Effects of organic acids on the leaching process of ion-adsorption type rare earth ore

To examine the activation of organic acids on the leaching process of ion-adsorption type rare earth ore (IRE-ore), the leaching behavior of rare earth (RE) and zeta potential of IRE-ore were investigated in the absence and presence of carboxylic acids. The results show that all the tested organic acids (acetic acid, malonic acid, citric acid, tartaric acid, succinic acid, and malic acid) can promote RE extraction. At relatively high concentrations of organic acids, the activation efficiency of organic acids on RE extraction is generally consistent with their complexation ability; whereas at their low concentrations, the change of zeta potential on the IRE-ore surface with organic acid concentration and pH has a close association with RE extraction, which indicates that organic acids can impact the surface electrical property of IRE-ore via their adsorption/desorption, and thereby increase/decrease the affinity of RE ions to IRE-ore. Therefore the influence of organic acids on the IRE-ore surface electrical property also plays an important role in RE extraction in addition to their complexation with RE ions.