RU2056354C1 - Method of zeolite preparing - Google Patents

Abstract

FIELD: high-silicon zeolite preparing. SUBSTANCE: at the stage of preparing reaction mixture the priming mass containing zeolite crystals with moisture 5-60 wt.-% after milling is used. EFFECT: improved method of zeolite preparing. 1 tbl

Description

 The invention relates to methods for producing zeolites used as adsorbents, detergents and catalysts. High-silica zeolites of the ZSM-5 and -11 type are used as catalysts for petrochemistry, oil refining, and synthesis of motor fuels.

The synthesis of zeolite is carried out from alkaline mixtures containing sources of silicon, aluminum, isomorphically substituting aluminum elements, alkali, water, zeolite seed and an organic template. As a source of silicon, water glass, silica sol, sodium silicate or silica gel are used. As a source of aluminum, aluminum salts, sodium aluminate, Al ₂ O ₃ or clay are used. As sources of isomorphically substituting aluminum elements, boron, iron or gallium compounds are most often used. Alcohols, amines, etc. are taken as an organic template. The mixture may also not contain an organic component and an isomorphically substitutional aluminum element. The synthesis of zeolite proceeds with stirring or without stirring at a temperature of up to 200 ^about C and the corresponding autogenous pressure.

The closest in technical essence to the proposed invention is a method for producing zeolite in the presence of seed material. The mixture obtained from sources SiO _2, Al ₂ O _3, alkali, water, organic component and seed material, crystallized at 175 ^{° C} for 12 hours. The seed material is prepared fault silica component (ZSM-5, mordenite, silica, amorphous SiO ₂ or magadiite) in the absence of fluid in a ball or oscillating mill for 3-12 hours

 The disadvantages of this method are low tech and some non-environmental. Low technology is associated, firstly, with the significant duration of the synthesis of zeolite and, secondly, with the low productivity of the grinding process, due to the low grinding efficiency of dry materials and the accompanying process of adhesion of the milled particles. The environmental friendliness is due to the significant formation of dust of the seed material at the stages of grinding the seed and introducing the seed during the preparation of the reaction mixture.

 The purpose of the invention is the improvement of technological and environmental indicators of zeolite production at the stages of preparation of the reaction mixture, its crystallization and grinding of the seed.

 The goal is achieved by the fact that isomorphically substituting elements and a seed that has undergone grinding in the presence of a liquid are added to the reaction mixture. This improves the technological indicators of zeolite production, associated, firstly, with a significant reduction in the duration of the synthesis of zeolite and, secondly, with an increase in the productivity of the grinding process, due to the greater efficiency of grinding in liquid media. An improvement in the environmental indicators of zeolite production is observed due to a decrease in the amount of dust at the stages of grinding the seed and preparation of the reaction mixture as a result of wetting the seed mass.

 A distinctive feature of this solution is the process of crystallization of zeolite in the presence of isomorphically substituting elements or without them, and the seed, which underwent grinding in a moist state.

PRI me R 1 (prototype). The seed mass is prepared by grinding a zeolite of type ZSM-5 in a ball mill for 3 hours. The reaction mixture is obtained by sequentially mixing 200 g of ACG aluminum silica gel (68.5 g of SiO ₂ , 0.4 g of Al ₂ O ₃ , 0.3 g of Fe ₂ O ₃ , the rest is water), 355 ml of water, 2.8 ml of a 0.25 M solution of Al ₂ (SO ₄ ) ₃ , 27.9 ml of a 9.64 M solution of NaOH, 28.1 ml of butanol and 2 g of seeds. The mixture was crystallized at 175 ^{° C} for 12 h. A product with a 91% content of the phase-type zeolite ZSM-5.

PRI me R 2. Zeolite containing 10% moisture, grind on a planetary mill RPM-3 with an energy intensity of 50 W / g for 2.5 minutes The reaction mixture is prepared by sequential mixing 200 g of alumina-silica gel (68.5 g of SiO ₂ , 0.4 g of Al ₂ O ₃ , 0.3 g of Fe ₂ O ₃ , the rest is water), 317 ml of water, 2.8 ml of 0.25 M Al ₂ (SO ₄ ) ₃ solution, 20.6 ml of 0.69 M H ₃ BO ₃ solution, 17.0 ml of 0.25 M FeCl ₃ solution, 29.2 ml of 9.64 M NaOH solution, 28.1 ml butanol and 2.3 g of ground moistened zeolite as a seed. The mixture was crystallized at 175 ^{° C} for 5 hours. The obtained product containing 95% zeolite phase.

Examples 3-10 are similar to example 2, but differ in the composition of the reaction mixtures and the degree of moisture of the seed. The compositions of reaction mixtures used for milling moisture seed content-isomorphically substitute elements (IZE) in the reaction mixtures, synthesis times at 175 ^{° C} (τ) and the content of zeolite in the products are presented in the table.

 As can be seen from the examples, the proposed method allows to improve the technological and environmental indicators of production during the crystallization of the zeolite in the presence of not more than 0.5 wt. isomorphically-substituting elements or without them and with the use of seeds that have passed grinding with a water content of 5-60 wt.

Claims (1)

 METHOD FOR PRODUCING ZEOLITE, including preparation of seed, preparation of pulp, consisting of sources of silicon, aluminum, isomorphically substituting aluminum elements or without them, water, alkali, organic matter in an amount of not more than 10 wt.% Of the pulp mass or without it and previously ground seed, zeolite crystallization, characterized in that boron and iron are used as isomorphically substituting aluminum elements in an amount of not more than 0.5 wt.% by weight of the pulp, and the seed is prepared by grinding when it is wet zhnosti 5 - 60 wt.%.

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