TECHNICAL FIELD

The present disclosure relates to the field of metallurgy and material sciences. Particularly, the present disclosure relates to photo-assisted selective separation of metals including but not limited to manganese, iron from ores such as low grade manganese ore.

BACKGROUND OF THE DISCLOSURE
Leaching of metal bearing materials with acid is widely applied in the industry. In the available methods available for selective extraction of metals from polymetallic leached solution, such as, solvent extraction, ion exchange resins, precipitation by pH adjustment and electrowinning, pH is a key factor for selective extraction of metals.

During separation of iron from solution, pH adjustment is considered as a very delicate step, since the precipitation of iron without loss of nickel, cobalt or copper requires fine control over pH adjustment, at the level of 0.1 pH unit. Such delicate control of pH although possible at lab scale, it is nearly impossible in a large reactor due to inhomogeneity and issues associated with mixing. Also, iron is often present at its two common valances, ferrous and ferric and these two species have vastly different solubility at various pH. The net result is that ferric ion precipitates, while ferrous material is still soluble and readily reoxidizes after filtration, thus requiring complicated extraction process.

Further, it is noted that separation of metals, such as manganese, nickel and cobalt along with iron from manganese bearing ores requires separation of iron from leachate solution prior to separation of other said metals. Thus, separation of manganese and iron from manganese bearing ores has drawbacks such as high energy consumption, environmental concerns and higher costs. Also, iron is normally precipitated out of leach solution as hydroxide by precipitation with a suitable pH adjuster such as lime, limestone, magnesium hydroxide, caustic, ammonia, etc. However, problem with such separation of iron is that iron hydroxide precipitated in this manner presents difficulties in filtering so that an unacceptable amount of metallic values is lost in the filter cake.

Thus, there is need for selective treating of polymetallic solution containing a multiplicity of metals associated with iron, for recovery of metals, such as manganese which overcomes the drawbacks associated with prior art such as high energy consumption, environmental concerns and higher cost.
STATEMENT OF THE DISCLOSURE
Accordingly, the present disclosure relates to a photo assisted selective process for separation of metals including but not limited to manganese and iron from an ore including but not limited to low grade manganese ore. The process is an improved process for separation of metals with improved recovery rate. The process is simple, environmentally friendly and economical.

In an embodiment, the process of separation of metals from ore including but not limited to low grade ore comprises: preparing a leach liquor of the ore; and exposing the leach liquor to radiation having wavelength ranging from about 10 nm to 700 nm to precipitate the metal.

In an embodiment of the present disclosure, said process of separation of metal from ore separates/recovers iron in the range of about 60% to 95%; separates/recovers manganese in the range of 70% to 99%; and separates/recovers bimetallic manganese-iron component, wherein iron content is in the range of 45% to 95% and manganese content is in the range of about 50% to 95%.

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 process flow chart depicting separation of manganese and iron from low grade manganese ore according to the process of the present disclosure.

FIGURE 2 a) illustrates percentage precipitation of manganese (Mn), iron (Fe (II)) and aluminium (Al) under a radiation having wavelength ranging from 400 nm to 700 nm (sunlight) as a function of oxalic acid; and b) illustrates percentage metal ion (Mn, Fe and Al) in the precipitate.

FIGURE 3 a) illustrates percentage precipitation of manganese (Mn) and iron (Fe (II)) under UV light as a function of wavelength; b) illustrates percentage metal ion (Mn and Fe) in the precipitate; c) illustrates X ray diffraction (XRD) plot of the precipitate; d) illustrates scanning electron microscope (SEM) micrograph image of pure manganese oxalate; and e) illustrates weight percent of ion obtained from energy dispersive X-ray analysis (EDAX) in the precipitate.

FIGURE 4 illustrates comparison plot for specific capacitance of iron (Fe), manganese (Mn) and bimetallic component (Fe-Mn oxalate) without activating agent in 1M KOH.

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.

The present disclosure relates to photo assisted selective process for separation of metals including but not limited to manganese and iron from ore. The ore is including but not limited to low grade ore, such as low grade manganese ore.

In some embodiments of the present disclosure, the process of separation of metals is simple, economical, environmentally friendly and provides for improved separation/recovery of metals.

In some embodiments of the present disclosure, the process of separation of metals from ore involves radiation specific separation.

In some embodiments of the present disclosure, the process of separation of metals provides for selective separation of metals without inclusion of impurities or negligible impurities so that the separated/recovered metals are of high purity.

In some embodiments of the present disclosure, the process of separation of metal from low grade ore comprises:
- Preparing leach liquor of the low grade ore; and
- Exposing the leach liquor to radiation having wavelength ranging from about 10 nm to 700 nm to precipitate the metal.

In some embodiments of the present disclosure, the metal is selected from a group comprising manganese, iron and combination thereof.

In some embodiments of the present disclosure, the metal includes but is not limited to manganese, iron and bimetallic manganese-iron.

In some embodiments of the present disclosure, the low grade ore includes but is not limited to low grade manganese ore.

In some embodiments of the present disclosure, the process of separation of metals leads to separation of metals in its pure form, for example- manganese and iron and/or separation of metals as bimetallic component, for example-manganese-iron component.

In some embodiments of the present disclosure, the separation/recovery rate of iron is at least about 95% and the recovery rate of manganese is at least about 99%.

In some embodiments of the present disclosure, exposing the leach liquor to radiation having wavelength ranging from about 10 nm to 400 nm, including all the values in the range, for instance 11 nm, 12 nm, 13 nm, 14 nm and so and so forth, precipitates manganese.

In some embodiments of the present disclosure, separation of manganese from low grade manganese ore comprises- exposing the leach liquor to radiation having wavelength ranging from about 10 nm to 400 nm for a duration ranging from about 2 hours to 8 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, followed by holding/aging the liquor in dark for a duration ranging from about 8 hours to 14 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 some embodiments of the present disclosure, upon separating/precipitating manganese through techniques including but not limited to filtration, the filtrate is exposed to radiation having wavelength ranging from about 400 nm to 700 nm, including all the values in the range, for instance 401 nm, 402 nm, 403 nm, 404 nm and so on and so forth for a duration ranging from about 2 hours to 8 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 to separate/precipitate iron.

In some embodiments of the present disclosure, the leach liquor is prepared by mixing the low grade ore with an acid at a temperature ranging from about 60 ºC to 80 ºC, including all the values in the range, for instance 61 ºC, 62 ºC, 63 ºC, 64 ºC and so on and so forth, for a duration ranging from about 0 hours to 4 hours, including all the values in the range, for instance 0.1 hours, 0.2 hours, 0.3 hours, 0.4 hours and so on and so forth.

In some embodiments of the present disclosure, the acid includes but is not limited to dicarboxylic acid such as oxalic acid having concentration ranging from about 0.5 M to 1.5 M, including all the values in the range, for instance 0.51 M, 0.52 M, 0.53 M, 0.54 M and so on and so forth.

In an exemplary embodiment of the present disclosure, the acid is oxalic acid having concentration ranging from about 0.5 M to 1.5 M, including all the values in the range, for instance 0.51 M, 0.52 M, 0.53 M, 0.54 M and so on and so forth.

In some embodiments of the present disclosure, ratio of the low grade ore to the acid is ranging from about 1:1 to 1:4 (wt/wt).

In some embodiments of the present disclosure, pulp density (solid to liquid ratio) of the leach liquor is varied from 5% w/v to 15% w/v, including all the values in the range, for instance 5.1% w/v, 5.2% w/v, 5.3% w/v, 5.4% w/v and so on and so forth.

In an exemplary embodiment of the present disclosure, separation of manganese and iron from low grade manganese ore is in the form of precipitate, easily filterable iron oxalate and manganese oxalate.

In some embodiments of the present disclosure, the process of separation of manganese and iron from low grade manganese ore comprises-
- Preparing leach liquor of the low grade manganese ore;
- Exposing the leach liquor to a radiation having wavelength ranging from about 10 nm to 400 nm for a duration ranging from about 2 hours to 8 hours and holding/aging the liquor in dark for a duration ranging from about 8 hours to 14 hours, followed by filtering to separate manganese; and
- Exposing the filtrate to a radiation ranging from about 400 nm to 700 nm for a duration ranging from about 2 hours to 8 hours to precipitate iron.

In some embodiments of the present disclosure, the radiation having wavelength ranging from about 10 nm to 400 nm, including all the values in the range for instance, 11 nm, 12 nm, 13 nm, 14 nm and so and so forth is provided through a source including but not limited to low pressure mercury arc lamp and high pressure mercury arc lamp. The wavelength ranging from about 10 nm to 400 nm is an ultraviolet radiation.

In some embodiments of the present disclosure, the radiation having wavelength ranging from about 400 nm to 700 nm, including all the values in the range for instance, 401 nm, 402 nm, 403 nm, 404 nm and so and so forth is a visible light and/or sunlight.

In some embodiments of the present disclosure, the process of separation of metals from low grade manganese ore by exposing the leach liquor to combination of radiation having wavelength ranging from about 10 nm to 400 nm and radiation having wavelength ranging from about 400 nm to 700 nm provides for separation of manganese and iron, respectively of high purity with negligible impurities or no impurities.

In some embodiments of the present disclosure, the leach liquor is tri-metallic oxalate leach liquor. The leach liquor when exposed to radiation having wavelength ranging from about 10 nm to 400 nm manganese is selectively precipitated and iron remains in the solution. Later, when the filtrate (obtained by filtration upon separating manganese) is exposed to wavelength ranging from 400 nm to 700 nm, iron is precipitated. However aluminium content in the leach liquor did not participate in precipitation.

In some embodiments of the present disclosure, the process of separation of manganese and iron from low grade manganese ore provides for separation/recovery of manganese in the range of about 70% to 99%, including all the values in the range, for instance 71%, 72%, 73%, 74% and so on and so forth and provides for separation/recovery of iron in the range of about 60% to 95% including all the values in the range, for instance 61%, 62%, 63%, 64% and so on and so forth.

In some embodiments of the present disclosure, in the process of separation of manganese and iron from low grade ore, manganese is recovered as manganese oxalate by controlling the intensity and time of exposure to radiation having wavelength ranging from about 10 nm to 400 nm and later the iron is recovered as iron oxalate from the filtrate after precipitation of manganese oxalate by controlling the intensity and time of exposure to radiation having wavelength ranging from about 400 nm to 700 nm.

In some embodiments of the present disclosure, the manganese separated from the above described process has specific capacitance (without any activating agent) ranging from about 70 F/g to 230 F/g, including all the values in the range, for instance 71 F/g, 72 F/g, 73 F/g, 74 F/g and so on and so forth.

In some embodiments of the present disclosure, the manganese separated from the above described process has specific capacitance (with carbon black as activating agent) ranging from about 50 F/g to 380 F/g, including all the values in the range, for instance 51 F/g, 52 F/g, 53 F/g, 54 F/g and so on and so forth.

In some embodiments of the present disclosure, the iron separated from the above described process has specific capacitance (without any activating agent) ranging from about 42 F/g to 85 F/g, including all the values in the range, for instance 43 F/g, 44 F/g, 45 F/g, 46 F/g and so on and so forth.

In some embodiments of the present disclosure, the process of separation of metal from low grade ore, including but not limited to low grade manganese ores provides for separation of bimetallic component such as bimetallic manganese-iron.

In some embodiments of the present disclosure, the separation of metal, such as bimetallic component from low grade ore comprises:
- Preparing a leach liquor of the low grade ore; and
- Exposing the leach liquor to a radiation having wavelength ranging from about 400 nm to 700 nm to precipitate the bimetallic component.

In some embodiments of the present disclosure, the bimetallic component includes but is not limited to bimetallic manganese-iron.

In some embodiments of the present disclosure, the bimetallic component is precipitated by exposing the leach liquor to a radiation ranging from about 400 nm to 700 nm, including all the values in the range, for instance 401 nm, 402 nm, 403 nm, 404 nm and so on and so forth for a duration ranging from about 2 hours to 8 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. The wavelength ranging from about 400 nm to 700 nm is visible light and/or sunlight.

In some embodiments of the present disclosure, in the process of separation of bimetallic component from low grade ore, the leach liquor is prepared by mixing low grade ore with an acid at a temperature ranging from about 60ºC to 80ºC, including all the values in the range for instance 61ºC, 62ºC,63ºC, 64ºC and so on and so forth for a duration ranging from about 0 hours to 4 hours including all the values in the range, for instance 0.1 hours, 0.2 hours, 0.3 hours, 0.4 hours and so on and so forth. In the leach liquor, ratio of low grade ore to the acid is ranging from about 1:1 to 1:4 (wt/wt), wherein the acid includes but is not limited to dicarboxylic acid having concentration ranging from about 0.5 M to 1.5 M, such as oxalic acid.

In some embodiments of the present disclosure, in the separated bimetallic manganese-iron component, iron content is ranging from about 45% to 95%, including all the values in the range, for instance 46%, 47%, 48%, 49% and so on and so forth and manganese content is ranging from about 50% to 95%, including all the values in the range, for instance 51%, 52%, 53%, 54% and so on and so forth.

In some embodiments of the present disclosure, in the separation of bimetallic component from low grade ore, the bimetallic component is recovered/separated as bimetallic oxalate.

In some embodiments of the present disclosure, the bimetallic manganese-iron separated from the above described process has specific capacitance (without any activating agent) ranging from about 45 F/g to 100 F/g, including all the values in the range, for instance 46 F/g, 47 F/g, 48 F/g, 49 F/g and so on and so forth.

In some embodiments of the present disclosure, the low grade ore including but not limited to low grade manganese ore employed in the processes described above is in a form selected from a group comprising lump, fines and combination thereof.

In some embodiments of the present disclosure, the low grade manganese ore employed in the processes described above comprises iron content ranging from 25% to 28%, manganese content ranging from about 25% to 27% and aluminum content ranging from about 1% to 2%.

In an embodiment of the present disclosure, figure 1 provides a flow chart depicting the process of separation of manganese, iron and bimetallic manganese-iron component. The figure also depicts that the separated manganese, iron and bimetallic manganese-iron component demonstrates super-capacitive property for energy storage applications.

The above described processes of the present disclosure for separation of metal from low grade ore overcomes the limitation and challenge associated with separation of iron and manganese, i.e., interference of iron in the process parameters for separating manganese from the ore. The process of iron and manganese separation described in the present disclosure is viable through selective precipitation by exposing the mixed leach liquor to UV light of specific intensity for specific duration. Where interference of iron precipitation is inhibited with the precipitation of manganese. And the process subsequently enables precipitation of iron from the leach liquor.
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.

EXAMPLE

Example 1: Separation of bimetallic manganese-iron from low grade manganese ore
About 250 g of low grade manganese ore (Fe/Mn- about 0.92 and Al- about 1%) was leached with a pulp density (solid to liquid ratio) of about 10% at a temperature of about 60 ºC to 80 ºC for about 4 hours in oxalic acid solution having concentration ranging from about 0.5 M to 1.5 M to obtain leach liquor. The leaching efficiency was found to be about 10% to 22% for Fe and Mn, respectively and about 80% to 95% for Al.

The leach liquor was exposed to sunlight (having wavelength ranging from 400 nm to 700 nm) for a duration of about 6 hours. Manganese-iron bimetallic oxalate was produced as a result of crystallization/precipitation.

The recovery of the manganese-iron bimetallic oxalate was found to be about 90% to 92%. Aluminium precipitation as oxalate was not observed. The Fe content and Mn content in the bimetallic manganese-iron was ranging from about 9% to 15% and 15% to 12%, respectively.
Figure 2 describes a plot depicting percentage precipitation of Mn and Fe and a plot depicting % metal ion (Mn and Fe) in the precipitate.

The obtained manganese-iron bimetallic was evaluated for super capacitive property (nafion was used as binder). The manganese-iron bimetallic showed specific capacitance of about 100 G/g at 10 mV/sec when 1M NaOH was used as electrolyte.

Example 2: Separation of manganese and iron from low grade manganese ore
About 250 g of low grade manganese ore (Fe/Mn- about 0.92 and Al- about 1%) was leached with a pulp density (solid to liquid ratio) of about 10wt/v at a temperature of about 60 ºC to 80 ºC for about 4 hours in oxalic acid solution having concentration ranging from about 0.5 M to 1.5 M to obtain leach liquor. The leaching efficiency was found to be about 10% to 22% for Fe and Mn, respectively and about 80% to 95% for Al.

The leach liquor was exposed to UV light (having wavelength ranging from 10 nm to 400 nm) at ambient temperature (32+5°C) for a duration of about 6 hours, followed by aging in dark. Manganese oxalate was obtained as a result of crystallization/precipitation and was filtered. After separation of manganese, the filtrate was exposed to visible light (having wavelength ranging from about 400 nm to 700 nm for a duration of about 4 hours. As a result, iron was precipitated, and the iron was recovered by filtration. The percent recovery of Fe and Mn is 90-92%. It was observed that the filtrate only contained aluminium.

Figure 3 describes a plot depicting percentage precipitation of Mn and Fe and a plot depicting % metal ion (Mn and Fe) in the precipitate.

Super capacitive property of the recovered manganese and iron was evaluated (nafion was used as binder). The manganese showed specific capacitance of about 230 F/g at 10 mV/sec when 1M KOH was used as an electrolyte. The iron showed specific capacitance of about 85 F/g at 10 mV/sec when 1M KOH was used as an electrolyte.

The foregoing description of the specific embodiments reveal 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.

Throughout this specification, the term ‘combinations thereof’ or ‘any combination thereof’ or ‘any combinations thereof’ are used interchangeably and are intended to have the same meaning, as regularly known in the field of patents disclosures.

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.

Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

Claims:WE CLAIM

1. A process for separation of metal from low grade ore, said process comprises:
- preparing a leach liquor of the low grade ore; and
- exposing the leach liquor to radiation having wavelength ranging from about 10 nm to 700 nm to precipitate the metal.

2. The process as claimed in claim 1, wherein the metal is selected from a group comprising manganese, iron, and combination thereof; and the low grade ore is low grade manganese ore.

3. The process as claimed in claim 1, wherein exposing the leach liquor to radiation having wavelength ranging from about 10 nm to 400 nm precipitates manganese.

4. The process as claimed in claim 3, wherein the leach liquor is exposed to radiation for a duration ranging from about 2 hours to 8 hours, followed by holding the liquor in dark for a duration ranging from about 8 to 14 hours.

5. The process as claimed in claims 3, wherein the process further comprises filtering precipitate and exposing filtrate to radiation having wavelength ranging from about 400 nm to 700 nm to precipitate iron.

6. The process as claimed in claim 5, wherein the filtrate is exposed to radiation for a duration ranging from about 2 hours to 8 hours.

7. The process as claimed in claim 1, wherein exposing the leach liquor to radiation having wavelength ranging from about 400 nm to 700 nm precipitates bimetallic component of manganese-iron.

8. The process as claimed in claim 7, wherein the leach liquor is exposed to radiation for a duration ranging from about 2 hours to 8 hours.

9. The process as claimed in claim 1, wherein the preparation of the leach liquor comprises mixing the low grade ore with an acid at a temperature ranging from about 60 ºC to 80 ºC for a duration ranging from about 0 hours to 4 hours.

10. The process as claimed in claim 9, wherein ratio of low grade ore to the acid is ranging from about 1:1 wt/wt to 1:4 wt/wt.
11. The process as claimed in claim 9, wherein the acid is dicarboxylic acid having concentration ranging from about 0.5 M to 1.5 M.

12. The process as claimed in claim 1, wherein the low grade ore is in a form selected from a group comprising lump, fines and combination thereof.

13. The process as claimed in claim 2, wherein the iron is recovered at a range of about 60% to 95% and the manganese is recovered at a range of about 70% to 99%.

14. The process as claimed in claim 7, wherein the precipitated bimetallic manganese-iron component has iron content ranging from about 45% to 95% and the manganese content ranging from about 50% to 95%.

15. The process as claimed in claim 13, wherein the manganese has specific capacitance ranging from about 50 F/g to 380 F/g; the iron has specific capacitance ranging from about 42 F/g to 85 F/g.

16. The process as claimed in claim 14, wherein the bimetallic manganese-iron component has specific capacitance ranging from about 45 F/g to 100 F/g.