Inclusion of secondary raw materials in the production circuit at Almalyk MMC

Abstract

This paper demonstrates a possibility to recover non-ferrous and precious metals from copper slags and zinc production waste clinker generated by Almalyk MMC. Thus, the zinc production waste clinker contains more than 50% of reducing elements in the form of metallic iron and carbon, as well as 1–10 g/t of gold and 100–750 g/t of silver. For the purposes of this study, clinker was used as a reductant for converter slag magnetite during depletion, as well as a source material for precious metals, which get recovered into matte as a result of depletion (reduction) and then into blister copper (up to 95%). The copper slags generated by Almalyk MMC contain 2.0 to 3.5% of copper. They should go through a reverberatory furnace so that valuable components could be extracted, including 75% of copper. However, after a Vanyukov furnace was introduced in the copper production circuit, a certain part of converter slags is sent back to the concentrator plant for the production of sulphide copper concentrate. In this case, the total recovery of blister copper from converter slag does not exceed 50%. In order to raise the reverberatory furnace recovery of copper from converter slag to 83% and to raise the recovery to 75% in case converter slag gets concentrated and the resultant concentrate is then smelted in the reverberatory furnace and converter, converter slags should first go through reduction processes.