MgCl₂ Enhances Phosphate Dissolution in Molten CaCl₂

Efficient dissolution of phosphate in molten CaCl₂ is crucial for the electrochemical production of white phosphorus (P₄). This work investigates the role of MgCl₂ in enhancing the dissolution of solid Ca₃(PO₄)₂ in molten CaCl₂ at 850 °C. The findings reveal that MgCl₂ substantially increases the solubility of phosphate and accelerates its dissolution. By reducing the activity of O²⁻ in the melt, the presence of MgCl₂ facilitates the conversion of PO₄³⁻ to more soluble forms such as P₂O₇⁴⁻ and PO₃⁻, thereby promoting the dissolution of phosphate. This improvement is vital for optimizing the molten-salt-mediated electrochemical production of white phosphorus.