Research on Extracting Magnesium from Carbide Slag and Magnesite in Flowing Argon Atmosphere

Carbide slag is a kind of industrial waste produced from the calcium carbide industry, which is difficult to treat and cannot be used reasonably. In this paper, carbide slag as a calcium source for extracting magnesium was proposed, i.e., carbide slag was directly mixed with low-grade magnesite instead of dolomite as raw material for extracting magnesium without pretreatment. The process is simple to operate and can obtain metal magnesium while reducing nearly 50% of CO2 emissions in the process of extracting magnesium. In the work, the strength of pellets, the effects of Ca/Mg ratio, and calcination temperature on the recovery rate of Mg were investigated. The results showed that low temperature calcination was beneficial to reduction and the recovery rate of Mg increased with the increase of Ca/Mg ratio, and the reduction rate was 87.95% when the Ca/Mg ratio was 1.2.