A method for synthesizing sapo-34 molecular sieves by utilizing industrial phosphate fertilizer by-product fluosilicic acid and its application

Abstract

The invention provides a method for synthesizing SAPO‑34 molecular sieves by using fluosilicic acid, a by-product of industrial phosphate fertilizers, and its application, belonging to the technical field of comprehensive utilization of resources. The method includes the following steps: 1) adding phosphorus source and aluminum source to water, stirring and adding triethylamine to obtain solution I; 2) mixing industrial fluosilicic acid and triethylamine to obtain solution II, and adding solution II to the The precursor solution is obtained in the solution I, and the molar ratio of the substance in the precursor solution is Al2O3: SiO2: P2O5: H2O: TEA=1:0.3-0.6:1-1.1:70-90:3.2-9.5; 3) the precursor 4) Roasting the SAPO-34 molecular sieve precursor to obtain microporous SAPO-34 molecular sieve. An application based on the SAPO-34 molecular sieve described above, the SAPO-34 molecular sieve is loaded into a chromatography column, crude phosphoric acid is added, and vacuum filtration is performed to defluorinate the crude phosphoric acid. The SAPO-34 molecular sieve prepared by the present invention has large crystal grains, high crystallinity, good purity, and less impurity phases, can defluorinate more than 65% of fluorine-containing 6g / L crude phosphoric acid, and the fluorine adsorption capacity of the molecular sieve can reach 350mg / g .

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of resources, and particularly relates to a method for synthesizing SAPO-34 molecular sieve by utilizing fluorosilicic acid, a by-product of industrial phosphate fertilizer, and application thereof. Background technique [0002] In the production process of wet-process phosphoric acid and phosphate fertilizer, a large amount of fluorine-containing gas is produced, which is absorbed by water to form industrial fluorosilicic acid. As a by-product of the development of the phosphate fertilizer industry, the output of fluorosilicic acid in my country is huge, but it is usually only processed into products with small demand such as fluoride salts, and the abundant resources such as silicon, aluminum and phosphorus have not been fully utilized. [0003] The published Chinese patent with publication number CN105271244A provides a method for synthesizing mesoporous molecular sieves by us...

AI Technical Summary

Problems solved by technology

CN108675317A prolongs the single-pass life of SAPO-34 molecular sieve through post-treatment process, making the industrial cost of methanol synthesis olefin (MTO) reduced, but the silicon source used in its synthetic molecular sieve is organosilicon source, although it is more organic template agent triethylamine Easy to disperse in synthetic systems, but more expensive

Therefore, the cost of SAPO-34 synthesized from organosilicon sources is relatively high. Although it can be used as a catalyst for the synthesis of olefins from methanol, it limits its wide application in industrial wastewater treatment and other industrial fields with less economic added value.

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