Application of multi-stage vacuum distillation for secondary resource recovery: potential recovery method of cadmium telluride photovoltaic waste

Abstract

With the widespread use of cadmium telluride solar cells, environmental protection, and effective recycling approaches for solar cell component waste have become topics of concern. As an emerging metal smelting technology, vacuum metallurgy technology has broad application prospects in primary metal refining and the recycling of secondary non-ferrous scraps. Thus, this study proposes a new method for the separation and recovery of rare metals from cadmium telluride waste through sulfur smelting and vacuum distillation. In this process, sulfur is smelted with cadmium telluride to produce tellurium with a high vapor pressure. The tellurium was then separated and purified by multi-stage vacuum distillation. The results show that the tellurium purity can reach up to 99.97% and the tellurium recovery rate was above 99%. The cadmium and sulfur contents in the tellurium were 0.0061% and 0.0194%, respectively. Moreover, the cadmium sulfide produced during the smelting process can be enriched by vacuum distillation, resulting in 99.6% purity. This technology strongly aligns with the “reduce, reuse, and recycle” principle for solid waste, and provides a basis for the sustainable development of the photovoltaic industry.