Dissolution of Rare Earth Elements Concentrate from Xenotime Sand with Strong Acids

Abstract

Rare Earth Elements (REE) concentrate from the processing of xenotime minerals still contains a mixture of REE and its impurities, so it requires a further separation process to purify the content of each element. The first step to separating each element of REE is to dissolve the REE concentrate in strong acid as a feed for the liquid-liquid extraction or ion exchange column process. The REE concentrate was dissolved in 3 variations of strong acids, namely hydrochloric acid, nitric acid, and sulfuric acid. XRF and FTIR analyses were done before and after the dissolution process. The results showed that sulfuric acid is the best dissolution reagent for the total rare earth elements (71.75%) but is less selective for separating light REE, heavy REE, and their impurities. Better selectivity for separating light REE and heavy REE is shown by dissolution with nitric acid with dissolution levels of 37.32% and 81.91%, respectively. Meanwhile, hydrochloric acid showed the lowest dissolution results for the total element of REE (63.14%) but had the best selectivity to prevent the dissolving of radioactive elements. The results of the FTIR analysis showed that REE-chloride, REE-nitrate, and REE-sulfate bonds had been formed in each dissolving filtrate.