Solvent Extraction of Scandium from the Waste Solution of TiO₂ Production Process

详细信息    查看全文

• 作者：J. Shibata ; N. Murayama
• 关键词：Scandium ; Solvent extraction ; TiO2 ; Dilute solution ; Rare metal
• 刊名：Transactions of the Indian Institute of Metals
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：70
• 期：2
• 页码：471-477
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Metallic Materials; Materials Science, general; Tribology, Corrosion and Coatings;
• 出版者：Springer India
• ISSN：0975-1645
• 卷排序：70

文摘

Extraction and stripping properties of Sc3+ were investigated by using a mixed extractant of Versatic Acid 10 (VA10) and Tri-n-butyl phosphate (TBP). The effect of adding TBP to VA10 was considered by analyzing the binding state of VA10 and TBP by FT-IR. Solvent extraction of scandium from an aqueous solution of Sc3+–Ti4+–Zr4+, which simulated waste water from the titanium oxide manufacturing process, the Bayers process and others, was performed, and the separation factor of Sc3+ over Ti4+ and Zr4+ was investigated. To clarify the operating conditions of a countercurrent multistage process for Sc3+, McCabe–Thiele analysis was applied to the extraction isotherm and stripping isotherm of Sc3+. The extraction pH of Sc3+ was found to shift to higher pH, and Sc3+ was stripped at a lower concentration of H₂SO₄ by adding TBP to VA10. Addition of TBP to VA10 suppresses the extraction of Sc3+ and promotes the stripping of Sc3+. IR spectra of the organic phase suggested that the dimeric portion of VA10 formed hydrogen bonds with TBP. The extractions of Sc3+, Ti4+ and Zr4+ were 77, 3 and 8%, respectively. The separation factors of these metal ions were β_Sc/Ti = 100 and β_Sc/Zr = 38 at pH4.6 on extraction with VA10 + TBP from aqueous solutionof Sc3+–Ti4+–Zr4+. Stripping efficiency of 100, 8 and 22% could be achieved for Sc3+, Ti4+ and Zr4+, respectively by using 0.5 mol/dm3 H₂SO₄. From these results, it was possible to separate Sc3+from impurities such as Ti4+ and Zr4+ by countercurrent multistage extraction, and Sc3+ was recovered by one-stage stripping with 0.5 mol/dm3 H₂SO₄. Extraction of Sc3+from the dilute aqueous solution containing 500 mg/dm3 of Sc3+reached 99% at the flow ratio (A/O) = 1.01 in the two-stage countercurrent extraction, and Sc3+ in the organic phase was stripped to attain a six-fold concentration by applying one-stage stripping with flow ratio of (O/A) = 6.00.