The current methods for separation of nickel from cobalt sulphate solutions have drawbacks of long flowsheets, release of large volumes of wastewater and incomplete separation of two metals. A synergistic solvent extraction (SSX) system consisting of dinonylnaphthalene sulfonic acid (DNNSA) and decyl 4-picolinate (4PC) is proposed in this work to extract nickel from cobalt sulphate solutions selectively. The extraction of nickel reached 99.7% after five-stage counter current extraction with an A/O volume ratio of 1/6 at 30 °C, resulting in a large increase of Co/Ni mass ratio to 25,700 in raffinate from 56 in feed. The loaded organic phase can be easily stripped using a dilute HSO solution. Application of this process in industry is expected to make an important impact on the production of high-purity cobalt sulphate solutions and to deliver economic benefits.

中文翻译：

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使用由二壬基萘磺酸 (DNNSA) 和 4-吡啶甲酸癸酯 (4PC) 组成的协同溶剂萃取系统从硫酸钴溶液中分离痕量镍

目前从硫酸钴溶液中分离镍的方法存在流程长、排放大量废水以及两种金属分离不完全等缺点。本文提出了一种由二壬基萘磺酸 (DNNSA) 和 4-吡啶甲酸癸酯 (4PC) 组成的协同溶剂萃取 (SSX) 系统，用于从硫酸钴溶液中选择性萃取镍。在30℃下，A/O体积比为1/6的五级逆流萃取后，镍的萃取率达到99.7%，导致萃余液中Co/Ni质量比由进料中的56大幅提高至25,700。使用稀 H2SO4 溶液可以轻松去除负载的有机相。该工艺在工业上的应用预计将对高纯硫酸钴溶液的生产产生重要影响并带来经济效益。