Extracting rubidium and potassium from complex rubidium ore: Process optimization and leaching kinetics

This paper introduces a new method for efficiently extracting Rb and K from complex rubidium ore. It mainly consists of two steps: 1) thermal activating of rubidium ore and water quenching, and 2) leaching with sulfuric acid. After thermal activating and water quenching, the water quenched slag was in a highly active state. Efficient extraction of rubidium and potassium could be achieved at atmospheric pressure. Under the conditions of a thermal activation temperature of 1300 °C, CaO dosage of 30%, holding time of 60 min, leaching temperature of 50 °C, sulfuric acid concentration of 120 g/L, liquid-solid ratio of 10 mL/g, leaching time of 90 min, and stirring speed of 500 r/min, the average leaching rates of Rb and K in multiple parallel experiments reached 99.24% and 98.97%, respectively. The consumption of sulfuric acid in the acid leaching process could be reduced by 200 kg/t after two-stage leaching. Leaching kinetics showed that the leaching process of the rubidium ore water quenched slag was consistent with the hybrid control model and the apparent activation energy of the leaching reaction E a =31.46 kJ/mol.