Abstract: 4A zeolite was synthesized with hydro-thermal method.The synthesis conditions were investigated via single factor experiment and orthogonally designed experiment using the calcium ion exchange capacity of 4A zeolite as index.The optimal reaction conditions were determined as:n(SiO₂)/n(Al₂O₃)=1.8;n(Na₂O)/n(SiO₂)=3.0;n(H₂O)/n(Na₂O)=40;crystallization temperature of 100 ℃ (normal pressure) and crystallization time of 6 h.Calcium ion exchange capacity of the product achieves 323 mg·g^-1.The product was characterized by XRD and SEM.

Key words: detergent builder, 4A zeolite, hydro-thermal method, calcium ion exchange capacity