Precious Metal Distributions Between Copper Matte and Slag at High P_{{{text{SO}}_{ 2} }} in WEEE Reprocessing

Abstract

The distributions of precious metals (gold, silver, platinum, and palladium) between copper matte and silica-saturated FeOx-SiO2/FeOx-SiO2-Al2O3/FeOx-SiO2-Al2O3-CaO slags were investigated at 1300 °C and P_{{{text{SO}}_{ 2} }} = 0.5 atm. The experiments were carried out in silica crucibles under flowing CO-CO2-SO2-Ar gas atmosphere. The concentrations of precious metals in matte and slag were analyzed by Electron Probe X-ray Microanalysis and Laser Ablation-High-Resolution Inductively Coupled Plasma-Mass Spectrometry, respectively. The precious metal concentrations in matte and slag, as well as the distribution coefficients of precious metals between matte and slag, were displayed as a function of matte grade. The present results obtained at P_{{{text{SO}}_{ 2} }} of 0.5 atm were compared with previous results at P_{{{text{SO}}_{ 2} }} of 0.1 atm for revealing the effects of P_{{{text{SO}}_{ 2} }} and selected slag modifiers (CaO and Al2O3) on precious metal distributions at copper matte smelting conditions. The present results also contribute experimental thermodynamic data of precious metal distributions in pyrometallurgical reprocessing of electronic waste via copper smelting processes.