Template-free hydrothermal synthesis method of small crystal ZSM-5 molecular sieve

The invention relates to a template-free hydrothermal synthesis method of a small crystal ZSM-5 molecular sieve, belonging to the technical field of preparation of a catalyst carrier. The method mainly comprises the following steps: mixing a silicon source, an aluminium source, alkali and water without adding a template agent to obtain a reaction mixture; carrying out hydrothermal crystallization on the reaction mixture at two temperature, wherein the first step is carried out at 100-160 DEG C, the second step is carried out at 170-180 DEG C, and no interval exists between the two steps. According to the synthesis method of the small crystal ZSM-5 molecular sieve provided by the invention, hydrothermal crystallization is divided into two steps, crystal nucleus is formed in a reaction mother liquor in the first step as far as possible, the crystallization temperature is improved in the second step, the molecular sieve crystal quickly grows, and synthesis of the small crystal ZSM-5 molecular sieve with good uniformity is achieved within a short period of time under the condition of not adding the template agent.