Precipitation of lithium phosphate from lithium solution by using sodium phosphate

Abstract

AbstractLithium was studied to precipitate into Li3PO4 by adding Na3PO4 under various experimental conditions such as initial lithium concentration of the solution, initial pH of the solution, temperature, and the mol equivalent ratio of Na3PO4. The precipitation mechanism of Li3PO4 was investigated with the change of pH value of the solution over time. The precipitation efficiency of Li3PO4 was 95.4% in the condition of the mol equivalent ratio of Na3PO4 of 1, initial Li concentration of 7 g/L, initial pH of 9.5, and at 90°C. When Na3PO4 was added three times, divided in the mol equivalent ratio of 1 via the hydrolysis reaction of PO43−, which inhibits the Li3PO4 precipitation reaction, an excellent precipitation efficiency of 98.4% was obtained. Co‐precipitated Na2HPO4 with Li3PO4 was washed by distilled water in the condition of solid/liquid ratio of 10% and at 90°C. The purity of the final Li3PO4 product was found to be 99.1%.