Study on leaching rare earths from bastnaesite treated by calcification transition

Extracting rare earths from bastnaesite concentrate treated by calcification transition was studied through the single factor test and XRD patterns of bastnaesite after calcification and slags after leaching in HCl solution. And the effects of the main calcified parameters such as temperature, liquid/solid and calcified time on transition performance of bastnaesite were investigated. It was found that under the optimal conditions of calcification temperature of 250 °C, liquid/solid of 20 mL/g, calcification time of 180 min, the highest leaching rate of rare earth were obtained, with the leaching ratio of rare earths 83.70% and Ce 77.01%, La 90.55%, Nd 92.03%, respectively; loss rates of fluorine with different calcification conditions were always less than 1% and XRD patterns of calcification slags and leaching slags showed that fluorine existed in the form of CaF2.

Graphical AbstractXRD patterns of calcified slag at 250 °C for 180 min with a liquid/solid ratio of 10–25 mL/g in 3.94% NaOH solution containing 13.9% CaOFigure optionsDownload as PowerPoint slide