Thiosulphate and Halogenous

Thiosulphate
The use of thiosulphate was the preferred method before the appearing of the cyanidation, one hundred years ago, and will displace it completely. Recently, betterings of the process have been performed and hava been used in lixiviation of gold and silver from residues of oxidation by pressure.its use in the lixiviation of complex sulphurate concentrates has also been studied in its use, using ammoniacal solutions of thiosulphate.

Halogenous
the halogenous have always been conidered for the dissolution of gold and of the silver, taking the chlorides as an example. In the decade of the seventies, the alcaline chlorination was used as a pretreatment for carbonaceous minerals.

Other halogenous, as is the case of bromine and ionide, have been studied and tested recently. The ionide is very effective and its complex is is more stable than that of bromine, which at the same time is more stable than that of chlorine. For the recuperation of gold and of the ionide a special electrolithic cell has been proposed.