The Effect of the Granulometric Composition of Slags on the Efficiency of Non-Ferrous Metals’ Extraction

The processing of metallurgical slags is an urgent task, as they contain residual amounts of precious and non-ferrous metals such as gold, silver and copper. The efficiency of extraction of these metals directly depends on the granulometric composition of the processed material, which determines the need for its detailed analysis. The purpose of this study is to study the effect of the granulometric composition of slags on the efficiency of extraction of precious metals using various enrichment methods. For this purpose, studies were carried out, including granulometric analysis, chemical composition analysis, flotation tests using Na₂S and 3418A reagents, as well as magnetic separation. The analysis showed that the main part of the slag consists of particles less than 3.36 mm, while the content of copper is 0.60%, zinc – 2.37%, gold – 0.1 g/t, and silver – 7.2 g/t. Flotation experiments have confirmed that the use of Na₂S and 3418A increases the recoverability of copper and silver, and reducing the particle size to d80 <10 microns increases the efficiency of copper extraction by 7%. Magnetic separation did not have a significant effect on the concentration of non-ferrous metals, but it allowed us to isolate an iron-containing fraction suitable for further processing. Thus, optimization of flotation processes and control of granulometric composition make it possible to increase the efficiency of metallurgical waste processing, reduce losses of valuable metals and reduce the environmental burden.