Highly Selective Solvent Extraction of Ti⁴⁺ from Zr⁴⁺ by Using Water-soluble Calixarenes and Methyltrioctylammonium Chloride

Abstract

In order to remove some metal impurities such as Ti and Fe in a zirconium ore, the solvent extraction study of Zr⁴⁺, A³⁺, Ti⁴⁺ and Fe³⁺ (M^m+) in an aqueous solution containing some water-soluble sodium calix[n]arene-P-sulfonates, Na_n1_n( n = 6, 8), was carried out by using methyltrioctylammo nium chloride, MTA⁺C1^-, in chloroform. Almost all of Ti⁴⁺ and about 60% of Fe³⁺ were extracted from the aqueous solution of pH 2-3 into the chloroform phase, by forming a metal complex with 1_n^n- and associating the resultant complex with MTA⁺. On the other hand, Zr⁴⁺ and Al³⁺ were hardly extracted and remained in the aqueous phase. As a result, almost all of Ti⁴⁺ and 60% of Fe³⁺ were removed from ze, by the single extraction procedure. The extracted M^m+ was recovered from the organic phase into a 3 M H₂SO₄ (1 M=1 mol dm^-3) solution, followed by the treatment with 4 M HC1, 1_n^n- innin the organic phase was also recovered separately.