Optimization studies were carried out for the synthesis of zeolite A by a hydrothermal method using alkali-activated bentonite as raw material. The process of alkali fusion activation and optimization of the composition were Studied by TG-DTA, XRD, and calcium ion exchange capacity. It was found that a mixture of additional alumina (aluminum hydroxide) and bentonite was converted to highly reactive sodium silicate, sodium aluminate, and aluminosilicate by alkali fusion activation using Na2CO3 at high temperature. Zeolite A with a maximum crystallinity of 82.7% and calcium ion exchange capacity of 302 mg of CaCO3/g was obtained at optimized conditions.