Abstract: The properties of melted slag,which is the product of melting and solidification,were studied.The experimental results show that main compositions of melted slag,i.e.CaO,Al₂O₃ and SiO₂,account for 99% of the total mass,but the mass fractions of SO₃,K₂O,Na₂O and Cl elements decrease from initial 10.74%,8.58%,3.81% and 20.59% to final 0.17%,0.04%,0.23% and 0.11%,respectively.In melted slags,alkaline oxide content is basically similar to that of acidity oxide,and the alkalinity is close to 1;the fixed rate of heavy metals Cr and Zn are higher（94.2% and 81.7%）,but those of Cu,Pb and Cd are lower,which are 31.4%,14.5% and 24.6%,respectively.The TCLP was conducted to study the heavy metal leachate concentrations,and the results showed that the leachate contents were lower than the regulatory thresholds of the standard of hazardous waste toxic identification.