Direct recovery of metallic tellurium from spent Bi–Te intermetallic alloy

抄録

With its low abundance in the Earth’s crust and high mining costs, metallic tellurium (Te) is a limited resource. In advanced material industries, it is irrecoverable from solid wastes. Hence, we investigated the hydrothermal treatment of a Bi–Te intermetallic alloy (BT-alloy) to develop an eco-friendly resource recovery technique for recovering metallic Te. High-purity (∼100 mass %) metallic Te powder can be directly recovered from BT-alloy powder (0.1 g) with H₂SO₄ solution (30 mL, 3.0 mol/L) at 200 °C for at least 20 h. With H₂SO₄ and heating, metallic Te was formed by the oxidation of Te²⁻ in the BT-alloy. In this study, we demonstrated for the first time that selective metal deposition by elemental extraction and oxidation from solid materials could be achieved with hydrothermal treatment. Therefore, hydrothermal resource recovery could be used to recover chemical resources, such as metals, directly from solid waste materials.