TREATMENT OF LIQUID CONTAINING CYANO GOLD COMPOUND

摘要

PURPOSE:To facilitate separation and recovery of gold through sufficient decomposition of a cyanogold cpd. in liquid, by heat treatment of waste liquid contg. the cyanogold compound at a specific temperature and in the presence of a specific amount of water-soluble metal hydroxide. CONSTITUTION:To waste liquid Wo contg. a cyanogold cpd. such as a dicyanoautate (I) in a raw liquid reservoir 1, water-soluble metal hydroxide such as NaOH is supplied in an amount of 0.1mol or more per 1 gram atom of gold in the liquid. This is supplied as already-treated enriched liquid Wo in an enriched liquid reservoir 2. This liquid to be treated Wo is passed through a heat exchanger and preheated, then supplied into a high-pressure reactor 8 and heated by a heater 9 to a temperature of 170 deg.C or more to cause gold and silver to be precipitated. Then, the liquid is guided to a flush tank 13 where steam and NH3 are evaporated. The remaining liquid Wo is stored in a reservoir 14 for treated liquid, and settled so that gold and silver are precipitated and deposited. Supernatant is guided via an evaporation tower 18 to the enriched liquid reservoir 2 and used to be added to the liquid being treated Wo.