Application of Green Solvents for Rare Earth Element Recovery from Aluminate Phosphors

Two processes applying green solvents for recovering rare earth elements (REEs) from different types of aluminate phosphors are demonstrated in this report. For magnesium aluminate-type phosphors, a pretreatment with peroxide calcination was implemented first, and then followed by supercritical fluid extraction (SFE) process. Supercritical carbon dioxide (sc-CO2) provides an effective medium extracting REEs dry materials. With the addition complex agent, tri-n-butyl phosphate-nitric acid complex, highly efficient selective using can be achieved. The highest efficiency 92% europium doped barium phosphor (BAM), whereas selectivity more than 99% combined trichromatic phosphor. On other hand, strontium type direct leaching process is suggested. It found out that acetic acid, which considerably green, could have high recovery rate dysprosium (>99%) (~83%) Nevertheless, both showed promising results potential industrial applications.