Study On The Synthesis Of Zeolite With Chemical Materials And Potassic Rocks As Raw Materials By Like-solid Phase Method

At present,most of the synthesis methods of zeolites are still based on the traditional hydrothermal synthesis method.There are many disadvantages in the production process,such as long crystallization time,high crystallization temperature,high liquid-solid ratio of the system,low utilization rate of raw materials,difficult treatment of mother liquor,cumbersome process flow and so on.In this paper,a new process of rapid and efficient preparation of zeolite with low energy consumption,mild conditions and friendly environment is proposed.The preparations of small-sized analcite,zeolite P with high calcium magnesium ion exchange performance and zeolite W with high added value by like-solid phase method are studied with chemical materials and potassic rocks as raw materials.With chemical reagents as raw materials,the small-sized analcites were synthesized by like-solid phase method.The effects of crystallization time,crystallization temperature,n（Na₂O）/n（SiO₂）and n（H₂O）/n（SiO₂）in the preparation process were investigated.The results show that the small-sized analcite with uniform morphology and good crystallization can be synthesized sucessfully under 150℃ for 8h with the material mole ratio of n（SiO₂）/n（Al₂O₃）=5,n（Na₂O）/n（SiO₂）=0.26 and n（H₂O）/n（SiO₂）=11.10.Compared with the analcite synthesized by the traditional hydrothermal method,the particle size of the product is obviously reduced,and its specific surface area,pore volume and pore diameter are increased.The defluorination rate of the products in the simulated wastewater with the concentration of 5mg/L is as high as 56.3%.With chemical reagents as raw materials,zeolite P products with high calcium and magnesium ion exchange performance were successfully prepared by like-solid phase method.The results show that the zeolite P products with uniform morphology and good crystallinity can be prepared,when the molar composition of the silicon aluminum xerogels is n（SiO₂）/n（Al₂O₃）=5,the crystallization time and crystallization temperature are 3h and140℃ respectively,and the molar compositions of the raw material are n（Na₂O）/n（SiO₂）=0.26 and n（H₂O）/n（SiO₂）=18.51.The crystal surface of the products is rougher than those of the products synthesized by traditional hydrothermal method,and a small number of products show"false"hollow structure.The calcium and magnesium ion exchange capacity of the products in 0.05mol/L CaCl₂and 0.05mol/L MgCl₂solutions is not less than 400mg Ca CO₃·g^-1dry zeolite and 160mg MgCO₃·g^-1dry zeolite,respectively.The calcium magnes-ium ion exchange performance of the zeolite P products is significantly improved compared with those synthesized by the traditional hydrothermal synthesis method.In order to reduce the production cost of preparing zeolite by like-solid phase method and enrich the raw materials of the production process,the potassic rocks as the initial raw materials were activated by KOH alkali fusion activation method,and the activation products obtained were used as the synthesis raw materials to synthesize zeolite W products by like-solid phase method.The results show that the potassium sodium mixed type products with uniform morphology and spindle-shaped,whose element compositions are Si:22.10wt%,Al:14.05wt%,K:7.44wt%,Na:14.66wt%,and O:49.18wt%,can be synthesized sucessfully under 150℃ for 12h with the material mole ratios of n（SiO₂）/n（Al₂O₃）=5,m（mineral powder）/m（xerogels）=0.26 and n（H₂O）/n（SiO₂）=16.66.The maximum potassium ion exchange capacity of the modified products in simulated seawater is 50.33mg·g^-1,which is significantly higher than those of the traditional hydrothermal synthesis method.In order to avoid the waste of resources and environmental pollution,the secondary circulation process was designed to realize the efficient utilization of potassic rocks and the stable production of zeolite W.