M.K. Razi
Azad university Tehran North Branch,
Iran, Islamic Republic of
Keywords: rare earth elements, phosphate concentrate, by products, environmental friendly
Summary:
The present invention relates to methods for extraction of total rare earth elements from phosphate concentrate as main product and calcium nitrate, NPK, MAP, DAP and iron oxide micro powder as by-products of apatite ores by nitro phosphate method. That comprises to multi-stage process are included Leaching, neutralization, filtration of impurities, solvent extraction, precipitation of REEs in complex compounds and calcination. The claimed batch methods carried out in semi-pilot plant that has the capability of industrial scale. The REE are important in many fields of advanced materials industries has increased significantly. The main attraction of the proposed process is to perform operations in the liquid phase and to be environmentally friendly. This process relates to the treatment of a solution directly separated from the acidic leaching of phosphate concentrate and recovery of organic solvents in SX. In such process, all of the rare earths become complex compounds and phosphate ions converted to di-calcium phosphate, mono-calcium phosphate, and ammonium phosphate. In addition, the impurities on filter of the first stage of acid leaching are converted to micro-powder of iron oxide as magnetite.