Abstract：In order to prepare 4A zeolites with better quality and higher Ca²⁺exchange capacity, the alkali calcined gangue was used as raw material to synthesize 4A zeolite by a hydrothermal method. The product was gained after filtering, washing, and drying, and it was characterized by X-ray diffraction(XRD),transmission electron microscope(TEM), Ca²⁺exchange capacity,white, FT-IR to study the influence of different liquid-solid ratio(the ratio of water to activated coal-gangue in the reaction) on the appearance, crystallinity, Ca²⁺exchange capacity, white of the 4A zeolites. The result shows that the better 4A zeolite with higher crystallinity, better crystal morphology and Ca²⁺exchange capacity of 322 mg/g(CaCO₃ was used as criterion) can be synthesized with the liquid-solid ratio being 8 when they are aged 2 h at 60 ℃and crystallized 40 min at 90 ℃.

Keywords: 4A zeolite; alkali calcined gangue; hydrothermal method; liquid-solid ratio