Minerals with Iron Sulphurs

The gold is presented, generally, in these minerals at the same time disseminated in the sulphurs and in Free State.

Certain sulphurs, the pyridine in particular, are dissolved in the solution of attack, consuming the reactive and inhibiting the dissolution of the gold. One aeration in presence of lime, in an upward movement from the Cyanidation, is treatment generally practiced in these cases.

The pyrite is the most frequent sulphur in this category of mineral. The habitual treatment consists in a flotation of sulphurs and of free gold, followed by a Cyanidation of the concentrate eventually re-grinded. A previous burning of the Cyanidation allows liberating the gold when it presents itself disseminated in submicroscopic inclusions in the pyrite.

Minerals of Sulphurs, Arsenic & Antimony
Generally, the gold is presented in these minerals very finely disseminated in the sulphurs.

The arsenic and the antimonies produce more those refractory minerals to the direct Cyanidation: the treatment consists then, in one concentrate of gold by flotation of the sulphurs followed by a burning and a Cyanidation of the concentrate.

Minerals with Telluriums of Gold
These minerals contain part of the gold under the form of telluric. These are frequently accompanied by natural gold and by disseminated gold in the sulphurs.

The treatment of this type of minerals is more complex than the previous ones.

It can typically support a flotation of sulphurs followed by a Cyanidation, of a burning of the residues and of the re-Cyanidation of the mortar.

The residues of the flotation are also eventually cyanidated.