INDIUM EXTRACTION FROM SOLUTIONS WITH MODIFIED ALUMINOSILICATES

The aim of this work was to study the adsorption of indium from aqueous solutions on modified highly dispersed aluminosilicates for the recovery of indium from technological solutions. The adsorption isotherms of indium, iron and zinc from multi component solutions on modified by di(2-ethylhexyl) phosphoric acid montmorillonite were obtained. It was shown that adsorption processes can be reliably described by models of Langmuir and Freundlich (R2 = 0.96–0.99). The shape of the isotherms is determined both by the surface properties of the sorbent and forms of presence of metal ions in aqueous solutions. The highest value of Langmuir constant Kads = 422.65 for reagent "Metоsol" was obtained for ions of indium, which indicates the preferential affinity of the sorbing mineral to this element, since the corresponding figures for the ions Fe2+ (1.09) and Zn2+ (0.78) are close to unity. At sorption of metal ions from model solution in the range of acidity of 1-20 g/dm3 of H2SO4 the extraction of indium remains unchanged at ~70 %, and iron – is reduced from 39 to 15% of the initial content. With the further increase of acidity to 100 g/dm3 of H2SO4, the recovery of indium is reduced to 40 %; iron down to 14 %. In the examined range of concentration of sulfuric acid the extraction of zinc is from 6.0 to 7.5 percent. The value of the static exchange capacity for the studied metals are mmol/g: 0.39–0.23 of indium; 0.11–0.04 of iron(III); 0.05–0.04 of zinc. A rank of affinity of reagent "Metоsol" to extract the metal ions from solution with pre-reduced iron(III) was In3+ > Fe2+ > Zn2+ which determines the feasibility of its use for the selective adsorption of indium from the complex composition of technological solutions of zinc production.