Experimental Study on Smelting of Waste Smartphone PCBs Based on Al2O3-FeOx-SiO2 Slag System

Waste smartphone, as an important type of secondary resource has high content of rare and precious metals. The traditional mechanical process could easily lead to the dispersion and loss of precious metals. In this research, a smelting method using Al2O3-FeOx-SiO2 slag system is proposed to recover the valuable metals in smartphone PCBs. Based on the evaluation of liquidus projection calculated and plotted by Factsage software, reasonable smelting temperatures and slag composition ranges were selected, namely 1300℃-1500℃, 10-15wt% Al2O3, FeO / SiO2 ratio of 0.8-1.5. Then several lab experiments were conducted, with Cu-Fe-Sn-Ni alloy obtained. The results show that distribution of valuable metals could be controlled by appropriate oxidation of iron. Rare metals primarily enrich in the alloy, and most of active metals like Fe, Al in slag as oxide. Recovery efficiencies of Cu, Ni, Sn, Au, Ag are more than 95wt%.