A PROCESS FOR RECOVERING ZINC VALUES AS COMPLEX ZINC CYANIDE SOLUTION AND USE OF THE SAME FOR STRIPPING COPPER FROM LOADED ANION EXCHANGE MATERIAL

摘要

A method for obtaining complex zinc cyanide anions from a precipitate comprising zinc hydroxide and calcium sulfate. The method comprises subjecting such a precipitate to a zinc leaching step comprising contacting the precipitate with calcium cyanide in an aqueous liquid medium so as to obtain an aqueous alkaline zinc containing solution comprising complex zinc cyanide anions and remaining product precipite comprising calcium sulfate. A thus obtained "complex zinc cyanide anions" containing solution is used to desorb copper from an ion exchange material wherein copper and precious metals are loaded, said ion exchange material having been contacted before with a cyanide leach liquor comprising complex metal cyanides, e.g. gold, silver, copper and the like. The zinc and cyanide values loaded on the anion exchange material after copper stripping are removed from the exchange material by acid zinc stripping with sulphuric acid.