The leaching kinetics and mechanism of potassium from phosphorus-potassium associated ore in hydrochloric acid at low temperature

The leaching kinetics of potassium from phosphorus-potassium associated ore in hydrochloric acid/fluorite (CaF2) system was studied. HCl concentration, liquor/solid ratio, CaF2 dosage, and temperature were found to be the main factors. The leaching rate of potassium can be reached more than 92% under the optimum operation conditions. A classic shrinking core model with the mixed chemically diffusion as the rate-controlling step was successfully modeled the leaching kinetics of potassium, and the activation energy was found to be 30.7 kJmol(-1). The leaching mechanism of potassium was also elucidated based on the experimental results.