This work proposes a solvent extraction process for removal of chloride in slag flush wastewater using tri-n-octylamine (N235) as extractant. The single stage extraction and stripping efficiencies were 78.9% and 99.2% respectively under the optimal conditions. The McCabe-Thiele diagram and Kremser equation were utilized to predict the number of stages required to reduce the Cl⁻ concentration to less than 350 mg/L. The results were authenticated utilizing a three-stage counter-current operation, that closely correspond the estimates of McCabe-Thiele diagram. The FT-IR spectra of organic phases indicate that the extractant N235 combines with H₂SO₄ first to form quaternary ammonium salt containing N-H⁺ after acidification by H₂SO₄, followed by an anionic exchange with Cl⁻. Further, the raffinate phase was stripped using a suitable stripping agent to increase the Cl⁻ concentration up to 100,000 mg/L so as to facilitate precipitation of NaCl by addition of NaOH as salting-out agent. The XRD analysis was utilized to confirm the crystallinity and the purity of the precipitated NaCl.

本工作提出了一种以三正辛胺 (N235) 作为萃取剂去除冲渣废水中氯化物的溶剂萃取工艺。最佳条件下单级萃取和反萃取效率分别为78.9%和99.2%。McCabe-Thiele 图和 Kremser 方程用于预测将 Cl ^-浓度降低到低于 350 mg/L 所需的阶段数。使用三级逆流操作对结果进行了验证，这与 McCabe-Thiele 图的估计值非常吻合。有机相的FT-IR光谱表明，萃取剂N235先与H ₂ SO ₄结合，经H酸化后形成含NH ⁺的季铵盐。₂ SO ₄，然后与Cl ^-进行阴离子交换。此外，使用合适的反萃取剂将萃余相反萃取以将 Cl ^-浓度提高到 100,000 mg/L，从而通过添加 NaOH 作为盐析剂促进 NaCl 的沉淀。XRD分析用于确认沉淀NaCl的结晶度和纯度。