Industrial production practice: purification of crude selenium by vacuum distillation

Selenium possesses unique physical and chemical properties and holds irreplaceable significance across multiple fields, including semiconductors, optoelectronics, energy, and healthcare, making it one of the key materials driving the development of modern science and technology. 90% of the world’s selenium is produced from copper electrolytic anode slime, and crude selenium with various impurities and complex forms can be obtained from copper anode slime after comprehensive treatment. Efficient and environmentally benign purification of selenium has emerged as a critical challenge in the metallurgical industry. Conventional selenium purification methods are plagued by inherent limitations: protracted processing, low metal recovery rates, and severe environmental impact. Vacuum distillation is considered an efficient and sustainable physical metallurgical process for selenium purification. Results demonstrate that the novel preconditioning-vacuum evaporation process successfully yielded 99.9% pure selenium with recovery exceeding 99%. This approach enabled clean, efficient purification of crude selenium while concurrently enriching precious metals (e.g. Ag, Au), thereby providing a viable strategy for integrated crude selenium utilisation.