SDS And PVP Enhanced Biological Leaching Of Manganese In Manganese Slags

Hunan province is famous for the nonferrous metals, with the continuedexploitation of the ore, a large number of waste residue and tail ore containing heavymetals were accumulated. Heavy metal ions were leached into the farmland、surfacewater and groundwater by rain, which seriously endangering the health of localresidents.Xiangtan manganese mine tailing ore were used as raw material, differentconcentrations (0-100mg/L)of non-ionic surfactant SDS and nonionic surfactant PVPwere added to the culture fluid in the leaching process. The effect of differentconcentrations and different types of surfactants on biological leaching wasinvestigated.The ORP potential and the number of Thiobacillus ferrooxidans were used toindicate the growth and activity of Thiobacillus ferrooxidans in the culture system. Thetailings manganese leaching rate was influenced by activity of the Thiobacill us, whichis indicated by ORP. The number Thiobacillus ferrooxidans was determined byhemacytometer. Under the best concentration condition, the effect of differentconcentrations and different types of surfactants on biological leaching wasinvestigated.The results stated clearly that both surfactants can effectively strengthenferrooxidans on the leaching performance of the tailings. The optimum concentrationof SDS and PVP is35mg/L and15mg/L, respectively. Under the best concentrationcondition, the value of pH of the culture medium could be significantly decreased andthe leaching rate would be increased too. The leaching rate reached88%and83%,respectively. The leaching rates of them are both higher than those of control groupwhich is only72%. Results show that SDS is more effectively to promote ORP, toimprove manganese leaching. Electron microscopy also show that SDS can morepromote the thiobacillus on manganese tailings surface erosion, reducing the particlesize of manganese ore surface, and increasing the leaching rate of manganese.According to the test results, the mechanism of leaching manganese ore waspreliminary discussed, a certain concentration range of surfactant can promotemanganese leaching rate, the possible reason is the surface active agent can enhancethe membrane permeability, facilitates the exchange of microbial substances, it may also enhance the cell membrane and improve the activity of enzyme which enhanceleaching directly, the specific mechanism needs further study.