Recovery Of Rare Earth From A Phosphoric Acid By-Product

It is well known that RE (rare earth) not only exist in the individual deposits, but also occur in apatite. China is a phosphorite deposits rich country. The reserve of phosphorite ores is about1.3billion which on average contain0.5‰～1.0‰of RE only in Zhijin, Guizhou. Phosphorite has became one of potential rare earth source, also has been an important part of second source of rare earth. But during the phosphoric acid industry process, much large of rare earth elements are precipitated in the phosphor-gypsum. Therefore, the research of reomving rare earth from a phosphoric acid by-product during wet-phosphoric acid process was taken out in this paper.1. The mainly effect factors during the nitric acid leaching process have been studied, such as temperature, acidity, the ratio of solid to liquid and reaction time of the leaching rate.2. The extraction capacity of different extractants have been compared, such as P204, P507, N1923and P503, and the optimum extractant was selected.3. At the same conditions, the effect of acidity, temperature, the concentration of extractant, the rate of aqueous to organic phase on the separation efficient between Fe and rare earth elements have been investigated. 4. Effect of different acids and acidities on Fe3+loaded organic phase stripping efficiency has been compared.5. The effect factors during the rare earth extraction process have been discussed, such as concentration of P204, the aqueous phase acidity, the rate of aqueous to organic phase.6. Rare earth stripping efficiency at different concentration of hydrochloric acid condition has been studied.The experiments results show that with the nitric acid leaching, the leaching efficiency is up to93.41%. And two steps are taken out with different extractants can separate and recover Fe and rare earth elements from the leaching solution. The recovery rate of Fe3+is81.00%, and rare earth elements is89.83%...