Removal of impurities from scandium chloride solution using 732-type resin

• Published in: Journal of rare earths 2018-03, Vol.36 (3), p.311-316
• Main Authors: Zhou, Guotao, Li, Qinggang, Sun, Pan, Guan, Wenjuan, Zhang, Guiqing, Cao, Zuoying, Zeng, Li
• Format: Article
• Language: English
• Subjects: Impurity; Ion exchange; Rare earths; Reduction; Removal; Scandium
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/j.jre.2017.09.009

The deep removal of Al, Fe(Ⅱ/Ⅲ), Ca, Zr, Ti and Si from scandium chloride solution was carried out by using 732-type strong acid cation exchange resin. The effects of pH value, contact time and complexing agents (EDTA) on the purification process are investigated. The results indicate that the 732-type resin have a good scandium selectivity and the adsorption order is Sc > Fe(Ⅲ)>Al > Ca > Zr > Ti > Si in the pH range of 1–3. The separation of Sc and Zr, Si, Ti can be directly carried out because the resin have a good adsorption effect on Sc, Al and Fe(Ⅲ) but poor adsorption effect on Zr, Si and Ti under the condition of pH = 2.5 and contact time 180 min. The Fe(Ⅱ), Ca and Al are selectively adsorbed on the resin by adding reducing agent ascorbic acid and EDTA into the solution for reducing Fe(Ⅲ) to Fe(Ⅱ) and complexing Sc. By using two-step ion exchange adsorption separation method, the removal rates of Fe(Ⅲ), Ti, Al, Ca, Zr and Si are 95.5%, 99.8%, 100%, 98.2%, 98.6% and 100%, respectively. (1) The 732-type resin hada goodselectivityof Sc. The adsorption order was Sc>Fe(Ⅲ)>Al>Ca>Zr>Ti>Siin the pH range of 1–3. (2) The resin could selectively adsorb Fe(Ⅱ), Ca, Alby adding ascorbic acid to reduce Fe(Ⅲ) and EDTA to complex Sc. The separation of Sc and Fe(Ⅱ), Ca and Al had been carried out by using EDTA as complexing agent and ascorbic acid as reducing agent. (3) A new two-step ion exchange process for removing impurities such as Al, Fe(Ⅲ), Ca, Zr, Ti and Si from scandium chloride solution has beenproposed in this paper. By using this new process, the removal rate of Fe(Ⅲ), Ti, Al, Ca, Zr and Si reached to 95.5%, 99.8%, 100%, 98.2%, 98.6% and 100%, respectively. [Display omitted]