AP19579175 – «Investigation of the selective reduction of iron by hydrogen gas from oolitic ores with a high phosphorus content»

The largest share of steel is produced by the reduction of iron oxides with carbon, which leads to the reproduction of anthropogenic CO2 emissions, which account for ≈ 30% of all industrial CO2 emissions. These numbers qualify manufacturing as a nationwide major cause of global warming and pose an urgent problem of decarbonisation. Throughout the steel chain, the production of iron ore reduction in blast furnaces with carbon up to 80-90% is within CO2.

In connection with the increase in steel production, iron ore deposits are involved in production, which have an increasingly complex mineralogical composition, as well as with an increased content of phosphorus (0.4-1.8%), in particular, oolitic ores, which are widely distributed in the form of quite large deposits. In the Republic of Kazakhstan, oolitic ores make up the bulk of the recorded iron ore reserves, more than 60% of which are concentrated in the Lisakovskoye, Ayatskoye, Kokbulak, Kutanbulak and Taldyespe deposits.

It is difficult to reduce the phosphorus content in the ore using traditional enrichment methods, since the phases of iron oxide and gangue are tightly bound, and they are difficult to dissociate. During the process of recovery of high-phosphorus ore in a blast furnace, almost all of the phosphorus will be transferred to pig iron, which will further lead to an increase in the volume of slag and loss of electricity during steelmaking. Thus, the dephosphorization of high-phosphorus iron ores is the most important stage in the processing of these ores.

It is proposed to carry out the process of gas-phase selective reduction of iron, in order to separate iron and phosphorus, with the production of a metallized material. Hydrogen is used to implement the selective reduction of iron without phosphorus. The issues of the use of hydrogen in metallurgy currently continue to gain relevance due to the need to reduce the burden on the environment from iron metallurgy.

1) Yerzhanov Almas – Doctor of Philosophy (PhD), associate professor, project leader.

Scopus ID: 56524559600

Researcher ID: AFL-9951-2022

https://orcid.org/0000-0002-8990-5919

2) Kuatbay Yerbol – Doctor of Philosophy (PhD), project executor.

Scopus ID: 57218196966  

Researcher ID: ABE-5679-2021 

https://orcid.org/0000-0002-8400-3537

3) Zhuniskaliev Talgat – Doctor of Philosophy (PhD), senior researcher at the Department of Science, Innovation and International Cooperation, project executo.

Scopus ID: 57218196497  

Researcher ID: AAG-6131-2021  

https://orcid.org/0000-0001-9757-0605

4) Gamov Pavel – candidate of technical sciences, associate professor.

Scopus ID: 55618981700

Researcher ID: LSO-9119-2024

https://orcid.org/0000-0002-1474-644X

5) Suleimen Bakyt – researcher at the Department of Science, Innovation and International Cooperation, project executor.

Scopus ID: 57215054180

Researcher ID: OBY-0860-2025

https://orcid.org/0000-0001-9306-1045

6) Kosdauletov Nurlybay – researcher at the Department of Science, Innovation and International Cooperation, project executor.

Scopus ID: 57215058827

Researcher ID: OBP-2228-2025

https://orcid.org/0000-0002-1570-4188

7) Adilov Galymzhan – researcher at the Department of Science, Innovation and International Cooperation, project executor.

Scopus ID: 57213596057

Researcher ID: ABL-6521-2022

https://orcid.org/0000-0002-1012-8097

8) Abdirashit Asylbek – Master of Technical Sciences, project executor.

Scopus ID: 57218196252

Researcher ID: ABE-5588-2021

https://orcid.org/0000-0003-0718-3041

During the implementation of the project, it will be shown that the use of selective solid-phase reduction in pyrometallurgical processes makes it possible to expand the raw material base of the ferrous metallurgy of Kazakhstan. The implementation of this project will provide an opportunity to comprehensively study the chemical and phase transformations of the components of oolitic iron ore. As a result, new theoretical and experimental data on the distribution of iron and phosphorus during reduction roasting will be obtained, and an assessment of the efficiency of dephosphorization and the possibility of its use in existing processes will also be given.

The possibility of practical use of the expected results of the project in the economy, including for the creation of new applied technologies, is assessed by the fact that on the basis of the results obtained, the optimal parameters of reduction roasting (time, temperature, composition of the gas phase) and the optimal parameters of separative melting (time, temperature, composition of the slag phase), which can be used in the development of technology for producing steel from oolitic ores using modern coke-free technologies to obtain phosphorus-free steel.

The environmental impact of the project will be the use of hydrogen gas to directly reduce iron from ore, which will significantly reduce massive anthropogenic CO2 emissions from the steel industry.

The scientific and technical effectiveness of the project is aimed at solving the national project of the Republic of Kazakhstan “Technological breakthrough through digitalization, science and innovation” and at improving the production of high-quality metal products.

The results of scientific research will be published at international conferences, as well as in peer-reviewed foreign or domestic publications recommended by the CQASHE in this area and therefore will be available to scientists. The test results will be validated and recommended to production organizations for the implementation of the technology for the complex processing of high-phosphorus oolitic iron ore using solid-phase selective reduction of iron with hydrogen-based gases and with further pyrometallurgical separation to obtain metallic iron and phosphorus slag.

1. An analytical review was carried out on the existing and proposed technologies and their shortcomings for the processing of high-phosphorus oolitic iron ores, as well as the prospects for using hydrogen in metallurgy. Several methods are known for the dephosphorization of oolitic ore and its concentrate, based on physical, chemical, and combined effects on ore particles of oolitic structure. Enrichment methods of oolitic ores are proposed through reductive roasting with the production of concentrates and their subsequent magnetic separation. However, during reductive roasting phosphorus passes into the metallic phase, and during subsequent magnetic separation it ends up in the magnetic fraction. Therefore, phosphorus cannot be removed from the concentrate by these enrichment methods. Also presented are the results of studies on the magnetizing roasting process of phosphorus-bearing oolitic ore in mixtures with various additives that affect the distribution of phosphorus between the metallic and oxide phases. However, such methods require the use of additional materials that increase processing costs. Moreover, additives do not always positively affect the metallization process, and ultimately yield significant results only at the laboratory scale. In addition to pyrometallurgical methods, hydrometallurgical processes for the dephosphorization of oolitic ores are known. Combined pyro-hydrometallurgical processing methods have also been proposed. However, the use of chemical reagents to separate phosphorus by hydrometallurgical processes is environmentally unfavorable and economically inefficient. Biological methods of acting on ore particles of oolitic structure are also proposed. Bioleaching usually requires a very long time. Biological methods demand extended treatment durations. Leaching bacteria require collection, separation, cultivation, and adaptation, which affect production efficiency. All the methods mentioned above for removing phosphorus from iron ore raw materials have not yet found practical application for the noted reasons. At present, the most relevant direction for processing high-phosphorus oolitic ores is the use of hydrogen as a reducing agent for the selective reduction of iron. The development and implementation of breakthrough technology for the use of hydrogen as a reducing agent in ferrous metallurgy at an industrial scale will allow the involvement of complex, lean, and refractory ores into production.

(May 2023 – June 2023)

2. To study the mineralogical composition of the initial ore, X-ray diffraction (XRD) analysis was carried out on a Rigaku Ultima IV diffractometer. According to the XRD results, the main phases of the original oolitic ore of the Lisakovskoye deposit are goethite (FeO(OH)), magnetite (Fe₃O₄), and quartz (SiO₂). In addition, iron, calcium, and magnesium carbonates were detected. Phosphorus in the initial ore is present in the form of iron hydrophosphates (FePO₄·2H₂O), calcium hydrophosphates (CaHPO₄·2H₂O), and aluminum phosphate (AlPO₄). During roasting at 1200 °C in air, goethite (FeO(OH)) loses water and transforms into hematite (Fe₂O₃). Phosphorus in the roasted product is present as FePO₅ and AlPO₄ compounds. The elemental composition of the original and roasted ore was determined by electron probe microanalysis (EPMA) using a Jeol JSM-7001F scanning electron microscope. It was revealed that both the original and roasted ores contain Mg, Al, Si, P, Ca, Ti, Cr, Mn, Fe, Co, Ni, and Zr. After oxidative roasting, the oolites do not disintegrate, they retain their spherical shape, but small cracks appear within them.

(July 2023 – November 15, 2023)

3. Thermodynamic analysis was performed using the TERRA thermodynamic system calculation software. The calculation was carried out for 100 g of roasted ore. For the calculations, missing thermochemical data for iron phosphide (Fe₃P) were added to the TERRA database. The change in standard enthalpy was calculated assuming a linear dependence of heat capacity on temperature in the range of 0–298 K, resulting in H°₂₉₈ – H°₀ = 15,076 J/mol·K. The reduction process was calculated for the temperature range of 600–1600 K with a step of 50 K. Constant system parameter: total pressure of 0.1 MPa (1 atm). The effective temperature interval considered was 1000–1400 K. In this interval, selective separation of phosphorus and iron during reduction is possible. At lower temperatures, iron shows low degrees of reduction and phosphorus is not reduced; at higher temperatures, phosphorus is reduced and selective separation cannot be achieved. Hydrogen was used as the reducing agent in the thermodynamic modeling. Based on the calculation results, a graph of the distribution of elements as a function of temperature and the amount of reducing agent was constructed.

(January 2024 – March 2024)

4. In the thermodynamic calculation, for the complete reduction of iron from 100 g of oxidized material, the stoichiometric amount of hydrogen required was 2.46 g H₂. After preliminary calculations, the hydrogen amount in the system was taken with an excess of 2.5 times, which corresponded to 6.15% H₂ per 100 g of ore. With the use of 6.15 g of hydrogen per 100 g of ore, at a temperature of 1375 K, all the iron completely transitioned into the metallic phase, while phosphorus remained unreduced in the oxide phase as 3(CaO)·P₂O₅. According to the calculation results, the following compounds were present in the system: Fe, FeO, Fe₃O₄, 3(CaO)·P₂O₅, H₂O, H₂, MnO, Al₂O₃, MgO·SiO₂, CaO·SiO₂, and SiO₂. Based on the obtained data, it can be concluded that selective iron reduction can be achieved at precisely controlled amounts of reducing agent, even at relatively high temperatures (up to 1375 K). The results showed that for the complete transition of iron into the metallic phase, 6% pure hydrogen per 100 g of ore is sufficient. With an increase in temperature and depending on the amount of reducing agent, phosphorus transitions into the metallic phase in the form of Fe₃P.

(April 2024 – June 2024)

5. The results of XRD analysis showed that in all samples after reduction, goethite disappears, α-Fe phase appears, and SiO₂ phase remains. In the samples reduced with carbon monoxide or hydrogen, fayalite and magnetite phases were detected. With increasing hydrogen reduction temperature from 600 to 900 °C, the peak intensities of these phases decrease, while the metallic iron peak increases. When reduced with hydrogen at 600 °C, phosphorus is present in the form of calcium, iron, and aluminum phosphates. With increasing temperature to 700 °C and above, phosphorus remains only in the AlPO₄ phase. These results were confirmed by electron microscopy studies of samples after reductive roasting. In the samples reduced with hydrogen at 600–800 °C, phosphorus was practically not reduced, but at 900 °C phosphorus was reduced and detected in the metallic phase by EPMA. This indicates that during hydrogen reduction, by controlling the temperature, it is possible to ensure the thermodynamic and kinetic conditions for the selective reduction of iron and phosphorus. At low temperatures, only iron is reduced, since hydrogen does not have sufficient energy to reduce phosphorus from stable oxides, while at higher temperatures, thermodynamic conditions become more favorable, reaction kinetics improve, and hydrogen reduces both iron and phosphorus. Thus, the experimental results indicate that during gaseous reduction, in particular with CO or hydrogen, it is possible to selectively reduce only iron from oolitic ore, leaving phosphorus in the oxide phase.

(July 2024 – November 15, 2024)

2023

1. Süleimen B. T., Qosdauletov N. Y., Adilov G. A., Erzhanov A. S., Gamov P. A. (2023) Kompleksnoe izertteu sastav jäne strukturalyq erekshelikteri jeleznıi rudasy Lisakovskoe kenorını. Nauka jäne tehnika Qazaqstan, № 3, 173-183 b.

https://doi.org/10.48081/OVIQ4178 

2024

2. Suleimen, B., Kosdauletov, N., Adilov, G., Gamov, P., Salikhov, S., Kuatbay, Y., Zhuniskaliyev T., Kelamanov B., Yerzhanov A., Abdirashit, A. (2024). Selective Reduction of Iron in High-Phosphorus Oolitic Ore from the Lisakovsk Deposit. Materials, 17(21), 5271.

https://doi.org/10.3390/ma17215271

2025

Application for Invention No. 2025/0423.1. Charge for Smelting Ferrosilicon Alloy / Applicant: NAO Karaganda Industrial University, Süleimen B.T.; Erzhanov A.S.; Qosdauletov N.Y.; Adilov G.A.; Kelamanov B.S.; Zhuniskaliev T.T.; Quatbai E.Q.; Äbdіrashit A.M.; Pushanova A.T.; Zhaslan R.Q.

The application has passed the formal examination at the National Institute of Intellectual Property QazPatent and received a positive conclusion.

Date of receipt: May 2, 2025.