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Article

Selective Reduction of Iron from Iron–Manganese Ore of the Keregetas Deposit Using Hydrogen

by
Nurlybai Kosdauletov
1,2,
Assylbek Nurumgaliyev
1,*,
Bakyt Zhautikov
1,
Bakyt Suleimen
1,2,
Galymzhan Adilov
1,2,*,
Bauyrzhan Kelamanov
3,
Konstantin Smirnov
2,
Talgat Zhuniskaliyev
4,
Yerbol Kuatbay
1,
Gulzat Bulekova
1 and
Assylbek Abdirashit
3
1
Department of Metallurgy and Materials Science, Karaganda Industrial University, Temirtau 101400, Kazakhstan
2
Department of Pyrometallurgical and Foundry Technologies, South Ural State University, Lenin Prospekt 76, Chelyabinsk 454080, Russia
3
Department of Metallurgy and Mining, K. Zhubanov Aktobe Regional University, Aktobe 030000, Kazakhstan
4
Department of Science, Eurasian Technological University, Almaty 050000, Kazakhstan
*
Authors to whom correspondence should be addressed.
Metals 2025, 15(7), 691; https://doi.org/10.3390/met15070691
Submission received: 6 May 2025 / Revised: 4 June 2025 / Accepted: 18 June 2025 / Published: 20 June 2025
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Abstract

:
This study presents the results of the solid-state reduction of iron–manganese ore from the Keregetas deposit (Kazakhstan) using hydrogen as a reductant. The findings demonstrate that hydrogen is an effective and environmentally friendly reducing agent, enabling selective reduction of iron. The investigated iron–manganese ore exhibits a complex mineralogical composition comprising oxides of Fe, Mn, Si, and aluminosilicate complex phases. X-ray diffraction (XRD) analysis of the raw ore confirmed the presence of goethite, hematite, quartzite, and MnO2 as the primary mineral phases. Oxidative roasting induced the dehydration of goethite and its conversion to hematite, along with the formation of Mn2O3 and Mn3O4 phases. The detection of Mn7SiO12 indicates interaction between manganese and silica under high-temperature oxidation conditions. Reduction experiments were conducted in an RB Automazione MM 6000 laboratory furnace at temperatures ranging from 700 to 1100 °C, with a holding time of 60 min and a hydrogen flow rate of 0.5 L/min. Results revealed high selectivity of hydrogen reduction: at 700–800 °C, iron and arsenic were predominantly reduced, as evidenced by the emergence of a metallic Fe-containing phase, while oxides of Mn, Si, Ba, and Al remained in the residue. Increasing the temperature to 900–1000 °C resulted in partial reduction of manganese. At 1100 °C, a decrease in the intensity of the metallic phase was observed, likely due to sintering of ore particles and reduced gas permeability. The reduced metal and oxides were readily separable by melting. These findings provide a basis for developing processing schemes for beneficiation and hydrometallurgical treatment of iron–manganese ores from Kazakhstan.

1. Introduction

Hydrogen is becoming increasingly popular as a clean energy source, and according to IRENA’s projections, it could account for 12% of global energy consumption by 2050. Developed countries, particularly in the EU, are actively developing hydrogen production facilities. Kazakhstan also aims to establish its position in this sector. In October 2024, Kazakhstan approved the Hydrogen Energy Development Concept until 2030, which considers hydrogen a key element in the transition to a low-carbon economy and the decarbonization of industrial processes and transport [1]. One of the main initiatives is a hydrogen production hub in the Mangystau region, initiated by the German–Swedish company Svevind Group. The USD 50 billion project includes the construction of a desalination plant with a capacity of 255,000 cubic meters per day, renewable energy stations (wind and solar) with a total capacity of 40 GW, and a 20 GW water electrolysis unit. The water for the project is planned to be sourced from the Caspian Sea. Additionally, the possibility of using groundwater for hydrogen production is being considered by “KazMunayGas Engineering” [2].
Hydrogen can serve as an alternative reducing agent for iron in the processing of iron–manganese ores [3,4,5,6]. The reduction of iron by hydrogen-containing gases from various types of ores, such as hematite, magnetite, and titaniferous ores, has been extensively studied in several works [7,8,9,10,11,12]. Hydrogen possesses a number of significant advantages over traditional carbon-based reductants when processing complex ores [13,14,15,16,17]. Primarily, it enables a cleaner reduction process: the reaction byproduct is water vapor rather than carbon dioxide, making the process more environmentally friendly and aligned with the goals of decarbonizing metallurgy. Moreover, hydrogen is characterized by a high reducing ability and can selectively reduce iron without reducing manganese, which is especially important when working with iron–manganese ores. This allows control over the phase composition of the final products and reduces energy consumption in subsequent component separation. Hydrogen also contributes to lowering the temperature of reduction processes, which positively impacts the economy and energy efficiency of production. Additionally, manganese ores from Kazakhstan have low quality due to the high impurity contents of iron and silicon [18]. Processing such ores by conventional methods in blast furnaces or electric reduction furnaces is either impossible or inefficient [19]. In the blast furnace smelting of ferromanganese, a significant portion of impurities contained in the raw materials transfers into the final metallurgical product. The main disadvantage of the electrothermal process is its high energy intensity and large manganese losses [20].
The physical beneficiation of iron–manganese ores is a method that allows for the separation of different minerals based on their density and magnetic properties [21,22,23,24]. However, due to the complex mineralogical structure of iron–manganese ores, separation of iron and manganese using physical methods alone is insufficient [25,26]. Chemical methods used to separate manganese minerals from iron are based on the use of different reagents [27,28,29,30,31,32,33].
Currently, carbothermic reduction is a relatively well-established method for processing iron–manganese ores. However, it has several significant drawbacks, including a relatively low manganese recovery rate (not exceeding 85%) and substantial carbon dioxide emissions, making this method environmentally disadvantageous [34,35].
Previously, in [36,37,38,39], we demonstrated the feasibility of pyrometallurgical separation of iron–manganese ores using a two-stage scheme. The scheme included the reduction of iron and phosphorus using a gaseous reductant with low reactivity, such as carbon monoxide (CO). This was followed by rapid separation melting of the reduction roasting product, which increased efficiency and optimized the technological process. The use of gaseous reductants such as carbon monoxide (CO) in industrial processes may have significant negative environmental consequences. One key aspect requiring particular attention is the potential formation of carbon monoxide (CO) due to incomplete combustion or reduction reactions. Carbon monoxide is a highly toxic substance that poses a serious threat to living organisms and contributes to smog formation in urban areas. Furthermore, the use of gaseous reductants leads to greenhouse gas emissions, including carbon dioxide (CO2). These emissions play a crucial role in global warming and climate change processes, which in turn have profound impacts on the planet’s ecosystems. To minimize the negative environmental impact and ensure sustainable development of industrial processes, it is necessary to develop and implement innovative technologies for processing iron–manganese ores using hydrogen. Hydrogen, as an environmentally friendly reductant, holds significant potential to reduce harmful emissions and decrease the carbon footprint of industrial processes.
The aim of this study is to investigate the selective reduction of iron from iron–manganese ores using hydrogen, with the goal of obtaining metallic iron and a concentrate of manganese oxides.

2. Materials and Methods

For the experiment on selective reduction of iron, the original ore from the Keregetas deposit (Kazakhstan) was used. Before the experiment, the ore was carefully ground in a mill (IDA-175) to a particle size of less than 1 mm. This enabled homogenization of the chemical composition. Then, the ore was mixed with water to give it a certain form. Afterward, the ore was dried in a drying oven at 150 °C for one hour to remove excess moisture.
The solid-state reduction of the iron–manganese ore was carried out in a laboratory setup—a vertical furnace RB Automazione (Genoa, Italy), model MM 6000 (Figure 1). This equipment is designed for reduction experiments of iron-containing materials. Ore samples weighing up to 30 g were placed in a reaction tube made of heat-resistant steel (AISI 310) with a diameter of 75 mm. The temperature regime was maintained by a system of five independently controlled heating zones with silicon carbide heaters, allowing precise temperature control throughout the working zone of the furnace. Reduction was performed at temperatures of 700, 800, 900, 1000, and 1100 °C with a holding time of 60 min. The reducing atmosphere was created by supplying gaseous hydrogen at a flow rate of 0.5 L/min, controlled by a digital mass flow controller. The furnace is equipped with an automatic control system and a touch panel, enabling programming of the temperature profile, parameter logging, and real-time recording of sample mass loss.
Hydrogen, used as the reducing agent, had a high purity degree, complying with the GOST 3022-80 standard [40], with a main component content of no less than 99.99%. High-purity argon gas, meeting the requirements of GOST 10157-2016 [41], was used as an inert gas. This argon is characterized by a purity of no less than 99.993%.
For qualitative phase composition analysis, a JEOL JSM-7001F scanning electron microscope (JEOL, Tokyo, Japan) was used, equipped with an OXFORD X-Max 80 energy-dispersive X-ray detector (Oxford Instruments, Abingdon, UK) for elemental composition determination. The microscope provides a high resolution up to 1.2 nm at an accelerating voltage of 30 kV, allowing detailed investigation of the microstructure and phase distribution on the sample surface. Secondary and backscattered electrons generated by the interaction of the primary electron beam with the sample surface served as the signal sources. The analysis was conducted in both point and area modes, enabling determination of the chemical composition of phases and inclusions. The obtained data were processed using the microscope’s integrated software, ensuring high accuracy and reproducibility of results.
The phase composition of the initial and reduced samples was studied using X-ray diffraction (XRD) on a Rigaku Ultima IV diffractometer (Rigaku, Tokyo, Japan). The instrument is equipped with a copper anode X-ray tube (Cu Kα, λ = 1.5406 Å). The tube voltage and current were set to 40 kV and 30 mA, respectively. Data acquisition was performed at a scan rate of 5° per minute over a 2θ range from 5° to 90°. Powdered samples, ground to a particle size below 0.063 mm, were used for the analysis. Samples were mounted on standard flat sample holders to minimize alignment errors. The obtained data allowed identification of major mineralogical changes in the ore after roasting. New oxide and silicate phases were formed. The results were interpreted using the Match software (Crystal Impact, Bonn, Germany), which identifies crystalline phases from XRD data using the PDF2 2009 crystallographic database.
The iron–manganese ore from the Keregetas deposit (Kazakhstan), characterized by a relatively high iron content, was used as the raw material. The deposit is located in the Zhanaarka district of the Karaganda region and was discovered in 1943. As of 1 January 2015, the balance reserves of manganese ores at the site amounted to 1258.1 thousand tons, and the deposit is currently at the exploration stage.
The ores of this deposit are unique in composition: they contain a variety of minerals including iron, manganese, silicon, barium, potassium, and aluminum, which form a complex textural and structural pattern. Additionally, the presence of significant amounts of phosphorus or arsenic is common, complicating the processing of the ore.
To average the chemical composition and determine the mean elemental content, the raw ore was melted in a corundum crucible in a Nabertherm resistance furnace at a temperature of 1650 °C, and rapidly cooled by casting into a metallic mold. The quenched material was analyzed using a JEOL JSM-7001F scanning electron microscope equipped with an OXFORD X-Max 80 energy-dispersive detector for elemental composition analysis.
The average chemical composition, determined after melting and quenching the ore to homogenize its composition, is presented in Table 1.
Figure 2 shows the X-ray diffraction (XRD) analysis of the original ore, conducted using a Rigaku Ultima IV diffractometer and “Match 3.0” software. The analysis revealed that the main phases of the raw ore are goethite (FeO(OH)), hematite (Fe2O3), manganese dioxide (MnO2), a combined manganese–iron oxide phase (FeMnO3), and silicon dioxide (SiO2). The peak intensities of other phases in the diffraction pattern were relatively low, which made it difficult to accurately identify phases containing K, Al, As, and Ba.
Changes occurring in the ore during heating in an air atmosphere were examined. For this purpose, uniform lump samples of iron–manganese ore from the Keregetas deposit were placed in a corundum crucible and heated in a Nabertherm muffle furnace at a rate of 200 °C per hour up to a temperature of 1000 °C, where they were held for two hours.
Figure 3 shows the appearance of the ore sample before and after oxidative roasting. After the oxidative treatment, cracks appeared in the ore lumps both internally and on the surface. This effect is attributed to the evaporation of hydrated and crystalline water, as well as the dissociation of oxygen from the higher manganese oxide.
Based on the results of X-ray diffraction analysis of the samples after oxidative roasting, the following phases were identified: Fe2O3, Mn2O3, Mn3O4, FeMnO3, and Mn7SiO12 (Figure 3). During oxidative roasting in an air atmosphere, oxygen dissociates from the crystal lattice of manganese dioxide, leading to a reduction in the oxidation state of manganese oxides and the formation of lower oxides such as Mn3O4 and Mn2O3. Goethite (FeO(OH)) loses moisture and transforms into hematite (Fe2O3). As a result of roasting in air, the total mass loss was 13.24%.
Figure 3 presents the appearance of a lump of iron–manganese ore studied and used in our experiments. The ore exhibits a characteristic color and texture, which make it easily distinguishable from other types of rocks.
According to micro-X-ray spectral analysis, the color of iron–manganese ore grains is non-uniform, ranging from gray to brownish, with inclusions of oxides of Si, K, Ca, As, Mn, and Fe (Figure 4). The results of the micro-X-ray spectral analysis indicate that the iron–manganese ore has a rather complex textural and structural pattern (Figure 5). In area 2, iron oxides were detected (with an iron atomic fraction of 32%) along with minor amounts of manganese (0.4 at.%), silicon (1.4 at.%), and arsenic (0.1 at.%). The ore also contains various manganese and iron compounds. For example, in area 1, the higher manganese oxide MnO2 was identified. In area 3, a mixed MnFeO3 phase was detected, where manganese and iron cations are in solid solution. The manganese content in this area was 16.4 atomic percent, and iron was 12.6 atomic percent (Table 2).

3. Results

To determine the spatial distribution of elements in the original iron–manganese ore ground to a −1 mm fraction, element mapping was performed using a scanning electron microscopy (SEM) system. The maps show the main elements identified in the ore (Figure 6 and Table 3). It can be observed that the phases consist predominantly of oxides of Si, Mn, and Fe, and barium oxides were also detected. Additionally, complex phases containing multiple elements (Mn, Si, Al) were observed. Arsenic distribution was not detected, most likely due to its low concentration.
The results of X-ray diffraction analysis, elemental distribution maps, and scanning electron microscope images of the original iron–manganese ore from the Keregetas deposit confirm its complex mineral composition, with iron and manganese present in the form of oxides (Figure 1, Figure 2 and Figure 4). This complexity may pose potential challenges in the production of manganese products from such ores.
Therefore, in order to determine the conditions for the selective reduction of iron from iron–manganese ores of the Keregetas deposit using hydrogen as a reducing agent, reduction roasting was carried out at temperatures of 700, 800, 900, 1000, and 1100 °C with a holding time of 60 min.
Figure 7 presents a graph showing mass loss at different temperature regimes. After reduction roasting of the iron–manganese ore, mass loss at 700 °C was 18.41%. With an increase in temperature to 1000 °C, the mass loss increased to 22.1%. Further temperature rise to 1100 °C led to sintering of the ore grains and reduced metal recovery, which in turn resulted in a decrease in mass loss to 19.8%.
Figure 8 presents the results of reduction roasting of iron–manganese ore samples at 700–1000 °C for 60 min in a hydrogen atmosphere with a flow rate of 0.5 L/min. The overall results of the reduction roasting are similar, with the main difference being that higher temperatures lead to more profound transformations in the ore samples. After reduction, metallic phase precipitates containing iron and arsenic were observed on the surface and inside the ore.
The composition of the released metal changes slightly with increasing temperature, as manganese begins to undergo reduction (see Figure 8 and Table 4). The residual oxide phase in all samples, regardless of temperature, consists of manganese oxides as well as non-metallic minerals.
Figure 9 shows the diffraction patterns of samples after reduction roasting in a hydrogen atmosphere at temperatures of 700, 800, 900, 1000, and 1100 °C with a holding time of 60 min.
According to the X-ray diffraction analysis, reduction roasting in a hydrogen atmosphere resulted in the formation of metallic iron (Fe), manganese monoxide (MnO), and quartzite (SiO2). In the samples roasted at 1100 °C for 60 min, phases such as FeMnSiO4 and Mn2SiO4 were detected.
This suggests that increasing the temperature to 1100 °C leads to the formation of complex phases that are more difficult to reduce, containing Fe, Mn, and Si cations simultaneously.

4. Discussion

The mineral composition of the initial sample includes oxides of iron, silicon, manganese, and barium, and complex phases of several elements such as Mn, Si, and Al (Figure 6). According to X-ray diffraction (XRD) analysis, the main phases in the original ore are FeO(OH), hematite (Fe2O3), manganese dioxide (MnO2), a mixed manganese–iron oxide phase (FeMnO3), and silicon dioxide (SiO2) (Figure 1).
After oxidative roasting, the identified phases include Fe2O3, Mn2O3, Mn3O4, FeMnO3, and Mn7SiO12. During oxidative roasting in an air atmosphere, oxygen dissociates from the crystalline lattice of MnO2, which leads to a decrease in the oxidation state of manganese and the formation of lower oxides such as Mn3O4 and Mn2O3. Goethite (FeO(OH)) undergoes dehydration and transforms into hematite (Fe2O3). As a result of roasting in an air atmosphere, the total weight loss of the Keregetas iron–manganese ore amounted to 13.24% (Figure 2 and Figure 3).
In all samples after reductive roasting in a hydrogen atmosphere, the formation of a metallic phase was observed. The chemical composition of the metallic phase shows that at 700–800 °C, only iron and arsenic are reduced, while at higher temperatures of 900–1000 °C, a small portion of manganese is also reduced into the metal. The oxide phase consists of unreduced oxides of active metals such as manganese, silicon, barium, and aluminum (Figure 7 and Figure 8).
According to XRD analysis results, after reductive roasting in hydrogen at 700 °C for 60 min, the reduction products included metallic iron (Fe), manganese monoxide (MnO), and quartzite (SiO2). The formation of tephroite (Mn2SiO4), previously observed in our studies [36,37,38,39] using carbon monoxide (CO) as the reducing agent, was not detected under the conditions of the current experiments. In samples roasted at 1100 °C for 60 min, phases such as FeMnSiO4 and Mn2SiO4 were identified (Figure 9). It can be assumed that increasing the temperature leads to sintering of ore grains, thereby reducing the contact area between the reducing gas and the sample, which in turn lowers the degree of reduction. This is clearly reflected in Figure 9, where the intensity of metallic iron peaks decreases significantly at 1100 °C, while the MnO and SiO2 phases disappear.
Thus, X-ray phase analysis of the reduced samples revealed the predominance of metallic iron (Fe) and manganese monoxide (MnO) in the solid phase. This indicates that under these conditions, selective reduction of iron to the metallic state and manganese to MnO occurs via the following reactions:
Fe2O3 + 3H2 → 2Fe + 3H2O
MnO2 + H2 → MnO + H2O

5. Conclusions

Micro-X-ray spectral analysis of the iron–manganese ore revealed the presence of Fe, Mn, Al, Si, Ba, and O. According to the X-ray diffraction analysis of the ore from the Keregetas deposit, the main phases identified are goethite (FeO(OH)), hematite (Fe2O3), manganese dioxide (MnO2), a combined manganese–iron oxide phase (FeMnO3), and silicon dioxide (SiO2). During oxidative roasting in an air atmosphere, oxygen dissociates from the crystal lattice of manganese dioxide, reducing the oxidation state of manganese and leading to the formation of lower oxides such as Mn3O4 or Mn2O3. Goethite (FeO(OH)) loses moisture and transforms into hematite (Fe2O3).
Reduction roasting of iron–manganese ore at 700–900 °C for 60 min in a hydrogen atmosphere results in the formation of soft iron and an oxide concentrate with a high manganese content, which can be easily separated by melting or magnetic separation. However, increasing the temperature to 1000 °C to accelerate the reduction of iron leads to manganese losses of up to 4.4 at.%, and further temperature increase to 1100 °C causes sintering of ore grains and a decline in the reduction process efficiency.
Thus, the experimental results show that using hydrogen as a reducing agent instead of solid carbon or carbon monoxide not only reduces greenhouse gas emissions but also opens up opportunities for more environmentally friendly production of iron- and manganese-containing concentrates from iron–manganese ores through selective reduction. The advancement of technology and the decreasing cost of electricity may make the transition to hydrogen even more feasible and economically viable in the future.

Author Contributions

Conceptualization, N.K., A.N., and B.K.; methodology, B.K., T.Z., and Y.K.; validation, Y.K., G.A., K.S., and G.B.; formal analysis, B.Z. and B.S.; investigation, B.K., N.K., G.B., and K.S.; resources, G.A., N.K., G.B., and B.S.; data curation, N.K., B.S., G.A., and A.A.; writing—original draft preparation, N.K., B.S., T.Z., and A.A.; writing—review and editing, N.K., A.N., and B.K.; visualization, Y.K., G.A., K.S., and G.B.; supervision, A.N. and B.Z.; project administration, N.K., A.N., and B.Z.; funding acquisition, N.K. and A.N. All authors have read and agreed to the published version of the manuscript.

Funding

This research is funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP 23490490).

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Conflicts of Interest

The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

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Figure 1. Diagram of the reactor setup used for the experiment. 1—reactor with flowing atmosphere; 2—samples; 3—corundum balls; 4—gas supply; 5—multimeter; 6—gas outlet; 7—thermocouple.
Figure 1. Diagram of the reactor setup used for the experiment. 1—reactor with flowing atmosphere; 2—samples; 3—corundum balls; 4—gas supply; 5—multimeter; 6—gas outlet; 7—thermocouple.
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Figure 2. X-ray diffraction pattern of the original iron–manganese ore.
Figure 2. X-ray diffraction pattern of the original iron–manganese ore.
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Figure 3. Appearance of iron–manganese ore samples: (a) in the original state; (b) after heating under oxidative conditions at 1000 °C.
Figure 3. Appearance of iron–manganese ore samples: (a) in the original state; (b) after heating under oxidative conditions at 1000 °C.
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Figure 4. Appearance of the original ore lump under a scanning electron microscope.
Figure 4. Appearance of the original ore lump under a scanning electron microscope.
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Figure 5. X-ray diffraction pattern of the original iron–manganese ore after oxidative roasting.
Figure 5. X-ray diffraction pattern of the original iron–manganese ore after oxidative roasting.
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Figure 6. Elemental distribution map of the original ore from the Keregetas deposit.
Figure 6. Elemental distribution map of the original ore from the Keregetas deposit.
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Figure 7. Mass loss of samples after reduction roasting in a hydrogen atmosphere at a hydrogen flow rate of 0.5 L/min.
Figure 7. Mass loss of samples after reduction roasting in a hydrogen atmosphere at a hydrogen flow rate of 0.5 L/min.
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Figure 8. Phase appearance of iron–manganese ore after reduction roasting. (a) 700 °C, (b) 800 °C, (c) 900 °C, (d) 1000 °C.
Figure 8. Phase appearance of iron–manganese ore after reduction roasting. (a) 700 °C, (b) 800 °C, (c) 900 °C, (d) 1000 °C.
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Figure 9. Diffraction patterns after 60 min roasting in a hydrogen atmosphere. Phases: 1—SiO2; 2—Fe; 3—MnO; 4—FeMnSiO4; 5—Mn2SiO4.
Figure 9. Diffraction patterns after 60 min roasting in a hydrogen atmosphere. Phases: 1—SiO2; 2—Fe; 3—MnO; 4—FeMnSiO4; 5—Mn2SiO4.
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Table 1. Chemical composition of the main elements in the feed ore after charging.
Table 1. Chemical composition of the main elements in the feed ore after charging.
Area AnalysisOAlSiKCaMnFeAsBa
At. %66.64.59.90.90.511.85.40.40.1
Mass. %42.54.811.11.50.725.812.01.10.5
Table 2. Elemental composition of the ore.
Table 2. Elemental composition of the ore.
at.%OSiKCaMnFeAsMinerals
Area 170.6 1.80.626.20.70.1MnO2
Area 266.11.4 0.432.00.1Fe2O3
Area 367.91.21.60.216.412.6 MnFeO3
Table 3. Chemical composition of elements on the distribution map from the JEOL JSM-7001F microscope.
Table 3. Chemical composition of elements on the distribution map from the JEOL JSM-7001F microscope.
at.%OAlSiKMnFeBaAs
Area68.53.611.51.68.25.60.70.2
Table 4. Results of micro-X-ray spectral analysis of the samples (Figure 8).
Table 4. Results of micro-X-ray spectral analysis of the samples (Figure 8).
SampleElement Content, at.%
Analysis PointsOAlSiMnFeAs
700 °C10.00.00.00.098.71.3
239.50.02.452.16.10.0
800 °C10.00.00.00.099.50.5
20.00.00.00.098.91.1
342.02.00.753.02.20.0
900 °C10.00.00.02.895.31.9
238.50.01.357.92.40.0
1000 °C10.00.00.04.493.62.0
239.80.01.955.62.70.0
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Kosdauletov, N.; Nurumgaliyev, A.; Zhautikov, B.; Suleimen, B.; Adilov, G.; Kelamanov, B.; Smirnov, K.; Zhuniskaliyev, T.; Kuatbay, Y.; Bulekova, G.; et al. Selective Reduction of Iron from Iron–Manganese Ore of the Keregetas Deposit Using Hydrogen. Metals 2025, 15, 691. https://doi.org/10.3390/met15070691

AMA Style

Kosdauletov N, Nurumgaliyev A, Zhautikov B, Suleimen B, Adilov G, Kelamanov B, Smirnov K, Zhuniskaliyev T, Kuatbay Y, Bulekova G, et al. Selective Reduction of Iron from Iron–Manganese Ore of the Keregetas Deposit Using Hydrogen. Metals. 2025; 15(7):691. https://doi.org/10.3390/met15070691

Chicago/Turabian Style

Kosdauletov, Nurlybai, Assylbek Nurumgaliyev, Bakyt Zhautikov, Bakyt Suleimen, Galymzhan Adilov, Bauyrzhan Kelamanov, Konstantin Smirnov, Talgat Zhuniskaliyev, Yerbol Kuatbay, Gulzat Bulekova, and et al. 2025. "Selective Reduction of Iron from Iron–Manganese Ore of the Keregetas Deposit Using Hydrogen" Metals 15, no. 7: 691. https://doi.org/10.3390/met15070691

APA Style

Kosdauletov, N., Nurumgaliyev, A., Zhautikov, B., Suleimen, B., Adilov, G., Kelamanov, B., Smirnov, K., Zhuniskaliyev, T., Kuatbay, Y., Bulekova, G., & Abdirashit, A. (2025). Selective Reduction of Iron from Iron–Manganese Ore of the Keregetas Deposit Using Hydrogen. Metals, 15(7), 691. https://doi.org/10.3390/met15070691

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