Silicon powder production from organosilicon waste by a beneficiation-metallurgy combination process

Abstract

A large amount of waste contact is produced in the preparation of organosilicon monomer. The current researches are mainly focused on copper extraction, with little attention paid to silicon. Moreover, the large accumulation of decoppered residue from organosilicon waste causes environmental pollution and resource waste. In this study, a novel beneficiation-metallurgy combination process was developed for the extraction of silicon from decoppered residue, which was defined as high gradient magnetic separation followed by roasting and acid leaching. The results showed that high gradient magnetic separation was effective in separating silicon from metallic impurities. Under the optimum conditions, the removal efficiencies of metallic impurities are more than 80 %. Fe content in the non-magnetic product can be further reduced to 0.82 % by cleaning. The non-magnetic products obtained by a roughing-cleaning process are subjected to roasting and acid leaching experiments. Under the optimum conditions, the removal efficiency of C and O can reach 94.26 % and 96.32 %, respectively. The final silicon powder product meets the standard of "YS/T1109–2016", which can be reused in the production of methylchlorosilane. This process is suitable for large-scale treatment of decoppered residue and is simple enough to help solve the problem of large-scale output of organosilicon waste.