This study aims to establish an in-situ cadmium removal method in high temperature combustion or gasification conditions for industrial waste including cadmium compounds. As a mineral sorbent to capture the metallic cadmium and the cadmium chloride, kaolinite was found to have the highest performance. The adsorption mechanism by which kaolinite captures cadmium chloride at high temperature was then experimentally elucidated. The results suggest that the adsorbed cadmium could not be desorbed, but rather that it combined more strongly with the kaolinite with increasing retention time. The amount of cadmium captured by the kaolinite is significantly dependent on the moisture concentration in the reaction system, and its minimum concentration depends on the molar ratio of cadmium to kaolinite. The results suggest that the presence of above 1 mole of moisture enhances the removal efficiency, promoting stoichimetric removal reaction in which I mole of kaolinite captures 1 mole of cadmium chloride.