There are generally three methods to obtain nickel electrolyte from nickel solution containing cobalt and other impurities:

1.Precipitation method + oxidation: Iron and copper are precipitated at a certain pH value, and then oxidized by a strong oxidant to precipitate cobalt and other impurities.

2.Precipitation + extraction method: Cobalt and nickel-containing liquid can be obtained by leaching cobalt and nickel-containing ores with sulfuric acid. Iron, copper and other impurities contained in the raw liquid are removed by precipitation, filtration and other methods before extraction. After the impurities are removed, the liquid is contacted with alkyl phosphonic acid alkyl ester in multiple stages to separate nickel and cobalt. High-purity nickel metal is obtained by electrolysis.

3.Extraction + membrane method: The acidic nickel-containing liquid, especially the sulfuric acid selectively leaches the nickel-containing solution for multi-stage countercurrent extraction with an extractant to remove metal impurities in the solution, and then the organic matter in the raffinate is removed by a membrane phase separation oil removal device, and a high-purity nickel product is obtained by an insoluble anode electrode. The cobalt-containing liquid after stripping can be extracted and purified by an extractant to produce a high-purity cobalt product.

Compared with the above three methods, the precipitation method has many steps and has slag operation, which has obvious disadvantages. The disadvantage of the precipitation + extraction method is that before the extraction and separation of nickel and cobalt, impurities must be removed by precipitation, filtration and other methods. The extraction + membrane method has a simple process and excellent effect.

The main process flow of the extraction + membrane method is: the raw material liquid is extracted with an extractant, which is an alkyl phosphine that can increase the concentration of cobalt in the organic phase. After extraction, the loaded organic phase enters the stripping section. After stripping cobalt, copper, lead and zinc, the impurity iron is stripped by high acid. The organic phase after stripping enters the saponification section, and the organic phase is homogeneously saponified and reused with a 40% sodium hydroxide solution. The raffinate enters the membrane phase separation and oil removal device to remove organic matter. The purified nickel electrolyte enters the electrolytic cell, and the standard No. 1 nickel plate is obtained by electrowinning the insoluble anode. The anode liquid is returned to leaching to achieve a closed-loop cycle. The cobalt liquid after low-acid stripping is separated and purified twice in the extractant extraction purification section to obtain a high-purity cobalt product.

In the process of nickel-cobalt extraction and separation, traditional mixer settlers or new CWL-M series centrifugal extractors can be used for extraction. The working principles of centrifugal extractors and mixer settlers are fundamentally different. The new CWL centrifugal extractor is a product with independent intellectual property rights launched by Zhengzhou Tiei Extraction - it perfectly meets the needs of high flow ratio industrial hydrometallurgical nickel-cobalt extraction and separation. The process is simple, easy to operate, and the metal extraction rate is high, up to 99.9%.

Welcome contact us for more details.
Whatspp: +86 19069612820