Leaching kinetics of rare earth elements from phosphogypsum with sulfuric acid

Researchers have done lots of work on the leaching of rare earth elements (REEs) from phosphogypsum (PG), but there are few studies on the leaching kinetics. Therefore, this paper studied the leaching kinetics of REEs from PG using sulfuric acid as the leaching agent. The study results showed that an increase in the leaching temperature and time could improve the REE leaching rate. At 80℃, the total leaching rate of REEs reached up to 55.8%, of which the leaching rate of Y was the largest of 63.9%. And the REE leaching had a strong linear correlation with the dissolution of calcium sulfate dihydrate. The kinetics model fitting showed that the interfacial transfer and diffusion was the rate-controlling step for REE leaching from the PG sample, and the apparent activation energy was 9.10 kJ/mol.