Feature Papers in Extractive Metallurgy

Extractive metallurgy deals with the processes for the recovery of valuable metals from ores and concentrates (primary metallurgy) or waste raw materials such as slags, slime, and flying ashes (recycling or secondary metallurgy). Regarding the type of obtained metals, these processes are divided into five different groups: extractive metallurgy of iron and steel, non-ferrous extractive metallurgy, extractive metallurgy of precious metals, extractive metallurgy of rare earth elements, and refractory metal extractive metallurgy. These processes in extractive metallurgy include unit processes for separating highly pure metals from undesirable metals in an economically efficient system. Extractive metallurgy is based on unit metallurgical operations that are usually separated into three categories: 1) hydrometallurgy (leaching, mixing, neutralization, precipitation, cementation, and crystallization); 2) pyrometallurgy (roasting and smelting); and 3) electrometallurgy (aqueous electrolysis and molten salt electrolysis).