Sustainable Mining and Metallurgy

The heavy metal contaminated soil in a mining area of Hubei Province was selected. The leaching toxicity and speciation changes of heavy metals Cu, Pb and Zn before and after remediation by blast furnace slag ( BFS ) and its compound material with potassium dihydrogen phosphate ( MKP ) were investigated by passivation experiment and metal speciation analysis experiment. The results showed that the passivation effect of BFS-MKP compound material on soil was better than that of BFS alone. The passivation effect of BFS-MKP compound material on Cu and Pb in soil was better than that of Zn. The passivation efficiency of Cu and Pb reached 86.1% and 88.2%, respectively. In addition, the BFS-MKP compound material can promote the transformation of Cu and Pb with higher activity into more stable forms in the soil. After adding compound materials and curing for 28 days, the proportion of exchangeable Cu and Pb in soil can be reduced from 16.6% and 22.7% to 0.6% and 4.3% respectively, while the proportion of residual Cu and Pb can be increased from 64.3% and 41.7% to 89.3% and 81.9% respectively.