Study on aluminum removal through 5-sulfosalicylic acid targeting complexing and D290 resin adsorption

In-situ leaching process are often used to extract rare earth resources for ion-adsorbed rare-earth ore, unfortunately this leaching process also extracts a large amount of non-rare earth impurities such as aluminum, iron and etc. In this paper, 5-sulfosalicylic acid was selected as a complexing agent to complex aluminum ions selectively, and then the aluminum complexing ion could be removed by D290 resin adsorption, which achieved the aluminum removal in the rare-earth leaching solution. The complexation reaction of 5-sulfosalicylic acid with aluminum ion was studied by ultraviolet spectrophotometry which showed that the coordination ratio of 5-sulfosalicylic acid to aluminum ion was 1:1. The effects of solution pH, amount of 5-sulfosalicylic acid and D290 anion exchange resin, flow rate and reaction time on the adsorption results were investigated comprehensively. The results showed that the final pH of the solution was 3.5, the ratio of 5-sulfosalicylic acid to aluminum was 1.5:1, flow rate was 0.2 mL/min and reaction time was 120 min, the aluminum removal was 75.63% and the rare earth loss was less than 5%. The adsorption kinetics of aluminum ions by 5-sulfosalicylic acid-D290 resin showed that the adsorption of aluminum ions conformed to the second-order adsorption kinetics model.