Advances in Understanding of the Application of Unit Operations in Metallurgy of Rare Earth Elements

Unit operations (UO) are mostly used in non-ferrous extractive metallurgy (NFEM) and usually separated into three categories: (1) hydrometallurgy (leaching under atmospheric high pressure conditions, mixing of solution with gas mechanical parts, neutralization solution, precipitation cementation metals from aiming purification, compound productions during crystallization), (2) pyrometallurgy (roasting, smelting, refining), (3) electrometallurgy (aqueous electrolysis molten salt electrolysis). The demand for critical metals, such as rare earth elements (REE), indium, scandium, gallium raises the need an advance understanding UO NFEM. aimed metal is first transferred ores concentrates to a using selective dissolution or dry digestion) below 1 bar at 100 °C agitating glass reactor (40–50 bar) temperatures (below 270 °C) autoclave tubular reactor. purification obtained was performed agents sodium hydroxide calcium carbonate more oxalic acid. separation possible liquid (water solution)/liquid (organic phase) extraction (solvent (SX) mixer-settler) solid-liquid filtration chamber filter-press until 5 bar. Crystallization process by which metallic converted crystalline state via supersaturated solution. final step production different methods basic copper, zinc, silver, REE aluminum). Advanced processes, ultrasonic spray pyrolysis, microwave assisted leaching, can be combined reduction processes order produce powders. Some preparation leaching roasting rotary furnace, where sulfidic ore oxidized oxidic form suitable transfer water successfully not only wining primary materials, but also its recovery secondary materials.