In this study,the mixed rare earth concentrate was used as raw material to study the decomposition process of monazite by sulfuric acid in low temperature liquid phase.The effects of sulfuric acid concentration,reaction temperature,reaction time,reaction liquid-solid ratio and leaching time on the decomposition rate of monazite were explored,the changes of the phases during the reaction were explained and the kinetic processes were analyzed.The optimal reaction conditions are sulfuric acid concentration 98％,reaction temperature 130 ℃,reaction time 120 min,reaction liquid-solid ratio 3∶1(mL/g)and leaching time 80 min.Under these conditions,the leaching rate of P2O5 is 99.84％,the leaching rate of F is 76.38％and the leaching rate of REO is 72.46％,respectively.The analysis shows that the monazite in the mixed rare earth concentrate is basically completely decomposed and the main material phase component in the water leaching residue is bastnaesite.The conversion process of element P was in accordance with the external diffusion control model with the reaction kinetics model as Kt=1-3(1-X)2/3+2(1-X),the apparent activation energy is 74.71 kJ·mol-1.
关键词
独居石/硫酸/低温液相/浸出率/动力学/稀土
Key words
monazite/sulfuric acid/low temperature liquid phase/leaching rate/kinetics/rare earths
维普
万方数据