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The degradation capacity of the four chlorimuron-ethyl-degrading strains, D310-1, LCY-2, LCY-3 and LCY-4, which identified asRhodococcussp.,Stenotrophomonas maltophilia sp,Bacillus subtilis sp., andRhodotorula mucilaginosasp., respectively, combined in different ways was examined in this study. Then the optimal degradation conditions and mitigation phytotoxicity of chlorimuron-ethyl on sensitive crop were investigated by both orthogonal test and pot culture experiment. The experimental results showed that the combination of four strains was adopted, and the removal rate of chlorimuron-ethyl reached the maximum of 90% in 30 days. Then the optimal degradation conditions were inoculum size 2.5%, temperature 28°C, pH 7.0 and the soil moisture 35%, and the mixed strains could eradicate 92.57% of chlorimuron-ethyl within 30 days. Furthermore pot culture experiment indicated that inoculation of mixed strains could also mitigate the phytotoxic effects of chlorimuron-ethyl on the growth of cucumber seedling.

Exhaustion of high-grade magnetite resources and large demand for iron ore in the rapidly developing steel industry promotes the mining enterprises to exploit low-grade magnetite. Low-grade magnetite with a low content of valuable minerals is hard to be separated with the conventional separation process flow because of its high beneficiation costs. By preconcentration technology, enriching valuable minerals and discarding large amounts of gangue as soon as possible before grinding, low beneficiation costs can be achieved in low-grade magnetite’s beneficiation. After continuous researches and production practices and the development of relevant efficient crushing and separating equipments, preconcentration technology has made great progress: from crushing-dry magnetic separation technology to grinding-wet magnetic separation technology, then to ultrafine crushing-wet magnetic separation technology. Now preconcentration has become an indispensable stage in low-grade magnetite’s beneficiation.

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