AP23485002 – «Development of technology for smelting silicon ferroalloys using substandard technogenic raw materials»

The prerequisites for the development of the project are the high cost of traditional carbon reducing agents – coke and semi-coke, their incomplete compliance for the electrothermy of ferroalloys, as well as the relatively low technological performance of smelting siliceous ferroalloys.

Traditionally, coke or semi-coke fractions of 10-25 mm are used as carbon reducing agents for the smelting of siliceous ferroalloys, as well as low-ash long-flame or gas coals as minor additives.

The most important requirements for the reducing agent imposed by the technology of smelting siliceous ferroalloys are: high electrical resistance, high reactivity and favorable ash composition.

Coke was originally intended for the smelting of pig iron in blast furnaces, where it is used as a carbon reducing agent, as well as a heat source due to its gorenje. Therefore, the use of coke and its analogues with high electrical conductivity for the smelting of siliceous ferroalloys in electric furnaces is not entirely acceptable.

The main disadvantages of traditional coke, semi-coke and some low-ash coals include their low electrical resistance (ER).

In relation to the smelting of ferrosilicon, the low ER values of coke and semi-coke contribute to the heating of the upper layers of the charge and, accordingly, its sintering and difficulties in the release of exhaust process gases. The depth of the electrodes is reduced. Silicon losses in the form of sublimations are increasing.

As applied to the smelting of ferrosilicon manganese of the SiMn17 brand, the main problem is the low extraction of silicon with a basicity of the final slag (CaO + MgO)/SiO₂ of more than 0.5. The silicon content in accordance with the State Union Standard 4756-91 for the SiMn17 brand should be 15-20%. In reality, about 30-40% of the alloy is smelted with a silicon content of less than 15%, which reduces its attractiveness and, consequently, its market value.

Another factor for the implementation of this project is the presence of silica waste at ferroalloy plants – screening of quartzite fractions of 0-5 mm and silica dust from the gas cleaning system. In particular, when ferrosilicon is smelted, the dust yield can be 0.2-0.4 tons per 1 ton of alloy being smelted. Silica dust from dry gas cleaners is practically not used for further processing in the Republic of Kazakhstan. The possible uses of silica dust described in the literature for construction and other industries are practically not feasible due to various reasons, as well as the lack of technical conditions for its use. Therefore, collecting and removing dust for burial is a laborious task. Dust storage in landfills involves its weathering and spreading to the entire surrounding area.

It is also known that the fine fraction of 0-5 mm of coke and semi-coke simply burns on the furnace grate and does not participate in the reduction processes, therefore, the fine fraction is screened out before their use. As a result, ferroalloy plants accumulate a large amount of small items that have limited use.

The presence of a huge amount of unclaimed pulverized carbonaceous and siliceous raw materials, as well as the problems of the technological plan for the smelting of siliceous ferroalloys were the main prerequisites for the implementation of the project.

1) Yerzhanov Almas, Doctor of Philosophy (PhD), Associate Professor. Project manager.

Scopus ID: 56524559600

Researcher ID: AFL-9951-2022

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

2) Chekimbayev Askar, Candidate of Technical Sciences. Co-head of the project.

Scopus ID: 6506357731

Researcher ID: EOB-4433-2022

https://orcid.org/0000-0002-4796-7935

3) Nurumgaliyev Assylbek, Doctor of Technical Sciences, Professor. Project executor.

Scopus ID: 10042501900

Researcher ID: DJP-4688-2022

https://orcid.org/0000-0002-8782-9975

4) Zhuniskaliyev Talgat, Doctor of Philosophy (PhD). Project executor.

Scopus ID: 57218196497

Researcher ID: AAG-6131-2021

https://orcid.org/0009-0002-1078-5959

5) Kuatbay Yerbol, Doctor of Philosophy (PhD). Project executor.

Scopus ID: 57218196966

Researcher ID: ABE-5679-2021

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

6) Aitkenov Nurbek, Doctor of Philosophy (PhD). Project executor.

Scopus ID: 57210125321

Researcher ID: IBL-6200-2023

https://orcid.org/0000-0001-7495-6337

7) Mukhambetkaliyev Azamat, Master of Technical Sciences. Project executor.

Scopus ID: 57218196432

Researcher ID: DIJ-5079-2022

https://orcid.org/0000-0001-9163-1438

8) Mynzhassar Yesmurat, Doctor of Philosophy (PhD). Project executor.

Scopus ID: 58245045400

Researcher ID: AGN-2853-2022

https://orcid.org/0000-0002-4268-5664

9) Akhmetov Begzat, Master of Technical Sciences. Project executor.

Scopus ID: –

Researcher ID: –

Orcid: –

At least three (3) scientific and (or) scientific and technical projects will be published based on the results of the implementation articles and/or reviews in peer-reviewed scientific publications indexed in the Science Citation Index Expanded of the Web of Science database and/or having a CiteScore percentile in the Scopus database of at least 50 (fifty), as well as at least 2 (two) articles or reviews in a peer-reviewed foreign or domestic publication recommended by the Committee for Quality Assurance in Science and Higher Education with the participation of at least 50% of the members of the research group.

According to the results of scientific research, the publication of monographs, books and (or) chapters in foreign and (or) Kazakhstani publishing houses is not considered.

The possibilities of patenting the results obtained in the patent offices in the Kazakh or Eurasian patent offices are being considered.

Based on the results of scientific research, technical instructions for the manufacture of carbon composites with various combinations of components and technological regulations for the smelting of ferrosilicon and ferrosilicon manganese alloys using new types of carbon composites will be developed.

The results of scientific research are commercial products and will be offered for implementation at domestic ferroalloy plants. The main results of the work will be published at international conferences, as well as in peer-reviewed foreign or domestic publications recommended by the Committee for Quality Assurance in Science and Higher Education, therefore they will be accessible to the scientific community.

The target consumers of the results obtained may be ferroalloy plants in Kazakhstan (JSC TNK Kazchrome, Taraz Metallurgical Plant LLP, KSP Steel LLP, YDD LLP, etc.), near and far abroad, as well as interested companies in the coal refining industry.

The research has a perfect novelty and prospects in terms of improving the technical and economic performance of smelting ferrosilicon and ferrosilicon manganese alloys. At the same time, the problem of waste disposal of carbonaceous and silica raw materials will be solved.

The applicability and commercialization of scientific results will be at a fairly high level. The developed technologies for smelting ferrosilicon and ferrosilicon manganese alloys using experimental carbon composites will be of particular interest to ferroalloy plants and enterprises.

The possibility of launching new enterprises that will process fine-grained and pulverized carbon and silica raw materials related to man-made waste will create a social and economic effect.

The expected economic effect of using the developed technologies in the ferroalloy industry will be to reduce the cost of production while increasing the productivity of electric furnaces. The cost of production will be reduced due to the lower cost of carbon composites compared to traditional carbon reducing agents. The increase in productivity will result from an increase in the power of electric furnaces due to the required electrophysical properties of carbon composites.

The environmental effect of the implementation of the scientific project and the introduction of the developed technologies in industry will consist in the disposal of man-made carbonaceous and silica waste by involving them again in metallurgical conversion. Accordingly, the environmental burden on ferroalloy plants and the surrounding areas will decrease.

In scientific and technical terms, the scientific base for the use and manufacture of carbon-mineral composite materials will be developed. The scientific and technical effectiveness of the scientific project corresponds to the national project «Technological breakthrough through digitalization, science and innovation» and is aimed at the development of coal refining and ferroalloy enterprises of the Republic of Kazakhstan.

When using the developed technologies for smelting ferrosilicon and ferrosilicon manganese alloys using experimental carbon composites, the multiplicative effect will consist not only in increasing the power of electric furnaces, but also in increasing silicon extraction and, consequently, improving the quality characteristics of the products being smelted.

The project will use a new software package for thermodynamic modeling of technological processes, which will significantly reduce the number of experiments required to develop technologies for smelting ferrosilicon and ferrosilicon manganese alloys.

Thermodynamic modeling will make it possible to predict the qualitative and quantitative parameters of the course of reduction reactions, the distribution of elements by metallurgical phases in high-temperature conditions of silicon ferroalloy smelting, as well as reduce time-consuming experiments with solving important technological problems based on the use of new software systems with an expanded database.

1. Industrial waste from ferroalloy plants was studied – screenings of coke, hard coal, semicoke, quartzite, and silica dust from dry gas cleaning systems. It was established that the most optimal method for agglomerating fine-fraction waste raw materials is briquetting using aqueous solutions of liquid glass as a binder. It was determined that the optimal ratio of the carbonaceous part to the mineral part of the experimental composites should be 70–75:30–25, while the addition of liquid glass solution should be 5–7% of the total mass. The pressing pressure is 600–800 kg/cm². In this case, the highest strength of the experimental composites was observed after forced drying at temperatures of 120–160 °C. A decrease in electrical resistance was established with an increase in the carbonaceous part of the composites.

(August 2024 – November 15, 2024)

2. Comparative studies were carried out to determine the specific electrical resistivity (SER) of the composites in the temperature range of 20–1200 °C. It was found that in the range of 800–1200 °C, the SER of the experimental composites exceeded that of traditional coke by 1.5–2.0 times. It was established that the cold strength of the experimental briquettes is achieved due to the reaction of the silica-containing additive with sodium hydroxide (NaOH) and the formation of a Na₂SiO₃ network. The experimental samples withstood at least 4 drops from a height of 0.4–0.5 m onto a rubber belt. After drying, the briquettes withstood at least 7 drops onto a steel plate from a height of 2 m. Hot strength was tested at 300, 500, 700, 900, and 1000 °C under static and dynamic loads. It was found that up to a temperature of 1200 °C, the briquettes did not disintegrate.

(August 2024 – November 15, 2024)