Tellurium is a metalloid, and the element symbol is Te. The name comes from tellus, which means "land", discovered by F.J.Müller von Reichenstein in 1782. Tellurium is an orthorhombic silver-white crystal, soluble in sulfuric acid, nitric acid, aqua regia, potassium cyanide, potassium hydroxide; insoluble in cold water, hot water, and carbon disulfide. High-purity tellurium is obtained from tellurium powder as raw material, extracted and refined with sodium polysulfide, with a purity of 99.999%. Used as additives in semiconductor devices, alloys, chemical raw materials, cast iron, rubber, glass and other industries.