RU2446101C1 - Method of producing synthetic granular type a zeolite - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of synthetic granular type A zeolites used as adsorbents and catalysts. Disclosed is a method of producing granular type A zeolite without binder, which involves mixing initial components in grinders with impact-shift loading type with power density of 0.1-70 kW/kg for 0.05-4 hours using annealed kaolin, solid sodium hydroxide and 3-7 wt % carboxymethyl cellulose or modified starch as the initial components. The mixture undergoes thermal activation at 450-700°C and hydrothermal activation at 70-90°C in a single step in an alkaline solution with sodium hydroxide concentration of 3-5 mol/l.

EFFECT: invention increases the strength of zeolite granules by more than 1,5 times and porosity by 23-25%.

2 cl, 1 tbl, 3 ex

Description

FIELD OF TECHNOLOGY

The invention relates to the production of granular zeolite type A, not containing a binder. The obtained zeolite can be used as a catalyst (or its component) in the chemical and petrochemical industries, as an adsorbent for drying and purifying natural gas during gas processing, for separating hydrocarbon mixtures at the molecular level, as an ion-exchange material when cleaning water streams from heavy metal cations and radionuclides.

BACKGROUND

A known method of producing synthetic granular zeolite type A, comprising mixing a natural clay mineral kaolin with charcoal, 30 ÷ 70 wt.% Zeolite type A and processing 2% sodium hydroxide solution, a 1.5% aqueous solution is added to the resulting mixture polyvinyl alcohol until a homogeneous plastic mass is formed, which is formed into granules, sent for aging, 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 granules cooled and subjected to hydrothermal crystallization in alkaline solution treatment is carried termoparovuyu pellets at 110 ÷ 160 ° C, washed with demineralized water, zeolite granules obtained were dried at 120 ÷ 200 ° C [Pat. 2203222 Russia, IPC ⁷ C01B 39/14. Claim 12/21/2001; publ. 04/27/2003].

The disadvantages of this method are the use of a large amount (30 ÷ 70 wt.%) Of type A zeolite powder, polyvinyl alcohol, as well as intermediate drying of granules in two stages, which leads to a significant increase in the cost of production and the complexity of the technology.

A known method for producing a synthetic zeolite adsorbent of structure A, comprising mixing the original natural clay mineral kaolin with wood flour, 5-15 wt.% Powder kaolin calcined at 500 ÷ 600 ° C, 5 ÷ 20 wt.% Type A zeolite powder, 2 wt. .% crystalline sodium chloride, introducing into the mixture with stirring a 5% solution of lignosulfonate to form a homogeneous plastic mass, which is then formed into granules, which are placed in a closed container for aging for 24 hours, then subjected to a fine molding. Next, the granules are dried at 80 ÷ 130 ° C and thermal activation is carried out at 700 ÷ 850 ° C, as a result of which an intermediate amorphous aluminosilicate is formed, as well as the complete burning out of wood flour, the obtained granules are cooled and subjected to hydrothermal crystallization in an alkaline solution, first at 30 ° C for 4 hours, and then at 80 ÷ 90 ° C for 24 hours. The resulting zeolite is treated with sharp water vapor for 6 hours at a temperature of 110 ÷ 160 ° C, washed with water and dried [US Pat. 2321539 Russia, IPC C01B 39/18. Claim 03/15/2006; publ. 04/10/2008. Bull. No. 10].

The disadvantages of this method are the use of lignosulfonate, which when burned forms toxic emissions, 2-stage molding of granules with an intermediate exposure of the plastic mass, prolonged 2-stage crystallization.

Closest to the technical nature of the invention, i.e. the prototype, is a method for producing granular zeolite type A, which includes mixing the starting components, molding, drying and thermal activation. In this case, the components are mixed in mills with shock-shear loading with an energy intensity of 0.1 ÷ 200 kW / kg for 0.05 ÷ 20 hours. Shock-shear loading is ensured by ball, vibration and planetary mills. Hydrargillite, hydrated sodium silicate and hydro-silica gel, or hydrargillite, hydro-silica gel and sodium hydroxide are fed for mixing. Thermal activation is carried out by calcining the granules at 450 ÷ 500 ° C for 3-4 hours [US Pat. 2317945 Russia, IPC C01B 39/14. Claim 07/07/2006; publ. 02/27/2008. Bull. No. 6].

The disadvantages of the prototype are not sufficiently high strength and porosity of the granules, as well as the high cost of raw materials (used ingredients of the brand "h").

SUMMARY OF THE INVENTION

The present invention is to develop a method for producing granular zeolite type A, having increased strength and porosity of the granules, an increase in the degree of crystallization, as well as lowering the cost of raw materials.

The problem is solved in that the method of producing granular zeolite type A involves mixing the starting components with sodium hydroxide in mills with shock-shear loading with an energy intensity of 0.1 ÷ 70 kW / kg for 0.05 ÷ 4 hours, molding of granules, them drying and thermal activation, while calcined kaolin is mixed with solid sodium hydroxide in the ratio kaolin: sodium hydroxide = 1: (0.25 ÷ 0.35) and a temporary technological binder, which is used as modified starch or carboxymethyl cellulose in col honors 3-7 wt.%, then water is added to obtain a homogeneous plastic mass, and after the thermal activation is carried out in the crystallization solution of sodium hydroxide with a concentration of 3 ÷ 5 mol / l in a single step. Thermal activation is carried out at a temperature of 450 ÷ 700 ° C for 2 ÷ 6 hours, and crystallization at a temperature of 70 ÷ 90 ° C for 2 ÷ 6 hours.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

Example 1. This example demonstrates the possibility of obtaining granular zeolite with a structure of type A with a ratio of kaolin: NaOH = 1: 0.28, 5 wt.% Modified starch, thermal activation temperature of 570 ° C and using a NaOH solution with a concentration of 4 mol / l at the ratio of T: W = 1: 2.5.

100 g of kaolin calcined at 700 ° C, 28 g of solid NaOH, 6.4 g of modified starch are charged into a vibratory roller-ring mill (energy intensity 5.4 kW / kg) and subjected to grinding for 0.15 hours.

The crushed mixture is loaded into the mixer and 24 ml of water are added, stirring is continued until a homogeneous plastic mass is formed. Then granules with a diameter of 3 mm are molded, which are dried at a temperature of 110 ÷ 120 ° C for 3 hours. The dried granules are subjected to thermal activation at a temperature of 570 ° C for 4 hours, after which they are cooled.

After calcination, the amorphous granules are placed in a crystallizer and 320 ml of a crystallization solution of sodium hydroxide with a concentration of 4 mol / L (160 g / L) are poured. Hydrothermal treatment is carried out at a temperature of 90 ° C for 2 hours. The obtained zeolite is washed with water and dried at a temperature of 110 ÷ 120 ° C for 3 hours.

Example 2. This example demonstrates the possibility of obtaining granular zeolite with a structure of type A, with a ratio of kaolin: NaOH = 1: 0.35, 7 wt.% Carboxymethyl cellulose, a temperature of thermal activation of 700 ° C and using a NaOH solution with a concentration of 5 mol / l at the ratio of T: W = 1: 2.2.

200 g of kaolin calcined at 700 ° C, 70 g of solid NaOH, 18.9 g of carboxymethyl cellulose are loaded into a drum ball mill (energy intensity 0.1 kV / kg) and subjected to grinding for 4 hours.

The crushed mixture is loaded into the mixer and 55 ml of water are added, stirring is continued until a homogeneous plastic mass is formed. Then granules with a diameter of 3 mm are molded, which are dried at a temperature of 110 ÷ 120 ° C for 3 hours. The dried granules are subjected to thermal activation at a temperature of 700 ° C for 2 hours, after which they are cooled.

After calcination, the amorphous granules are placed in a crystallizer and 563 ml of a crystallization solution of sodium hydroxide with a concentration of 5 mol / L (200 g / L) are poured. Hydrothermal treatment is carried out at a temperature of 80 ° C for 4 hours. The obtained zeolite is washed with water and dried at a temperature of 110 ÷ 120 ° C for 3 hours.

Example 3. This example demonstrates the possibility of obtaining granular zeolite with a structure of type A, with a ratio of kaolin: NaOH = 1: 0.25, 3 wt.% Modified starch, a temperature of thermal activation of 450 ° C and using a NaOH solution with a concentration of 3 mol / l with a ratio of T: W = 1: 2.8.

50 g of kaolin calcined at 700 ° C, 12.5 g of solid NaOH, 1.9 g of modified starch are loaded into a planetary mill (energy intensity 70 kW / kg) and subjected to grinding for 0.05 hours.

The crushed mixture is loaded into the mixer and 11 ml of water are added, stirring is continued until a homogeneous plastic mass is formed. Then granules with a diameter of 3 mm are molded, which are dried at a temperature of 110 ÷ 120 ° C for 3 hours. The dried granules are subjected to thermal activation at a temperature of 450 ° C for 6 hours, after which they are cooled.

After calcination, the amorphous granules are placed in a crystallizer and 151 ml of a crystallization solution of sodium hydroxide with a concentration of 3 mol / l (120 g / l) are poured. Hydrothermal treatment is carried out at a temperature of 70 ° C for 6 hours. The obtained zeolite is washed with water and dried at a temperature of 110 ÷ 120 ° C for 3 hours.

The crystal lattice of the zeolite samples obtained in Examples 1-3 was identified by comparing the diffraction patterns with the ASTM International database (American Society for Testing and Materials), the degree of crystallization was calculated by the integrated intensity of the reflexes [Zevin L.S., Zavyalov L.L. Quantitative x-ray phase analysis. M .: Nedra, 1974. 184 pp.], The mechanical strength of the granules for crushing was determined according to the method of work [Schukin ED, Bessonov AI, Paransky SA Mechanical tests of catalysts and sorbents. M .: Nauka, 1971. 56 pp.], And the general porosity - according to the method of work [Workshop on the technology of ceramics and refractories / Ed. D.N. Poluboyarinova and R.Ya. Popilsky. M.: Stroyizdat, 1972. 352 p.].

Physico-chemical characteristics of the obtained granular zeolite are presented in the table.

Table Physico-chemical characteristics of granule samples (⌀3 mm) of synthetic zeolite type A Example The degree of crystallization, wt.% Mechanical crushing strength, MPa Total porosity, vol.% one 85,4 3.9 54,2 2 83.6 3,5 55,2 3 82.1 3.8 54.1 Prototype 72.8 ÷ 75.4 2.0 ÷ 2.5 44.0

As can be seen from the data presented in the table, the use of the proposed method allows to increase the degree of crystallization on average by 13%, the strength of the granules - more than 1.5 times, while the total porosity increases by 23 ÷ 25%. In addition, when using natural kaolin instead of “h” brand ingredients, the cost of the product is reduced.

Claims (2)

1. A method of producing a synthetic granular zeolite of type A, comprising mixing the starting components with sodium hydroxide in mills with shock-shear loading with an energy intensity of 0.1-70 kW / kg for 0.05-4 hours, forming granules, drying them and thermal activation, characterized in that the calcined kaolin is mixed with solid sodium hydroxide in a ratio of kaolin: sodium hydroxide equal to 1: (0.25-0.35), and a temporary technological binder, which is used as a modified starch or carboxymethyl cellulose in col 3-7 wt.%, then water is added until a homogeneous plastic mass is obtained, and after thermal activation at a temperature of 450-700 ° C, crystallization is carried out in one stage at a temperature of 70-90 ° C in a solution of sodium hydroxide with a concentration of 3-5 mol / l with a ratio of solid and liquid phases equal to 1: (2.2-2.8). 2. The method of producing synthetic granular zeolite type A according to claim 1, characterized in that the thermal activation is carried out for 2-6 hours and crystallization for 2-6 hours