Poster (EARTH)

[PE1-015] Thermodynamic analysis and slag optimization of WPCBs recycled by bath smelting process

○shuyang yan¹, xueyi guo¹ (1. Central South University)

Keywords:WPCBs, recycle, thermodynamic analysis, slag optimization, bath smelting

Recycling wasted printed circuit boards(WPCBs) by bath smelting process is a feasible method, but the mechanism is unclear. In this work, the component of WPCBs is analyzed and the thermodynamic behavior of metal elements of WPCBs is studied in the high-temperature bath smelting process. The distribution law of valuable metals in the matte phase, gas phase and slag phase is discussed. It is found that metallic oxides (magnesium oxide, aluminum oxide and zinc oxide) entering into the furnace slag affect the physicochemical properties of slag (melting point, density, viscosity and so on). The effects of metallic oxides on the physicochemical properties of furnace slag are studied by analyzing the multi-components phase diagrams and the slag type is optimized to obtain optimum melting conditions. The results show that, the copper and lead elements enter into matte phase mainly in the form of sulfide, While the zinc and tin are concentrated in the fume dusts mostly. The precious metals such as Au and Ag are mainly enriched in matte, and the aluminum and silicon elements are concentrated in furnace slag. Metallic oxides such as magnesium oxide, aluminum oxide and zinc oxide enter into the slag and increase the melting point and viscosity of furnace slag. By adjusting the ratio of silicon dioxide and calcium oxide, the optimum furnace slag could be obtained. The mechanism of WPCBs recycled by bath smelting process is researched in this study and it has certain guiding significance on effective recycling WPCBs.