Silver recovery from complex ores - by multistage flotation and cyanide leaching

摘要

In the extn. of Ag from complex ores by subjecting the ground ore to conditioning and flotation and cyanide leaching the flotation concentrate, the tailings from the flotation stage are reground (pref. to 20-50 microns size), conditioned (pref. by slurrying to 200-250 g/ton solids content, adding 500-100 g/ton sodium water glass and 400-1000 g/ton copper sulphate, hydrophobising by addn. of 1000-3000 g/ton long chain K xanthate and pH adjustment to 8.5-9.5, and adding 50 g/ton foamer) and subjected to flotation, the resulting concentrate then being combined with the original concentrate (ground to the same particle size), subjected to post-cleaning flotation and then cyanide leached. The process gives a higher grade concentrate for leaching and gives a silver recovery of 95% or higher. Fine grained silver-contg. tetrahedrite, antimony and sulphides can be recovered together with metallic silver in the flotation concentrate.