Method for synthesizing ZSM-5 molecular sieve by using silica fume

Abstract

The invention discloses a method for synthesizing a ZSM-5 molecular sieve by using silica fume, belonging to the technical field of molecular sieve preparation. The method comprises the following steps: directly and uniformly mixing the industrial waste silica fume with a template agent and ammonia water; transferring into a polytetrafluoroethylene-lined steel reaction kettle, and performing a crystallization reaction for certain time at certain temperature; washing the reaction product; performing suction filtration; and drying for 12h at 60 DEG C to obtain the ZSM-5 molecular sieve. In the invention, the silica fume without any pretreatment serves as all silicon sources aluminum sources and replaces the Si and Al chemical reagents such as sodium silicate, silica sol, fumed silica, white carbon black and aluminum sulfate to synthesize the molecular sieve; and thus, the synthesis cost of the ZSM-5 molecular sieve is lowered, the high-value utilization of the silica fume is realized, and environmental dust pollution caused by the silica fume is also reduced. Meanwhile, the synthesis path only involves the mixing with initial raw materials, the use of large quantity of solvents is avoided, the waste of water resources and the waste liquid pollution of organic plate agents are eliminated, the synthesis technology is simple, the energy is saved while the emission is reduced, and the method has a huge industrial application prospect.

Description

technical field [0001] The invention relates to the technical field of molecular sieve preparation, in particular to a method of using industrial waste micro-silicon powder, without any pretreatment, directly mixed with template agent and ammonia water, crystallized at a certain temperature for a certain period of time, and the reaction product was washed. , suction filtration, and drying at 60°C for 12 hours to obtain ZSM-5 molecular sieves. Background technique [0002] ZSM-5 molecular sieve is an aluminosilicate zeolite molecular sieve with a two-dimensional pore system and a unique cross pore structure with a high silicon / aluminum ratio developed by Mobil Corporation of the United States in the 1970s. ZSM-5 molecular sieve is lipophilic and hydrophobic, with high hydrothermal stability, special pore geometry and adjustable silicon-aluminum ratio, good molecular shape selection performance, adjustable acidity and strong anti-carbon performance. , so it is widely used in ...

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Problems solved by technology

[0006] 1. In view of the insufficient technology of existing synthetic ZSM-5 molecular sieves and the problems that the output of microsilica powder is very large and the utilization rate of resources is extremely low, one of the purposes of the present invention is to provide a kind of direct utilization of microsilica powder to synthesize ZSM-5 molecular sieves. 5 molecular sieve method, the method has low synthesis cost, simple treatment process, short crystallization time, fast reaction speed; high single-pot yield and high production efficiency; and the prepared ZSM-5 molecular sieve has high crystallinity and physical and chemical properties excellent

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