Leaching bacteria involved in gold ore

Thiobacillus Fe (Ac i dithi obacillus ferroox idans, bacteria referred A. f), Thiobacillus thiooxidans (Ac i dithi obacillus thiooxidans, referred At bacteria), spirochetes oxyalkylene hook end (Leptosp irillum ferrooxidans, abbreviated L. F Sulfur and heat-resistant thiobacillus ( Su lfo baci ll um t hermosul fidooxidans , all of the above bacteria are acidophilic, aerobic, inorganic and self-supporting, taking CO ₂ in the air as the carbon source, of which the first three They are all moderate-temperature bacteria, and the most suitable pH for growth is 1.5 ~ 2.0, and the temperature is 25 ~ 35 ° C. Among them, Af and At are the most used. The dominant bacteria in oxidative leaching in acidic environment is A. f . A. f is easy to separate and culture, and has certain tolerance to metal ions Cu ²⁺ , Mg ²⁺ , Fe ^{3+ ,} etc. in solution, but it is not heat resistant, and the temperature used generally cannot exceed 40 ° C. oxidation effects mixed bacteria that best .Schrenk et al biological oxidation of sulfide minerals of iron system ferric oxide and iron oxide coli bacteria Leptospirillum strongly acidic environment stated, L. f Af fungi and bacteria are widely distributed on the The biooxidation of sulfide minerals is extremely industrial Application prospects. From the kinetics of leaching reaction, medium-high temperature bacteria can not only significantly accelerate the reaction speed, shorten the pre-oxidation cycle, but also prevent excessive passivation of sulfide minerals and hinder the leaching reaction. More and more attention is paid to the application of medium-high temperature bacteria in biometallurgy. Henry et al. showed that highly thermophilic bacteria grown above 60 °C are difficult to apply in the sulphide ore bioleaching industry, and the optimal growth temperature is 45. Moderate thermophiles at ~55 °C are highly advantageous in industrial applications, because highly thermophilic bacteria are mostly archaea, most of which lack cell walls, and it is often difficult to withstand the high shear forces caused by high pulp concentrations. Moderate thermophilic bacteria have a higher tolerance to pulp concentration. Australia BacTech Company has developed a high temperature heat-resistant bacteria with a heat-resistant temperature of 45-90 ° C and an optimum temperature of 60 ° C. It can survive for several hours under oxygen conditions, and the semi-industrial test of the bacteria has been completed and is planned to be built in Kazakhstan. The Chinese Academy of Sciences Lanzhou Chemical Physics The isolates of T-901 strain and Li Yaxu et al., which have been isolated for 10 years, are moderately thermophilic, capable of simultaneously oxidizing iron and sulfur, and the optimum temperature for oxidizing metal sulfide minerals is 45-50 ° C. Yao Guocheng et al. In order to adapt to the North American climate, Canadian scholars have developed high-activity Af bacteria at low temperatures, the suitable temperature range is 5-35 ° C, and the Af bacteria pair The low temperature oxidation behavior of refractory sulfide ore was studied.

As a living organism, bacteria need various nutrients to ensure their own growth, and on the other hand, they participate in the reaction as a catalyst. Therefore, the acquisition of excellent strains is the key and core of microbial technology. The nutrient medium on which microorganisms depend for survival and reproduction is the medium, which is mainly composed of nitrogen, potassium, phosphorus and trace elements. The medium is divided into liquid medium and solid medium. The liquid medium is mainly used for rough separation and cultivation. Microorganisms, while solid media are primarily used for pure seed isolation of microorganisms. Commonly used leaching media are 9K and Leathen media. Studies by scholars at home and abroad have shown that there is a significant positive correlation between the biomass of the leaching bacteria and the leaching rate and leaching rate. The activity, concentration and biomass of the bacteria directly affect the effect of biooxidation, so many scholars have passed the leaching microorganisms. Nutritional research attempts to promote the problem of low biometallurgical efficiency is effectively addressed. Russian scientists have degraded the discarded collagen in the feed industry into preparations for use in metallurgical microbial leaching processes, which have a good effect on the leaching effect. There is less than 5% yeast hydrolysate in the nutrient solution of the BIOX process. At present, there are few studies in the domestic perspective on the nutritional conditions required for microbial growth. Before using the leaching bacteria, it is necessary to adapt and acclimate various conditions in the industrial environment so that the bacteria enter the logarithmic phase as soon as possible. Liao Mengxia and others have been breeding, separating and domesticating for nearly 10 years. High-efficiency leaching engineering strain Mdl of arsenic 18g/L.

The biological oxidation pretreatment process is a complex reaction process, which needs to be completed by bacteria. Its essence is the life activity of bacteria. The leaching mechanism exhibited by bacteria is direct or indirect, and its internal physiological and biochemical characteristics are It is determined that the number of bacteria used for biological pre-oxidation refractory gold ore and the ability of bacteria to oxidize minerals are affected by the environment. It can be seen that only the strains with strong oxidizing ability and fast propagation speed can be used as strains to ensure cell growth and breeding environment, and the oxidation rate and oxidation rate can be improved.

EPP Packing

Epp Packing,Expanded Polypropylene Packaging,Expanded Polypropylene Foam,Expanded Polypropylene Block

Taizhou Tianma Plastic Products Co. LTD , https://www.tianmaepp.com