7). To verify the local homogeneous distribution of Si on Fe2O3 surface STEM-EDX studies was carried out. Figure 8 shows the point EDX of all the SiO2-Fe2O3 heterostructure nanocomposites for points A1, A2, and A3. The point EDX studies indicate the presence of Si, Fe, Al and O at all the points in the sample which confirms the homogeneous distribution of Si in the nanocomposite.

Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based on the description provided herein. The embodiments herein provide various features and advantageous details thereof in the description. Descriptions of well-known/conventional methods and techniques are omitted so as to not unnecessarily obscure the embodiments herein.

The foregoing description of the specific embodiments fully reveals the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments in this disclosure have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

As regards the embodiments characterized in this specification, it is intended that each embodiment be read independently as well as in combination with another embodiment. For example, in case of an embodiment 1 reciting 3 alternatives A, B and C, an embodiment 2 reciting 3 alternatives D, E and F and an embodiment 3 reciting 3 alternatives G, H and I, it is to be understood that the specification unambiguously discloses embodiments corresponding to combinations A, D, G; A, D, H; A, D, I; A, E, G; A, E, H; A, E, I; A, F, G; A, F, H; A, F, I; B, D, G; B, D, H; B, D, I; B, E, G; B, E, H; B, E, I; B, F, G; B, F, H; B, F, I; C, D, G; C, D, H; C, D, I; C, E, G; C, E, H; C, E, I; C, F, G; C, F, H; C, F, I, unless specifically mentioned otherwise.

While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.