With the continuous large-scale mining of gold mines, the easily leachable gold resources are increasingly exhausted. In order to obtain more valuable gold resources, the miners have turned their goal to the direction of refractory gold resources. However, technically, it is difficult to beneficiate refractory gold ores, so it is necessary to pretreat them first. Next, the editor will explain why pre-treatment is necessary and how to pretreat gold ore.
Generally, the gold ore that needs pretreatment is basically difficult to select. For example, the gold ore contains arsenic, carbon and other impurities, and the leaching stirring rate is less than 80%. So why do we need to preprocess? The purpose is to expose these refractory coated gold particles to facilitate subsequent leaching operations.
1. Through pretreatment, the sulfide containing gold minerals can be oxidized, and then form porous minerals, so that the cyanide solution has a chance to contact with gold particles;
2. It can remove arsenic, antimony, organic carbon and other impurities in gold that hinder cyanide leaching;
3. Pretreatment can turn refractory gold telluride into leachable gold.
At present, the common pretreatment methods of gold ore in mineral processing mainly include: hot pressure oxidation process, roasting oxidation process and biological oxidation process.
1. Hot pressure oxidation of gold ore
It is a process of using air (or oxygen-enriched) to conduct hot pressure gasification in an autoclave. The crystals of sulfide ore and some gangue minerals are destroyed by heating and oxygenation to expose the wrapped gold, and then the oxidation leaching of gold is completed to obtain gold concentrate. The main characteristics of this method are that the oxidation products of pyrite and arsenopyrite are soluble and the gold recovery rate is high; It can directly process the raw ore, which is more effective for the recovery of gold ore that is not easy to float; No smoke pollution problem.
2. Gold ore roasting and oxidation process
Inflation at high temperature will decompose the sulfide ore containing gold into porous oxides, which will expose the gold and obtain qualified gold after leaching. This process has fast processing speed and strong adaptability, especially for ores containing organic carbon, and can comprehensively recover arsenic, sulfur and other associated elements.
3. Biological oxidation of gold ore
It is mainly to use the microorganisms in nature to select the mineral-free strains that are sulfur and iron tolerant. After adaptive cultivation and acclimation, under the appropriate environment, the direct effect of the metabolism of these microorganisms or the indirect effect of the metabolites can be used to directly or indirectly oxidize and decompose the chalcogenide matrix, destroy the pyrite, arsenopyrite and other harmful components that contain gold, and fully expose the gold, So as to create favorable conditions for the subsequent cyanidation gold extraction process and realize efficient recovery. At the same time, in the process of oxidation, the harmful elements such as arsenic and sulfur that cause pollution to the environment in the ore are decomposed into relatively stable harmless salt substances, which are stored after neutralization and sedimentation, without causing pollution to the environment and the atmosphere.
The above is why the gold ore is pretreated and the introduction of several common gold ore pretreatment methods. In order to obtain more gold resources, it is not only difficult to treat gold, but also investment recovery can be carried out when the gold content in the old tailings is more than 3%. Xinhai Mining Equipment can customize the gold ore dressing process plan, gold ore dressing construction plan and complete set of gold ore dressing equipment for various gold mines. If you have any demand, please consult.
