From one poorly soluble phase to another: feasibility of leaching rare earth phosphates with concurrent precipitation of rare earth oxalates

This project was on the feasibility of leaching minerals of rare earth phosphate with oxalic acid in order to precipitate rare earth oxalates concurrently. The precipitation of rare earth oxalates was modelled based on experiments. A logarithmic distribution coefficient was proposed based on thermodynamic terms. A qualitative kinetic study was conducted on the dissolution of rare earth phosphates in mixtures of hydrochloric and oxalic acid. The use of esters of oxalic acid was trialled in an attempt to overcome the limited extent of conversion.