Articles

The study focused on the solvent extraction of Cr(III) from sulfate media using Cyanex 302 (bis (2,4,4-trimethylpentyl) monothio-phosphinic acid). Various parameters were systematically evaluated, including phase contact time, initial pH, metal ion concentration, extractant concentration, sulfate ion concentration, temperature, and the type of diluent. Equilibrium was reached within 30 minutes, with the highest extraction efficiency occurring at pH 5.0. Adding more Cyanex 302 improved the extraction efficiency. The study showed that each Cr(III) ion paired with a single dimeric extractant molecule. The presence of sulfate ions was found to hinder extraction by forming non-extractable chromium complexes. The extraction process was endothermic, as indicated by positive enthalpy changes. Among the diluents tested, toluene showed the highest extraction efficiency; however, kerosene was chosen for practical reasons. The maximum loading capacity of Cyanex 302 for Cr(III) was determined to be 2.742 g per 100 g of the extractant. Research found that sulfuric acid was good for stripping, but HCl and HNO3 did not work in the conditions tested. Cyanex 302 had a medium level of extraction efficiency compared to other extractants. These results suggest that Cyanex 302 holds promise for industrial applications in Cr recovery processes, although further optimization may be required to enhance its effectiveness.