Stripping of Fe(III) from the loaded mixture of D2EHPA and TBP with sulfuric acid containing reducing agents

Abstract

Solvent extraction of Fe(III) from chloride solution by using a mixture of D2EHPA (Di-(2-ethylhexyl)- phosphoric acid) and TBP (Tri-butyl phosphate) and the reductive stripping of Fe(III) from the loaded organic were investigated. Quantitative extraction of Fe(III) from the solution (Fe concentration = 90 g/L) was accomplished in two cross-current extraction stages by using the mixture of D2EHPA and TBP. In order to facilitate the stripping efficiency, a reductive stripping method was employed by using H 2 SO 3 or Na 2 SO 3 as a reducing agent. The addition of H 2 SO 4 into reducing agents led to improvement in the stripping efficiency while high concentration acid would suppress it. Both of the mixtures of H 2 SO 4 + H 2 SO 3 and H 2 SO 4 + Na 2 SO 3 showed good efficiency for the stripping of Fe(III), while the latter was recommended as the stripping solution based on the economics and experimental condition.