Preparation of ultra-high pure scandium oxide with crude product from titanium white waste acid

• Published in: Journal of rare earths 2023-05, Vol.41 (5), p.764-770
• Main Authors: Peng, Xiujing, Li, Ling, Zhang, Miaomiao, Cui, Yu, Jiang, Xuchuan, Sun, Guoxin
• Format: Article
• Language: English
• Subjects: Rare earths; Recovery; Scandium; TCHDGA; Titanium white waste acid; Ultra-high pure
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/j.jre.2022.04.006

Recovery of scandium from titanium white waste acid is an essential source of scandium. Simple and economical production of high purity scandium remains a challenge. A new extractant, N,N,N',N'-tetracyclohexyl-diglycolamide (TCHDGA), was synthesized, and the separation performance of scandium from impurity metal ions (Ti, Mn, Ba, Fe, Al and Mg) was investigated. The effects of mixing time, acid concentration and temperature on the scandium extraction were considered. The extraction mechanism was studied by infrared spectroscopy and the Equimole Series Method. Under optimized conditions, the extractant shows a strong affinity to scandium in the nitric acid medium and high extraction separation factors between scandium and these impurity metal ions. A process for the purification of scandium was established. The crude product obtained from titanium white waste acid, 95% purity scandium oxide, can be purified to 99.99% after only one step of extraction, scrubbing, and stripping. This technology is economical and straightforward and can realize the high-value recovery of scandium in the titanium white waste acid. TCHDGA has a strong extraction ability of scandium but poor extraction ability of impurity elements, such as Ti, Mn, Ba, Fe, Al, and Mg. It can realize the efficient separation of scandium and impurity elements. [Display omitted]