Leaching rubidium from a low-grade rubidium-bearing aluminosilicate ore

In this study, Rb leaching from a low-grade aluminosilicate mineral in the H2SO4–CaF2 system at low temperature was investigated. The results showed that parameters such as the H2SO4 concentration, CaF2 dosage, and temperature affected the leaching of Rb. Residue characterization and kinetic analysis showed that the gypsum formed on the unreacted particles at lower acid concentrations (0.5–5 mol/L) did not hinder the diffusion of the leaching agents, indicating that the leaching rate was controlled by chemical reaction. When the acid concentration was increased to 5 mol/L, the unreacted particles were covered with a large amount of anhydrite, which was characterized as a pyknotic film. This indicated that leaching was controlled by a combination of chemical reaction and diffusion of the leaching agent through the product layer.