The so-called refractory gold ore refers to the ore and concentrate that cannot be satisfactorily leached by the traditional cyanidation process under normal grinding conditions. Some people also call it difficult metallurgical or refractory gold ore. According to the reasons for its difficulty in handling, it can be divided into the following three categories. (1) Wrapped gold mines. Such gold ores, the gold at a relatively fine granularity encapsulated in sulfide ore arsenopyrite, pyrite, arsenopyrite, yellow copper ore, pyrrhotite, galena, sphalerite, and the like, thereby preventing the The effective contact of gold with cyanide hinders the leaching of gold. The gold minerals of this type are very fine in size, and it is difficult to expose the gold particles by fine grinding or ultrafine grinding. Such gold mines are usually cyanated directly by conventional cyanidation with an extraction rate of less than 40%. (2) Gold-bearing material type gold ore. This type of gold ore contains a certain amount of organic carbon and inorganic carbon. When gold is extracted, in addition to the cyanidation process in which gold is transferred into the solution, there is also a "golden effect" caused by the adsorption of the gold cyanide complex in the solution by the carbon material. ", so that the gold that has been leached back into the dregs, affecting the leaching of gold. (3) Complex polymetallic symbiotic gold deposits. Many gold often with copper, zinc, antimony, mercury, tellurium oxide and sulfide minerals intergrowth of these complex multi-metal associated to economically mine sorted single concentrate, when cyanide, multi-metallic minerals symbiotic unstable Sulfides and harmful impurities in the ore (usually present in large amounts) react with cyanide, oxygen or alkali, consuming large amounts of cyanide, oxygen, and alkali. The cyanide product formed by the reaction often reduces the dissolution rate of gold after entering the solution. When the metal sulfide in the ore is in contact with gold, the gold anode is dissolved and passivated. For such ore, the conductive sulfide ore needs to be transformed into a non-conductive oxidized ore. Some metal minerals such as gold telluride and black blunt The gold-containing compounds formed during the reduction roasting of gold ore, etc. dissolve slowly or even insoluble in the cyanide solution; the compounds such as iron oxide, antimony and lead present in the ore form a protective film on the surface of the gold particles, hindering the leaching of gold. Gold ore, which is usually suitable for pretreatment with bacterial oxidation, is the first major category, the most common being arsenopyrite and pyrite-type gold. To sum up, the reasons for the difficulty of processing these gold mines can be summarized as follows: (1) mechanical wrapping of physical wrapping, chemical crystal solid solution and chemical coating film, so that cyanide can not be in contact with gold minerals; (2) consumption The presence of cyanide oxygen-depleting substances, metal sulfides and oxides such as arsenic, copper, antimony, iron, manganese , nickel , cobalt, etc. have higher solubility in solution, and consume a large amount of cyanide and dissolved oxygen in the solution; The existence of gold robbing, such as carbonaceous materials, clay and other gold shards can absorb gold complexes when leaching gold, gold is "hijacked"; (4) the presence of conductive minerals, gold and bismuth, tin , antimony and other conductive Certain compounds formed by minerals make the cathode dissolution of gold passivated. Therefore, top treatment is generally required before leaching. vacuum oil filter,high efficiency oil purifier,oil filter cart Huatao Group , https://www.huataofilter.com
With the large-scale mining of gold ore, leaching of gold resources depleting easy, refractory gold ores will be a major resource for future gold industry. According to statistics, about one-third of the world's total gold production is currently produced by gold mines. Among the proven gold reserves in China, 30% are difficult to handle gold mines. For refractory gold mines, the pretreatment methods currently used include roasting method, pressurized oxidation method, chemical oxidation method, etc., but have the disadvantages of low gold recovery rate, large investment, large pollution, and high environmental control cost. Therefore, under the conditions of increasing minerals, easy-to-treat mineral resources, increasing environmental protection requirements, and increasing demand for metals in modern industrial and technological development, non-polluting microbial oxidation technology is attracting attention.