Innovations & Shafts of Refinement

With the abiding in the course of gold and the constant renewal, whose proof is the mining industry of today, numerous innovations are on the way, bettering the existing procedures or opening the possibility of treating the new minerals.

A magazine of the recent innovations has been presented not too long ago by Von Michaelis.

In the last thirty years, the most marked innovations in the industrial exploitation are: the lixiviation of gold in large amounts and the process of absorption of gold by active carbon in pulp.

These procedures have been described previously.

The bettering in the course towards the development and the main axis of refinement are presently:

- The bettering of the permeability of the large amounts by aglomeration of the cement and the extremities of the mineral.

The fine particles, placed by the cement to the thicker ones, are not separated any more, thus avoiding the formation of an impermeable layer.

A complementary bettering consists in adding the cyanide in sodium, under the form of well concentrated solution to the moment of aglomeration. This disposition allows to accelerate the placing in solution of gold.

- The search of new reactives, allowing particularly to work amid acids. In effect, some pretreatments are done (accomplished) in an acid means, which forces the change of water and an expensive neutralization, to pass the basic means of cyanidation. In the same manner, certain minerals present in the solution a natural acidity, being able, for example, condemn the lixiviation in the pile.

Among the examined reactives, the thiourea appears to be the most promising.

The procedure of attack in a thourized means is not known in the industrial development, but has been tested to the scale of the pilot.

The advantages of this reactive are: a quick cynetic (two to three hours), one less sensibility to the variation of composition of the feeding and theconditions of preliminary burning, one recuperation of gold, most of the time better than with the cyanide.

Other reactives, as is the case of thiosulphates, are also object of investigation.

- The lixiviation of gold under pressure. Or an oxidation of concentrates of gold under pressure.

The purpose of these works is to replace the burning of the concentrates of sulphur (problems of getting closer together), of bettering the velocity of extraction, of extraction of gold or of working the refractory or carbonated minerals directly.

The solvent of gold, cyanide or other reactives, is introduced during the treatment under pressure or only after, once the rusted sulphurs and the gold are liberated.

To the present time, these procedures have not had industrial development.

Other numerous domains of the treatment of the minerals of gold, are object of investigation. For example, the bettering of the conception of the instalations of carbon in pulp, towards the more compact and efficient systems the focus of the units of mobile treatment, etc.

The techniques of treatment of the minerals of gold are in total evolution and numerous innovations must be seen in the industrial scale.