Study On Separation Of Manganese,cobalt And Nickel With Weak-acid Strong-base Salt Saponified Acid Extractant

The excellent properties of cobalt and nickel make them widely used in alloy materials,catalysts,new energy materials and other fields.China is extremely deficient in cobalt and nickel resources.Cobalt and nickel raw materials are largely dependent on imports.Therefore,it is particularly important and urgent to recycle secondary resources such as waste cobalt and nickel.Solvent extraction is a common method for separation and purification of manganese,cobalt and nickel.In order to improve the extraction effect of extractant,strong alkali is usually used to saponify acid extractant before extraction.In this paper,the traditional acid extractant saponification extraction method was improved.A new method of separating manganese,cobalt and nickel by using weak-acid strong-alkali salt saponification acid extractant was established.The main research contents are as follows:1.Research on extraction and separation of manganese and cobalt with P204.The effects of p H of the aqueous phase and the ratio of mixed extractants on the separation of manganese and cobalt by P204-N235 were systematically studied.For the mixed solution of 2 g/L manganese and 2 g/L cobalt,it was extracted with 20%P204-25% N235-55% sulfonated kerosene.The equilibrium p H of the raffinate was4.05 and 4.46 respectively.The extraction rates of manganese and cobalt were 21.70%and 7.40% respectively.Meanwhile,the effects of p H of saponification solution,p H of aqueous phase,P204 concentration and metal ion concentration on the extraction and separation efficiency of manganese and cobalt by sodium acetate-acetic acid saponification P204 were systematically studied.The results showed that the effect of extraction and separation of manganese and cobalt by P204 saponified by sodium acetate-acetic acid solution was better than that of P204 saponified by Na OH solution.The method is simple and feasible,the acidity of the material solution does not need to be adjusted in the extraction process,and the sodium acetate-acetic acid buffer solution can be recycled repeatedly,which greatly reduces the consumption of Na OH,and basically no saponification wastewater is discharged.2.Research on extraction and separation of cobalt and nickel with P507 or Cyanex272.The effects of p H of the aqueous phase,phase ratio and the ratio of extractant on the separation of cobalt and nickel by P507-N235 and Cyanex272-N235 were systematically studied.For 1g/L cobalt solution,30% P507-15% N235-55%sulfonated kerosene was used for extraction,the equilibrium p H of the raffinate was3.71,and the extraction rate of cobalt was 28.59%;For the mixed solution of 2 g/L cobalt and 2 g/L nickel,it was extracted with 30% Cyanex272-15% N235-55%sulfonated kerosene.The equilibrium p H of the raffinate was 3.96,and cobalt and nickel were hardly extracted.Meanwhile,the effects of concentration of sodium acetate solution,p H of aqueous phase,extractant concentration and metal ion concentration on the extraction separation of cobalt and nickel by P507 or Cyanex272 were systematically studied.The results show that the method of saponification of P507 and Cyanex272 with sodium acetate solution is simple and feasible,and the extraction separation effect of cobalt and nickel is better than that of saponification with Na OH.This method has the advantages of simplifying the extraction process,reducing the consumption of sodium hydroxide and hydrochloric acid,and reducing the salt content in the extraction wastewater.