Mixed rare earth concentrate leaching with HCl–AlCl3 solution

A method of Baotou mixed rare earth concen- trate leaching was investigated. According to the principle of complex leaching, the quadratic orthogonal regression experiment was used to investigate effect of six factors. An optimal condition of low energy and environment friendly was determined as follows: HCl acidity is 4 molL -1 , AlCl3 concentration is 2 molL -1 , reaction temperature is 85 � C, reaction time is 90 min, liquid to solid ratio is 35 mlg -1 , and stirring speed is 100 rmin -1 . According to this condition, the leaching ratio of mixed rare earth con- centrate is 76.5 %. The analyses of X-ray diffraction shows that bastnasite disappears, and the main peaks of filter residue is monazite and cheralite after leaching of HCl- AlCl3 solution. The result indicates that REFCO3 of the mixed rare earth concentrate can be dissolved, but REPO4 remains in the leaching residue. This method provides a way to separate and extract rare earth.