Study on the Extracting Potassium from Potash Feldspar Ores with Calcium Chloride

Extracting potassium from soluble sylvite mine is currently the main source of potassium. But soluble sylvite mine distributes mainly in a few countries. However, potash feldspar is found in many parts of the world. Therefore, it is very significant to study extracting potassium from potash feldspar. The studied extracting process was following, the calcium chloride was used as leaching agent, and melted under high temperature, then made potash feldspar be leached so as to extract potassium. Experiment results showed that the best reaction conditions are the reaction temperature of 870~960℃, size of potash feldspar ores below 0.208mm, and the mass ratio of calcium chloride to potash feldspar ores being 1. The kinetic study showed that the leaching process is controlled by the internal ionic diffusion of Ca2+ in potash feldspar. The relations between diffusion coefficient and reaction temperature was expressed by the Arrhenius formula: Deff=D0exp(-Ea/RT). In this formula, Ea=126.94kJ穖ol-1, D0=21.80mm2穐-1. The leaching rate of potassium can be over 65% under the best reaction condition mentioned above and the feldspar ore can be utilized sufficiently.