Compound leaching of rare earth from the ion-adsorption type rare earth ore with magnesium sulfate and ascorbic acid

To reduce the consumption of MgSO4 and to leach the colloidal sediment phase rare earth, a MgSO4-ascorbic acid compound leaching agent was introduced to deal with the ion-adsorption type rare earth ore. The ascorbic acid was used as an assistant to enhance the leaching of the ion-exchangeable phase rare earth and to reductively leach the colloidal sediment phase rare earth, making use of its ability to coordinate with rare earth ions and its reductive properties. It was determined that the total rare earth leaching efficiency was 86.2% and the Ce partition was 5.62% at a flow rate of 0.60 mL/min, an initial pH of 2.50, a liquid to ore ratio of 1.30 mL/g, and 0.15 mol/L magnesium sulfate and 1.0 g/L ascorbic acid in the leaching agent. The concentrations of Al and Fe in the leaching liquor were 21.36 mg/L and 30.22 mg/L, respectively. Moreover, the contents of the ion-exchangeable phase and the colloidal sediment phase rare earth in the leaching tailings were 0.03‰ and 0.06‰, respectively. The leaching efficiency of the colloidal sediment phase rare earth was approximately 57.1%. Hence, an alternative process would be provided for the leaching of rare earth from ion-adsorption type rare earth ore. The process could reduce the consumption of MgSO4 and would have great significance for environmentally-friendly extraction of ion-adsorption type rare earth ore and the improvement of resource utilization.