Effect of mineralizer and synthesis duration on sorption properties of sitinakite and ivanyukite

Titanosilicates with the structure of sitinakite and ivanyukite were synthesized with the use of enrichment wastes of quartz-leucoxene concentrate (Yarega deposit, Komi Republic) by autoclave method. It was found that using a mixture of mineralizer KOH and NaOH at a concentration of 0.15 and 1 mol/l, K-Na sitinakite was formed. Increasing the concentration of KOH to 0.45 mol/L and decreasing NaOH to 0.7 mol/L led to crystallization of ivanyukite. The obtained titanosilicates are characterized by high sorption activity towards Sr2+ and Cs+ cations. Sorption capacity of K-Na sitinakite and ivanyukite for Sr2+ was 95–110 and 102–114 mg/g, respectively. The Cs+ sorption capacity for K-Na sitinakite is 240 mg/g, the sorption capacity for ivanyukite is much higher — 370–380 mg/g. It was shown that the differences in the sorption capacity of K-Na sitinakite and ivanyukite are caused by the features of the crystal structure.