Preparing 5N Selenium from Crude Selenium Using a Simple Oxidation–Atmospheric Sublimation–Dissolution–Reduction Method

High-purity selenium (Se) is widely used in the electronics industry. It is derived from copper anode slime in the electrolysis process. Therefore, the development of preparation and purification technologies for Se is crucial for copper smelting enterprises. In this study, a simplified method for purifying Se from crude selenium (Se) powder through a sequence of oxidation, sublimation, water dissolution, and reduction under atmospheric pressure was introduced. The efficacy of the method was validated through a laboratory test involving 50 g of crude SeO₂ powder and a semi-industrial scale experiment with 50 kg. Additionally, an independently designed purification equipment was developed for this process. The saturated vapor pressures of different oxides are calculated and compared theoretically. The findings demonstrate that all fourteen impurities present in the high-purity Se product meet 5N Se standard, and the direct yield of selenium was greater than 97%. This method necessitates basic equipment and is easy to operate, offering a novel technical approach for producing high-purity 5N Se.