Description:FIELD OF THE INVENTION
The present invention relates to the recovery of metallic iron from iron bearing waste resources as input material including a combination of hydrometallurgical and electrometallurgical process of recovery of iron values from variety of waste resources that includes lean iron ore, iron ore tailing, accumulated iron ore slime, pickle liquor from steel pickling plant and mill scale reprocessing.
The present process developed involves above iron-bearing waste as input material for iron recovery. Acid digestion of the ore selectively dissolves iron values in the ore or waste materials. A combination of hydrometallurgy and electrometallurgy process is followed to recover iron as pure iron solid more than 99 % pure. The hydrometallurgical process involves the leaching of a lean ore or tailing with sulphuric acid, which contains recoverable iron values. The process involves the dissolution of Iron in the waste with acid treatment to form initially ferric sulphate. This is followed by the conversion of the ferric sulphate to ferrous sulphate by treating the ferric sulphate with iron metallic scrap suitably to form ferrous sulphate. The ferrous sulphate is subject to an electro-winning process to recover pure iron. The electrolysis setup consists of an anolyte and catholyte compartment separated by a suitable anion exchange that selectively allows sulphate ions to move from the catholyte compartment to the anolyte compartment when iron deposition takes place. At the end of the process, the anolyte compartment has sulphuric acid, which can be reused for leaching. The iron is deposited in an iron plate used as the cathode, while the anode was made of lead where oxygen is liberated. The catholyte consists of ferrous sulphate, sodium sulphate, and boric acid, while the anolyte consisted of sodium sulphate and boric acid. The iron deposited as a metallic deposit could be scrapped for recovery from the plate. Thus, a viable process has been developed to extract iron from lean iron resources.
BACKGROUND OF INVENTION
Low-grade iron ores and tailings generated during iron ore beneficiation have a significant amount of iron content in them. Low-grade ore such as banded hematite quartzite (BHQ) ore has 25 to 48% Fe, along with 28 to 55 % silica and 1 to 2 % alumina. The iron ore tailing in an ore beneficiation plant has 35 to 50% Fe, along with 12 to 18 % silica and 7 to 15 % alumina. The typical iron ore mill scale has 60-69 % Fe, 2-4 % CaO, 2-3 % MgO, 1-3 % silica and 1-2 % alumina. Recovery of iron from such low-grade resources is an important area in extractive metallurgy. Processes such as reduction roasting where the low concentration non-magnetic hematite ore is reduced to magnetite, which is magnetic, extract such lean grade ores. There are also efforts to extract iron values in hematite using heavy media separation, a combination of spiral with column flotation. However, iron extraction using leaching techniques is rare. In some non-ferrous extraction processes, solvent extraction or ion exchange processes are used to upgrade iron values that are precipitated as iron oxides.In addition, in a steel mill, there are steel pickling units, where, the surface oxides are removed by acid pickling. The leach liquor from sulphuric acid pickling can be used as a feed material for the extraction of iron as pure iron material. It is also possible to recycle the mill scale generated in a steel plant with sulphuric acid to generate ferrous sulphate.
Many earlier workers have done electrolytic extraction of iron from aqueous solutions of a ferrous salt. In the electrolysis process for iron extraction, an electrolytic cell contains two-compartment separated by an ion-exchange membrane. The aqueous solution in a compartment around the cathode is called the catholyte, where a reduction reaction that involves the reduction of Fe2+ ion to metallic iron happens, and the aqueous solution around the anode is called anolyte where an oxidation reaction happens. The cathode for iron extraction is made of steel plate and is connected to the negative polarity of a direct current power source. The anode for iron electro-winning is made of inert electrode metal such as a lead sheet. The anode is connected to the positive side of the direct current power source. At the cathode, there is the deposition of iron and hydrogen while oxygen is released in the anode.
In general, about 200 kg of iron ore tailing waste slime is generated for every ton of iron ore processed. The tailing discarded has an iron content varying between 35 and 45% Fe with remaining gangue content. It is difficult to beneficiate such tailings with low iron values economically and hence there is the need for development of extraction process for the recovery of iron values from the slime or lean ore.
Reference is invited to following prior arts:
Patent CN101413057B entitled “Method for efficiently separating low-ore grade and complicated iron ore” they have used a reduction roasting route to upgrade low-grade iron ore mines or low-grade mine tailing iron. The upgraded ore contains silica, alumina, and other impurities in small quantities, and upgraded ore fines are used in DRI or Blast furnaces or steel making as raw materials. In this patent, we have leached iron in the form of ferrous sulphate from different sources like low-grade iron or iron ore tailing or mill scale and get pure ferrous sulphate for electrolysis it to produce pure iron and oxygen collected in a specific arrangement.

Patent US3337328A entitled “Iron ore beneficiation process “ they have heavy gravity and spiral process to upgraded low-grade iron-containing minerals or iron ore tailing more particularly, to the beneficiation of ores by gravity separation. In iron ore beneficiation they upgraded Fe > 60% and silica <7% and it agglomerated. In this patent, we have leached iron in the form of ferrous sulphate from different sources like low-grade iron or iron ore tailing or mill scale and we achieved a pure form of ferrous sulphate and finally electrolyzed it to produce pure iron and pure oxygen collected in a specific arrangement.

Patent US8192556B2 entitle “Pickling or brightening/passivating solution and process for steel and stainless steel” they have used a combination of acid at least one strong acid to remove the scale on the surface of steel and the pickled solution contains a mixture of compounds. In this patent, we have used pure concentrated sulphuric acid for the pickling of the scaled steel surface. The used solution contains ferrous sulfate and sulphuric acid cooled and precipitated ferrous sulphate crystal and further ferrous sulphate used for electrolysis to produce pure iron and pure oxygen collected in a specific arrangement
Patent US3041253 entitled “Electrolytic production of iron” they are produced iron powder from Mohr’s salt by electrolysis at the cathode. In our patent, we have used ferrous sulphate leached from iron to produce iron powder or iron sheets depending on the requirement and oxygen collected in a specific arrangement.
Patent US2626895 entitled “Electrolytic preparation of iron powder” they are producing iron powder from ferrous chloride by electrolysis at the cathode. They also have used ammonium salt for the conductivity of some nitrogen embedded in the deposit. In our patent, we have used ferrous sulphate leached from iron to produce iron powder or iron sheets depending on the requirement and oxygen collected in a specific arrangement. In this, we have used sodium sulphate for the conductivity of the solution.
Patent US2503234 entitled “Method of making electrolytic” they are producing iron powder from ferrous bath prepared from iron sulfide ores by electrolysis at the cathode. They also have use ammonium salt for the conductivity due to the ammonium salt nitrogen embedded in the iron deposit. In our patent, we have leached iron in the form of ferrous sulphate from different sources like low-grade iron or iron ore tailing or pickled ferrous sulphate or mill scale and finally electrolyzed it to produce pure iron and oxygen collected in a specific arrangement.
The Ferrowin process was developed where ferrous sulphate generated in the TiO2 mineral containing material was digested and converted to ferrous sulphate used in a detailed aqueous electrolysis process to electrowin Fe metal [Canadian Patent CA 2717887 C; Chinese Patent CN 102084034B; European Patent EP 2 268 852 B1, Brazil Patent BRPI 0911653 B1 ; Indian Patent IN 294372 B Japanese Patent JP 5 469 157 B2; South African Patent ZA 2010/07214].
It is thus the need in the art to provide for an economically viable process that would allow utilization of the discarded tailings that usually have iron content varying between 35 and 45% Fe with remaining gangue content for facile and economical beneficiation of such tailings with low iron to thus provide for a beneficiation/extraction process for the recovery of iron values from the slime or lean ores.

OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to utilize low-grade iron ore or an iron ore tailing waste or pickle liquor or mill scale generated in a steel plant by a process involving leaching of iron value using sulphuric acid and such that the iron value so extracted can be subjected to further chemical treatment with metallic iron which would convert the ferric iron from the initial leaching stage to ferrous ion in a sulphate solution that can be further electrochemically reduced to metallic iron so as to adequately provide for a beneficiation process for recovery of metallic iron from iron bearing waste resources.
Another object of the present invention is to involve finely ground ore or slime to react with sulphuric acid where the ore fineness and acid concentration and the slurry agitation during extraction would ensure that more than 70% of the original iron values in the waste is recoverable by acid digestion.
Another object of the present invention is to provide for beneficiation process for recovery of metallic iron from iron bearing waste resources whereby silica-rich gangue material can be obtained especially in the siliceous ore such as banded hematite quartzite (BHQ) ore high in silica material that can be used as a raw material for cement plants or glass or ceramic for the foundry industry, whereby it can be ensured that the gangue is a value for another industry.
Another object of the present invention is to develop an select processing conditions that includes iron ore or slime of select particulate size, sulphuric acid of select concentration, the temperature of leaching, time of leaching, decanting of the liquor, stirring mechanism, that would all aid leaching to dissolve iron values from iron bearing waste resources such that more than 70% of the iron values in the original waste is recovered.
Another object of the present invention is to convert the ferric iron in the leach liquor to the ferrous iron at an optimum addition of iron scrap or DRI metallic fines of optimum content to the leach liquor containing ferric iron and sulphate ions, which eventually generates ferrous sulphate, whereby the ferric sulphate solution, which is greenish-yellow in color after digestion, is converted to a greenish-blue ferrous iron-containing sulphate solution, with the colour difference thus obtained being a visual quality parameter of progressin of the process, and with the quality of ferrous sulphate obtained being such that it forms solid ferrous sulphate salt when it was refrigerated to a temperature less than 0 oC.
Another object of the present invention is to provide for said beneficiation process whereby the ferrous sulphate solution so produced from the leach liquor can be subjected to electrolytic recovery, where solid iron metal can be electrodeposited at the cathode, with the electrolytic cell frame consisting of a cathode steel plate where Iron is deposited and an anode made of a lead plate wit the anode volume and cathode volume to be divided by a membrane, that would allow selective passage of Fe2+ ions.
Another objective of the present invention is to involve buffer solutions of sodium sulphate, potassium sulphate in said process to improve the conductivity of the ions in the electrolytes of the electrolytic cell along with the use of boric acid to improve the dissociation of ferrous sulphate and improve metallic iron recovery.
Another object of the invention is to provide for said beneficiation process where electricity for the electrolysis of ferrous sulphate to directly produce solid iron would involve an energy consumption of 6500 kWh/t, that would be attractive over the traditional pyrometallurgical extraction of iron being capital and energy-intensive process operation.
Another object of the present invention is to provide for a beneficiation process that would enable development of an iron extraction process with renewable energy and the developed process for iron extraction would be superior to hydrogen-based iron extraction as it would save the cost of hydrogen generation, storage, and usage, where higher infrastructural costs and efficiency losses are seen.

SUMMARY OF THE INVENTION

Thus according to the basic aspect of the present invention there is provided a beneficiation process for recovery of metallic iron from iron bearing waste resources as input material including a combination of hydrometallurgical and electrometallurgical process of recovery of iron values from waste resources comprising steps of:
(a) leaching iron values from provided iron bearing waste resources as input material with hot sulphuric acid at ˜200-210 oC such as to recover iron values from said iron bearing waste resources as ferric sulphate solution;
(b) adding metallic iron including Fe scrap or DRI fines to the thus separated iron bearing ferric sulphate in solution to thereby convert the ferric sulphate to ferrous sulphate solution suitable for electrometallurgical processing; and finally,
(c) subjecting said ferrous sulphate solution to electrolysis to recover therefrom the metallic iron values from said iron bearing waste resources.

Preferably in said beneficiation process for recovery of metallic iron wherein said iron bearing wastes/tailings involved as input material includes conventional lean iron ore, iron ore tailing of low grade BHQ ore, accumulated iron ore slime, pickle liquor from steel pickling plant and waste iron from mill scale reprocessing.

According to another preferred aspect of the present invention there is provided said beneficiation process for recovery of metallic iron having improved sustainability enabling viable extraction of high purity iron from lean iron sources as compared to existing beneficiation processes with said high purity iron attained thereby reduces/eliminates the need for coke based reduction process with the anode evolving oxygen ˜20000 L/ton during electrolysis additionally provides a greener environment.

Preferably said beneficiation process for recovery of metallic iron is provided wherein
said step (a) involves leaching iron values from said iron bearing waste resources as input material with 6N sulphuric acid thereby generating a residue for re-digestion of iron therefrom enabling quarterzite by-product,
wherein said residue post separation/ filtration to recover additional ferric sulphate solution for additional extraction of residual iron therefrom also enables recovery of gangue material from which 99% pure quartzite/ silica is recovered when low grade BHQ ore is initial waste input material that is suitable for cement industry or in glass industry, and when said gangue material is recovered from lean conventional ore as initial waste input material is suitable for paver blocks.

According to another preferred aspect of the present invention there is provided said beneficiation process for recovery of metallic iron wherein recovery of iron values from lean iron ore such as tailings of banded hematite quartzite (BHQ) generated in an ore beneficiation plant can be suitably leached to recover iron values in the ore as Ferric sulphate with an iron value 105 g/L with values as high as 80% of the original value that could be taken into solution,

Prefrably in present beneficiation process for recovery of metallic iron wherein conventional iron slime/ tailing of ore beneficiation processes with 6N sulphuric acid could digest iron from tailing into Ferric iron sulphate in acid solution to give ferrous sulphate based on addition of metallic iron with high Fe values as high as 87% leachable with acid, with the ferrous sulphate being suitable for electrolytic extraction of iron.

More preferably in said beneficiation process recovery of metallic iron enables iron beneficiation from the following:
pickle liquor generated in a hot rolling plant including scales rich in ferric and ferrous sulphate treated with said iron to convert the ferric sulphate to ferrous sulphate being suitable for electrolysis;
mill scale iron that is a by-product in a hot rolling mill digestable with sulphuric acid forming ferric sulphate that is convertible to Ferrous sulphate suitable for recovery of iron by aqueous electrolysis;
slime accumulated in iron and steel plant to effectively recover iron content from the same.

According to another preferred aspect of the present invention there is provided said beneficiation process for recovery of metallic iron wherein
said step (a) (i) of lean iron bearing waste resources provided as initial waste input material as feed for leaching includes solid feed with said solid feed including conventional lean iron ore, tailing from beneficiation of banded hematite quartzite ore (BHQ), mill scale, or mixtures thereof, wherein said solid feed is finely ground material from beneficiation plant having particle size is less than 150 microns with mill scale solid feed having less gangue material that is subjected to grinding to attain fine powder for faster dissolution with average particle size less than 100 microns;
said step (a) (ii) of leaching iron values from said iron bearing input waste resources/solid feed is carried out by subjecting said solid feed to digestion with hot 6N sulphuric acid at ˜200-210 oC for 6 hr duration by maintaining ore to acid solution ratio between 1.4-1.6 w/w for recovering iron values as greenish yellow ferric sulphate solution for visual quality measure and generating residue for re-digestion of iron therefrom towards quarterzite by-product generation;
said step (b) involves addition of excess scrap iron to said ferric sulphate solution to hydrometallurgically convert to bluish green ferrous sulphate solution enabling visual quality measure that is separated from the solids by decantation and filtration with the filtered ferrous sulphate being a feed material for electrolysis, wherein said feed material for electrolysis also including pickle liquor from the sulphuric acid pickling plant whereby directly ferrous sulphate liquor is obtained;
said step (c) involves subjecting said ferrous sulphate solution/combined ferrous sulphate solution by including pickle liquor from the sulphuric acid pickling plant to electrolysis at room temperature of 25-40 ?C in electrolytic cell including monopolar and bipolar cells having iron plate as cathode and lead as anode to recover therefrom solid iron at cathode of ˜99% purity and by-product oxygen at anode together with anolyte preferably sulphuric acid, wherein the anolyte can be combined for use in further leaching.

Preferably in said beneficiation process for recovery of metallic iron wherein for a quantity of waste iron ore input feed of 200 g/L, sulphuric acid of 300 g/L concentration was involved of strength 6N for leaching and digestion at temperatures of 200-210 deg for a duration of 6 hr, to which digested solution ferric sulphate solution 45 g /L of iron is added in the form of solid scrap to convert to ferrous sulphate solution.

More preferably said beneficiation process for recovery of metallic iron is provided wherein said electrolysis of ferrous sulphate is carried out in cells including monopolar and bipolar cells, with monopolar cells being single cells with a single cathode and anode connected with –ve and +ve direct current (DC), and wherein said bipolar cells includes ‘n’ number of cells separated by ion exchange membrane and bipolar electrodes with only the end cathode and end anode being connected with DC source with the bipolar electrodes free of any connection to the current source, wherein said DC current source is integrate able with nuclear power source or renewable power supply towards obtaining iron from solar or wind-generated electric power.

According to another preferred aspect of the present invention there is provided said beneficiation process for recovery of metallic iron wherein said process of electrolysis is carried out by involving buffer solutions including sodium sulphate, potassium sulphate to improve conductivity of the ions in the electrolytes of electrolytic cell along with involving boric acid to improve the dissociation of ferrous sulphate and improve metallic iron recovery, and
wherein in said process of electrolysis of ferrous sulphate to directly produce solid iron involves an energy consumption of 6500 kWh/t which is attractive over the traditional pyrometallurgical extraction of iron, being capital and energy-intensive process operation.

Preferably in said beneficiation process for recovery of metallic iron wherein Fe value % recovered from lean BHQ iron ore with composition Fe 43.28 %, 36.70, alumina 1.76 % is 80.066 % with the residue containing >75% silica, said silica based residue is leachable with concentrated 6N sulphuric acid at 200 oC to recover residual Fe and enrich silica in said residue to achieve silica of 98.52 % purity as quartzite that can be employed directly without further purification in cement, glass, ceramic and foundry applications.

The present invention differs from the prior art in using lean BHQ ore, slimes, pickle liquor and mill scale generated in the plant. The digestion method involves ferric sulphate formation in the first stage followed by conversion to ferrous sulphate. The ferrous sulphate so obtained could be used for extraction of Iron metal by aqueous electrolysis where solid high purity metal could be ontained. The process developed is a sustainable process which is good for steel plants to recover Fe from accumulating wastes in the steel plant. The electrolysis process conditions have some variation from the ferrowinn process.

DETAILED DESCRIPTION OF THE INVENTION/ EMBODIMENTS

As described hereinbefore, the present invention provides for a unique beneficiation process route for recovery of metallic iron from iron bearing waste resources as input material including a combination of hydrometallurgical and electrometallurgical process of recovery of iron values from waste resources in which process the iron values from the various lean resources and waste mentioned above in steel plants were first extracted using the hydrometallurgical leaching technique, where a significant amount of iron values could be taken into aqueous media. The iron values so obtained in aqueous media were suitably converted to ferrous sulphate. The ferrous sulphate so obtained was subjected to an aqueous electrolysis process route where metallic iron could be obtained. Thus, iron from low-grade resources could be successfully extracted as a pure solid iron, which bypasses the conventional iron extraction processes that involve energy-intensive iron extraction processes.
The presently invented process thus involves hydrometallurgical leaching of ore. The hydrometallurgical leaching processes ensure a large extent of iron value recovery as ferric ions. It is preferred to extract iron with preferably sulphuric acid where the ore digestion dissolves Fe values as Fe3+ ions. The solution containing ferric iron is treated with DRI fines and scrap, to convert ferric ions to ferrous ions. The ferrous ion-containing solution can be electrolyzed to recover solid Fe at the cathode as high purity iron beneficiated from lean iron sources as compared to existing beneficiation processes, and with said high purity iron attained thereby reduces/eliminates the need for coke based reduction process with the anode evolving oxygen ˜20000 L/ton during electrolysis additionally providing for a greener environment.
Finally, the aqueous ferrous sulphate is subjected to electrometallurgical processes to obtain the extraction of iron as solid metallic iron from aqueous ferrous sulphate.
The present invention extracts the low iron-rich solution by hydrometallurgucal means followd by electrolytic process to make metallic iron. The present process ensures upgradation of iron from low-grade slimes or ores. This mitigates, the effective recovery of iron from slimes and low-grade ores bringing an effective environmental solution. The process developed is effective in the conversion of iron to metallic iron, along with the separartion of gangue from the slime. In the case of siliceous iron ore such as BHQ ore, if the the iron content is significantly removed, the gangue material is pure silica. If high purity silica can be simultaneously extracted, it will be a useful raw material for cement plants. It can be further treated to make pure silica that may be used in the glass industry.

The present invention thus relates to a method of generating iron values from lean iron ore, tailings generated in the beneficiation process, or Fe in acid liquor generated by sulfuric acid pickling of iron bars or sheets or mill scale. The iron values in the form of oxides are dissolved in sulphuric acid to form sulphate salts of iron. The leaching is accelerated by having very finely ground ore or tailing or mill scale or an iron pickling liquor. For a typical quantity of iron ore of 200 g/L, a sulphuric acid of 300 g/L concentration and temperature was maintained at 200-210 deg C and the ore digestion was performed for a duration of 6 hr.
Ferrous sulphate by leaching, further ferrous sulphate is used in electrolysis for the extraction of iron. This process uses iron ore waste to produce pure iron, pure oxygen, and a useful silica-rich by-product is formed.

Brief description of the accompanying drawings:

Figure 1: illustrates view schematically showing a leaching setup to produce ferrous sulphate that is used in the extraction of pure iron and pure oxygen;

Figure 2(a): illustrates typical monopolar electrolytic cell for iron metal recovery;

Figure 2(b): illustrates typical bipolar electrolytic cell for iron metal recovery.

The process begins with the flow chart shown in Figure 1 schematically showing leaching setup to produce ferrous sulphate that is used in the extraction of pure iron and pure oxygen. The feed can be conventional lean iron ore, tailing from beneficiation of banded hematite ore or mill scale or pickle liquor using sulphuric acid as a pickle. The solid feed is usually finely ground material that comes from the beneficiation plant particle size is less than 150 microns. In the case of mill scale, it has less gangue material; it must be subjected to grinding to get fine powder for faster dissolution of average particle size less than 100 microns. The feed pickle liquor comes as ferrous sulphate in an acid pickling plant. The solid iron ore, BHQ ore, and mill scale are fine ground material that has particle size subjected to digestion with 6 N sulphuric acid. The ore to acid solution ratio was maintained between 1.4-1.6 w/w. The entire solids with acid are heated at 200-210 o C and allow the leaching to take place at a temperature of 200 deg C for a 6 hr duration. The Iron from the solids is transferred to ferric sulphate in the acid bath. The acid digestion should take place in a vessel that is not reactive to the acid plastic or FRP coated vessel may be used. After the ore is digested. After digestion, the solution appears greenish-yellow in color. To this solution, Fe 45 g /L is added in the form of solid scrap. The addition of solid Iron, which is available as scrap metal or direct reduced iron powder fines to the ferric sulphate bath. In presence of excess iron, ferric sulphate gets converted to ferrous sulphate. As a visual quality measure, the color change to bluish could be monitored.
The liquids containing iron values are separated from the solids by decantation and filtration. The filtered liquor is the feed material for electrolysis. It is also possible to use the pickle liquor from the sulphuric acid pickling plant where directly ferrous sulphate could be obtained. The color of the solution changes to a bluish-green color. A small fraction of the solution when it is refrigerated to a temperature less than 0 oC there is a light green ferrous sulphate obtained.
The ferrous sulphate liquid so obtained is subjected to room temperature electrolysis in an electrolytic cell. The cell used can be both monopolar or bipolar. A monopolar cell design is shown schematically in Figure 2. There are power leads that are connected to a DC rectifier. There are two compartments separated by an anion exchange membrane. The anode is made of Lead and the cathode is made of an iron plate.
In monopolar cells, single cells have a single cathode and anode connected with –ve and +ve DC. But the other side in bipolar cells has n number of cells separated by a membrane and only the end cathode and end anode are connected with DC remaining electrode not connected with the current. Heat loss from the cell can be decreased and the efficiency of space utilization is greatly improved compared to a single cell. The power consumptions also decrease unit basis. In figure 2(a) a typical monopolar electrolytic cell and 2(b) a bipolar electrolytic cell for the iron metal recovery from the aqueous solution have been shown. Monopolar and bipolar electrolytic cell parameter has been given in Table 1.

Table 1: The features of a monopolar electrolytic cell assembly
Parameters Monopolar cell Bipolar cell
Cell dimension 42.5*35*10.5 42.5*35*21
Cell material Acrylic sheet Acrylic sheet
Anode material Lead sheet Lead sheet
Anode dimension, L*W*T 40*25*3 40*25*3
Cathode material Steel sheet Steel sheet
Cathode dimension 40*25*1.5 40*25*1.5
Rectifier Voltage 20 20
Rectifier Current capacity 300 Ampere 500 Ampere
Rectifier power capacity 6000 W 10000 W
Contact resistance 0.005 ohm 0.0049 ohm
Membrane Ion exchange membrane Ion exchange membrane

The process conceived, uses direct current and produces iron metal directly. This process can be easily integrated with a renewable power supply and can create iron from solar or wind-generated electric power. This is a better process than the other processes being evolved based on hydrogen generation, initially, store the same and use the hydrogen for reduction of iron at high temperatures. There is an additional cost in hydrogen generation, storage, and use. All these are bypassed in the invented electrolytic iron recovery process.
In the conventional iron-making process there is coking coal or reductant coal required for the generation of impurity-containing hot metal. The processes are carried out in high-temperature furnaces. The invented process does not require the scarce coking coal requirement for iron making. While the processes involved with carbon reductants emit CO2, NOX, and SOX during reduction, the invented process does not require fossil fuel at all. Unlike the traditional process, the invented process gives oxygen to the anode, which greens the planet. For every one ton of metal extracted in the process, about 20000 Litre of oxygen is generated in the process, which can be collected and used for production applications. The environmental impact of the invented process drastically decreases.
In the conventional process route, there is a steel-making process from the initial iron made from the blast furnace route or direct reduced iron route. The steel-making process essentially removes the impurities present in the hot metal namely C, Si, Mn, S, and P. Steelmaking involves high-temperature oxidation of impurities and fluxing the impurities with lime in the refractory lined crucible. The invented process on the other hand saves the high level of infrastructure required for high-temperature operation. The energy required for extraction at high temperatures is brought down. The invented process does not require refractories, lime, and other fluxing agents. The solid iron obtained in the electrolytic process is purer than in the conventional process and is equivalent in purity to the steel made by the primary steel-making process by a basic oxygen furnace or an electric arc furnace.
In the actual steel-making process, molten steel is the end product, whereas the electrolytic process gives solid steel. The solid scrap obtained in the electrolytic process is suitable for induction melting or electric arc melting process to alloy with alloying requirements of alloyed steels. As the impurity content of electrolytic iron is very low, the requirement of refining time decreases and the requirement of fluxes and refractory would drastically decrease. Hence, the invented process has several advantages over the conventional steel-making process.
The invented entire process route can be also linked to a nuclear power source such as a pressurized heavy water reactor with 700 MW or 1000 MW types common in India. This can be linked to electrolytic cells to produce Iron.
A detailed description of the invention with reference to accompanying drawings and examples:
The present invention is directed to a method set up to use iron ore waste to produce ferrous sulphate and further this ferrous sulphate is used for the extraction of the pure iron and oxygen through electrolysis.
The experimental procedure and the observations made to implement the invention are described hereunder with the following illustrative example:

Example 1: Experiments with Iron Ore BHQ

In this experiment lean iron, containing BHQ iron ore has been used for the extraction of pure iron. BHQ contains Fe 43.28 %, 36.70, alumina 1.76 %. BHQ ore was ground in a ball mill and sieved to -150 microns. 1 kg BHQ ore of -150 micron dissolved in sulphuric acid 6 N, solution heated 206 oC for 310 min. Ferric sulphate separated from the solution, and in ferric sulphate solution 45g/65 g/L, Iron scrap/Iron DRI fines were added so that ferric sulphate will convert to ferrous sulphate. In a solution containing ferrous and ferrous ions, refrigeration will precipitate ferrous sulphate as the crystal of FeSO4.7H2O. Iron recovery achieved 80.66 % from Iron ore tailing waste slime to ferrous sulphate and residue contained silica % > 75. An electrolytic cell is used for the extraction of iron contains catholyte and anolyte.
The electrolysis for the extraction of pure iron is as follows. In 1-liter catholyte, the solution contains iron 104.73 g, boric acid 12.10 g, sodium sulphate 63.30 g, and another side 1-liter anolyte solution contains boric acid 12.1g and sodium sulphate 63.3g, catholyte PH 3.06, anolyte PH 4.82, the current density 0.053 A/cm2, Voltage 6.10, and temperature 41.80 deg C
Typical analysis of BHQ fines used as input in lab-scale trials for producing ferrous sulphate has been used in the extraction of iron size and chemical composition in the accompanying Table-2. Out of 43.28%, Fe content in the BHQ ore, the final Fe content of the ore is 8.37% Fe post leaching. This implies that 34.91 % of iron from the lean ore has been leached off. The LOI content is 10.48. It is not possible to achieve such a high level of iron extraction in any known conventional iron beneficiation process. Hence, leaching of lean iron ore is an effective means to recover Fe from lean grade ores. The silica content of the gangue remaining is about 75% with 10% moisture content. This silica can be leached with concentrated 6 N sulphuric acid at 200 oC to recover residual Fe and get a silica with 98.52 % purity. The quartzite produced can be directly used for cement or glass applications. It can be further purified and used in the glass, ceramic, or foundry industry. Leaching , electrolysis parameters have been given in Table-2, Table-3 and Table-4 , table -5 subsequently.

Table 2: Chemical Composition Before and after leached BHQ iron ore
Composition Raw Iron ore BHQ, % Leached iron BHQ ore waste,% Fe value recovered,%
Fe(T) 43.28 8.37 80.66
SiO2 36.37 74.62
Al2O3 1.76 0.43
LOI 0.92 10.48
Others 0.39 1.34

Table 3: Parameters of iron extraction by leaching from BHQ iron ore
Leaching Parameter Ferrous sulphate leached from iron ore tailing/Slime
Quantity of Iron ore, kg 1
Starting acid concentration 6 N
Solution color Light greenish
Initial Ferric Iron g/L 69.82
Initial solution PH 0.21
Iron scrap/DRI powder quantity added g/L 40 to 65
Final ferrous iron g/L 104.73
Temperature , degC 206
Time, min 310
Final solution PH 4.60
Final Colour Bluish green
Quality check Solid formed on refrigeration/Wet chemical
Chemical analysis FeSO4.7H2O % > 96

Table 4: Electrolysis condition iron values from BHQ iron ore
Electrolysis parameter Ferrous sulphate leached from iron ore BHQ
Anode Lead sheet
Cathode Steel sheet
Membrane Ion-exchange membrane
Catholyte, composition, pH Fe-104.73 g/L, Na2SO4 63.3 g/L, H3BO3 12.1 g/L
Catholyte, PH 3.06
Anolyte, composition Na2SO4 63.3 g/L, H3BO3 12.1 g/L
Anolyte, PH 4.82
Deposition rate g/min 2.16
Cell voltage, V 6.10
Cell current density, AMP/cm2 0.053
Current efficiency,% 90
Energy consumed, kWh/kg 6.60
Form of Iron Ferrite
Purity of Fe, % > 99
Temperature , degC 41.8

Table 5: Redigestion of silica again with fresh acid to produce high purity quartzite
Leaching Parameter Ferrous sulphate leached from iron ore tailing/Slime
Quantity of silica residue, kg 1
Starting acid concentration 6-8
Solution color Light Greenish
Initial Ferric Iron g/L 5.50
Initial solution PH 0.23
Iron DRI powder quantity added g/L 6
Final ferrous iron g/L 13.4
Temperature , degC 200
Time, min 310
Final solution PH 4.6
Final Colour Bluish-green
Quality check Solid formed on refrigeration/Wet chemical
Chemical analysis of silica residue (Dry) 98.52

Example 2: Experiments with Iron ore tailing/ slime

In this experiment, the iron ore tailing generated in steel plants, was used for the extraction of pure iron. Iron ore tailing consisted of Fe 44.15 %, SiO2 16.69 %, alumina 11.10 %, and other materials 9.14 %. Iron oxide in iron ore tailing exits in the form of Fe2O3. Iron ore tailing was ground in the ball mill and sieved under a 150-micron screen. 1 kg iron ore tailing/slime fines dissolved in 6 N sulphuric, solution heated 204 degC, for 308 minutes. The ferric sulphate formed is separated from the solution, and in ferric sulphate solution, 48/70 g/L of iron scraps/DRI fines were added so that ferric sulphate will convert to ferrous sulphate. Ferrous sulphate solution refrigeration precipitated in the hydrated crystal of FeSO4.7H2O. Iron recovery achieved 87.54 percentage from Iron ore tailing waste slime to ferrous sulphate and residue contained silica > 75 %. An electrolytic cell is used for the extraction of iron contains catholyte and anolyte.
The electrolysis for the extraction of pure iron is as follows. In catholyte, 1-liter solution contains iron 115.95 g, boric acid 12.20 g, and sodium sulphate 64.30 g, and another side 1-liter anolyte solution contains boric acid 12.20 g and sodium sulphate 64.3 g, catholyte 3.00, anolyte PH 4.80, current density 0.055 Amp/cm2, voltage 6.20, and temperature 41.10 deg C.
Typical analysis of iron ore tailing waste slime fines used as input in lab-scale trials for producing ferrous sulphate has been used in the extraction of iron size and chemical composition in the accompanying Table-6. Out of 44.15%, Fe content in the iron ore tailing/slime, the final Fe content of the ore is 5.50 % Fe post leaching. This implies that 38.65 % of iron from the lean ore has been leached off. The LOI content is 10.48. It is not possible to achieve such a high level of iron extraction from slime in any known conventional iron beneficiation process. Hence, the leaching of lean iron ore is an effective means to recover Fe from iron ore tailing/slime. The silica content of the gangue remaining is about 74.62% with 10% moisture content. This silica can be directly used for cement applications. It can be further purified and used in the glass, ceramic, or foundry industry. Leaching and electrolysis parameters have been given in Table-6, Table-7 and Table 8 subsequently.

Table 6: Chemical composition Before and after leached iron ore tailing/slime
Composition Iron ore tailing/slime, % Leached iron ore tailing/slime,% Fe value recovered from iron ore tailing/slime,%
Fe (T) 44.15 5.50 87.54
SiO2 16.69 75.11
Al2O3 11.10 2.50
LOI 7.40 9.90
Others 1.65 4.94

Table 7: Parameters of iron extraction by leaching from iron ore tailing/slime
Leaching Parameter Ferrous sulphate leached from iron ore tailing
Ore quantity 1 kg
Acid concentration 6 N
Initial PH 0.22
Solution color Light-greenish
Initial Ferric Iron g/L 77.30
Iron scrap / DRI powder quantity added g/L 48/70
Final ferrous iron g/L 115.95
Temperature , degC 204
Time, min 308
Final Colour Bluish-green
Final solution PH 4.50
Quality check Solid formed on refrigeration/Wet chemical
Chemical analysis FeSO4.7H2O % > 96.5

Table 8: Electrolysis condition iron values from iron ore tailing/slime
Electrolysis Parameter Ferrous sulphate leached from iron ore tailing/slime
Anode Lead sheet
Cathode Steel sheet
Membrane Ion-exchange membrane
Catholyte chemicals, composition Fe-115.90 g/L, Na2SO4 64.30 g/L, H3BO3 12.20 g/L
Catholyte, PH 3.00
Anolyte chemicals & composition, and PH Na2SO4 64.30 g/L, H3BO3 12.20 g/L
Anolyte, PH 4.80
Deposition rate g/min 2.21
Cell voltage, V 6.50
Cell current density, Amp/cm2 0.055
Current efficiency,% 91.00
Energy consumed, kWh/kg 6.50
Form of Iron Ferrite
Purity of Fe, % > 99
Temperature , oC 41.10

Example 3: Operation with ferrous sulphate obtained from sulphuric acid pickling route
In this experiment, pickled ferrous sulphate was used received from the pickling plant for the electrolysis. To remove the iron mill scale from the cooled rolled coil surface we used 10 -20% hot sulphuric acid. Iron mill scale on the surface mainly in the form of ferric oxide. Ferric oxide in the presence high concentration of sulphuric acid forms the ferrous sulphate. Bath solutions contain ferrous sulphate and sulphuric acid. Ferrous sulphate and the sulphuric acid mixture cooled and a crystal FeSO4.7H2O precipitated. Precipitated ferrous sulphate has 99% purity with small amount of sulphuric acid. This ferrous sulphate hydrated crystal has been used in an electrolytic cell for the extraction of iron contains catholyte and anolyte.
The electrolysis for the extraction of pure iron is as follows. In the extraction experiment 1 liter catholyte solution, contains iron 102.50 g in the form of ferrous sulphate, boric acid 11.30 g, sodium sulphate 62.20 g, and another side anolyte solution contains boric acid 11.30 g/L, sodium sulphate 62.20 g/L, and catholyte solution PH 3.06, anolyte solution PH 4.81, the current density 0.053 Amp/cm2, Voltage 6.20, and temperature 43.50 degC. Iron recovery achieved 91%, from pickled ferrous sulphate. The extraction of iron from aqueous ferrous sulphate solution by electrolysis parameters have been given in Table 9.
Table 9: Electrolysis condition iron values from pickled ferrous sulphate
Electrolysis Parameter Ferrous sulphate from the pickling route
Anode Lead sheet
Cathode Steel sheet
Membrane Ion-exchange membrane
Catholyte chemicals & composition, PH Fe-102 g/L, Na2SO4 62.2 g/L, H3BO3 11.3g/L,
Catholyte, PH 3.16
Anolyte chemicals, composition, and PH Na2SO4 62.2g/L, H3BO3 11.3g/L
Anolyte, PH 4.96
Deposition rate g/min 2.15
Cell voltage, V 6.50
Cell currentdensity, Amp 0.053
Current efficiency,% 89.70
Energy consumed, kWh/kg 6.60
Form of Iron Ferrite
Purity of Fe, % > 99
Temperature , degC 43.5

Example 4: Operation with ferrous sulphate obtained from mill scale
In this experiment iron mill scale, has been used for the extraction of pure iron. The iron mill scale contains Fe 68.33 %, silica 1.31%, alumina 0.328%, and 6.07% gain of ignition. The iron mill scale was ground in the ball mill and sieved under 150 microns. 1 kg iron mill scale under 150 micron dissolved in sulphuric acid 10 N, solution heated 205 degC for 306 min. Ferric sulphate was separated from the solution, and in ferric sulphate solution 70/100 g, Iron scrap/Iron DRI fines were added so that ferric sulphate will convert to ferrous sulphate. In Ferric sulphate solution on refrigeration, ferrous sulphate will precipitate in the crystal of FeSO4.7H2O. An electrolytic cell is used for the extraction of iron contains catholyte and anolyte.
In the extraction experiment 1-liter catholyte solution, contains iron 101.79 g, boric acid 11.20 g, sodium sulphate 62.10 g, and on another side 1-liter anolyte solution contains boric acid 11.2 g and sodium sulphate 62.1g, catholyte PH 3.12, anolyte PH 4.85, the current 0.053 A/cm2, Voltage 6.20, and temperature 43.20 deg C. Iron recovery achieved 99%, from pickled ferrous sulphate.
Typical analysis of mill scale fines used as input in lab-scale trials for producing ferrous sulphate has been used in the extraction of iron size and chemical composition in the accompanying Table-9. Out of 68.33%, Fe content in the iron mill scale, the final Fe content of the iron mill scale is 14.62% Fe post leaching or 99 % iron recovery achieved. Hence, leaching of mill scale iron ore is an effective means to recover Fe from lean grade ores. This silica can be directly used for cement applications. It can be further purified and used in the glass, ceramic, or foundry industry. Leaching and electrolysis parameters have been given in Table-10 , Table-11 and Table-12 subsequently.
Table 10: Chemical composition Before and after leached mill scale
Composition Iron mill scale, % The residue after leaching iron mill scale,% Fe value recovered,%
Fe(T) 68.33 14.62 99.00
SiO2 1.13 68.92
Al2O3 0.328 0.693
GOI/LOI 6.07 6.88
Others 0.84 1.07

Table 11: Parameters of iron extraction by leaching from mill scale
Parameter Ferrous sulphate leached from mil scale
Mill scale weight, g/L 102.50
Solution color Light-greenish
Initial Ferric Iron g/L 68.33
Final ferrous iron g/L 102.50
Iron scrap / DRI powder quantity added g/L 70/100
Temperature , degC 205
Time, min 306
Initial PH 4.70
Final Colour Bluish green
Quality check Solid formed on refrigeration/Wet chemical
Chemical analysis FeSO4.7H2O % > 96

Table 12: Electrolysis condition iron values from mill scale
Electrolysis Parameter Ferrous sulphate from the pickling route
Anode Lead sheet
Cathode Steel sheet
Membrane Ion-exchange membrane
Catholyte, composition Fe-101.79 g/L, Na2SO4 61.30 g/L, H3BO3 11.10g/L
Cotholyte, PH 3.12
Anolyte, composition Na2SO4 61.30g/L, H3BO3 11.10g/L
Anolyte, PH 4.85
Deposition rate g/min 2.15
Cell voltage, V 6.50
Cell current density, Amp 0.053
Current efficiency,% 89.9
Energy consumed, MJ/kg 6.70
Form of Iron Ferrite
Purity of Fe, % > 99
Temperature , degC 43.2

It is thus possible by way of the present invention to provide for a process for recovery of Iron values from lean iron ore such as banded hematite quartzite from waste tailings generated in an ore beneficiation plant that could be suitably leached with hot sulphuric acid at 200 oC, with 6 (N) concentration of sulphuric acid to recover iron values in the ore as Ferric sulphate with an iron value 105 g/L, with values as high as 80% of the original value could be taken into solution. The output of leaching gives iron containing residue that is redigested with acid with 6N concentration to dissolve once again with fresh acid to extract residual iron and giving quartzite as a by-product such that the quartzite is 99% pure. The final quartzite is suitable for use in cement industry or in glass industry. The leaching of conventional iron slime/ tailing which come from ore beneficiation with 6N sulphuric acid could digest iron into Ferric iron in acid solution. The residual iron from tailing to the conversion of Ferric sulphate to ferrous sulphate by addition of metallic iron. Fe values as high as 87% could be leached with acid. The ferrous sulphate so obtained is suitable for electrolytic extraction of iron.The pickle liquor in a hot rolling plant which removes the scale is rich with ferric and ferrous sulphate. The pickle liquor also could be treated with iron to convert the ferric culphate to ferrous sulphate which is suitable for electrolysis. Further mill scale is a by-product in a hot rolling mill which could be digested with sulphuric acid which forms ferric sulphate which could again be conveted to ferrous sulphate which is suitable for recovery of iron by aquous electrolysis. The processes where ferric sulphate is generated and converted to ferrous sulphate by hydrometallurgy could be successfully involved to extract high purity iron that enables recovery of slime accumulated in iron and steel plant to effectively recover iron content in that. The ferrous sulphate could be successfully used in aqueous electrolysis route to get metallic iron of 99% purity which can be produced. In a combined manner thus the proess of the present invention provides a good sustainability solution enabling extraction of high purity iron feasible from lean iron sources where existing beneficiation process cannot extract in a viable manner. The high purity iron making in the overall process developed reduces the need for coke based reduction process. In addition the anode evolves oxygen about 20000 L/ton during electrolysis which further gives an opportunity of a greener environment. , Claims:WE CLAIM:

1. A beneficiation process for recovery of metallic iron from iron bearing waste resources as input material including a combination of hydrometallurgical and electrometallurgical process of recovery of iron values from waste resources comprising steps of:
(a) leaching iron values from provided iron bearing waste resources as input material with hot sulphuric acid at ˜200-210 oC such as to recover iron values from said iron bearing waste resources as ferric sulphate solution;
(b) adding metallic iron including Fe scrap or DRI fines to the thus separated iron bearing ferric sulphate in solution to thereby convert the ferric sulphate to ferrous sulphate solution suitable for electrometallurgical processing; and finally,
(c) subjecting said ferrous sulphate solution to electrolysis to recover therefrom the metallic iron values from said iron bearing waste resources.

2. The beneficiation process for recovery of metallic iron as claimed in claim 1 wherein said iron bearing wastes/tailings involved as input material includes conventional lean iron ore, iron ore tailing of low grade BHQ ore, accumulated iron ore slime, pickle liquor from steel pickling plant and waste iron from mill scale reprocessing.

3. The beneficiation process for recovery of metallic iron as claimed in claims 1 or 2 having improved sustainability enabling viable extraction of high purity iron from lean iron sources as compared to existing beneficiation processes with said high purity iron attained thereby reduces/eliminates the need for coke based reduction process with the anode evolving oxygen ˜20000 L/ton during electrolysis additionally provides a greener environment.

4. The beneficiation process for recovery of metallic iron as claimed in claims 1-3 wherein
said step (a) involves leaching iron values from said iron bearing waste resources as input material with 6N sulphuric acid thereby generating a residue for re-digestion of iron therefrom enabling quarterzite by-product,
wherein said residue post separation/ filtration to recover additional ferric sulphate solution for additional extraction of residual iron therefrom also enables recovery of gangue material from which 99% pure quartzite/ silica is recovered when low grade BHQ ore is initial waste input material that is suitable for cement industry or in glass industry, and when said gangue material is recovered from lean conventional ore as initial waste input material is suitable for paver blocks.

5. The beneficiation process for recovery of metallic iron as claimed in claims 1-4 wherein recovery of iron values from lean iron ore such as tailings of banded hematite quartzite (BHQ) generated in an ore beneficiation plant can be suitably leached to recover iron values in the ore as Ferric sulphate with an iron value 105 g/L with values as high as 80% of the original value that could be taken into solution,

6. The beneficiation process for recovery of metallic iron as claimed in claims 1-5 wherein conventional iron slime/ tailing of ore beneficiation processes with 6N sulphuric acid could digest iron from tailing into Ferric iron sulphate in acid solution to give ferrous sulphate based on addition of metallic iron with high Fe values as high as 87% leachable with acid, with the ferrous sulphate being suitable for electrolytic extraction of iron.

7. The beneficiation process for recovery of metallic iron as claimed in claims 1-6 enabling iron beneficiation from the following:
pickle liquor generated in a hot rolling plant including scales rich in ferric and ferrous sulphate treated with said iron to convert the ferric sulphate to ferrous sulphate being suitable for electrolysis;
mill scale iron that is a by-product in a hot rolling mill digestable with sulphuric acid forming ferric sulphate that is convertible to Ferrous sulphate suitable for recovery of iron by aqueous electrolysis;
slime accumulated in iron and steel plant to effectively recover iron content from the same.

8. The beneficiation process for recovery of metallic iron as claimed in claims 1-7 wherein
said step (a) (i) of lean iron bearing waste resources provided as initial waste input material as feed for leaching includes solid feed with said solid feed including conventional lean iron ore, tailing from beneficiation of banded hematite quartzite ore (BHQ), mill scale, or mixtures thereof, wherein said solid feed is finely ground material from beneficiation plant having particle size is less than 150 microns with mill scale solid feed having less gangue material that is subjected to grinding to attain fine powder for faster dissolution with average particle size less than 100 microns;

said step (a) (ii) of leaching iron values from said iron bearing input waste resources/solid feed is carried out by subjecting said solid feed to digestion with hot 6N sulphuric acid at ˜200-210 oC for 6 hr duration by maintaining ore to acid solution ratio between 1.4-1.6 w/w for recovering iron values as greenish yellow ferric sulphate solution for visual quality measure and generating residue for re-digestion of iron therefrom towards quarterzite by-product generation;

said step (b) involves addition of excess scrap iron to said ferric sulphate solution to hydrometallurgically convert to bluish green ferrous sulphate solution enabling visual quality measure that is separated from the solids by decantation and filtration with the filtered ferrous sulphate being a feed material for electrolysis, wherein said feed material for electrolysis also including pickle liquor from the sulphuric acid pickling plant whereby directly ferrous sulphate liquor is obtained;
said step (c) involves subjecting said ferrous sulphate solution/combined ferrous sulphate solution by including pickle liquor from the sulphuric acid pickling plant to electrolysis at room temperature of 25-40 ?C in electrolytic cell including monopolar and bipolar cells having iron plate as cathode and lead as anode to recover therefrom solid iron at cathode of ˜99% purity and by-product oxygen at anode together with anolyte preferably sulphuric acid, wherein the anolyte can be combined for use in further leaching.

9. The beneficiation process for recovery of metallic iron as claimed in claims 1-8 wherein for a quantity of waste iron ore input feed of 200 g/L, sulphuric acid of 300 g/L concentration was involved of strength 6N for leaching and digestion at temperatures of 200-210 deg for a duration of 6 hr, to which digested solution ferric sulphate solution 45 g /L of iron is added in the form of solid scrap to convert to ferrous sulphate solution.

10. The beneficiation process for recovery of metallic iron as claimed in claims 1-9 wherein said electrolysis of ferrous sulphate is carried out in cells including monopolar and bipolar cells, with monopolar cells being single cells with a single cathode and anode connected with –ve and +ve direct current (DC), and wherein said bipolar cells includes ‘n’ number of cells separated by ion exchange membrane and bipolar electrodes with only the end cathode and end anode being connected with DC source with the bipolar electrodes free of any connection to the current source, wherein said DC current source is integrate able with nuclear power source or renewable power supply towards obtaining iron from solar or wind-generated electric power.

11. The beneficiation process for recovery of metallic iron as claimed in claims 1-10 wherein said process of electrolysis is carried out by involving buffer solutions including sodium sulphate, potassium sulphate to improve conductivity of the ions in the electrolytes of electrolytic cell along with involving boric acid to improve the dissociation of ferrous sulphate and improve metallic iron recovery, and
wherein in said process of electrolysis of ferrous sulphate to directly produce solid iron involves an energy consumption of 6500 kWh/t which is attractive over the traditional pyrometallurgical extraction of iron, being capital and energy-intensive process operation.

12. The beneficiation process for recovery of metallic iron as claimed in claims 1-11 wherein Fe value % recovered from lean BHQ iron ore with composition Fe 43.28 %, 36.70, alumina 1.76 % is 80.066 % with the residue containing >75% silica, said silica based residue is leachable with concentrated 6 N sulphuric acid at 200 oC to recover residual Fe and enrich silica in said residue to achieve silica of 98.52 % purity as quartzite that can be employed directly without further purification in cement, glass, ceramic and foundry applications.

Dated this the 1st day of August, 2023 Anjan Sen
Of Anjan Sen and Associates
(Applicants Agent & Advocate)
IN/PA-199