Claims:WE CLAIM:
1. A method for producing a manganese ore concentrate and a manganese rich sponge iron from ferruginous manganese ore, comprising steps of:
subjecting the ferruginous manganese ore to reduction roasting in presence of a reducing agent in a rotary kiln to obtain a roasted material,
wherein the ferruginous manganese ore comprises manganese (Mn) at a wt% of about 20 to 35, iron (Fe) at a wt% of about 24 to 34, silicon dioxide (SiO2) at a wt% of about 1.5 to 7.9, aluminum oxide (Al2O3) at a wt% of about 2.6 to 5.8, phosphorous (P) at a wt% of about 0.04 to 0.08 and sulphur (S) at a wt% of about 0.004 to 0.008 and a Mn/Fe ratio of about 0.6 to 1.4, and the ferruginous manganese ore has a particle size ranging from 0-12 mm;

crushing the roasted material; and

subjecting the crushed material to magnetic separation to obtain the manganese ore concentrate and the manganese rich sponge iron,
wherein the manganese ore concentrate comprises Mn at a wt% of about 40 to 51, Fe at a wt% of about 11 to 21, SiO2 at a wt% of about 4 to 9.74, Al2O3 at a wt% of about 3.84 to 7, carbon (C) at a wt% of less than 5.74%, and Mn/Fe ratio of about 2 to 5,
and the manganese rich sponge iron comprises Mn at a wt% of about 6.74 to 15.1, total iron [Fe(t)] at a wt% of about 55 to 71, SiO2 at a wt% of about 2.1 to 9, Al2O3 at a wt% of about 3 to 5.84, and C at a wt% of about 0 to 0.5.

2. The method of claim 1, wherein the ferruginous manganese ore has a Mn/Fe ratio of about 0.9 to 1.

3. The method of claim 1, wherein the reducing agent is coal, preferably a low ash coal comprising fixed carbon (FC) of about 40-50%, volatile matter (VM) of about 25-35%, ash content of about 10-20% and moisture content of about 5%; and wherein the coal has a particle size ranging from 0-10 mm.

4. The method of claim 1 or claim 3, wherein the coal:ferruginous manganese ore ratio of about 20:80 to 35:65 is employed during reduction roasting.

5. The method of claim 1 or claim 3, wherein about 50-70 wt% of coal employed during reduction roasting comprises a particle size of about 0-2 mm and is injected individually into the rotary kiln, and about 30-50 wt% of coal employed during reduction roasting comprises a particle size of about 2-12 mm which is injected along with the ferruginous manganese ore into the rotary kiln.

6. The method of claim 1, wherein the ferruginous manganese ore is fed into the rotary kiln at a feed rate of about 3 to 6 tons per hour (tph).

7. The method of claim 1, wherein the reduction roasting of the ferruginous manganese ore in the rotary kiln is carried out at a temperature between 400 ? to 1000 ? and for a time-period of about 4 to 8 hours.

8. The method of claim 1, wherein the air flow rate in the rotary kiln is kept between 330 m3/ton to 500 m3/ton of the ferruginous manganese ore.

9. The method of claim 1, wherein the crushing of the roasted material comprises screening the roasted material and crushing the screened material using an impact crusher to produce a material size of about 0 mm to 5 mm.

10. The method of claim 1, wherein the magnetic separation is carried out by passing the crushed material over magnetic separator at about 4000 to 6000 gauss magnetic intensity; and wherein said magnetic separation is carried out over two separate magnetic separators with the first separator receiving a material size of about 0 mm to 2 mm and the second separator receiving a material size of about 2 mm to 5 mm.

11. The method of claim 1, wherein said method provides a yield of about 40-60% of the manganese ore concentrate and about 20-40% of the manganese rich sponge iron.

12. The method of claim 1, wherein said method leads to a manganese recovery of about 70-78% in the manganese ore concentrate.

13. A manganese ore concentrate comprising Mn at a wt% of about 40 to 51, Fe at a wt% of about 11 to 21, SiO2 at a wt% of about 4 to 9.74, Al2O3 at a wt% of about 3.84 to 7, C at a wt% of about 2 to 5.74%, and Mn/Fe ratio of about 2 to 5, obtained by the method of claim 1.

14. A manganese rich sponge iron comprising Mn at a wt% of about 6.74 to 15.1, total iron [Fe(t)] at a wt% of about 55 to 71, SiO2 at a wt% of about 2.1 to 9, Al2O3 at a wt% of about 3 to 5.84, and C at a wt% of about 0 to 0.5, obtained by the method of claim 1.

Dated this 10th day of September 2018

DURGESH MUKHARYA
IN/PA-1541
Of K&S Partners
Agent for the Applicant(s)

To:
The Controller of Patents,
The Patent Office, at: Kolkata
, Description:TECHNICAL FIELD
The present disclosure is in the field of metallurgy, more particularly towards beneficiation of low-grade ores. The present invention provides a simple, economical and efficient method of reducing iron-rich manganese ore to produce valuable products including manganese ore concentrate and high manganese sponge iron.

BACKGROUND OF THE DISCLOSURE
Manganese (Mn) alloys are important constituent of steelmaking and are usually produced using manganese ores. The ores used to produce suitable grade Mn alloys contain Mn > 38 % and Mn/Fe >2.5. The Mn/Fe ratio is maintained by blending of different quality manganese and iron bearing materials such as ores, fines, sludges etc. Most of the manganese ores found in the world contain iron minerals also. The presence of iron (Fe) dictates quality of manganese ores and end use in ferroalloy production. The high Fe in manganese ore (Mn/Fe <2.5) increases the Fe percentage in ferroalloys which results in production of poor quality ferro or silicomanganese. Conventionally, this problem is controlled by blending of different Mn/Fe ores to produce suitable grade feed blend for ferroalloy production.

In many parts of world including India, iron rich manganese ores are abundantly available which have limited usability mainly due to the presence of excess iron. Beneficiation of these ores is the most acceptable method for upgrading these ores but similar mineralogical characteristics such as density, surface energy etc. of manganese and iron minerals imposes challenges for conventional beneficiation processes such as gravity, heavy media separation, floatation etc. Further, magnetic separation is known to be a suitable method to beneficiate the iron bearing minerals. However, said technique has also shown limited success because of the paramagnetic nature of manganese bearing mineral pyrolusite. Thus, paramagnetic iron minerals hematite is reduced into ferromagnetic mineral magnetite and metallic Fe to increase the difference in magnetic susceptibility for efficient magnetic separation.

Hence, it will be of great importance and lucrative to the industry if simpler, efficient and cost-effective methods are developed for beneficiation of low grade iron-rich/ferruginous manganese ores.

SUMMARY OF THE DISCLOSURE
The present disclosure relates to a method of producing manganese ore concentrate and manganese rich sponge iron from ferruginous/high iron-bearing manganese ore comprising steps of reduction roasting in a rotary kiln, crushing & sizing, and magnetic separation.

In an embodiment of the present method, the ferruginous manganese ore comprises Mn at a wt% of about 20 to 35, Fe at a wt% of about 24 to 34, SiO2 at a wt% of about 1.5 to 7.9, Al2O3 at a wt% of about 2.6 to 5.8, P at a wt% of about 0.04 to 0.08 and S at a wt% of about 0.004 to 0.008, and has a Mn/Fe ratio of about 0.6 to 1.4, preferably about 0.9 to 1. In another embodiment, the ferruginous manganese ore has a particle size ranging between 0-12 mm.

In yet another embodiment of the present method, the reduction roasting is carried out with coal as a reductant, and wherein said coal has a particle size ranging between 0-10 mm.

In still another embodiment of the present method, the coal:ferruginous manganese ore ratio of about 20:80 to 35:65, preferably 30:70 is employed during reduction roasting.

In still another embodiment of the present method, the ferruginous manganese ore is fed into the rotary kiln at a feed rate of about 3 to 6 tons per hour (tph).

In a further embodiment of the present method, the method provides a yield of about 40-60% of the manganese ore concentrate and about 20-40% of the manganese rich sponge iron. In another embodiment, the method results in a manganese recovery of about 70-78%.

The present disclosure further provides manganese ore concentrate obtained as the primary product of the present method, wherein said manganese ore concentrate comprises Mn at a wt% of about 40 to 51, Fe at a wt% of about 11 to 21, SiO2 at a wt% of about 4 to 9.74, Al2O3 at a wt% of about 3.84 to 7 , C at a wt% of about 2 to 5.74, and has a Mn/Fe ratio of about 2 to 5.

The present disclosure also provides a manganese rich sponge iron comprising Mn at a wt% of about 6.74 to 15.1, total iron [Fe(t)] at a wt% of about 55 to 71, SiO2 at a wt% of about 2.1 to 9, Al2O3 at a wt% of about 3 to 5.84, and C at a wt% of about 0 to 0.5, obtained as a by-product of the present method.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1 is a diagram illustrating the reduction roasting method of the present invention for production of pre-reduced manganese ore concentrate and manganese rich sponge iron.

DETAILED DESCRIPTION OF THE DISCLOSURE
As used herein, the phrases ‘ferruginous manganese ore’, ‘iron rich manganese ore’, ‘low-grade ferruginous manganese ore’ and ‘low-grade iron rich manganese ore’ are used interchangeably and refers to the input/feed material subjected to the method of the present disclosure.

As used herein, the phrases ‘manganese ore concentrate’, ‘pre-reduced manganese ore concentrate’, ‘manganese-rich ore concentrate’, and ‘non-magnetic manganese ore concentrate’, ‘manganese rich non-magnetic concentrate’, ‘sponge iron’, ‘high manganese sponge iron’ and ‘manganese rich sponge iron’ refer to the products of the present disclosure. In particular, manganese ore concentrate, pre-reduced manganese ore concentrate and manganese-rich ore concentrate are used interchangeably and refer to the primary product, whereas sponge iron and manganese rich sponge iron are used interchangeably which refers to the by-product obtained by the method of the present disclosure.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results. Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising” or “containing” wherever used, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The present disclosure is in relation to the beneficiation of low grade iron-rich manganese ores. An object of the present disclosure is to develop a reduction roasting based manganese ore beneficiation method for ferruginous manganese ores. More particularly, a simple, dry and coarse ore processing method is provided herein to produce pre-reduced manganese ore concentrate and high manganese sponge iron products with minimum impurities.

Another object of the present disclosure is to provide an energy efficient method to produce pre-reduced manganese ore concentrate of coarser size between 0-5 mm using low grade ferruginous manganese ores which can be employed in briquetting and sintering to produce manganese alloys.

Yet another object of the present disclosure is to develop a reduction roasting process which can use coal as a reductant and provide least contaminated product.

It is also an object of the present disclosure is to use the oxygen gas liberated by metal oxides during the reduction roasting method to achieve efficient metal oxide reduction at below 1000? to save energy and reduction time.

A further object of the present disclosure is to produce a sponge iron from the ferruginous manganese ore with minimum manganese impurities.

Accordingly, the present disclosure provides a method for manganese ore upgradation, more particularly, upgradation/beneficiation of ferruginous manganese ores with high iron content (>22%). In particular, the present disclosure relates to a method for reduction of high iron bearing manganese ores in a rotary kiln, metallization and separation of manganese and iron oxides. The method includes raw material feed preparation, reduction, crushing & sizing and magnetic separation to generate manganese ore concentrate and high manganese sponge iron from ferruginous manganese ores.

The process of ferruginous manganese ore processing has been developed in the present disclosure which can treat the ferruginous manganese ores having an exemplary composition comprising Mn : 24-35 %, Mn/Fe : 1 to produce a pre-reduced manganese ore concentrate comprising Mn : 40-51 %, Mn/Fe : 2- 5 and a manganese rich sponge iron comprising Mn : 6.74-15.1 %, Fe(t) : 55-70%, Fe(metal) :40-50%. In particular, the process steps comprises reduction roasting of manganese ore fines having a particle size of about 0-12 mm in a rotary kiln in presence of low ash thermal coal (FC: about 40-50%, VM: about 25-35%, ash: about 10-20% and moisture: about 5%), crushing the roasted material into 0-5 mm size, and magnetic separation of the material at 4-6k gauss intensity. In an exemplary embodiment, the coal composition, particle size and partial pressure of oxygen is designed to minimize the unburnt coal and energy efficient reduction of iron and manganese minerals. More particularly, the present method comprising roasting, crushing and magnetic separation, along with operating parameters including temperature, particle size, air flow rate and magnetic intensity are designed to minimize the unburnt coal in the pre-reduced manganese ore concentrate and recovery of manganese rich sponge iron as a by-product.

In an exemplary embodiment, the present method of producing pre-reduced manganese ore concentrate and manganese rich sponge iron from low grade ferruginous manganese ores is illustrated in Figure 1. As shown in Figure 1, the present method comprises crushing of ore and coal (1A, 2A, 1B, 2B) followed by reduction roasting of suitable input blend in rotary kiln (3). The roasted product is passed through crushing and screening system (5, 6, 7), followed by a magnetic separation systems (8, 9). The process design additionally comprises a coal fines injection system (2E), a cooler for cooling the reduced material (4), and product storage bins (10, 11).

In another exemplary embodiment, the method of the present disclosure is carried out as follows: The low-grade manganese ore lumps of about 0-70 mm having a composition of Mn: 27-35%, Fe: 24-32%, SiO2: 1.53-4.43%; Al2O3: 2.65-3.95%, P: 0.04-0.06% are fed into the process flow sheet/system depicted in Figure 1. These ore lumps are crushed to <12 mm and stored in a bunker. The low-medium ash steam coal of 0-50 mm are used as a reducing agent and this material is also crushed to 0-10 mm. The crushed coal fines are screened at 2 mm and fines are stored in a different hopper to charge into the kiln through a burner. Particle size distribution and coal injection play very vital role to achieve the desired grade products. The presently developed method deals with fines in the feed without affecting the process efficiency. The method can process fines of 0-12 mm (D50 : 3-7mm). This is achieved in the present method due to employment of a temperature below 1000? which optimizes the iron metallization and avoiding use of the flux (such as dolomite) which helps in minimizing the crust formation during handling of fines. The preferred roasting temperature in rotary kiln at different zones range from about 400-1000 ?. The coal feed rate is kept at about 20-35% with respect to the ore feed. Further, 50-70% of the coal is injected in the form of particles of about 0-2 mm through burner at the end of the kiln and 30-50% of the coal is fed in the form of particles of about 2-12 mm along with the ferruginous manganese ore particles. Coal plays a vital role during this process and unburnt coal within the employed input coal can contaminate the final product quality. In the present disclosure, the experimental studies with coal size and input ferruginous manganese ore composition further resulted to bring down the unburnt carbon in the final product to <5%. Additionally, during the method, the manganese present in the ores decompose during reduction roasting and increase the oxygen concentration inside the rotary kiln. In a preferred embodiment, the feed rate of ferruginous manganese ores is kept between 3 to 6 tonnes per hour (tph). One ton of ferruginous manganese ores contain 250 to 320 kg MnO2 which liberates about 150 to 360 kg/hour oxygen. This additional oxygen increases the oxygen concentration from 21 to 41 % which increases the rate of reduction of coal and helps to liberate more heat in short time span. This further reduces the ignition time and temperature of coal. This process feature finally reduces the unburnt coal in the final product.

The present disclosure further relates to products including manganese ore concentrate and manganese rich sponge iron, respectively, obtained by the method of the present disclosure. In particular, the present disclosure provides a manganese ore concentrate having a composition comprising Mn: 47.58-50.96%; Fe: 14.60-14.99%, SiO2: 4.89-7.1%, Al2O3: 4.63-5.09%, C: 2.95-5.73%; and a manganese rich sponge iron having a composition comprising Mn: 8.2-15.1%, Fe(t): 60.1-65.2%, SiO2: 2.1-4.5%, Al2O3: 3.1-4.8%, C: 0.5%.

The present disclosure is thus successful in providing a simple and efficient method of beneficiating low-grade ferruginous manganese ore having composition as described herein to yield useful products i.e. manganese ore concentrate and manganese rich sponge iron. Said products are immensely useful and can be employed in different industries, especially in manganese alloy preparation and steel making. In particular, the developed non-magnetic fraction (pre-reduced manganese ore concentrate) is suitable for preparation of high grade manganese alloys and the magnetic fraction (manganese rich sponge iron) can be used as an alternative of sponge iron in foundry industry. Additionally, the present method has numerous advantages compared to the conventional methods of beneficiating/upgrading low-grade ferruginous manganese ores. For instance, the conventional processing methods of manganese pre-reduction and iron reduction usually requires a temperature of more than 1100?, and most of the conventional methods are limited to laboratory scale results and thus lack scaling-up to industrial production. However, successful results were achieved consistently by the present method in a commercial rotary kiln at below 1000? which further confirms efficient reduction of the input ores.

In an embodiment, the foregoing descriptive matter is illustrative of the disclosure and not a limitation. 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. 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.

EXAMPLES

EXAMPLE 1: Reduction method using lumpy medium grade ferruginous manganese ores with an Mn content of 30-34% and Mn/Fe ratio of >1
Experiments were performed using manganese ore lumps of 0-75 mm size having compositions of Mn: 27-35%, Fe: 24-32%, SiO2: 1.53-4.43%; Al2O3: 2.65-3.95%, P: 0.04-0.06%. The ores were fed to crusher for sizing to obtain 0-12 mm (D50 :7mm) sized material which was then fed to commercial scale rotary kiln of 30m length, 2.1m internal diameter and 1:40 slope. The feed rate of the material was kept at three different levels 3, 4.5 and 6 tph to control retention time. The kiln was supplied low ash coal (FC content of 40-50%, VM content of 25-35%, ASH content of 10-20%) of 2-12 mm at three different feed rates 25, 30, and 35 % of the ore feed. The coal fines of 0-2 mm were fed through burner in the reduction zone of kiln. Since unburnt coal in the product is a contaminating material and needs to be minimized, the present method employed a 30:70 ratio of coal:ore which controlled the unburnt coal, and the unburnt coal in the product was brought down to <5 %. As mentioned above, the feed rate of manganese ores were kept between 3 to 6 tph which liberated 150 to 360 kg/hour additional oxygen. This additional oxygen increased the oxygen concentration from 21 to 41 % which further increased the rate of oxidation of coal and help in liberating more heat in short time span. Further, it provides more CO at lower temperature for reduction of metal oxides. It also reduces the ignition time and temperature of coal. Thus, the present process reduced the unburnt coal in the product. The air flow rate was kept between 330 m3/ton to 500 m3/ton of ore. The roasted material was passed through a cooler of 15m length and 1.5m dimeter. The cooled product was screened into two different sizes 0-2 mm and 2-5 mm. These size fractions were passed over separate magnetic separators at 4k gauss magnetic intensity. The experiments yielded desired results/products. Further, the analysis of results indicated that best results were achieved with 3 tph & 25 % coal and 4.5 tph & 29% coal. Temperature in the kiln was maintained between 400- 950? in different zones. Said temperature is relatively low from the conventional sponge iron making processes. The main reason of employing the above temperature range in the present process is to avoid crush formation in the kiln while processing of fines. Further, the objective of the reduction is to get an optimum combination of magnetic iron bearing phases such as Fe(m), FeO and Fe3O4.

Two products which can be further used in manganese alloy production and steel making were produced. The chemical analysis of the product was conducted which revealed a major product of pre-reduced manganese ore concentrate having Mn: 47.58-50.96%; Fe: 14.60-14.99%, SiO2: 4.89-7.1%, Al2O3: 4.63-5.09%, C: 2.95-5.73%. Mn content of these ores were improved by about 17-19 % and Mn/Fe was improved up to 3.5. The product yield was about 47-55 % and the Mn recovery from the initial ferruginous manganese ore was about 70-78 %. The yield of the by-product (high Mn iron sponge) was 22-27% and it was composed of Mn: 8.2-15.1%, Fe(t): 60.1-65.2%, SiO2: 2.1-4.5%, Al2O3: 3.1-4.8%, C: 0.5%. The nonmagnetic manganese ore concentrate is a unique product produced by this route and mainly contains pre-reduced manganese oxide with MnO: 50-70%, Mn3O4: 10-30%; MnO2: 10-20% and metallic iron [Fe(m)] in this material can reduce energy and coke consumption in the ferroalloy production process. This material can be further used to produce high Mn ferroalloys (HC FeMn, LC FeMn, SiMn, etc.). The magnetic sponge iron material produced contains MnO and Fe(m) which can be used as a raw material in induction furnace which can provide Mn as an alloying agent as well as it’s use as low cost sponge iron for steel manufacturing.

EXAMPLE 2: Reduction method using lumpy low grade ferruginous manganese ores with an Mn content of 25-28% and Mn/Fe ratio of <1
Experiments were conducted with manganese ore lumps of 0-75 mm size with compositions of Mn: 24.59-28.54%, Fe: 29.34-33.43%, SiO2: 3.74-6.73%; Al2O3: 3.33-5.41%, P: 0.04-0.08 %. The ores were fed to crusher for sizing and 0-12 mm (D50: 4mm) sized material was fed to rotary kiln. The feed rate of the material was kept at three different levels 3, 4.5 and 6 tph to control retention time. The kiln was supplied low ash coal (FC content of 40-50%, VM content of 25-35%, ASH content of 10-20%) of 2-12mm size at three different feed rates 25, 30, 35 % of ore feed. The coal fines of 0-2 mm were fed through burner in the reduction zone of kiln. Coal was fed at a ratio of about 30:70 of coal:ore through burner. The roasted material was passed through a cooler. The cooled product was screened into two different sizes similar to the procedure of Example 1. These sized fractions were passed over separate magnetic separators at 4k gauss magnetic intensity. The chemical analysis of the product revealed compositions of Mn: 40-46.24%, Fe: 15.74-21%, SiO2: 4.86-9.74%, Al2O3: 3.84-6.71%, C: 2 -5%. Mn content of these ores was improved by about 11-17% and Mn/Fe was improved up to 2.5. The product yield was about 45-50% and Mn recovery was about 70-75 %. The yield of the by-product (high Mn sponge iron) was about 23-28% and it was composed of Mn: 6.74-14.87%, Fe: 62-71.26%, SiO2: 4.79-8.81%, Al2O3: 3.21-4.78%, C: 0.5. The nonmagnetic manganese ore concentrate is a unique product produced by this route and it mainly contained pre-reduced manganese oxide (MnO: 50-70%, Mn3O4: 10-30%, MnO2: 10-20%) and metallic iron [Fe(m)] of this material can reduce energy and coke consumption in the ferroalloy production process. The magnetic material (high Mn sponge iron) is also a unique product containing MnO and Fe(m) which can be used as a raw material in induction furnace which can provide Mn as an alloying agent as well as it’s use in low cost sponge iron for steel manufacturing.

EXAMPLE 3: Reduction method using low grade ferruginous manganese ore fines with an Mn content of 25-28% and Mn/Fe ratio of about 1
Experiments were conducted with manganese ore fines of 0-15 mm size having compositions of Mn: 25.54-27.47%, Fe: 26.88-29.25%, SiO2: 6.13-7.91%; Al2O3: 4.71-5.85%, P: 0.04-0.08%. Said ores were fed to crusher for sizing and 0-12 mm (D50: 3mm) material was obtained which was fed to rotary kiln. The feed rate of the material was kept at three different levels 3, 4.5 and 6 tph to control retention time. The kiln was supplied with low ash coal (FC: 40-50%, VM: 25-35%, ASH: 10-20%) of 2-12 mm at three different feed rates 25, 30 and 35 % of ore feed. The coal fines of 0-2 mm were fed through burner in the reduction zone of kiln. Coal was fed at a ratio of 30:70 ratio of coal:ore through burner. The roasted material was passed through a cooler. The cooled product was screened into two different sizes as described in Example 1. These sized fractions were passed over separate magnetic separators at 4k gauss magnetic intensity.

The chemical analysis of the major product revealed a composition of Mn: 45-46%, Fe: 11.70-14.67%, SiO2: 7.80-8.33%, Al2O3: 5.1-6.71%, C: 2-4%. Mn content of these ores were improved by about 13-17% and the Mn/Fe was improved up to 4. The product yield was about 45-50% and the Mn recovery was about 70-77%. The yield of high Mn sponge iron was about 25-30 % and it was composed of Mn: 7.27-10.44%, Fe: 61.36-65.71%, SiO2: 5.87-7.91%, Al2O3: 4.41-5.84%, C: 0.5. The nonmagnetic ore concentrate is a unique product produced by this route and it mainly contained pre-reduced manganese oxide (MnO: 50-70%, Mn3O4: 15-30%; MnO2: 15-20%) and metallic Fe(m) in this material can reduce energy and coke consumption in the ferroalloy production process. The magnetic material (high Mn sponge iron) is also a unique product containing MnO and Fe(m) which can be used as a raw material in induction furnace which can provide Mn as an alloying agent as well as low cost sponge iron for steel manufacturing.

The present method is therefore successfully able to achieve efficient reduction of ferruginous manganese ores to yield valuable products viz. non-magnetic fraction of manganese ore concentrate and a magnetic fraction of high manganese sponge iron. Said products have multiple utilities as discussed above, especially in ferroalloy production and steel making. The present method is easily translatable to industrial scale economically without much complications.