Promoted Flotation of Lead and Silver Oxidized Minerals Using a Synergetic Combination of Collectors

Annually, millions of tons of lead and silver concentrates are produced using flotation processes from ores. Xanthates are used as collectors to recover minerals containing lead and silver in conventional flotation plants. However, many flotation plants suffer from reduced lead–silver recovery during their processes. This work examined the promoted flotation of oxidized lead and silver minerals using potassium amyl xanthate and sodium diethyl dithiocarbamate. The effective parameters on flotation including 80% passing size (d₈₀), dosage and conditioning time of sodium sulfide, lime addition, and type of collectors were investigated. The optimal condition under the conditions of d₈₀ equal to 90 µm, a solid percentage of 25%, 7000 g/ton sodium sulfide with conditioning time of 10 min, 60 g/ton MIBC, and combined collectors of 450 g/ton potassium amyl xanthate with 150 g/ton sodium diethyl dithiocarbamate were obtained. The optimized condition was compared with the traditional condition in Iranian flotation plants. The combination of collectors could improve by 4.3, 1.8, and 2.1% of the concentrate lead grade, recovery, and separation efficiency, respectively, in comparison with the conditions of an industrial conventional plant. For silver flotation, the silver grade and recovery increased from 960 ppm and 48.5% recovery to 1100 ppm and 52.6%, respectively.