China Nonferrous Metallurgy

Phosphogypsum (PG) is a waste product containing rare earth elements from the phosphate fertilizer industry,with low levels of rare earth elements, but have large reserve quantity, and the recycling of rare earth elements from it has large economic value. The study focuses on the in-depth characterization of phosphogypsum and the study of the leaching process. Microwave assisted acid leaching of phosphogypsum was proposed to acid leaching of the rare earth elements. The results show that under the conditions of nitric acid concentration of 2.0mol/L, solid/liquid ratio of 6∶100，leaching temperature of 80℃ and leaching time of 30min, the leaching rate of total rare earth elements in phosphogypsum was 96.52% under the microwave reactor. The mechanism of microwave acid leaching was investigated with the characterization of SEM and XRD, which further showed that the interaction of microwave and high temperature in the process of microwave acid leaching would destroy the crystal structure to refine the particles, thus promoting the effect of microwave leaching 12.3% higher than that of water bath leaching.