Abstract:XRF, XRD, Laser particle size detection, SEM-EDS and other techniques were used to analyze neutralization slag with many kinds of valuable elements and low content obtained from treatment of acid wastewater in copper mine. Sulfuric acid leaching property of neutralization slag was also studied. Leaching toxicity of leaching residue of neutralization slag was investigated. The analysis results show that main elements in neutralization slag are Ca(40.67%), Fe(5.79%), Cu(2.43%), Zn(0.13%), As(0.009%), Ni(0.056%), and is a mixture of metal oxides, hydroxides, sulfates, silicates and arsenates. Main phases are CaSO4, Ca6Fe2(SO4)2, CaO, CuAlO2, Fe2O3, Fe(OH)3, FeAsO4, CuO, Cu(OH)2, and ZnO. Particle size of neutralization slag is 5.00~75.00 μm. The leaching experiment shows that leaching rate of Cu, Fe, As, Zn, Ni is 99.42%, 96.71%, 88.89%, 99.23% and 98.21%, respectively, under the conditions including volume concentration of sulfuric acid of 10%, L/S of 6︰1, leaching temperature of 25 ℃, and leaching time of 180 min. The results of leaching toxicity test show that content of Ni, Cu and As in leaching residue of neutralization slag meets the standard and could be discharged without toxicity.