Study of the Leaching Process for Copper From the Production Waste of the Balkhash Copper Smelter With the Addition of an Oxidizing Agent

The use of metallurgical slags as secondary raw materials is a pressing issue today. The most rational way to get rid of the negative impact of such objects on the environment is the organisation of heap-leaching sulphuric acid solution. The disadvantages of this process (high temperature, duration of dissolution and concentration of the sulphuric acid) are related to the known high chemical stability of metallic copper and the resulting delayed dissolution. The study aims to improve the process of slag leaching at the Balkhash Metallurgical Plant. The main idea isthat the addition of an oxidizing agent - hydrogen peroxide - to sulphuric acid by analogy with uranium leaching will reduce the duration of dissolution and concentration of sulphuric acid, as well as will not require heating. Modern physical and chemical analytical methods were used to identify the products: the composition of metallurgical slag and post-treated waste was investigated by X-ray spectral analysis on the RLM-21 device, and the phase composition was analysed on the D8 Advance device (Bruker). Processing of the obtained diffractogram data and calculation of interplanar distances were carried out using EVA software. Sample interpretation and phase search were carried out using the Search/Match programme with the PDF-2 Powder Diffractometry Database. This paper presents the first results on the effect of hydrogen peroxide on the leaching of copper. The extraction of copper from the test material is analogous to uranium leaching where the addition of an oxidant in the form of 10 % hydrogen peroxide accelerates the leaching process. We increased the copper recovery to 50 % in 63 days of leaching. Oxygen is known to interact with copper in slag only when heated. In our experiment, the sample was oxidised with 10 % hydrogen peroxide solution and leached with 20 % sulphuric acid solution. In our opinion, oxygen interacts with copper through the formation of monosulphuric and nadsulphuric acids, which are stronger oxidants than hydrogen peroxide. Therefore, the process was carried out without additional heating.