Method for recovering gold and silver from refractory gold ores

Abstract

The invention discloses a method for recovering gold and silver from refractory gold ores, and belongs to the field of metallurgy. The method includes two steps: firstly, pre-oxidizing and breaking inclusions of the gold and the silver in a hot-pressing manner, oxidizing organic carbon in the ores, and recovering sulfur in the ores; secondly, recovering the gold and the silver in presoaked residues by cyanidation or other non-cyanide leaching. The gold and the silver are recovered from the refractory gold ores by the method, the recovery rate of the gold and the silver is higher than 90% and increased by 40 percentage points as compared with that of a conventional cyanidation method, and the recovery rate of the sulfur is higher than 50%. By the aid of the scheme, production cost is about 400 Yuan / ton. Compared with biological oxidation, two-stage roasting and conventional hot-pressing oxidation processes, investment and the production cost can be reduced, the recovery rate is increased, multi-element comprehensive recovery is realized, environmental pollution is reduced, and economic and social benefits are obvious.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, in particular to a method for recovering gold and silver from refractory gold ores. Background technique [0002] Refractory gold ores mainly refer to those ores that are not suitable for direct cyanidation without pretreatment. There are mainly three types of such ores: [0003] 1) Gangue, such as silica or carbonate-coated gold, the gold particles in this type of ore are too small to be dissociated by grinding means, so it is difficult for the gold particles to contact the cyanide solution; [0004] 2) Gold is encapsulated by sulfide minerals—mainly pyrite and arsenopyrite, which is the largest type of refractory gold ore; at the same time, fine grinding is not enough to make the encapsulated gold particles contact the leaching solution; [0005] 3) Carbonaceous gold ore, this type of ore contains a certain amount of organic carbon, and the organic carbon has certain properties of activated...

AI Technical Summary

Problems solved by technology

[0007] The advantage of two-stage roasting is that arsenic and sulfur can be recycled, but the disadvantage is that the recovery rate of gold is low, generally about 85% to 88%, and the oxides produced by roasting arsenic-containing minerals are highly toxic and cause great environmental pollution.

[0008] The advantage of biological oxidation is that the recovery rate of gold is high, generally up to 95% to 97%. The disadvantage is that it is difficult to recycle arsenic and sulfur, and they are mainly stored in the form of neutralized slag; The requirements on the nature of ore feeding and operating conditions are relatively strict, and ore blending conditions, pre-oxidation temperature, and pH have become the key conditions restricting production. If you are not careful, it is easy to cause a major accident in which a large number of bacteria die

The advantages of hot-press leaching are the same as those of biological oxidation. The recovery rate of gold is relatively high, which is about 90% to 97%. The disadvantage is that arsenic and sulfur cannot be recovered, and both exist in the neutralization slag; because sulfur is oxidized into sulfuric acid, the neutralization cost is also high, and at the same time, the high temperature and high pressure process conditions also lead to high equipment cost and maintenance costs

Images