ABSTRACT

This work reports a study of the extraction of iron (III) deeply from the chromium sulphate solution in which most of the iron was precipitated with oxalic acid. Di(2-ethylhexyl)phosphoric acid (P204) was employed, and the conditions of the extraction process were optimised according to a sequential experiment design. The concentration of iron (III) in the solution could be reduced to less than 2 mg L⁻¹ and the iron (III) extraction efficiency can reach up to 99.7% when the solution feed pH value, the phase ratio, P204 concentration, saponification rate, and extraction stages were 2.0, 1:1, 15% (v/v), 60%, and 2, respectively. During this process, other impurities in the solution such as Ni and Mn can also be reduced simultaneously. Further, post-extraction, highly pure chromium sulphate can be obtained. The experimental results show that when the organic was stripped with 4 mol L⁻¹ HCl, 95% Fe in the organic phase can be stripped after three stripped series with O/A being 1:1, and then P204 can be re-utilised. The extraction process can also address the difficulty in separating iron (III) thoroughly from the chromium sulphate solution in the new chromic salt process with ferrochrome as raw material.

摘要

这项工作报告了从硫酸铬溶液中深层提取铁 (III) 的研究，其中大部分铁与草酸一起沉淀。采用二(2-乙基己基)磷酸(P2O4)，按序贯实验设计优化提取工艺条件。溶液中铁 (III) 的浓度可降低至小于 2 mg L ^-1当溶液进料pH值、相比、P2O4浓度、皂化率、萃取级数为2.0、1:1、15%(v/v)、60时，铁(III)萃取效率可达99.7%。 % 和 2，分别。在此过程中，还可以同时减少溶液中的其他杂质，如Ni和Mn。此外，提取后可以获得高纯度的硫酸铬。实验结果表明，当有机相用4 mol L ^-1 HCl汽提时，有机相中95%的Fe在O/A为1:1的三个汽提系列后可以被汽提，然后P2O4可以被重新利用。该萃取工艺还可以解决以铬铁为原料的新型铬盐工艺中从硫酸铬溶液中彻底分离铁（III）的困难。