Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

The extraction chromatography method was employed to investigate separation characteristics of heavy rare earth element mixtures(Gd, Tb, Dy, Ho) for various resin packing, eluents, temperatures, concentrations of eluents and flow rates. When P507 was used as the extraction resin, separation efficiencies were improved with packed heights. Therefore, high separation efficiencies (aGdTb=0.280, aTbDy=0.468, aDyHo=0.566) could be achieved with packed height of 28 cm compared to those (aGdTb=0.232, aTbDy=0.278, aDyHo=0.347) with packed height of 14 cm. Also, HCl appeared as the best eluent compared to HNO3 and H2SO4 with improved efficiencies of 12.3 and 59.4% respectively. However, CH3COOH was found not suitable as an eluent. Furthermore, separation efficiencies were improved at high extraction temperature. On the other hand, high concentrations and high flow rates of eluents decreased separation efficiencies and amounts of effluents. Consequently, the highest separation efficiencies (aGdTb=1.050, aTbDy=1.020, aDyHo=0.960, effluent 6,460 ml ) could be obtained under the optimum condition (temperature: 50oC, eluent: 0.5 mol / l HCl, flow rate of eluent: 4 ml / min). At this condition, 99% of high purity Gd, Tb, Dy( > 99.9%) could be recovered respectively.