阅读说明：本技术 一种拟薄水铝石的制备方法 (Preparation method of pseudo-boehmite ) 是由 邹凌峰 于 2019-10-21 设计创作，主要内容包括：本发明公开了一种拟薄水铝石的制备方法,包括如下步骤：(1)偏铝酸钠溶液的制备；(2)将调配好Al<Sub>2</Sub>O<Sub>3</Sub>浓度的偏铝酸钠溶液与硫酸铝溶液按一定比例同时并流加入到反应釜中进行反应,反应后将浆料转入另一气液反应釜中,往气液反应釜中通入二氧化碳气体,并控制空气与二氧化碳的体积比进行反应；(3)将获得的产物进行老化、交换洗涤、过滤、干燥即得所述陶瓷刚玉磨料专用拟薄水铝石干粉。本发明制备的拟薄水铝石杂质含量很低、胶溶性好、成胶性能好、胶透明、胶粘度高、粘结性能好,是一种陶瓷刚玉磨料专用拟薄水铝石。而且采用此方法,可以大幅度提高单釜拟薄水铝石的产量,从而极大限度地降低生产成本。(The invention discloses a preparation method of pseudo-boehmite, which comprises the following steps: (1) preparing a sodium metaaluminate solution; (2) will be prepared with Al 2 O 3 Simultaneously adding sodium metaaluminate solution with concentration and aluminum sulfate solution into a reaction kettle in parallel according to a certain proportion for reaction, transferring the slurry into another gas-liquid reaction kettle after the reaction, introducing carbon dioxide gas into the gas-liquid reaction kettle, and controlling the volume ratio of air and carbon dioxide for reaction; (3) and (3) aging, exchanging and washing, filtering and drying the obtained product to obtain the special pseudo-boehmite dry powder for the ceramic corundum abrasive. The pseudo-boehmite prepared by the invention has the advantages of low impurity content, good peptization, good gelling property, transparent glue, high glue viscosity and good bonding property, and is a special pseudo-boehmite for ceramic corundum abrasive. And by adopting the method, the yield of the single-kettle pseudo-boehmite can be greatly improved, so that the production cost is greatly reduced.)

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

(1) preparing a sodium metaaluminate solution for producing pseudo-boehmite special for a ceramic corundum abrasive;

(2) will be prepared with Al₂O₃Sodium metaaluminate solution with concentration and prepared Al₂O₃Simultaneously adding aluminum sulfate solution with concentration into a reaction kettle with stirring according to the volume ratio of aluminum sulfate to sodium metaaluminate of 0.2 ~ 1.5.5: 1, staying in the reaction kettle for a certain time, controlling the pH value of reaction slurry to be more than or equal to 13, controlling the reaction temperature to be 20-50 ℃, transferring the slurry into another gas-liquid reaction kettle after reaction, introducing carbon dioxide gas into the gas-liquid reaction kettle, and controlling the volume ratio of air to carbon dioxide to be 1: 0.2-0.5, wherein the reaction is carried out under the condition that the volume ratio of aluminum sulfate to sodium metaaluminate is 0.2: 78.5The temperature of the reaction is 20-50 ℃, and the reaction time is 5-40 minutes;

(3) and (3) aging, exchanging and washing, filtering and drying the product obtained in the step (2) to obtain the special pseudo-boehmite dry powder for the ceramic corundum abrasive.

2. The method for preparing sodium metaaluminate solution according to claim 1, wherein the method for preparing sodium metaaluminate solution in step (1) comprises: mixing 25-50% sodium hydroxide solution and Al₂O₃Adding aluminum hydroxide powder with content of more than 60% into a reaction kettle with stirring, and controlling Al₂O₃:Na₂The molar ratio of O is 1: 1.2-1.6; the reaction pressure is 0.1-0.4 MPa; the reaction temperature is 115-140 ℃, the reaction time is 2-6 hours, and the sodium metaaluminate solution for producing the pseudo-boehmite special for the ceramic corundum abrasive is prepared.

3. The process according to claim 1, wherein Al in the sodium metaaluminate solution in the step (2)₂O₃The concentration is 20-100 g/l.

4. The method according to claim 1, wherein the volume ratio (CO) of carbon dioxide to air is controlled in the step (2)₂Air) is 0.2-0.5: 1.

5. The process according to claim 1, wherein Al in the aluminum sulfate solution in the step (2)₂O₃The concentration is 20-100 g/l.

6. The method according to claim 1, wherein the aging step in the step (3) is: heating and aging the slurry obtained in the step (2), wherein the temperature is controlled to be 75-95 ℃, and the aging time is 2-10 hours; and filtering and separating the aged slurry by a filter press to obtain an aged filter cake.

7. The preparation method of claim 1, wherein the step (3) of exchange washing comprises five times of washing of the aged filter cake, wherein ~ times of washing are added for exchange washing, an exchange medium and fresh water are added for washing for the fourth time, and fresh water is used for washing for the fifth time, the exchange washing temperature is 35-85 ℃, the exchange medium is an inorganic ammonium salt, and the inorganic ammonium salt is ammonium bicarbonate.

8. The method according to claim 1, wherein the filtration in the step (3) is: and filtering the exchange washing slurry by using a filter press to obtain the pseudo-boehmite filter cake special for the ceramic corundum abrasive.

9. The preparation method according to claim 1, wherein the drying in step (3) is to perform flash evaporation drying on the pseudo-boehmite filter cake by using pure hot air as a heat source to obtain the pseudo-boehmite dry powder special for the ceramic corundum abrasive.

10. The special pseudo-boehmite for the ceramic corundum abrasive prepared according to the method of claims 1-9.

Technical Field

The invention belongs to the technical field of ceramic corundum abrasive alumina, and particularly relates to a preparation method of special pseudo-boehmite for a ceramic corundum abrasive.

Background

The special pseudo-boehmite for the ceramic corundum abrasive is a special pseudo-boehmite with high viscosity, is also called pseudo-boehmite or pseudo-boehmite, is an alumina crystal containing 1.8-2.5 crystal water molecules, is a crystal phase formed firstly in the synthesis of aluminum hydroxide, is a transition state of the aluminum hydroxide, has incomplete crystallization, is a typical crystal form which is a very thin flaky crystal with folds, and is a product gamma-Al of the pseudo-boehmite calcined at 400-700 DEG C₂O₃Widely used as catalyst carriers, catalysts, adsorbents, and the like; calcining at 1100-1200 ℃ to obtain the nano-grade alpha-Al₂O₃Widely used as paint additive,High-grade ceramics, efficient catalysts of petrochemical industry, submicron (or nanometer) grade grinding materials, polishing materials, cosmetic fillers, inorganic membrane materials and the like, and is a novel material with wide development prospect.

The pseudoboehmite has incomplete crystal water molecules, and the molecules of the pseudoboehmite have the characteristics of spatial network structure, larger pores, developed specific surface, thixotropy changed into sticky colloidal substances in an acidic environment and the like. The pseudo-boehmite special for the ceramic corundum abrasive material is changed into a sticky colloid under an acid environment, so that the pseudo-boehmite special for the ceramic corundum abrasive material produced by the method is changed into the high-sticky colloid by adding acid, the pseudo-boehmite special for the ceramic corundum abrasive material is taken as a raw material, nitric acid is added to form sol, modifier is added to form gel, and then the gel is dried, crushed, screened, calcined and sintered to prepare the ceramic corundum abrasive material.

Aiming at the characteristic that pseudo-boehmite required by the ceramic corundum abrasive has high viscosity in an acid environment, the invention provides a preparation method of the high-viscosity pseudo-boehmite special for the ceramic corundum abrasive so as to meet the requirement of producing the ceramic corundum abrasive.

Disclosure of Invention

The invention provides a special pseudo-boehmite for a ceramic corundum abrasive and a preparation method thereof, aiming at the requirement of the pseudo-boehmite for producing the ceramic corundum abrasive at present.

In order to solve the problems, the invention adopts the technical scheme that:

a preparation method of pseudo-boehmite special for a ceramic corundum abrasive material comprises the following steps:

(1) preparing a sodium metaaluminate solution for producing pseudo-boehmite special for a ceramic corundum abrasive;

(2) will be prepared with Al₂O₃Sodium metaaluminate solution with concentration and prepared Al₂O₃Aluminum sulfate solution with concentration is added into a reaction kettle with stirring in parallel flow, the adding volume ratio of the aluminum sulfate solution to the sodium metaaluminate solution is controlled to be 0 ~ 1.5.5: 1, the aluminum sulfate solution and the sodium metaaluminate solution stay in the reaction kettle for a certain time, and the PH value of reaction slurry is controlledNot less than 13 ℃, controlling the reaction temperature to be 20-50 ℃, placing the reaction product into another gas-liquid reaction kettle after the reaction, introducing carbon dioxide gas into the gas-liquid reaction kettle, and controlling the volume ratio of the introduced air to the carbon dioxide to be 1: 0.2-0.5, wherein the reaction temperature is 20-50 ℃, and the reaction time is 5-40 minutes;

(3) and (3) aging, exchanging and washing, filtering and drying the product obtained in the step (2) to obtain the special pseudo-boehmite dry powder for the ceramic corundum abrasive.

Preferably, the preparation method of the sodium metaaluminate solution in the step (1) comprises the following steps: mixing 25-50% sodium hydroxide solution and Al₂O₃Adding aluminum hydroxide powder with content of more than 60% into a reaction kettle with stirring, and controlling Al₂O₃:Na₂The molar ratio of O is 1: 1.2-1.6; the reaction pressure is 0.1-0.4 MPa; the reaction temperature is 115-140 ℃, the reaction time is 2-6 hours, and the sodium metaaluminate solution for producing the pseudo-boehmite special for the ceramic corundum abrasive is prepared.

Preferably, Al in the sodium metaaluminate solution in the step (2)₂O₃The concentration is 20-100 g/l.

Preferably, Al in the aluminum sulfate solution in the step (2)₂O₃The concentration is 20-100 g/l.

Preferably, the volume ratio of the aluminum sulfate solution to the sodium metaaluminate solution in the step (2) is controlled to be 0.2-1.5: 1.

Preferably, the volume ratio (CO) of carbon dioxide to air is controlled in step (2)₂Air) is 0.2-0.5: 1.

Preferably, the aging step in step (3) is: heating and aging the slurry obtained in the step (2), wherein the temperature is controlled to be 75-95 ℃, and the aging time is 2-10 hours; and filtering and separating the aged slurry by a filter press to obtain an aged filter cake.

Preferably, the exchange washing in the step (3) comprises the following specific steps: : washing the aged filter cake for five times, wherein the first, second and third times adopt reuse water for exchange washing, ammonium bicarbonate and fresh water are added for exchange washing for the fourth time, and fresh water is added for washing for the fifth time, wherein the exchange washing temperature is 35-85 ℃; the exchange medium is inorganic ammonium salt, and the inorganic ammonium salt is ammonium bicarbonate.

Preferably, the filtration in step (3) is: and filtering the exchange washing slurry by using a filter press to obtain the pseudo-boehmite filter cake special for the ceramic corundum abrasive.

Preferably, the drying in the step (3) is to perform flash evaporation drying on the pseudo-boehmite filter cake by using pure hot air as a heat source to obtain the pseudo-boehmite dry powder special for the ceramic corundum abrasive.

In addition, the invention also claims the special pseudo-boehmite for the ceramic corundum abrasive prepared by the method.

Compared with the prior art, the invention has the following obvious beneficial effects:

the invention adopts aluminum hydroxide, sodium hydroxide, carbon dioxide, aluminum sulfate and the like as raw materials, creatively adopts a two-step method in the gelling reaction process, namely firstly uses aluminum sulfate solution to gel with equal PH in a reaction kettle with stirring, neutralizes to a certain PH value, then enters a second gas-liquid reaction kettle to be introduced with carbon dioxide gas, and successfully prepares the special pseudo-boehmite for the ceramic corundum abrasive material, which has low impurity content, good peptization property, good gelling property, transparent glue, high adhesiveness and good bonding property, by accurately controlling the addition amount and the addition speed of the carbon dioxide gas. And by adopting the method, the yield of the single-kettle pseudo-boehmite can be greatly improved, so that the production cost is greatly reduced.

Drawings

FIG. 1 is an XRD pattern of a product prepared according to example 1 of the present invention;

FIG. 2 is an XRD pattern of a product prepared in example 2 of the present invention;

FIG. 3 is an XRD pattern of a product prepared according to example 3 of the present invention;

FIG. 4 is an XRD pattern of a product prepared according to example 4 of the present invention;

FIG. 5 is an XRD pattern of a product prepared according to example 5 of the present invention;

fig. 6 is an XRD pattern of the product prepared in comparative example 1 of the present invention.

Detailed Description

In order that the objects and advantages of the invention will be more clearly understood, the following description is given in conjunction with the accompanying examples. It is to be understood that the following text is merely illustrative of one or more specific embodiments of the invention and does not strictly limit the scope of the invention as specifically claimed.