RARE EARTH ORE PROCESSING METHODS BY ACID MIXING, SULPHATING AND DECOMPOSING

文件类型：PDF文档
文件大小：3035K
Described is a process for the selective extraction of rare earth elements from an ore or mineral concentrate material containing one or more gangue-derived elements, such as, iron, aluminum, zirconium and niobium. The process comprises the steps of (i) preparing a mineral concentrate using one or more beneficiation methods to reduce the amount of ore processed and economically maximize the recovery of rare earth elements; ii) mixing concentrated sulphuric acid in super-stoichiometric amount to the mineral concentrate to produce a homogenous agglomerate or powder mixture; (iii) heating said mixture to promote the sulphation of the rare earth and non-rare earth metals in a first thermal vessel; (iv) increasing the temperature to selectively decompose non-rare earth metal sulphates in a second thermal vessel; (v) leaching the material formed in (iv) to produce a leach solution containing the rare earth elements, that is substantially free of gangue elements.