Roasting Pyrometallurgy

roasting consists of thermal gas–solid reactions, can include oxidation, reduction, chlorination, sulfation, , pyrohydrolysis.

the common example of roasting oxidation of metal sulfide ores. metal sulfide heated in presence of air temperature allows oxygen in air react sulfide form sulfur dioxide gas , solid metal oxide. solid product roasting called calcine . in oxidizing roasting, if temperature , gas conditions such sulfide feed oxidized, process known dead roasting . sometimes, in case of pre-treating reverberatory or electric smelting furnace feed, roasting process performed less required amount of oxygen oxidize feed. in case, process called partial roasting because sulfur partially removed. finally, if temperature , gas conditions controlled such sulfides in feed react form metal sulfates instead of metal oxides, process known sulfation roasting . sometimes, temperature , gas conditions can maintained such mixed sulfide feed (for instance feed containing both copper sulfide , iron sulfide) reacts such 1 metal forms sulfate , other forms oxide, process known selective roasting or selective sulfation .