1. Properties

Selenium was discovered in 1817 by Jöns Jakob Berzelius in the red roasting residues of pyrite from the Fahlun mine (Sweden), used to manufacture sulfuric acid.

Tellurium was discovered by Müller von Reichenstein in 1782, but it was Martin Heinrich Klaproth who isolated and named it in 1798, in the gold ores of Transylvania.

Selenium's chemical properties first favored its use in the glass industry as early as 1915, as a bleaching agent replacing manganese [10] . The development of semiconductors and photoconductors over the last thirty years has been partly ensured by the availability of selenium and tellurium in high purity levels. Similarly, steelmaking and alloy metallurgy have continued to evolve towards products...