Removal of nitrate from nickel sulfate solution

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A method for separating nitrate from high-concentration nickel sulfate solutions, belonging to the field of hydrometallurgy of non-ferrous metals, aims to address the issue of nitrate separation in such high-concentration solutions. This method involves using resin for the adsorption of nitrate in high-concentration nickel sulfate solutions; the newly prepared resin is then washed with sulfuric acid solution, after which it is used to adsorb nitrate from nickel sulfate. Sulfuric acid solution is employed to elute the nitrate from the resin, and the liquid resulting from this elution, containing more than 2 g/l of nitrate, is discharged, while sulfuric acid and nitric acid are reused. The liquid with a nitrate content of less than 2 g/l is used in the next cycle of eluting the resin. This invention features simple operation, high efficiency in removing nitrate, no introduction of any impurities, and ensures the purity and high concentration of the nickel sulfate solution throughout the process. It also generates no wastewater or waste residues, making it an example of green metallurgy.