2013 Volume 129 Issue 2_3 Pages 65-71
The extraction of metals from printed circuit board waste (PCBW) in an autoclave at a high temperature and high oxygen pressure was studied for the purpose of metal recycling. Metals were extracted from the crushed PCBW sample in 1.0mol/L H2SO4 solution under the optimum extraction conditions at a pressure of 2MPa, temperature of approximately 120°C, retention time of 0.5h respectively and in the case of 100g/L pulp density. The extraction rates of Cu, Ni, Mn and Co were over 95%, those of Zn and Al were up to 94%, and over 80% of Cr was dissolved into the solution.
Several methods of selective metal recovery from extracted solution involving neutralization, sulfidation, and solvent extraction were investigated in this study. Over 99% of Cu in the solution was precipitated as CuS by sulfidation using NaHS. Zn and Co were recovered by solvent extraction at pH values of 2.4 and 4.2 respectively, using extractant PC88A. Cr and Al were precipitated as hydroxides by neutralization at pH6 using powdered CaCO3. Ni was recovered by solvent extraction at pH 6.0 using extractant LIX84I. Mn was recovered as its hydroxide by neutralization at pH10.3.
