Flotation of copper smelter slags intensified by impact crushing

Abstract

This paper examines the mineral and chemical composition of converter slags generated by Balkhash Copper Smelter, as well as the forms in which copper ispresent in them. The paper describes the results of flotation of the above product, which was prior subjected to fine crushing in jaw and hammer crushers. The paper features a comparative analysis that looks at the size distribution and the distribution of the key valuable components by grain size of the slag pre-crushed in jaw and hammer crushers. It is shown that the different breaking techniques realized by these crushers influence the size distribution of the crushed product, the share of particles smaller than 0.071 mm and the distribution of copper by fraction. The authors looked at the grinding kinetics of the copper smelter slags pre-crushed in the above specified crushers and compared the share of –0.071 mm particles, as well as that of –0.045 mm particles (which are the finest fraction). It was established that the optimum hammer crushing duration is 45 min. A longer duration leads to overgrinding. At the same time for the jaw crusher, the overgrinding effect and the accumulation of the –0.045 mm particles become expressed if the crushing cycle lasts for 60 min. Flotation of the pre-crushed converter slags resulted in a quality concentrate containing 27.5 to 39.0 wt % copper (depending on the slag crushing duration). In all cases, the recovery of copper was every time higher (by 5% on average) for slags pre-crushed in the hammer crusher. It is pointed out that impact crushing of copper smelter slags significantly intensifies the flotation process. This should be taken into consideration when optimizing the processing schemes.This research was funded by the Russian Science Foundation; Agreement No. 22-27-00526.