Microbial Pretreatment of Refractory Gold Ore

For coarse grain size of  gold after crushing and grinding by flotation, gravity concentration, cyanide  leaching process or several process combined treatment will be able to complete  the separation of gold and gangue minerals, but there are some curing  refractory gold ores due to coarse size or thin and gangue minerals symbiosis  relations complex factors through the above process unable to complete the  separation process, before the separation must be certain pretreatment. The  common pretreatment methods for gold sulfide gold deposit are oxidizing  roasting method, curing method, acid pressure oxidation, bacterial oxidation  method, nitric acid oxidation method, etc.

Gold ore which is difficult to concentrate often  referred to gold or refractory gold ore, which use conventional cyanide process  cannot effectively extract most of the gold ore. Therefore, it is commonly said  that the treatment of gold is the case of the cyanide method. Part of  refractory gold ores of gold particles with fine gold or submicroscopic gold a  parcel or disseminated exist in sulfide ore and the sulfide is usually pyrite,  arsenopyrite, pyrrhotite, even in some mineral deposits, most of the gold can  enter the crystal lattice of pyrite, arsenopyrite, in the state of super micro  gold. Even if the ore is very thin, it cannot make gold, the gold leaching  effect is very poor. It can be said that this is the most difficult to deal with  the gold in the refractory gold ore. Thiobacillus ferrooxidans was to  autotrophic bacteria that it to sulfide, elemental sulfur, ferrous sulfate,  thiosulfate and other low sulfur compound oxidation in the process of releasing  energy for energy, and carbon dioxide in the air for nutrients to synthesize  bacterial reproduction. These characteristics of Thiobacillus ferrooxidans  makes it become the oxidative decomposition of pyrite and arsenopyrite, exposed  the Au coated ideal bacteria.

Some of the plant refractory gold ore cyaniding leaching  before containing ferrous oxide coli acid bacteria liquid of ore processing,  since Thiobacillus ferrooxidans for aerobic bacteria and sulfide oxidation is  exothermic reaction, so in this strain to treat refractory gold ore must note  oxygen and temperature control. Bacterial leaching with decomposition of pyrite  and arsenopyrite sulfide ability strong, gold and silver recovery rate is high,  no environmental pollution, infrastructure investment and production cost  advantages of bacterial oxidation pre-treatment package containing gold ore is  becoming a clean technology and energy saving by the attention of the countries  all over the world, recognize bacterial pre oxidation treatment process is  likely to replace in the industry to obtain application of oxidizing roasting  and pressure oxidation process.