Solubility of Copper and Nickel in CaO-SiO2-Al2O3-MgO Slag

In this study, the solubility of Cu and Ni, which are the main metal components of waste PCB in a CaO-SiO2-Al2O3-MgO slag system, was investigated by the chemical equilibration technique in the temperature range 1673-1823 K, under a CO-CO2 atmosphere. The concentrations of Cu and Ni in the slag increased with increasing oxygen partial pressure and MgO content in the slag. The concentrations of Cu and Ni in the slag decreased with increasing temperature. The concentration of Cu in the slag decreased with increasing activity of CaO, but that of Ni increased. The dissolution mechanisms of Cu and Ni in the CaO-SiO2-Al2O3-MgO slag could be described by the following equations from the effect of oxygen partial pressure and slag basicity on Cu and Ni dissolution behaviors: Cu (1) + 1/4 O-2 (g) = Cu+ (slag) + 1/2 O2-(slag) Ni (1) + 1/2 O-2 (g) + O2-(slag) = NiO22-(slag) From the results obtained, the enthalpy changes from dissolution of Cu into the CaO-SiO2-Al2O3-MgO slag were calculated to be -59.17 kJ/mol, and that for Ni was calculated to be -78.89 kJ/mol.