Synthesis of zeolite X from low‐grade bauxite

BACKGROUND Zeolite X is one of the most important synthetic zeolites and has been used extensively. Therefore, to satisfy its high demand the synthesis of zeolite X from inexpensive sources is very desirable. Low‐grade bauxite, an inexpensive aluminium and silicon source has been used to synthesize zeolite A. In the present paper, the production of zeolite X from this inexpensive low‐grade bauxite is attempted for the first time. RESULTS The combination of alkali fusion activation and hydrothermal reaction synthesis provides a successful method to synthesize zeolite X from this low‐grade bauxite. The molar ratios of SiO 2 / Al 2 O 3 , Na 2 O / SiO 2 andH 2 O / Na 2 O are the most crucial parameters, which determine the phase composition and crystallinity of products. Using sodium silicate solution to adjust SiO 2 / Al 2 O 3 molar ratio, highly crystallized zeolite X is achieved under the optimized experimental conditions of 2Na 2 O : 0. 2Al 2 O 3 : 1SiO 2 : 76H 2 O at 95°C for 24 h. The synthesized zeolite X was further characterized by SEM , BET , FT‐IR , and thermal stability. CONCLUSION The results indicate that the inexpensive raw material can be utilized to synthesize highly‐crystallized zeolite X under optimized experimental conditions.