Copper-Containing Slags will be Fully Recycled within the Project of the Ural REC

 It is possible to recycle toxic copper waste. Scientists at South Ural State University (SUSU) are developing an environmentally friendly recycling approach to returning valuable metals to production as raw materials and sending the rest to the oil industry. The project is carried out within the framework of the Ural Interregional REC. 

Toxic metallurgy waste 

Focus on ecology is the trend of modern production. It is especially relevant for ferrous and non-ferrous metallurgy, where waste appears in the form of enrichment tailings: slag, sludge, dust. For example, in the city of Karabash (the Chelyabinsk region), about 30 million tons of industrial waste is stored: this is 10 tons of iron, as well as copper, sulfur, arsenic, selenium, zinc, and other hazardous elements. 

The elements that make up the waste can form toxic chemical compounds. Their storage requires large areas and harms the environment. Therefore, areas, where metallurgy is the leading industry need proper waste disposal with the extraction of hazardous substances and the reuse of some elements, which is beneficial from an environmental and economic point of view. 

Working with copper-containing waste

Most often, valuable elements are extracted using the hydrometallurgical method. Useful components into a dissoluble form are transferred to the liquid, and metals and compounds are extracted from the solution. However, the extraction of each of the elements of the slag dumps separately is unprofitable. In addition, it is almost impossible to obtain pure substances: heavy non-ferrous metals are often mixed with them, which significantly reduce the mechanical properties of machine-building steel.

Copper-containing waste is undesirable to be used at metallurgical plants due to the danger of increasing the concentration of copper in charge of steelmaking units. However, the elements that make up the waste can form toxic compounds of the second and first hazard classes in terms of the impact on the human body. Today in Russia, there are more than 140 million tons of slag in the dumps of copper smelters alone,” said Pavel Gamov, Candidate of Technical Sciences, Head of the Department of Pyrometallurgical Processes at SUSU Institute of Engineering and Technology.

 

Waste-free slag processing 

Scientists at South Ural State University know how to achieve waste-free dumping. Together with colleagues from the Russian State University of Oil and Gas (NRU) named after I.M. Gubkin, the Skolkovo Foundation, and the Belarusian National Technical University, they are developing a project for processing industrial waste from copper smelters. The project is included in the portfolio of the Ural Interregional Research and Education Center in the direction of Ecology. 

The project involves the development of theoretical and technological foundations for the extraction of the most valuable components from slag-iron and zinc. They intend to produce proppant out of slag residue. Iron, which has the highest value in copper smelting waste, is suitable for the manufacture of cast iron grinding media. The residual content of copper and sulfur will not affect product quality. In addition, during operation, they are almost completely abraded, so that even such harmful impurities as copper will not end up in ferrous scrap. 

The research has shown the possibility of obtaining a commercial product in the form of grinding media, in which sulfur is not a harmful impurity, but by preventing carbon graphitization, it contributes to its release in the form of solid carbides and increases wear resistance. Copper, in turn, is also a useful impurity that increases the impact-resistant properties of cast iron. With high quality, they have a significantly lower cost, since the cast is produced from the waste of the copper industry (slag) and does not contain expensive additives (chromium),” said representatives of the industrial partner of the project LLC EC AS Teplostroy. 

The second most expensive component, zinc, is necessary for the industry. Copper-smelting slags contain about 2.5% of this non-ferrous metal, so its return to production as Waelz oxide will make it possible to compensate for the lack of zinc at modern enterprises. The implementation of the project for the processing of man-made waste is planned for the next five years. Now laboratory tests have been completed. The scientists plan to create a semi-industrial line based on Severstal PJSC. The enterprise can become a potential customer of the project. The project manager is Alexander Povolotsky, Ph.D., Director of the Research and Education Center “Metallurgy” (the Institute of Engineering and Technology). 

South Ural State University is a university of digital transformations, where innovative research is carried out in most priority areas for science and technology development. Following the strategy of scientific and technological development of the Russian Federation, the university focuses on the development of large scientific interdisciplinary projects in the field of the digital industry, materials science, and ecology. In 2021, SUSU won the competition under the Priority 2030 program. The university performs the functions of the regional project office of the Ural Interregional Research and Education Center. 

The Ural Interregional Research and Education Center "Advanced Production Technologies and Materials" created within the frameworks of the Science National Project, will unite the potentials of educational and scientific organizations, enterprises, and companies of the real economy sector of the Sverdlovsk, Chelyabinsk, and Kurgan regions with regard to conducting applied scientific research and engineering developments, creating competitive technologies and products and commercializing those, as well as to training specialists for solving scientific and engineering tasks to achieve breakthrough development in the priority fields and enhance the competitiveness of the economies of the entities within the Center’s area.

Daria Tsymbalyuk, photo by Oleg Igoshin, Danil Rakhimov
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