Rare metal technology 2022 This collection presents papers from a symposium on extraction of rare metals from primary and secondary materials and residues as well as rare extraction processing techniques used in metal production. Authors cover the extraction of less common or minor metals including elements such as antimony bismuth barium beryllium boron calcium chromium gallium germanium hafnium indium manganese molybdenum platinum group metals rare earth metals rhenium scandium selenium sodium strontium tantalum tellurium and tungsten. Contributions also discuss rare metals of low tonnage sales compared to high tonnage metals (iron copper nickel lead tin zinc or light metals such as aluminum magnesium or titanium and electronic metalloid silicon). Authors also cover biometallurgy hydrometallurgy and electrometallurgy while novel high temperature processes such as microwave heating solar thermal reaction synthesis and cold crucible synthesis of rare metals are addressed. Also included in this collection is the design of extraction equipment used in these processes from suppliers as well as laboratory and pilot plant studies.