A Study on the Extraction Equilibria of the Holmium(III) and Erbium(III) with Acidic Extractants

• Main Authors: Yi - Chun Chang, 張詒鈞
• Other Authors: 蔡德華
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/8szfxj

碩士 === 國立臺北科技大學 === 化學工程研究所 === 99 === In this study, the equilibrium of the separation of Holmium(III) and Erbium(III) by solvent extraction methods were investigated at 25°C. The acidic extractants D2EHPA and PC-88A were used. The extraction equilibria of Holmium(III) and Erbrium(III) in extractants-kerosene solution and extractants-aqueous solution were studied, respectively. The extraction equilibria of Holmium(III) and Erbium(III) from an aqueous chlorate medium with D2EHPA and PC-88A as an acid extractant were studied. The experimental results indicated that the distribution coefficients for the extraction of Holmium(III) and Erbium(III) increased with increasing either concentrations of extractant in the organic phase or equilibrium pH values in the aqueous phase. Based on graphical and numerical analysis. The compositions of Ho/D2EHPA complex formed in the organic phase were found to be HoA3(HA) and HoA3(HA)2, and the respective corresponding equilibrium constants were KHo31 = 2.514 kmol/m3 and KHo32 = 33.541 (kmol/m3)0.5 ; The compositions of Ho/PC-88A complex formed in the organic phase were found to be HoA3 and HoA3(HA), and the respective corresponding equilibrium constants were KHo30 = 0.036 (kmol/m3)1.5 and KHo31 = 0.463 kmol/m3 ; The compositions of Er/D2EHPA complex formed in the organic phase were found to be ErA3(HA) and ErA3(HA)2, and the equilibrium constants were KEr31 = 7.876 kmol/m3 and KEr32 = 45.98 (kmol/m3)0.5 ; The compositions of Er/PC-88A complex formed in the organic phase were found to be ErA3, and the respective corresponding equilibrium constants were KEr30 = 0.50 (kmol/m3)1.5.