An analysis of the composition of brass metallurgical waste was carried out using X-ray fluorescence analysis (XRF). The results showed that the copper content in the slag reaches 15 wt. %, and the zinc content – 83 wt. %. Sulfuric acid leaching was performed to separate zinc from the metallurgical dust. Optimal process parameters were selected: leaching duration – 60 minutes, sulfuric acid concentration – 0.1 M. After sulfuric acid leaching, the acid solution was subjected to electrochemical treatment to recover copper and zinc, and the copper cake (copper in unoxidized form) was subjected to copper-ammonia leaching for 40 minutes. The concentration of copper in the copper-ammonia solution reached 35 g/L. At the final stage, solvent extraction of copper from the copper-ammonia leach solutions was carried out, for which the most effective extractant was selected. Extractants of different nature and classes were studied: D2EHPA (a strong acidic organophosphorus extractant), DХ510А and LIX54 (belonging to the class of β-diketones). The concentration of extractants ranged from 50 to 100%, the diluent was kerosene. Copper stripping from the copper-ammonia extract was performed using 2M sulfuric acid. The best extractant was found to be LIX54 at 50% concentration in kerosene. The final stage was copper electrowinning from the stripping solutions at a current density of 3 A/dm, with a current efficiency of 65%. Based on the conducted research, a process flowsheet was developed for the recovery of copper and zinc from brass metallurgical dust.
I. Maksimov (Wed,) studied this question.