Separation Of Nickel And Magnesium In The Bioleaching Solution Of Low Grade Nickel-bearing Sulfide

In the complex bacterial leaching solution, the concentration of the valuable metal was higher than impurity and the pH was low, which made separation more difficult. The regular method of precipitation not only made the valuable metal loss in the precipitate,but also increased costs in the low pH value. It is necessrty to develop the dfficient and low-cost research.According to the character of complex bacterial leaching solution, this paper carried out technical study of the separation of Ni2+and Mg2+in the low pH value and discussed the related mechanism.The study of ion exchange separation showed that the resin CN-27has the better separation prospect.The resin CN-27had adsorption selectivity on the Ni2+and Mg2+and the Mg2+can be separated effectively.In the process of desorption, the Mg2+can be separated because of the different desorption acidity.The exchange capacities of Ni2+was0.487mmol/g resin(0.613mmol/ml resin), and the saturated capacities was0.515mmol/g resin(0.648mmol/ml resin) for Ni2+and0.262mmol/g resin(0.323mmol/ml resin) for Mg2+; Theaverage concentration of Ni2+in the solution was4.84g/L and the concentration ratio was more than over8times. The desorption acidity of Ni2+and Mg2+in the single component was almost the same. However, the desorption acidity of Ni2+was higher than Mg2+in the mix component.The study of solvent extraction separation showed that the concentration of TFe has to be reduced as low as possible before the extraction.The extraction rate of Ni2+and Mg2+using P204,P507and Cyanex272can be improved by saponification, and the extraction capacity of Ni2+was bigger than Mg2+after saponification. The extraction of Ni2+became harder wher the concentration of Mt2+was too high in the mix component.However, the extractants have almost no influence on the extraction capacity of Mg2+Versatic10can separate Ni2+and Mg2+effectively at pH=6.5and Cyanex301had a good separating effect at pH=3.0.However, the stripping of Ni2+from Versatic10was easy using sulphuric acid(1.5M) and it is hard to strip from Cyanex301.The separation rate of Fe was99.81%at pH=4.0in the actual solution, and the loss ratio of Ni2+w as less than3%at the same time.Part of Mg2+was desorbed when the sulphuric acid(25g/L) was used to adsorb resin exchange column. Then the sulphuric anid(150g/L) was used to desorb and the concentration of Ni2+canreach4.04g/L. The concentration ratio was over10times and the ration of Ni2+and Mg2+reached1:2.3. The extraction ratio of Ni2+was98.65%and Mg2+was4.33%when Versatic10(saponification value=75%) was used to extraction. The stripping ratio of Ni2+can reach99.83%when the sulphuric acid(1.5M) was used to strip.