Abstract: Poor quality gangue with high iron and silica contents was treated to remove iron impurity by acid leaching and activated by sodium carbonate melting，the iron removal ratio was up to 96.8%.Kaolinite and silica were activated completely,and gangue turned into intermediate product nepheline (NaAlSiO₄) and active metakaolinite,4A molecular sieves were obtained by hydrothermal crystallization.Green ore,pretreated material,and products were characterized by XRF,XRD and SEM etc..Results showed that the products were pure 4A molecular sieve with particle size less than 2 μm and the Ca²⁺ ion exchange capacity of dry product was 295.5 mg CaCO³/g.

Key words: gangue, iron removal, alkali melting, 4A molecular sieve