Extracting White Phosphorus from AlPO₄ through Molten Salt Processing

抄録

The authors focus on the development of a molten salt processing technology for extracting white phosphorus (P₄) from sewage sludge ash, which is recognized as a potential secondary P source due to its composition of various metal phosphates. This work offers insights into the interaction between solid AlPO₄ and molten CaCl₂. The results show that solid AlPO₄ exhibits favorable solubility in molten CaCl₂, although at a slower rate compared to solid Ca₃(PO₄)₂ due to the presence of stable Al–O bonds. The study also demonstrates the feasibility of extracting high-purity P₄ from the molten mixture through electrolysis. The purity of the obtained electrolyzed P₄ from AlPO₄ is comparable to the commercially available high-purity-grade product. These findings underscore the potential of sewage sludge ash containing AlPO₄ as a viable source for extracting high-purity P₄. This research contributes to the advancement of sustainable P utilization technologies from secondary sources.