Research On Separating Magnesium And Cobalt From Nickel Sulfate Solution Using Cyanex 272

The world’s nickel sulfide ores are gradually depleted.Meanwhile,the exploitation of laterite nickel ores has been challenging lately.As the country with the world’s richest lateritic nickel ore resources,Indonesia has to maximize the utilization of it’s lateritic nickel ore.In recent years,Chinese overseas enterprises have established several lateritic nickel ore processing companies in Indonesia.They have made significant contributions to the comprehensive utilization of lateritic nickel ore resources in Indonesia.Chinese overseas companies generally deal with low-grade laterite nickel ores by hydrometallurgy.The leaching solution contains the impurity element such as magnesium.Magnesium must be removed from the leaching solution to prepare high-purity nickel products.In addition,the properties of nickel and cobalt are very similar.Cobalt is often leached simultaneously with nickel.Therefore,removing magnesium and recovering cobalt from the nickel sulfate solution is necessary.In view of the different extraction abilities of the Cyanex 272 extractant for nickel,cobalt,and magnesium under various p H conditions,the Cyanex 272 extractant was used to extract magnesium and cobalt.The synthetic solution made to simulate the leaching solution contained 53.87g/L nickel,0.74 g/L cobalt,and 1.03 g/L magnesium.Magnesium and cobalt are separated by acid stripping.The specific research contents are as follows: under the conditions of p H 5.5,temperature 40 ℃,extractant concentration 25% and A/O ratio 1/1,Cyanex272 diluted with kerosene can extract 95% cobalt by single-stage extraction and 54% magnesium by seven-stage extraction.After washing the residual nickel with 0.25 M sulfuric acid,the nickel content in the loaded Cyanex 272 decreased from2.78 g/L to 0.001 g/L.Magnesium was extracted from the organic phase using 0.5 M sulfuric acid.The scrubbing rate of magnesium reached 73%after four stages of scrubbing at 25 °C.When the O/A ratio is 8/1,five stages of stripping are required for magnesium removal.Under the optimum extraction conditions,the stripping rate of cobalt reached 83%.Finally,when the O/A ratio is 10/1,and the p H value is 4.0(1 M sulfuric acid),cobalt can be completely separated after three-stage stripping.This research is a small-scale laboratory experiment.The experimental process needs further exploration,including the effects of other conditions such as extractant concentration,diluent,feed flow rate,and extractant synergy.More impurities,such as iron,manganese,cadmium and other metals,can be added in further research.It is suggested that further studies should be carried out in the future by adding other characterizations.