flash smelting

Flash smelting is a metallurgical process that uses the oxidation of sulfides in unroasted ore to generate the heat needed for melting. This autogenous process involves blowing fine, unroasted ore with preheated air into a reaction shaft. The instantaneous reaction causes liquid droplets to fall onto a settling hearth, separating into slag and matte layers. The off-gas, rich in sulfur dioxide, is ideal for sulfur recovery. This method is a modern development in matte smelting, which aims to melt and recombine metallic sulfides into a matte, while separating waste rock into a slag.1

Smelting, in general, is a process of extracting a metal from its ore by heating it beyond its melting point, often with oxidizing or reducing agents. Historically, copper was one of the first metals to be smelted. Modern smelting processes typically involve concentrating the ore first, then heating it with a flux to remove impurities as slag.2