Effects of activation methods on the activation of natural aluminosilicate minerals and zeolite synthesis

Four natural aluminosilicate minerals including kaolin, rectorite, montmorillonite and illite were activated by thermal activation, alkali fusion activation, sub-molten salt activation and quasi-solid-phase activation method, respectively. Comparing the activation effects of the four methods, it is found that both sub-molten salt method and quasi-solid-phase method present better activation effect at lower energy consumption, which are obviously superior to the other two activation methods. The quasi-solid-phase activation method is the most promising method for activating the natural aluminosilicate minerals due to its much lower energy consumption and more feasible industrial operation. Comparatively, the framework structure of kaolinite rectorite and montmorillonite are relatively more easily to be depolymerized, the structure of illite is much stable, after being sub-molten salt activated and quasi-solid-phase activated, the resulted illite has little active SiO₂ and Al₂O₃ which can be used to synthesize zeolites due to their high chemical reactivity. Therefore, different from the other three natural aluminosilicate minerals, illite is not an ideal raw material for zeolite synthesis.