SU975573A1 - Process for producing zeolite of the faujasite type - Google Patents

Description

one

The invention relates to methods for producing zeolites and can be used in the zeolite and catalyst industries of the refining and petrochemical industries.

A known method for producing a zeolite of the type of faujasite, according to which a type U zeolite is crystallized from silica gel, prepared as follows: to the sodium silicate solution with stirring is added an 8-S / O sulfuric acid solution in order to partially neutralize the excess sodium hydroxide in the sodium silicate solution, Sodium aluminate solution is then added to the resulting silica gel to form silica gel of the required composition, which crystallizes into type Y zeolite. Before crystallization into silica gel, add is dissolved seeded representing the a crystalline aluminosilicate faujasite structure 1.

However, according to this method, the quality of the zeolite is significantly affected by the fact that adding a dilute solution of sulfuric acid leads to a strong heating of the formed

silicahydrogel (temperature 50-55 ° C), which leads to a decrease in its adsorption properties. In the mother liquor, after crystallization of the zeolite U, sodium sulfate is formed. There is also a significant

5 release of acid vapors requiring special equipment for protection against them - suction into the absorbers from the zeolite crystallization units. In addition, the use of dilute sulfuric acid leads to corrosion and corrosion of equipment and requires special equipment with anti-corrosion coating, which greatly complicates the process technology.

The closest to the proposed technical essence and the achieved result is a method for obtaining a zeolite of the faujasite type, including grinding kaolin, mixing it with alkali, hydrothermal treatment, washing and substance 2. The disadvantage of the known method is 20 low phase purity and silicon module of the target product .

The purpose of the invention is to simplify the process, increase the silicon module and the phase purity of the target product.

The goal is achieved in that according to the method of obtaining a zeolite of the faujasite type, including grinding alumina raw material, mixing it with a chemical reagent to obtain a suspension, hydrothermal treatment, washing and drying, use an amorphous alumina silicate powder as an aluminosilicate raw material.

To obtain a type X zeolite, the mixture is made from caustic soda pacTBopOiM at a volume ratio of aluminosilicate chips to caustic soda solution equal to (3.7-4.1): (0.9-1.2).

In order to obtain a type-type zeolite, the blending is performed with caustic soda solution and sodium silicate at a volume ratio of aluminosilicate chips to caustic soda solution and sodium silicate solution equal to (0.6-0.9): (0.091-0.121): ( 0,809-1,08) and the resulting suspension is inoculated with an amorphous silica-alumina composition 16 N32O-A 2Q -15 SiOj-BSO in an amount of 2- 3.5 vol. / 0.

The essence of the proposed method lies in the fact that the aluminosilicate chips, thrown into the dump, is crushed and subjected to grinding to particle sizes less than 50 microns. A solution of sodium hydroxide is added to the obtained aluminosilicate powder to a volume ratio: aluminosilicate is a solution of sodium hydroxide, respectively (3.7-4.1): (0.9-1.2), water to obtain silica gel of the required composition and crystallized into a zeolite of the type faujasite (type X zeolite). To obtain a type U zeolite, a solution of caustic soda and sodium silicate is added to a grain size of a crumb of aluminosilicate to a volume ratio: aluminosilicate — sodium hydroxide solution — Sodium silicate solution, respectively (0.6-0.9): (0.091-0.121 ): (0,809-1,08) and water in order to provide the necessary composition of the reaction mass crystallized into type U zeolite. In order to accelerate the crystallization process, amorphous fine aluminum silicate is introduced into the initial silica-alumina zeolite before the crystallization process gel composition, in moles of oxides per 1 mol of (): Na2O-, Al20j I5S O2320. The zeolite thus crystallized (type X and type Y) is filtered to separate the mother liquor, washed with water and dried at 120-250 ° C).

Research has shown that a size of 50 µm is the upper boundary of particles of amorphous silica-alumina crumb, only if this boundary is observed, the fractional composition of crystals of the resulting zeolite corresponds to the composition given in Specification 38 4037-80. The lower limit for the particle size of amorphous silica-alumina chips is due to the energy costs of grinding and the possibilities for fine grinding of materials, and is practically 10-20 microns.

To obtain a zeolite, amorphous silica-alumina crumb is subjected to a milled particle size of less than 50 microns and mixed with sodium hydroxide solution in a volume ratio of: aluminum silicate to sodium hydroxide solution, respectively (3.7-4.1) - (0.9-1.2),

and to obtain zeolite Y, the amorphous silica-alumina grit is also milled to particles less than 50 µm and mixed with sodium hydroxide solution and sodium silicate solution in a volume ratio: aluminosilicate — sodium hydroxide solution — solution

sodium silicate, respectively (0.6-0.9):: (0.091-0.121): (0.809-1.08), then the resulting suspension is inoculated with an amorphous silica gel of composition 16 NajOAl Oj 15SiO2-320 in an amount of 2-3 , 5 about. %

The indicated volume ratios of the reagents correspond to the chemical compositions of the starting alumino-silica, expressed in molar ratios of oxides. For zeolite, Na X and Na Y are the following ratios, respectively

NaA :: l, 4-2,1 ALO, 33-SiO, 71 - 80

Sow: 1.7-33 AI2O5 6-8.9 SiO2 120-200 NzO.

To obtain a phase-pure (without admixtures of other zeolites) zeolite of the faujasite type, it is necessary to strictly observe the boundaries of the chemical composition of the original alumina silica, crystallized into zeolite. The indicated molar ratios of oxides are within the region of the optimal chemical composition of the starting alumino-silica gel, which crystallizes into a fuzzite-type zeolite.

However, the volume ratio: aluminosilicate crumb-caustic soda dl.

NaA zeolite (dl, 1CHaU zeolite) correspond to the optimum ratio of oxides contained in the aluminum-silica, only if the concentrations of caustic soda and sodium silicate are constant.

Constant concentration of these solutions. Necessary to obtain high-quality and phase-clear fujazite, variations in concentrations both upwards and downwards lead to a deterioration in the quality of the resulting

zeolite and increase the consumption of raw materials and reagents above the optimal level.

Example 1. To 87 ml of water, 24 g of ground aluminosilicate with a particle size of less than 50 microns and having a chemical compound are added with continuous transfer.

tav, o / o: SiO 63.5; A12Oz 33; Na, O 0.26; 3.2.

Then, 20 ml of sodium hydroxide solution with a NaOH concentration of 584 g / l are poured into the resulting suspension. The silica-alumina thus prepared is subjected to crystallization at 100 ° C for 12 hours. The crystallized zeolite is filtered, washed and dried at 150 ° C. The crystalline product is fujazite with a molar ratio of SiO: Al2Oj oxides of 2.8 (type X zeolite).

The quality indicators of zeolite are given in table. 1. Synthesized type X zeolite is not inferior in its quality to the zeolite obtained by known methods.

Example 2. To 295 ml of a sodium silicate solution with a SiO content of 220 g / l and a silicate module 2.76 are poured with stirring at 584 g / l NaOH. 80 g of ground aluminosilicate, having a particle size of not more than 50 microns and chemical composition, may, are added to the obtained silk solution of sodium silicate. %: SiOs 63.5; AlgOj 33.0; 3.2; Mazo 0.26.

304 ml of water are then added to the suspension. 24 ml are then added.

amorphous silica-alumina as a seed of composition 16 Na2O-A12Oz-15 SiO 320 NaO and crystallized at 100 ° С for 20 h. The crystallized zeolite is filtered, washed with water and dried at 150 ° С.

The crystalline product is fujazite with a molar of 1m SiO2: Al2Oj ratio of 4.7 (type Y zeolite). The quality indicators of zeolite are given in table. 1. Synthesized type U zeolite

quality is not inferior to the zeolite obtained by known methods.

The characteristics of the data obtained and known methods of zeolites priel.-iy table. 2

The use of this invention allows to simplify the process of obtaining a zeolite of the faujasite type due to the utilization of salts of the mother liquor and effluent, to increase the silicon module of the faujasite, as well as the phase purity of the product.

Table 1

65-80

20-35 AZ-45 55-57

18.0-21.0

200.0

30.0-50.0

20.0-25.0 22.0-30.0

7.0-9.0

Claims (3)

1. A method for producing zeolite of the type of faujasite, including grinding alumina raw material, mixing it with a chemical reagent to form a suspension, hydrothermal treatment, washing and drying, characterized in that, in order to simplify the process, increase the silicon module and the phase purity of the target product, as aluminosilicate raw materials use waste production of ball adsorbent - amorphous aluminosilicate chips. 2. A method according to claim 1, characterized in that, in order to obtain a type X zeolite, the mixture is produced with caustic soda solution at a volume ratio of aluminosilicate chips to caustic soda solution equal to (3.7-4.1): (0 , 9-1,2). 3. A method according to claim I, characterized in that, in order to obtain a type U zeolite, mixing is carried out with sodium hydroxide solution and sodium silicate with a volume ratio of aluminosilicate chips to sodium hydroxide solution and sodium silicate solution (0.6 -0.9): (0.091-0.121):: (0.809-1.08) and a seed is introduced into the suspension - amorphous silica gel 16Na O-15SiO2-Al; iO -320HaO in the amount of 2-3.5 vol. % Sources of information taken into account in the examination 1. US patent number 3671191, class. 23-113,15,171. 2. The patent of Germany No. 1221615, cl. 12 i 33, 1966.