Mineralogical and morphological factors affecting the separation of copper and arsenic in flash copper smelting slag flotation beneficiation process

Abstract

Separating copper and arsenic has always been a major problem in the copper slag flotation process, which influences copper slag utilization and the environmental safety. A comparative study of flash smelting furnace (FSF) slag and its flotation products (concentrate and tailing) reveals the factors affecting the separation of copper and arsenic in the beneficiation process from the perspective of mineralogy and morphology. The elemental fractionation in the process shows a positive correlation of As, Cu and Cd and an obvious correlation between speciation transformation of copper and arsenic was observed. The occurrence of arsenic and copper in FSF slag correlate the key phases of arsenic copper alloys, accounted for 88.91 % of total arsenic-bearing phases and 32.28% of copper-bearing phases. Closely-embeded matte and copper-arsenic alloys incerease the difficulty of the separation suggesting the finer grinding is needed for slag. Arsenic is liberated and oxidized into arsenate compounds while the recombination of As-O and Cu-S happened in the process affecting the selectivity of copper and arsenic. Arsenic fixed in silicate minerals is discharged into tailing which suggested to induce and fix arsenic into silicate minerals can facilitate arsenic removal from concentrate. FSF slag and its flotation concnetrate show risks of some of some of HMs which should be cautiously transported, disposed, and utilized.