Control of Copper Loss in Flash Smelting Slag

Pyrometallurgical route is the most effective way to extract copper from Cu–Fe–S ores. In the smelting process, the concentrate is partially oxidized to Cu-rich matte and most of the impurities are reported to the slag. Copper content in the slag represents the direct recovery of copper in the smelting process. High-temperature experiments have been carried out to investigate the effects of slag composition, matte grade, and temperature on copper content in the smelting slag. Industrial and synthetic slag samples were equilibrated with matte at different temperatures in argon gas flow. The quenched samples were analysed by electron probe X-ray microanalysis to obtain the microstructure and phase compositions at high temperatures. Optimised parameters including slag composition, matte grade, and temperature have been proposed for the flash smelting furnace operations to minimize the copper content in the slag. The experimental results are also compared with the FactSage calculations.