Solvent extraction of iron(III) from aqueous hydrochloric acid solutions using D2EHPA, PC-88A, cyanex-272 and their mixtures

Abstract

Background/purpose. D2EHPA, PC-88A and cyanex-272, the phosphoric acid based solvents are widely used in the solvent extraction of non-ferrous, nuclear and other metals. However, information on their use, especially the latter two, for iron extraction is limited. As many hydrometallurgical leaching techniques used for recovering non-ferrous metals result in solutions containing the desired metals as well as iron and as solvent extraction is one of the commonly used technique for metal recovery/separation, detailed information on the extraction behaviour of iron with these solvents is very much essential. Methods. Extraction studies were carried out on laboratory scale using separatory funnels. The acid concentration was adjusted to the desired value before equilibration. The extractants were diluted with kerosene. After phase separation, iron analysis was carried out by atomic absorption spectrophotometry/titration method. Results and conclusions. Iron extraction was found to vary with HCl concentration. The loading capacity of 0.1 M D2EHPA, PC-88A and cyanex-272 was found to be 1.7, 1.3 and 1.8 kg/m(3) respectively. Sodium sulphate and sodium chloride lowered iron extraction efficiency, while sodium nitrate enhanced the extraction efficiency. Synergism was observed with binary mixtures of the extractants.