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 付宝建 李秀刚 刘伯文 董玉珍 于 2020-12-21 设计创作，主要内容包括：本发明提供一种拟薄水铝石的制备方法,包括步骤：1)将铝锭熔化并加入催化剂,将熔融合金液浇铸为铝合金块；2)所得铝合金块与水蒸气发生反应,生成拟薄水铝石和氢气；3)生成的拟薄水铝石粉体经干燥、筛分得到成品,生成的氢气经冷凝、干燥后收集。本发明提出的拟薄水铝石的制备方法,基于铝金属的水解反应,但不用水、而是用水蒸气参与反应,克服了现有技术固液分离难、用水量大的不足之处,不用添设固液分离设施,节约了原料和设备成本,降低了能耗。(The invention provides a preparation method of pseudo-boehmite, which comprises the following steps: 1) melting an aluminum ingot, adding a catalyst, and casting molten alloy liquid into an aluminum alloy block; 2) reacting the obtained aluminum alloy block with water vapor to generate pseudo-boehmite and hydrogen; 3) drying and screening the generated pseudo-boehmite powder to obtain a finished product, and condensing and drying the generated hydrogen and then collecting. The preparation method of the pseudo-boehmite provided by the invention is based on the hydrolysis reaction of aluminum metal, but water is not used, but water vapor participates in the reaction, so that the defects of difficult solid-liquid separation and large water consumption in the prior art are overcome, a solid-liquid separation facility is not required to be added, the raw material and equipment cost is saved, and the energy consumption is reduced.)

1. A preparation method of pseudo-boehmite is characterized by comprising the following steps:

1) melting an aluminum ingot, adding a catalyst, and casting molten alloy liquid into an aluminum alloy block; the catalyst is an alloy consisting of one or more of the following low melting point metals, or a compound containing one or more of the following low melting point metals: the catalyst comprises tin, bismuth, mercury, indium, lead, bismuth, zinc, potassium, lithium and antimony, wherein the mass of the catalyst accounts for 0.05-1.5% of the total mass of the raw materials;

2) reacting the obtained aluminum alloy block with water vapor to generate pseudo-boehmite powder and hydrogen;

3) drying and screening the generated pseudo-boehmite powder to obtain a pseudo-boehmite finished product, condensing and drying the generated hydrogen, and collecting.

2. The method for preparing pseudoboehmite according to claim 1, characterized in that in step 2), the pressure of the water vapor is 0.1-1.0Mpa and the temperature is 100-180 ℃.

3. The method for preparing pseudoboehmite according to claim 1, characterized in that in step 2), the volume flow rate Vs of the water vapor is 2.95-0.34L/(min-cm)²)。

4. The method for preparing pseudoboehmite according to claim 2, characterized in that the pressure of the steam is 0.3-0.8Mpa, the temperature is 130-170 ℃, and/or

The volume flow Vs of the water vapor is 1.05-0.42L/(min cm)²)。

5. The method for preparing pseudo-boehmite according to claim 1, characterized in that an aluminum alloy container is arranged in a reactor used for the hydrolysis reaction, the wall of the aluminum alloy container is provided with a plurality of holes, and water vapor is introduced into the reactor to react with an aluminum alloy block arranged in the aluminum alloy container.

6. The method for preparing pseudo-boehmite according to claim 5, characterized in that the reactor is a closed high-pressure vessel, the side wall of the vessel is provided with a steam inlet, the bottom is provided with a powder outlet, the top is provided with a hydrogen outlet, and the hydrogen outlet is connected with a condenser, a molecular sieve drier and a hydrogen storage tank in sequence through pipelines;

the steam inlet is connected with a steam generator, and the condenser is connected with the steam generator through a condensate pipeline.

7. The method for preparing pseudoboehmite according to claim 5, characterized in that the aluminum alloy container is cylindrical and is connected with a motor, and the aluminum alloy container rotates around a long shaft under the driving of the motor.

8. The method for preparing pseudoboehmite according to claim 7, characterized in that the direction in which the water vapor enters is parallel to the direction of the long axis of the aluminum alloy holder; and/or the autorotation speed of the aluminum alloy container is 5-50 r/min.

9. The preparation method of pseudo-boehmite according to any one of claims 4-7, characterized in that the aluminum alloy container is made of stainless steel wire mesh with mesh size of 1 x 1-5 x 5mm²。

10. The method for preparing pseudo-boehmite according to any one of claims 4-7, characterized in that the aluminum alloy block accounts for 30-60% of the volume of the aluminum alloy container.

Technical Field

The invention belongs to the field of aluminum compounds, and particularly relates to a preparation method of pseudo-boehmite.

Background

The chemical formula of the pseudo-boehmite is AlOOH & nH₂O, wherein n is 0.08 to 0.62, is nontoxic, odorless, colloidal in wet form or dry in form, has a higher surface area and a larger pore volume, and is widely used as a catalyst carrier, a catalyst, an adsorbent, a coating additive, a catalyst carrier, a catalyst, a coating additive, a catalyst carrier, a coating additive, a coatingCeramics, grinding materials, polishing materials, cosmetic fillers and the like are materials with wide development prospects.

The preparation method of pseudoboehmite mainly comprises the steps of neutralizing or hydrolyzing to form colloid, then carrying out aging treatment, and finally carrying out filtration, washing, drying and crushing to obtain the pseudoboehmite. The neutralization method adopts different aluminum-containing raw materials and corresponding precipitants to carry out neutralization reaction under certain conditions to generate an oxygen alumina product with an amorphous basic phase, and the reaction formula is

AlCl₃+NaOH+aq→Al₂O₃+nH₂O+NaCl+aq

The raw material cost of the neutralization method is low, the pore volume and the specific surface area of the product still need to be improved, and the method also needs to separate the byproducts.

The hydrolysis glue is prepared by the hydrolysis of organic aluminum alkoxide with the reaction formula

Al(OR)₃+aq→Al₂O₃+nH₂O+R₃OH+aq

OR is an aluminumoxy group.

Compared with the products produced by other processes, the pseudoboehmite prepared by the organic aluminum alkoxide hydrolysis method has the characteristics of high chemical purity, less miscellaneous items, good crystallinity and peptization performance and the like. But the product is expensive.

Under the action of low-melting-point metal, aluminum alloy and deionized water can be subjected to hydrolysis reaction to obtain pseudo-boehmite slurry and hydrogen. The pseudo-boehmite dry powder can be obtained by the processes of filtering, drying and the like. Because the pseudo-boehmite contains a large amount of interlayer water, the viscosity of aqueous medium slurry is higher, the difficulty of solid-liquid separation is increased, and the technical process is longer.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a more economical and practical preparation method of pseudo-boehmite.

The technical scheme for realizing the above purpose of the invention is as follows:

a preparation method of pseudoboehmite comprises the following steps:

1) melting an aluminum ingot, adding a catalyst, and casting molten alloy liquid into an aluminum alloy block; the catalyst is an alloy consisting of one or more of the following low melting point metals, or a compound containing one or more of the following low melting point metals: the catalyst comprises tin, bismuth, mercury, indium, lead, bismuth, zinc, potassium, lithium and antimony, wherein the mass of the catalyst accounts for 0.05-1.5% of the total mass of the raw materials;

2) reacting the obtained aluminum alloy block with water vapor to generate pseudo-boehmite powder and hydrogen;

3) drying and screening the generated pseudo-boehmite powder to obtain a pseudo-boehmite finished product, condensing and drying the generated hydrogen, and collecting.

The catalyst can be one of pure mercury, pure bismuth, pure indium, indium-tin alloy, bismuth indium-tin-zinc alloy, bismuth indium-tin-lead alloy, bismuth potassium alloy, bismuth lithium alloy, zinc-mercury alloy, tin-mercury alloy, bismuth indium-mercury or bismuth tin-mercury alloy.

For example, the indium tin alloy may be InSn_49.2The bismuth indium tin zinc alloy can be Bi₃₅In_48.6Sn₁₆Zn_0.4The bismuth indium tin lead alloy can be BiIn₂₁Sn₁₂Pb₁₈The bismuth-potassium alloy may be BiK_2.5The bismuth-lithium alloy may be BiLi₁₄The mercury alloy comprises 5-45% of mercury, the tin-mercury alloy can be composed of 34-69% of mercury, 0.5-5% of antimony and the balance of mercury.

The drying may be by heating, or natural drying, or any suitable drying method. The particle size of the hydrolyzed powder product is uniform and is about dozens of micrometers. Sieving is to remove impurities.

Wherein, in the step 2), the pressure of the water vapor is 0.1-1.0Mpa, and the temperature is 100-180 ℃.

Further, in the step 2), the volume flow rate Vs of the water vapor is 2.95-0.34L/(min cm)²)。

The invention has the preferable technical proposal that the pressure of the water vapor is 0.3-0.8Mpa, the temperature is 130-170 ℃, and/or

The volume flow Vs of the water vapor is 1.05-0.42L/(min cm)²)。

The preparation method of the pseudo-boehmite can adopt any equipment suitable for the reaction of water vapor and an aluminum alloy block, and the invention provides a preferable scheme as follows:

an aluminum alloy container is arranged in the reactor, the wall of the aluminum alloy container is provided with a plurality of holes, and water vapor is introduced into the reactor to react with an aluminum alloy block arranged in the aluminum alloy container.

The reactor is a closed high-pressure container, a steam inlet is arranged on the side wall of the container, a powder outlet is arranged at the bottom of the container, and a hydrogen outlet is arranged at the top of the container and is sequentially connected with a condenser, a molecular sieve dryer and a hydrogen storage tank through pipelines;

the steam inlet is connected with a steam generator, and the condenser is connected with the steam generator through a condensate pipeline.

The aluminum alloy container is cylindrical, is connected with a motor and rotates around a long shaft under the drive of the motor;

preferably, the direction of the water vapor entering is parallel to the long axis direction of the aluminum alloy container; and/or the autorotation speed of the aluminum alloy container is 5-50 r/min.

More preferably, the aluminum alloy container is made of a stainless steel wire mesh, and the mesh size of the wire mesh is 1 x 1-5 x 5mm²。

Wherein the aluminum alloy block accounts for 30-60% of the volume of the aluminum alloy container.

The invention has the beneficial effects that:

the preparation method of the pseudo-boehmite provided by the invention is based on the hydrolysis reaction of the aluminum metal, but water is not used, but water vapor participates in the reaction, so that the defects of difficult solid-liquid separation and large water consumption in the prior art are overcome, a solid-liquid separation facility is not required to be added, the raw material and equipment cost are saved, and the energy consumption is reduced;

the method of the invention uses water vapor to pass through the continuously rotating porous aluminum alloy container from the outside, and the reaction product (powder) leaks out of the holes, the reaction is complete, the production is easy to control, and the method has industrial practicability.

Drawings

FIG. 1 is a schematic view showing the structure of a reaction system in the process for producing pseudoboehmite according to the present invention;

in the figure, the position of the upper end of the main shaft,

1 is high pressure reactor, 2 is steam generator, 3 is the condensate water pipeline, 4 is the aluminum alloy container, 5 is the powder export, 6 is the motor, 7 is the hydrogen storage tank, 8 is the molecular sieve desicator, 9 is the condenser.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Unless otherwise specified, all technical means used in the specification are technical means existing in the field.

Example 1

The embodiment provides a preparation method of pseudo-boehmite, which comprises the following steps:

1) melting an aluminum ingot, adding a catalyst, and casting molten alloy liquid into an aluminum alloy block; the catalyst is an alloy consisting of one or more of the following low melting point metals, or a compound containing one or more of the following low melting point metals: the catalyst comprises tin, bismuth, mercury, indium, lead, bismuth, zinc, potassium, lithium and antimony, wherein the mass of the catalyst accounts for 0.05-1.5% of the total mass of the raw materials;

2) reacting the obtained aluminum alloy block with water vapor to generate pseudo-boehmite powder and hydrogen;

3) drying and screening the obtained pseudo-boehmite powder to obtain a pseudo-boehmite finished product, condensing and drying the obtained hydrogen, and collecting the hydrogen in a hydrogen storage tank.

In the embodiment, the specific step 1) is to cast molten alloy liquid into an aluminum alloy block; the catalyst is a tin-mercury alloy (the weight percentage of each component is 45% of mercury, 50% of tin and 5% of antimony), and the mass of the catalyst accounts for 0.5% of that of the aluminum alloy; adding catalyst, stirring for 30min, filtering, and casting to obtain aluminum alloy block.

The adopted reaction system is shown in figure 1, wherein the appearance of the high-pressure reactor 1 is in the shape of a cylindrical lower connecting cone, the bottom of the cone is provided with a powder outlet 5, and the outlet is provided with a valve; an aluminum alloy container 4 is arranged in the cylindrical part, the wall of the aluminum alloy container 4 is provided with a plurality of holes, and water vapor is introduced into the high-pressure reactor 1 to react with an aluminum alloy block arranged in the aluminum alloy container 4.

The high-pressure reactor 1 of this embodiment is a closed pressure vessel, is provided with the steam air inlet on the lateral wall of container, sets up the hydrogen gas outlet at the top, the hydrogen gas outlet passes through the pipeline and connects in proper order in condenser 9, molecular sieve desicator 8 and hydrogen storage tank 7, and condenser 9 is including catch water.

The steam inlet is connected with a steam generator 2, gas discharged from the condenser 9 is separated by a steam-water separator, condensed water is connected with the steam generator 2 through a condensed water pipeline 3, and separated hydrogen is dried by a molecular sieve dryer 8 and stored in a hydrogen storage tank 7.

The aluminum alloy container 4 is cylindrical and is connected with a motor 6, and the aluminum alloy container rotates around a long shaft under the driving of the motor 6; the direction of the water vapor is parallel to the long axis direction of the aluminum alloy container; in this embodiment, the aluminum alloy container 4 is made of stainless steel wire mesh, and the mesh size of the wire mesh is 1 × 1mm²。

In this embodiment, the volume of the aluminum alloy occupies 50% of the volume of the aluminum alloy container.

In the step 2), the pressure of the water vapor is 1.0Mpa, the temperature is 180 ℃, and the volume flow Vs of the water vapor is 0.34L/(min cm)²) And the autorotation speed of the aluminum alloy container is 50 r/min.

The purpose of the rotation of the container is to enable the reaction product pseudo-boehmite to be quickly separated from the surface of the aluminum alloy and fall into the collecting bin below, and simultaneously expose a new surface of the aluminum alloy, so that the reaction is continuously carried out. Meanwhile, the rolling of the aluminum alloy also enables the reaction to be more uniform. The higher the reaction temperature, the faster the reaction rate and the correspondingly faster the rotation speed. However, the rotation speed is too high, and the difficulty of process control is also increased.

Example 2

The embodiment provides a preparation method of pseudo-boehmite, which comprises the following steps:

1) melting an aluminum ingot, adding a catalyst, and casting molten alloy liquid into an aluminum alloy block;

2) reacting the obtained aluminum alloy block with water vapor to generate pseudo-boehmite powder and hydrogen;

3) drying and screening the obtained pseudo-boehmite powder to obtain a finished product, and condensing, drying and collecting the generated hydrogen in a hydrogen storage tank.

The aluminum alloy blocks and the reaction equipment used in this example were the same as those used in example 1.

In this embodiment, the volume of the aluminum alloy occupies 50% of the volume of the aluminum alloy container.

In the step 2), the pressure of the water vapor is 0.1Mpa, the temperature is 100 ℃, and the volume flow Vs of the water vapor is 2.95L/(min cm)²) And the autorotation speed of the aluminum alloy container is 5 r/min. When the temperature is lower, the reaction speed is lower, the rotation speed of the aluminum alloy container is correspondingly slowed down, and the generated pseudo-boehmite powder can be ensured to fall off from the surface of the aluminum alloy in time.

Example 3

The embodiment provides a preparation method of pseudo-boehmite, which comprises the following steps:

1) melting an aluminum ingot, adding a catalyst, and casting molten alloy liquid into an aluminum alloy block;

2) reacting the obtained aluminum alloy block with water vapor to generate pseudo-boehmite powder and hydrogen;

3) drying and screening the obtained pseudo-boehmite powder to obtain a finished product, and condensing, drying and collecting the generated hydrogen in a hydrogen storage tank.

The aluminum alloy blocks and the reaction equipment used in this example were the same as those used in example 1.

The pressure of the water vapor is 0.8Mpa, the temperature is 170 ℃, and the volume flow Vs of the water vapor is 0.42L/(min cm)²). The autorotation speed of the aluminum alloy container is 30 r/min. When the temperature is higher, the reaction speed is higher, and the rotation speed of the aluminum alloy container is correspondingly increased, so that the generated pseudo-boehmite powder can timely fall off from the surface of the aluminum alloy.

The particle diameter D of the obtained finished pseudo-boehmite powder₅₀45.62 μm, a specific surface area of 352.47m²The total pore volume is 0.513ml/g, and the average pore diameter is 5.09 nm.

Example 4

The embodiment provides a preparation method of pseudo-boehmite, which comprises the following steps:

1) melting an aluminum ingot, adding a catalyst, and casting molten alloy liquid into an aluminum alloy block;

2) reacting the obtained aluminum alloy block with water vapor to generate pseudo-boehmite powder and hydrogen;

3) drying and screening the obtained pseudo-boehmite powder to obtain a finished product, and condensing, drying and collecting the generated hydrogen in a hydrogen storage tank.

The aluminum alloy blocks and the reaction equipment used in this example were the same as those used in example 1.

The pressure of the steam in this example was 0.3MPa, the temperature was 130 ℃ and the volume flow Vs of the steam was 1.05L/(min cm. cm)²). The autorotation speed of the aluminum alloy container is 15 r/min.

The obtained pseudo-boehmite powder has a particle size D50 of 30.51 μm and a specific surface area of 325.57m²The total pore volume is 0.435ml/g, and the average pore diameter is 4.64 nm.

Example 5

The embodiment provides a preparation method of pseudo-boehmite, which comprises the following steps:

1) melting an aluminum ingot, adding a catalyst, and casting molten alloy liquid into an aluminum alloy block;

2) reacting the obtained aluminum alloy block with water vapor to generate pseudo-boehmite powder and hydrogen;

3) drying and screening the obtained pseudo-boehmite powder to obtain a finished product, and condensing, drying and collecting the generated hydrogen in a hydrogen storage tank.

The aluminum alloy blocks and the reaction equipment used in this example were the same as those used in example 1.

The pressure of the steam in this example was 0.5MPa, the temperature was 150 ℃ and the volume flow Vs of the steam was 0.65L/(min cm. cm)²). What is needed isThe rotation speed of the aluminum alloy container is 20 r/min. The temperature of the water vapor is 150 ℃, and the rotating speed of the aluminum alloy container is 20r/min, so that the process conditions are mild and easy to control.

The particle diameter D of the obtained pseudo-boehmite powder₅₀40.83 μm, and a specific surface area of 346.37m²(ii)/g, total pore volume of 0.499ml/g, average pore diameter of 4.87 nm.

Although the present invention has been described in the foregoing by way of examples, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.