Screening Of Microorganisms For Arsenic Removal And Study On Arsenic Removal From Refractory Gold Ores

Arsenic is widely found in nature.However,it is highly toxic and can damage the gastrointestinal system,respiratory system,skin and nervous system,cardiovascular system,liver and kidney system,blood system and reproductive system if accidentally inhaled,increasing the risk of skin cancer and lung cancer.At present,refractory gold concentrate has become the main resource of the gold industry.Because the gold particles are usually wrapped in pyrite or arsenopyrite,it is difficult to extract by traditional chemical cyanidation method,and the leaching slag has a high arsenic content,which is easy to pose a threat to the ecological environment and human health.However,some leaching bacteria can oxidize and decompose sulfide minerals and arsenic compounds to remove arsenic and expose gold for subsequent chemical gold extraction.This article from the mine wastewater of dexing copper mine in jiangxi province for removing arsenic bacteria was isolated,and select the Burmese refractory gold concentrate of a gold mine plant bacterial leaching experiment was carried out,through the response surface method to optimize the conditions of the bacterial culture,studied the different pulp density and temperature on the influence of the process of bacteria oxidation leaching of gold concentrate,are analyzed in detail under different temperature system of leaching slag,and bacterial oxidation leaching process of gold concentrate,microbial oxidation reactor leaching experiment was carried out,the following conclusions:(1)The leaching bacteria was successfully isolated from the mine wastewater of Dexing Copper Mine in Jiangxi Province.The bacteria can oxidize Fe²⁺to Fe³⁺under the condition of pH 2.0;(2)Response surface methodology was used to optimize the conditions such as pH value,temperature,inoculation amount of bacteria and initial amount of ferrous iron in the process of bacterial culture.Finally,the optimal parameters of bacterial culture were obtained:pH 2.046,temperature 30.867?,inoculation amount of bacteria was 10.987%,and initial amount of ferrous iron was 43.769g/L.Under these conditions,the maximum predicted oxidation rate of ferrous iron was 94.49%.(3)for refractory gold concentrate containing arsenic shaker leaching experiment,the experimental results show that the best pulp concentration is 5%,in 31?,35?and 40?,45?and 50?and 55?,under different temperature 35?and 40?of bacterial oxidation activity is best,leaching rate up to 68.6%,and the mineral surface oxidation decomposition phenomenon is the most obvious,but the jarosite more,affect the subsequent leaching process.(4)The leaching test results of microbial oxidation reactor show that when the temperature is 40?and the pulp concentration is 5%,the leaching effect is the best.However,in order to improve the processing capacity and economic benefits in industrial production and application,10%pulp concentration is the most appropriate.On the basis of these conditions,the distribution of microbial community in the reactor was analyzed.It was found that the dominant species was Sulfobacliius,which accounted for 99%,and the number of other bacteria was less,only 1%.