CN107303504B

CN107303504B - Peptization method of pseudo-boehmite

Info

Publication number: CN107303504B
Application number: CN201610243283.1A
Authority: CN
Inventors: 高雄厚; 潘志爽; 袁程远; 李雪礼; 刘明霞; 高永福; 田爱珍; 蔡进军; 张海涛; 谭争国; 黄校亮; 段宏昌; 丁伟; 郑云锋; 孙书红
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2016-04-18
Filing date: 2016-04-18
Publication date: 2020-06-09
Anticipated expiration: 2036-04-18
Also published as: CN107303504A

Abstract

The invention relates to a peptization method of pseudo-boehmite, which comprises the following steps: (1) pulping and dispersing the pseudo-boehmite and water uniformly; (2) then adding the anion Cl^‑Or NO₃ ^‑Or ClO₄ ^‑Or CH₃COO^‑Or COOH^‑Stirring and standing the soluble salt; (3) and (3) finally, uniformly stirring the slurry obtained in the step (2), and adding acid until the slurry becomes transparent colloid. The pseudoboehmite peptized by the method can reach a complete peptization state, and the peptization degree is equivalent to that of peptization by hydrochloric acid and nitric acid, so that the pseudoboehmite replaces the hydrochloric acid and nitric acid peptization agent, the pollution to the environment due to the volatilization of the hydrochloric acid and the nitric acid is reduced, the flexibility of selecting the peptization agent by a production enterprise is improved, the peptization speed is controllable, and the fluidity of slurry is good; the peptization process does not need heating, thus reducing the energy consumption of production enterprises.

Description

Peptization method of pseudo-boehmite

Technical Field

The invention relates to a peptization method of alumina, in particular to a peptization method of pseudo-boehmite.

Background

Pseudo-boehmite (AlOOH. nH)₂O and n is 0.08-0.62), is a low-crystalline alumina hydrate, is a precursor of active alumina, has the characteristics of no toxicity, no odor, good formability and thixotropic gel, and is widely used for preparing functional materials such as adsorbents, catalysts, superfine alumina carriers and the like. The pseudo-boehmite is used as a binder, and besides the proper mechanical strength can be provided for a catalyst finished product, the alumina also has porosity, so that the porosity of the catalyst can be increased. The peptization performance of the pseudo-boehmite is directly related to the performances of the catalyst such as strength, pore volume, apparent bulk density and the like.

The peptizing agents commonly used in the catalytic cracking catalyst preparation process are hydrochloric acid and nitric acid, and in addition phosphoric acid and sulfuric acid are also used as peptizing agents. CN1916117 provides a peptization method of pseudo-boehmite, which comprises the following steps: mixing pseudoboehmite with water sufficient to cause slurrification thereof under agitation, wherein the acid is used in an amount such that the weight ratio of the acid to alumina in the pseudoboehmite is 0.05-0.3; then aging the mixed slurry at room temperature to 90 deg.C for 0.5-4 hr.

The preparation method of the aluminum phosphate sol provided by CN102050434A comprises the following steps: pulping and dispersing an acid-soluble aluminum precursor and deionized water into slurry with the solid content of 10-35 wt%, adding 60-98% phosphoric acid and HNO into the slurry according to the weight ratio of P/Al to 1.0-2.5 under stirring₃/Al₂O₃Adding 40-98% nitre according to the weight ratio of 0.2-2.0And (4) reacting with acid to obtain the aluminum phosphate sol. The method also causes serious environmental pollution by introducing the decomposition of nitrate during the roasting process of the catalyst.

CN1417296A provides an acidification method of aluminum hydroxide, which is: pulping aluminum hydroxide or aluminum oxide which can be peptized by acid and deionized water to disperse into slurry with the solid content of 15-35 wt%, adding concentrated phosphoric acid into the slurry according to the weight ratio of P/Al to 1.2-6 while stirring, heating to 65-95 ℃, and reacting for 15-90 min at the temperature until the transparent colloid is formed.

In patent CN103818928A, pseudo-boehmite is acidified by phosphoric acid, and the specific steps are as follows: adding 1mol of pseudo-boehmite into 20-110 mol of deionized water, and fully stirring to obtain a suspension of the pseudo-boehmite; taking the pseudoboehmite suspension, 0.6-1.2 mol of phosphoric acid with the mass concentration of 84-86% and 0-1.0 mol of silicon dioxide, mixing and stirring uniformly until the pseudoboehmite is completely peptized, wherein the phosphoric acid needs to be added slowly when being added.

Patent CN103332709A discloses a method for sulfuric acid acidification of pseudo-boehmite, which comprises the following specific steps: a: preparing 1-20% of pseudo-boehmite slurry by mass percentage, and grinding the slurry in a ball mill or a colloid mill for 1-30 min; then preparing an acid solution with the mass percentage of 5-20% to ensure that H in the acid solution⁺The ratio of the molar weight of the aluminum hydroxide to the molar weight of Al in the pseudo-boehmite slurry is 0.2-1; the acid is one of nitric acid, hydrochloric acid and sulfuric acid; adding the acid solution into the pseudo-boehmite slurry within 30min under the condition of vigorous stirring to peptize the pseudo-boehmite, and continuously stirring for 1h after the dropwise addition is finished to prepare the pseudo-boehmite peptization.

Patent CN103896318A discloses a method for peptizing pseudo-boehmite with sulfuric acid, comprising the following steps: (1) adding pseudo-boehmite powder into deionized water, pulping uniformly, and dropwise adding 1-2mol/L inorganic acid solution to peptize; addition of acid H⁺：Al³⁺The molar ratio of (A) to (B) is 0.03-0.1, or the pH of the solution is adjusted to 2.5-5.0; the inorganic acid is one or two of hydrochloric acid, sulfuric acid and nitric acid.

When hydrochloric acid or nitric acid is used as a peptizing agent, acid can corrode equipment and influence the environment in the spray drying and forming process of the catalyst, and meanwhile, the formed hydrochloric acid gas can also damage the structure of a molecular sieve in the catalyst, so that the activity of the catalyst is reduced. When phosphoric acid or sulfuric acid is used as a peptizing agent to acidify the peptized pseudo-boehmite, the acidification speed is slow, the peptization depth is shallow, the peptized pseudo-boehmite colloid is unstable, and the strength requirement of the catalytic cracking catalyst cannot be met.

Disclosure of Invention

The invention aims to provide a peptization method of green and environment-friendly pseudo-boehmite, which improves the stability and the peptization depth of the peptized pseudo-boehmite and meets the requirements of a catalytic cracking catalyst preparation process.

The object of the invention can be realized by the following technical scheme, and the peptization method of the pseudoboehmite comprises the following steps: (1) mixing and pulping the pseudo-boehmite with water which is enough for pulping the pseudo-boehmite, and uniformly dispersing the pseudo-boehmite and the water, wherein the water is preferably added in an amount of 10-30% by mass of alumina in the pseudo-boehmite; (2) then adding an anion selected from Cl^-、NO₃ ^-、ClO₄ ^-、CH₃COO^-Or COOH^-Uniformly stirring the soluble salt of the one of the compounds, preferably stirring for 10-60min, standing for 1-24h, preferably 4-12h, wherein the molar ratio of the soluble salt to the alumina in the pseudo-boehmite is 0.10-6.0, preferably 0.15-2.0; (3) and (3) finally, uniformly stirring the slurry obtained in the step (2), adding acid, and stirring until the slurry becomes a transparent colloid, wherein the adding speed of the acid is preferably 10-60g/min, more preferably 10-30g/min, and the adding amount of the acid is that the molar ratio of hydrogen atoms in the acid molecular formula to soluble salts is 0.2-3.0, preferably 0.5-1.5.

The peptization method of pseudoboehmite is characterized in that the pseudoboehmite is one or the combination of boehmite, gibbsite and bayer stone, and is preferably boehmite.

The peptization method of the pseudo-boehmite is characterized in that the acid is one or the combination of phosphoric acid, boric acid, hydrofluoric acid, sulfuric acid, periodic acid, oxalic acid, phthalic acid, carbolic acid and silicic acid, and phosphoric acid, sulfuric acid or silicic acid is preferred.

The cation in the soluble salt is alkali metal ion, IIIB group metal ion, alkaline earth metal ion or ammonium ion, preferably IIIB group metal ion, alkaline earth metal ion or ammonium ion, wherein the IIIB group metal ion is selected from one or the combination of La, Ce, Pr and Nd, and the alkaline earth metal ion is selected from one or the combination of Be, Mg, Ca, Sr and Ba.

The anion in the soluble salt according to the invention is preferably Cl^-、NO₃ ^-、CH₃COO^-。

Acidifying and peptizing pseudoboehmite to form a micelle with a double electric layer structure, wherein the micelle selectively adsorbs positively charged H from the solution⁺Forming positively charged colloidal particles, while negatively charged anions form a diffusion layer around the colloidal particles due to attraction and diffusion. The pseudo-boehmite is peptized by phosphoric acid or sulfuric acid, and a diffusion layer of the micelle is easy to compress due to high charge number of phosphate radical and sulfate radical, so that the diffusion layer is reduced, the electromotive potential is reduced, and the stability of the peptized pseudo-boehmite micelle is reduced; the concentration of phosphate radical and sulfate radical continues to increase, the electric charge is reduced to 0, and the micelle can not selectively adsorb H⁺And the acidification peptization degree is reduced, at the moment, agglomeration can occur between colloidal particles, so that the colloidal particles are enlarged, the homogenization effect in the preparation process of the catalyst is influenced, and the strength of the catalyst is finally influenced.

The invention adopts the compound with Cl^-、NO₃ ^-、ClO₄ ^-、CH₃COO^-Or COOH^-Adding soluble salt of monovalent anion into peptization system, because the monovalent anion and aluminum ion do not produce combination or only have weak combination, not only can protect diffusion layer, but also can avoid anion (such as F)^-) The strengthening effect with aluminum ions results in no peptization of the pseudoboehmite. The invention adds the monovalent anion soluble salt before adding phosphoric acid or sulfuric acid to peptize pseudo-boehmite, and adsorbs H in a glue nucleus⁺Form colloidal particles and simultaneously adsorb the anions to form a diffusion layer to reduce phosphate or sulfate pairsThe stability of the micelle is improved due to the influence of the diffusion layer; acids which are non-peptizing for pseudoboehmite, such as boric acid, periodic acid, oxalic acid, phthalic acid, carbolic acid and silicic acid, are in ionized equilibrium in aqueous solution, and pseudoboehmite and weak acid radical are simultaneously in equilibrium with H⁺And (4) reacting. The invention adds univalent anions to form a diffusion layer to improve H adsorption of the pseudo-boehmite⁺Dynamic, reducing weak acid radical and H⁺Carrying out reaction; consumption of H in acidification of pseudo-boehmite⁺H in solution⁺The concentration is reduced, which is beneficial to the weak acid to react towards the ionization direction and generate more H⁺。H⁺The increase of the concentration is beneficial to improving the peptization depth of the pseudo-boehmite. Therefore, the anion can increase the thickness of the diffusion layer, improve the electric charge, attract hydrogen protons to migrate to the micelle, accelerate the acidification and dissolution of the micelle and improve the peptization depth of the pseudo-boehmite; the stability and the peptization depth of peptized pseudo-boehmite are improved, the homogenization of catalytic cracking catalyst slurry is facilitated, and the abrasion resistance of the catalyst is improved. Compared with the peptization method by acidifying with hydrochloric acid and nitric acid, the pseudoboehmite peptized by the method can reach the state of complete peptization by using hydrochloric acid and nitric acid, and the abrasion index of the catalyst is equivalent to that of the catalyst prepared by peptization by using hydrochloric acid and nitric acid; in the preparation process of the catalyst, the peptizing system can replace hydrochloric acid and nitric acid peptizing agents, and reduce the pollution to the environment and the damage to the molecular sieve due to the volatilization of the hydrochloric acid and the nitric acid; the peptization speed of the invention is controllable, and the fluidity of the slurry is good; the peptization process does not need heating, so that the energy consumption of production enterprises is reduced; the peptization speed is controllable, so the method can improve the operation flexibility of production enterprises and provide reliable technical support for the control of production processes.

Detailed Description

The following examples are given for the purpose of further illustrating the present invention, but the present invention is not limited to the examples.

The analysis and test method comprises the following steps:

item	Method of producing a composite material	Standard number
			Particle size distribution	Laser particle size analysis	GB/T 19077.1-2008
Wear index	Determination of abrasion index (straight tube method)	GB/T 15458-1995

(II) producing area and specification of raw materials

Pseudo-boehmite: 75.4 wt% of alumina, produced by Shandong alumina works.

Kaolin: china kaolin company, kaolinite 86 wt%.

USY zeolite, REY zeolite and ZSM-5 are all produced by catalyst factories of Lanzhou petrochemical company.

Hydrochloric acid, sulfuric acid, chlorinated rare earth, phosphoric acid, water glass, alkaline silica sol: industrial products from catalyst factories of landlocked petrochemical company.

Ammonium chloride, lanthanum chloride heptahydrate, magnesium nitrate hexahydrate, ammonium acetate: pure analysis, and is produced in Beijing chemical plants.

Example 1

Adding 2540 g of deionized water and 1656 g of pseudo-boehmite into a reaction kettle, pulping for 10 minutes, adding 187 g of ammonium chloride reagent, stirring for 15 minutes, standing for 24 hours, stirring, adding 138 g of concentrated phosphoric acid at the speed of 13g/min, and stirring for 20 minutes to obtain a sample labeled A1.

Sample A1 was a gel-like mass with no particles, indicating that the pseudoboehmite had completely peptized and that the particle size in D (0.5, μm) was 1.96.

Example 2

Adding 2530 g of deionized water and 882 g of pseudo-boehmite into a reaction kettle, pulping for 10 minutes, adding 3612 g of lanthanum chloride heptahydrate reagent, stirring for 15 minutes, standing for 20 hours, stirring, adding 185 g of concentrated sulfuric acid at the speed of 18g/min, and stirring for 20 minutes to obtain a sample labeled A2.

Sample A2 was a gel-like material without particles, with the pseudo-boehmite completely peptized, and the particle size in D (0.5, μm) was 1.61.

Example 3

Adding 2530 g of deionized water and 1082 g of pseudo-boehmite into a reaction kettle, pulping for 10 minutes, adding 2307 g of magnesium nitrate hexahydrate reagent, stirring for 15 minutes, standing for 13 hours, stirring for 20 minutes, adding 2240 g of water glass (the content of silicon dioxide is 31.6 percent, and the pH value is adjusted to 1.5 by hydrochloric acid) at the speed of 50g/min, and obtaining a sample, namely A3.

Sample A3 was a gel-like material without particles, with the pseudo-boehmite completely peptized, and the particle size in D (0.5, μm) was 1.76.

Example 4

1140 g of deionized water and 356g of pseudo-boehmite are added into a reaction kettle, after pulping for 10 minutes, 28.87 g of ammonium acetate reagent is added, stirring is carried out for 15 minutes, standing is carried out for 24 hours, then stirring is carried out, 360g of alkaline silica sol (the PH value is adjusted to be 1.0 by hydrochloric acid) is added at the speed of 10g/min, and stirring is carried out for 20 minutes, thus obtaining a sample marked as A4.

Sample A4 was a gel-like mass with no particles, indicating that the pseudoboehmite had completely peptized and that the particle size in D (0.5, μm) was 1.89.

Example 5

1140 g of deionized water and 356g of pseudo-boehmite are added into a reaction kettle, after 20 minutes of pulping, 36.71 g of magnesium formate reagent is added, the mixture is stirred for 15 minutes, the mixture is kept stand for 24 hours, then the mixture is stirred, 279 g of oxalic acid is added at the speed of 15g/min, and the mixture is stirred for 20 minutes, so that a sample marked as A5 is obtained.

Sample A5 was a gel-like mass with no particles, indicating that the pseudoboehmite had completely peptized and that the particle size in D (0.5, μm) was 2.07.

Example 6

1140 g of deionized water and 356g of pseudo-boehmite are added into a reaction kettle, after 25 minutes of pulping, 47.03 g of potassium perchlorate reagent is added, the mixture is stirred for 25 minutes, the mixture is kept stand for 12 hours, then the mixture is stirred, 375 g of boric acid is added at the speed of 25g/min, and the mixture is stirred for 20 minutes, so that a sample marked as A6 is obtained.

Sample A6 was a gel-like mass with no particles, indicating that the pseudoboehmite had completely peptized and that the particle size in D (0.5, μm) was 1.88.

Comparative example 1

Adding 2540 g of deionized water and 1656 g of pseudo-boehmite into a reaction kettle, pulping for 10 minutes, adding 187 g of ammonium chloride reagent, stirring for 15 minutes, standing for 24 hours, and stirring for 20 minutes to obtain a sample labeled as D1.

Sample D1 was a settled and stratified particle, pseudoboehmite was peptized, and D (0.5, μm) had a particle size of 51.56.

Comparative example 2

Adding 2540 g of deionized water and 1656 g of pseudo-boehmite into a reaction kettle, pulping for 10 minutes, simultaneously adding 187 g of ammonium chloride reagent and 138 g of concentrated phosphoric acid, stirring for 20 minutes, and standing for 24 hours to obtain a sample labeled as D2.

Sample D2 was a settled and stratified particle, pseudoboehmite was peptized, and D (0.5, μm) had a particle size of 51.37.

Comparative example 3

Adding 2540 g of deionized water and 1656 g of pseudo-boehmite into a reaction kettle, pulping for 10 minutes, adding 138 g of concentrated phosphoric acid, stirring for 15 minutes, standing for 24 hours, adding 187 g of ammonium chloride reagent, and stirring for 20 minutes to obtain a sample labeled as D3.

Sample D3 was a settled and stratified particle, pseudoboehmite was peptized, and D (0.5, μm) had a particle size of 51.66.

Comparative example 4

2169 g of deionized water and 1656 g of pseudo-boehmite are added into a reaction kettle, and after being pulped for 10 minutes, 696 g of concentrated phosphoric acid is added, the mixture is stirred for 20 minutes, and the temperature is increased to 90 ℃ to react for 1 hour, thus obtaining a sample, which is marked as D4.

Sample D4 was a settled and delaminated particle with incomplete peptization of pseudoboehmite, and D (0.5, μm) had a particle size of 30.89.

Comparative example 5

2617 g of deionized water and 1656 g of pseudoboehmite are added into a reaction kettle, 248 g of industrial hydrochloric acid is added after pulping for 10 minutes, stirring is carried out for 20 minutes, and the temperature is raised to 60 ℃ for aging for 1 hour, thus obtaining a sample labeled as D5.

Sample D5 was a gel-like material without particles, with the pseudo-boehmite completely peptized, and the particle size in D (0.5, μm) was 1.91.

Comparative example 6

Adding 2530 g of deionized water and 882 g of pseudo-boehmite into a reaction kettle, pulping for 10 minutes, simultaneously adding 3612 g of lanthanum chloride heptahydrate reagent and 185 g of concentrated sulfuric acid, stirring for 15 minutes, and standing for 20 hours to obtain a sample, namely D6.

Sample D6 was a settled and stratified particle, pseudoboehmite was not peptized, and D (0.5, μm) had a particle size of 50.85.

Comparative example 7

Adding 2530 g of deionized water and 1082 g of pseudo-boehmite into a reaction kettle, pulping for 10 minutes, adding 2240 g of water glass (the content of silicon dioxide is 31.6 percent, and the pH value is adjusted to 1.5 by hydrochloric acid), stirring for 15 minutes, adding 2307 g of magnesium nitrate hexahydrate reagent, stirring for 15 minutes, and standing for 13 hours to obtain a sample, namely D7.

Sample D7 was a settled and stratified particle, pseudoboehmite was peptized, and D (0.5, μm) had a particle size of 49.79.

The medium particle size of the pseudo-boehmite in example 1, example 2, example 3 and example 4 was significantly smaller than that in comparative example 1, comparative example 2, comparative example 3, comparative example 4(D4 is a sample prepared according to the method provided in patent CN 1417296A), comparative example 5, comparative example 6 and comparative example 7, illustrating that the order of addition of soluble salts affects the peptization properties of the pseudo-boehmite; compared with a comparative example 5, the particle size of the pseudo-boehmite in the examples 1, 2, 3 and 4 is equivalent to the particle size of the complete peptization of hydrochloric acid, a new method is provided for the peptization reaction of the pseudo-boehmite, the peptization speed of the invention is slow, the homogenization of materials is facilitated, the heating and the temperature rise are not needed in the peptization process, the flexibility of selecting the peptizing agent by production enterprises is improved, and the production operability is also improved.

Example 7

1600g of the sample in the example 1, 1770g of kaolin, 360g of gREY molecular sieve, 340g of USY zeolite, 120g of ZSM-5 and 4280g of deionized water are mixed, homogenized, the temperature of spray-molded tail gas is controlled to be 150 ℃, and then the mixture is roasted for 45min at 450 ℃ to obtain a catalyst A7, wherein the abrasion index of the catalyst A7 is 2.0%.

Example 8

2712g of the sample in example 2, 2779g of kaolin, 731g of gREY molecular sieve, 675g of USY zeolite, 161g of ZSM-5 and 3325g of deionized water are mixed, homogenized, the temperature of spray-molded tail gas is controlled to be 150 ℃, and then the mixture is roasted for 45min at 450 ℃ to obtain a catalyst A8, wherein the abrasion index of the catalyst A8 is 2.3%.

Example 9

2650g of the sample in the example 3, 2356g of kaolin, 681g of gREY molecular sieve, 735g of USY zeolite, 80g of ZSM-5 and 3021g of deionized water are mixed, homogenized, the temperature of spray-molded tail gas is controlled to be 150 ℃, and then the mixture is roasted at 450 ℃ for 45min to obtain a catalyst A9, wherein the abrasion index of the catalyst A9 is 2.0%.

Example 10

1890g of the sample of example 4, 1079g of kaolin, 633g of gREY molecular sieve, 675g of USY zeolite, 92g of ZSM-5 and 3525g of deionized water were mixed, homogenized, the temperature of spray-molded tail gas was controlled at 150 ℃, and then calcined at 450 ℃ for 45min to obtain catalyst A10, the attrition index of which was 1.9%.

Example 11

3728g of the sample in the example 5, 2779g of kaolin, 851g of zeolite Y, 782g of USY zeolite, 72g of ZSM-5 and 3811g of deionized water are mixed, homogenized, the temperature of spray-molded tail gas is controlled to be 150 ℃, and then the mixture is roasted at 450 ℃ for 45min to obtain the catalyst A11, wherein the abrasion index of the catalyst A11 is 1.8%.

Example 12

1517g of the sample of example 6, 2351g of kaolin, 731g of gREY molecular sieve, 377g of USY zeolite, 260g of ZSM-5 and 2700g of deionized water were mixed, homogenized, the temperature of the spray-molded tail gas was controlled at 150 ℃, and then calcined at 450 ℃ for 45min to obtain catalyst A12, the attrition index of which was 2.2%.

Comparative example 8

1600g of the sample of the comparative example 1, 1770g of kaolin, 360g of gREY molecular sieve, 340g of USY zeolite, 120g of ZSM-5 and 4280g of deionized water are mixed, homogenized, the temperature of the tail gas of spray forming is controlled to be 150 ℃, and then the mixture is roasted for 45min at 450 ℃ to obtain the catalyst D8, wherein the abrasion index of the catalyst D8 is 25.7%.

Comparative example 9

1600g of the sample of the comparative example 2, 1770g of kaolin, 360g of gREY molecular sieve, 340g of USY zeolite, 120g of ZSM-5 and 4280g of deionized water are mixed, homogenized, the temperature of the tail gas of spray forming is controlled to be 150 ℃, and then the mixture is roasted for 45min at 450 ℃ to obtain the catalyst D9, wherein the abrasion index of the catalyst D9 is 23.9%.

Comparative example 10

1600g of the sample of the comparative example 3, 1770g of kaolin, 360g of gREY molecular sieve, 340g of USY zeolite, 120g of ZSM-5 and 4280g of deionized water are mixed, homogenized, the temperature of the tail gas of spray forming is controlled to be 150 ℃, and then the mixture is roasted for 45min at 450 ℃ to obtain the catalyst D10, wherein the abrasion index of the catalyst D10 is 24.2%.

Comparative example 11

1600g of the sample of the comparative example 4, 1770g of kaolin, 360g of gREY molecular sieve, 340g of USY zeolite, 120g of ZSM-5 and 4280g of deionized water are mixed, homogenized, the temperature of the tail gas of spray forming is controlled to be 150 ℃, and then the mixture is roasted for 45min at 450 ℃ to obtain the catalyst D11, wherein the abrasion index of the catalyst D11 is 20.3%.

Comparative example 12

1600g of the sample of the comparative example 5, 1770g of kaolin, 360g of gREY molecular sieve, 340g of USY zeolite, 120g of ZSM-5 and 4280g of deionized water are mixed, homogenized, the temperature of the tail gas of spray forming is controlled to be 150 ℃, and then the mixture is roasted for 45min at 450 ℃ to obtain the catalyst D12, wherein the abrasion index of the catalyst D12 is 2.1%.

Comparative example 13

2712g of the sample of comparative example 6, 2779g of kaolin, 731g of gREY molecular sieve, 675g of USY zeolite, 161g of ZSM-5 and 3325g of deionized water were mixed, homogenized, the temperature of the spray-molded tail gas was controlled at 150 ℃, and then calcined at 450 ℃ for 45min to obtain catalyst D13, the attrition index of which was 19.7%.

The attrition index of the catalyst of example 7 is significantly lower than that of the catalysts of comparative examples 8, 9, 10, 11 and 13, and is comparable to that of comparative example 12, indicating that the strength of the catalyst prepared by the peptization method of pseudoboehmite according to the present invention can achieve the effect of the catalyst of acidifying the pseudoboehmite with hydrochloric acid. In the preparation process of the catalyst, the peptizing system can replace a hydrochloric acid peptizing agent, reduce the pollution to the environment due to the volatilization of hydrochloric acid, simultaneously reduce the corrosion of a large amount of chlorine to equipment and the damage to the molecular sieve structure of the catalyst, improve the service life of a production device and the production quality of the catalyst, and provide a feasible technical scheme for reducing the production cost and improving the benefit of enterprises.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications as fall within the true spirit and scope of the appended claims be embraced thereby.

Claims

1. The peptizing method of the pseudoboehmite is characterized by comprising the following steps:

(1) mixing and pulping the pseudo-boehmite and water which is enough for pulping the pseudo-boehmite, and uniformly dispersing the pseudo-boehmite and the water; (2) then adding an anion selected from Cl^-、NO₃ ^-、ClO₄ ^-、CH₃COO^-Or HCOO^-Uniformly stirring one of the soluble salts, standing for 1-24h, wherein the molar ratio of the soluble salt to the alumina in the pseudo-boehmite is 0.10-6.0; (3) finally, after the slurry obtained in the step (2) is uniformly stirred, adding acid and stirring until the slurry becomes transparent colloid, wherein the adding amount of the acid is that the molar ratio of hydrogen atoms in the molecular formula of the acid to soluble salts is 0.2-3.0;

wherein the acid is one or combination of phosphoric acid, boric acid, sulfuric acid, periodic acid, oxalic acid, phthalic acid, carbolic acid and silicic acid.

2. The peptizing method of pseudo-boehmite according to claim 1, characterized in that the water is added in the step (1) in an amount such that the mass percentage of alumina in the pseudo-boehmite is 10-30%.

3. The peptizing method of pseudoboehmite according to claim 1, characterized in that the standing time after adding the soluble salt is 4-12 h.

4. The peptizing method of pseudoboehmite according to claim 1, characterized in that the molar ratio of the addition amount of the soluble salt to the alumina in the pseudoboehmite is 0.15-2.0.

5. The peptization method of pseudo-boehmite according to claim 1, characterized in that the acid is added at a rate of 10-60 g/min.

6. The peptization method of pseudo-boehmite according to claim 1 or 5, characterized in that the acid is added at a rate of 10-30 g/min.

7. The peptizing method of pseudoboehmite according to claim 1, characterized in that the acid is added in an amount such that the molar ratio of the hydrogen atoms in the acid molecular formula to the soluble salt is 0.5-1.5.

8. The peptization method of pseudoboehmite according to claim 1, characterized in that the pseudoboehmite is one of boehmite, gibbsite and bayerite or a combination thereof.

9. The peptization method of pseudoboehmite according to claim 1, characterized in that the pseudoboehmite is boehmite.

10. The peptizing method of pseudo-boehmite according to claim 1, characterized in that the acid is phosphoric acid, sulfuric acid or silicic acid.

11. The peptizing method of pseudo-boehmite according to claim 1, characterized in that the cation in the soluble salt is alkali metal ion, IIIB group metal ion, alkaline earth metal ion or ammonium ion.

12. The peptizing method of pseudo-boehmite according to claim 1 or 11, characterized in that the cation in the soluble salt is a group IIIB metal ion, an alkaline earth metal ion or an ammonium ion.

13. The peptizing method of pseudo-boehmite according to claim 12, characterized in that the group IIIB metal ion in the soluble salt is one or a combination of La, Ce, Pr and Nd.

14. The peptizing method of pseudo-boehmite according to claim 12, characterized in that the alkaline earth metal ions in the soluble salt are one or a combination of Be, Mg, Ca, Sr and Ba.

15. The peptization method of pseudo-boehmite according to claim 1, characterized in that the anion in the soluble salt is Cl^-、NO₃ ^-Or CH₃COO^-。