RU2321539C2 - Synthetic granulated a-type zeolite preparation process - Google Patents

Abstract

FIELD: inorganic compounds technologies.

SUBSTANCE: naturally occurring clay mineral, kaolin, is mixed with wood flour. To initial mixture are added 5-15% of calcined powder kaolin, 5-20% of powder A-type zeolite, and sodium chloride, after which the total mixture is stirred. Upon stirring, lignosulfonate solution is added to form homogeneous plastic mass, which is then granulated and granules are dried and subjected to thermal activation. Resulting amorphous granules are cooled and subjected to hydrothermal crystallization in alkali solution. Finished zeolite is treated with live steam, washed with water, and dried.

EFFECT: increased mechanical strength and capacity.

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Description

The invention relates to the production of granular synthetic zeolite type A. The resulting adsorbent can be used: in the chemical and petrochemical industry for the separation of hydrocarbon mixtures at the molecular level; in the oil and gas industry for drying and purification of natural and petroleum associated gases, in heat and nuclear energy as ion-exchange material for removing metal cations and radionuclides from water streams.

Closest to the technical nature of the proposed invention is the "Method of producing granular zeolite type A of high phase purity" (Application No. 2001134534, publication date 04/27/2003).

In accordance with the known method, a zeolite is prepared as follows: natural clay mineral kaolin is mixed with charcoal, 30–70 wt.% Type A zeolite is added, treated with 2% sodium hydroxide solution, 1.5% an aqueous solution of polyvinyl alcohol until a homogeneous plastic mass is formed, which is formed into granules, sent to ripen, subjected to final molding, dried in two stages at 54 and 100 ° C, respectively, then thermal activation is carried out at 550-630 ° C, the obtained amorphous cooling granules wait and undergo hydrothermal crystallization in an alkaline solution, conduct thermocouple treatment of the granules at 110-160 ° C, wash with softened water, the obtained zeolite granules are dried at 120-200 ° C.

The disadvantages of this method are the use of a large amount (30 ÷ 70 wt.%) Of powder zeolite type A, polyvinyl alcohol, as well as intermediate drying of granules in two stages.

The use of crystalline zeolite type A, polyvinyl alcohol and drying in two stages lead to a significant increase in the cost of production and the complexity of the technology. The above disadvantages of the known method lead to a decrease in the technical and economic indicators of the production of synthetic granular zeolites.

The objective of the present invention is to improve the technology for producing synthetic type A zeolite and to obtain zeolite granules with high adsorption and strength characteristics.

The problem is solved by using the following new technological methods:

- the introduction into the initial mixture of 5-15 wt.% powder kaolin, calcined at 500-600 ° C, will allow to obtain granules of type A zeolite of high phase purity with a developed secondary porous structure;

- the introduction of 5 ÷ 20 wt.% powder zeolite type A significantly reduces the cost of production;

- the use of sodium chloride increases the yield of zeolite crystals;

- the use of wood flour as an additive instead of charcoal will allow to obtain a developed secondary transport structure of granules;

- the use as a liquid of a 5% solution of lignosulfonate in water to obtain a plastic mass, as well as to give granules greater mechanical strength after molding;

- at the stage of intermediate drying, the finished granules are dried in one step at a temperature of 80 ÷ 130 ° C, which leads to a reduction in energy consumption.

These technological methods lead to a significant simplification of the technology for producing synthetic zeolites, reducing their cost and provide granular zeolite type A with improved performance.

The proposed method is as follows. The main source material is the natural clay mineral kaolin mixed with wood flour.

5 ÷ 15 wt.% Powder kaolin, calcined at 500 ÷ 600 ° С, 5 ÷ 20 wt.% Type A zeolite powder, 2 wt.% Crystalline sodium chloride are introduced into the initial mixture and mixed.

With stirring, a 5% lignosulfonate solution is added to the finished mixture until a uniform plastic mass is formed, which is then formed into granules.

The obtained granules are placed in closed containers, where they mature within 24 hours, then subjected to finishing molding.

Next, the granules are dried with hot air at 80 ÷ 130 ° C in an oven.

Then, thermal activation is carried out at 700 ÷ 850 ° С, as a result of which an intermediate amorphous aluminosilicate is formed, which is able to crystallize into a zeolite structure, and the complete burning out of wood flour ensures the permeability of the granule for sorbed substances. The obtained amorphous granules are cooled and subjected to hydrothermal crystallization in an alkaline solution. The finished zeolite is treated with sharp water vapor at a temperature of 110 ÷ 140 ° C, washed with softened water and dried at a temperature of 250 ÷ 350 ° C.

The essence of the method is illustrated by specific examples of its implementation.

Example 1. This example demonstrates the possibility of obtaining granulated type A zeolite from kaolin, wood flour, calcined kaolin powder, taken in an amount of 5 wt.% Type A zeolite powder, taken in an amount of 5 wt.%, And sodium chloride.

240 g of kaolin with a ratio of SiO ₂ : Al ₂ O ₃ = 2: 1 and 24 g of wood flour powder are loaded into the mixer. The mixture is stirred for 15 minutes. Then add 15 g of calcined powder kaolin, 15 g of powder zeolite type A, 6 g of crystalline sodium chloride and further stirred for 15 minutes.

Then add a 5% solution of lignosulfonate in an amount of 106 ml. Stirring is continued until a homogeneous plastic mass is obtained.

Then molding is carried out, obtaining granules with a diameter of 6 mm, which are placed in a closed container for aging within 24 hours. Next, finishing molding is carried out in a screw extruder, obtaining granules with a diameter of 3 mm.

Next, the granules are dried at 80 ÷ 130 ° C in an oven for 2 hours.

The dried granules are subjected to thermal activation in a chamber furnace at 700 ÷ 800 ° C for 2 hours, after which they are cooled.

After calcination, amorphous granules are placed in a crystallizer and poured with a crystallization solution obtained by mixing 1500 ml of water and 220 g of granulated sodium hydroxide with a concentration of 146 g / L in sodium oxide.

The resulting reaction mass is maintained at 20 ÷ 30 ° C for 4 hours, then the temperature rises to 80 ÷ 90 ° C, and the reaction mass is maintained for 24 hours.

The resulting zeolite is treated with hot steam for 6 hours at a temperature of 110 ÷ 160 ° C, washed with softened water and dried at 250 ÷ 350 ° C.

The type of crystal lattice and degree of crystallization of the finished sample were determined by X-ray diffraction; mechanical strength of granules - by crushing them on an MP-9C device.

Physico-chemical characteristics of type A zeolite are given in the table.

Example 2. This example demonstrates the possibility of obtaining granular zeolite type A according to the method described in example 1, characterized in that the calcined powder is added to the initial mixture, taken in an amount of 10 wt.%.

Example 3. This example demonstrates the possibility of obtaining granular zeolite type A according to the method described in example 1, characterized in that the calcined powder is added to the initial mixture, taken in an amount of 15 wt.%.

Example 4. This example demonstrates the possibility of obtaining granular zeolite type A according to the method described in example 1, characterized in that the powder type zeolite A is taken in the initial mixture, taken in an amount of 10 wt.%.

Example 5. This example demonstrates the possibility of obtaining granular zeolite type A according to the method described in example 1, characterized in that the calcined powder kaolin taken in an amount of 10 wt.% And type A zeolite in an amount of 10 wt. %

Example 6. This example demonstrates the possibility of obtaining granular zeolite type A according to the method described in example 1, characterized in that powdered calcined kaolin taken in an amount of 15 wt.% And powder zeolite type A in an amount of 10 wt. %

Example 7. This example demonstrates the possibility of obtaining granular zeolite type A according to the method described in example 1, characterized in that powder type zeolite A, taken in an amount of 20 wt.%, Is introduced into the initial mixture.

Example 8. This example demonstrates the possibility of obtaining granular zeolite type A according to the method described in example 1, characterized in that the calcined powder is taken in the initial mixture, taken in an amount of 10 wt.%, And powder zeolite type A in an amount of 20 wt. %

Example 9. This example demonstrates the possibility of obtaining granular zeolite type A according to the method described in example 1, characterized in that powdered calcined kaolin taken in an amount of 15 wt.% And type A zeolite in an amount of 20 wt. %

Physico-chemical characteristics of type A zeolite are given in the table.

Table Physicochemical Characteristics of Type A Zeolite Samples Example Zeolite type The content of the main crystalline phase according to x-ray diffraction analysis, wt.% The dynamic capacity of zeolite during gas dehydration to the dew point minus 60 ° C, g / 100 g Abrasion resistance under dynamic load,% one BUT 78.3 20,2 87.3 2 BUT 82.9 20.8 89.0 3 BUT 81.5 20.5 88.8 four BUT 82.3 20.1 93.1 5 BUT 83,2 20,2 91.2 6 BUT 81.3 19.1 90.2 7 BUT 85.7 18.8 95.0 8 BUT 83.7 19.2 88.8 9 BUT 83.0 19.7 88.1 Prototype BUT 99,2 18.1 78.0

As can be seen from the table, the obtained zeolite has a relatively higher rate of mechanical strength and dynamic capacity in comparison with the prototype, which ensures its more efficient use in technological processes.

Claims (1)

A method of producing a synthetic granular zeolite of type A, comprising mixing a natural clay mineral - kaolin with an additive, containing carbon, introducing powder of zeolite A into the mixture, adding liquid to the mixture to obtain a homogeneous mass, molding of granules, aging, final molding, intermediate drying, thermal activation hydrothermal crystallization in an alkaline solution, thermocouple treatment, washing and final drying, characterized in that as an additive containing carbon, by mixing Wood flour is fed, zeolite A powder is introduced into the mixture in an amount of 5-20 wt.%, while 5-15 wt.% powder kaolin, previously calcined at 500-600 ° C, and 2 wt.% crystalline are added to the mixture sodium chloride, as a liquid, a 5% solution of lignosulfonate is added to the resulting mixture, intermediate drying of the granules is carried out at 80-130 ° C, thermal activation is carried out at 700-850 ° C, and final drying at 250-350 ° C.