A preparation method of nano-alumina sol

Abstract

The present application relates to a method for preparing a nano-alumina sol, comprising the following steps: providing pseudo-boehmite powder, mixing the pseudo-boehmite powder with water to form a slurry; introducing an acid agent into the slurry in the form of a spray, maintaining the slurry at a predetermined temperature and stirring until a clear colloidal solution is obtained; and hydrothermally treating the colloidal solution to obtain a nano-alumina sol. The method for preparing a nano-alumina sol provided herein involves directly preparing a colloidal solution by directly preparing a slurry of pseudo-boehmite powder with an acid agent, and then hydrothermally treating the colloidal solution to obtain the nano-alumina sol. The production process has low equipment requirements, and the raw material, pseudo-boehmite powder, is low-cost.

Description

Technical Field

[0001] The present application relates to the field of aluminum industry, and in particular to alumina sol. Background Art

[0002] Alumina sol is a colloidal solution of positively charged aluminum oxide particles dispersed in water. When dried and solidified, it exhibits strong bonding properties and can be used as an inorganic binder. It can also be used as a component of certain products to purify raw materials. Because the system contains no alkali metals, the drying temperature of alumina sol when used as a binder is only around 150°C. It is moisture-resistant and unreactive with iron, among other substances. It can be mixed with water in any proportion, making it easy to use in industrial applications.

[0003] At present, the production process of alumina sol mainly relies on the high-temperature and high-pressure distillation cycle of pure aluminum ingots and hydrochloric acid, which has high requirements on equipment and is somewhat dangerous. Another method is to produce aluminum sol by hydrolyzing organic alcohol aluminum salts and adding a peptizing agent. Its advantages are high product purity and good stability, but its disadvantages are high cost and difficulty in recovering organic alcohol, which causes environmental pollution. Summary of the Invention

[0004] The embodiments of the present application provide a method for preparing nano-alumina sol to solve the technical problems of high equipment requirements and high costs in the production process of alumina sol.

[0005] The present invention provides a method for preparing a nano-alumina sol, which comprises the following steps:

[0006] Providing pseudo-boehmite powder, and mixing the pseudo-boehmite powder with water to form a slurry;

[0007] introducing an acid agent into the slurry in the form of a spray, and maintaining the slurry under stirring at a predetermined temperature until a clear colloidal solution is obtained;

[0008] The colloidal solution is subjected to hydrothermal treatment to obtain nano-alumina sol.

[0009] In some embodiments of the present application, pseudo-boehmite powder is provided, comprising the following steps:

[0010] Providing pseudo-boehmite, and grinding the pseudo-boehmite to obtain a powder;

[0011] The powder is sieved, and the material at the bottom of the 120-200 mesh sieve is the pseudo-boehmite powder.

[0012] In some embodiments of the present application, the pseudo-boehmite has an aluminum oxide concentration of 60-80% and a peptization index of 95-98%.

[0013] In some embodiments of the present application, the pseudo-boehmite powder is mixed with water to form a slurry, and the solid content of the obtained slurry is 20-35%.

[0014] In some embodiments of the present application, the predetermined temperature is 20-40° C.; and / or,

[0015] The stirring speed is 300-500 r / min.

[0016] In some embodiments of the present application, the acid agent is a mixed acid of nitric acid, hydrochloric acid, and acetic acid.

[0017] In some embodiments of the present application, the acid agent is obtained by compounding 35-38% hydrochloric acid, 34-36% nitric acid, and 34-36% acetic acid in a mass ratio of 1:1:1.

[0018] In some embodiments of the present application, the acid agent is introduced into the slurry in the form of a spray, and the spray is introduced intermittently at a time interval of 5-10 minutes.

[0019] In some embodiments of the present application, the pH of the nano-alumina sol is controlled to be 5.5-6.6.

[0020] In some embodiments of the present application, the temperature of the hydrothermal treatment is 110-130° C., and the time is 1-3 hours.

[0021] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0022] The preparation method of the nano-alumina sol provided in the embodiment of the present application is to prepare a colloidal solution by directly configuring pseudo-boehmite powder into a slurry and then mixing it with an acid agent, and then obtaining the nano-alumina sol after hydrothermal treatment of the colloidal solution. The production process has low requirements on equipment, and the raw material is pseudo-boehmite powder, which is low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 A schematic flow chart of a method for preparing a nano-alumina sol provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] Unless otherwise specified, the terms used herein should be understood as having the same meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. In the event of any conflict, the present specification shall take precedence.

[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0029] The existing alumina sol production process has technical problems such as high equipment requirements and high costs.

[0030] The technical solutions provided in the embodiments of this application are intended to solve the above technical problems, and the overall idea is as follows:

[0031] This application embodiment provides a method for preparing nano-alumina sol, please refer to Figure 1 The preparation method of the nano-alumina sol comprises the following steps:

[0032] S1: providing pseudo-boehmite powder, and mixing the pseudo-boehmite powder with water to form a slurry;

[0033] S2: introducing an acid agent into the slurry in the form of a spray, and keeping the slurry stirred at a predetermined temperature until a clear colloidal solution is obtained;

[0034] S3: performing hydrothermal treatment on the colloidal solution to obtain nano-alumina sol.

[0035] Pseudo-boehmite powder can be obtained by conventional means in the art, such as by grinding pseudo-boehmite, or directly purchased on the market.

[0036] Introducing the acid agent into the slurry in the form of a spray can allow the acid agent to fully contact with the pseudo-boehmite powder in the slurry.

[0037] Hydrothermal treatment can make the particle size of the colloid more uniform and avoid the aggregation of colloids to improve the stability of the nano-alumina sol.

[0038] The present application prepares a colloidal solution by directly configuring pseudo-boehmite powder into a slurry and then mixing it with an acid agent, and then obtains a nano-alumina sol after hydrothermal treatment of the colloidal solution. The production process has low requirements on equipment, and the raw material is pseudo-boehmite powder, which is low in cost.

[0039] In some embodiments of the present application, pseudo-boehmite powder is provided, comprising the following steps:

[0040] S11: providing pseudo-boehmite, and grinding the pseudo-boehmite to obtain a powder;

[0041] S12: Screening the powder, taking the 120-200 mesh bottom material, which is the pseudo-boehmite powder.

[0042] The 120-200 mesh bottom material is taken as the pseudo-boehmite powder, in order to control the particle size of the pseudo-boehmite powder and to increase the peptization rate.

[0043] In some embodiments of the present application, the pseudo-boehmite has an aluminum oxide concentration of 60-80% and a peptization index of 95-98%.

[0044] In some embodiments of the present application, the pseudo-boehmite powder is mixed with water to form a slurry, and the solid content of the obtained slurry is 20-35%.

[0045] In some embodiments of the present application, the predetermined temperature is 20-40° C.; and / or,

[0046] The stirring speed is 300-500 r / min.

[0047] In actual production, it is found that if the predetermined temperature is higher than 40°C, the sol will be converted into gel, and if the predetermined temperature is lower than 20°C, the pH of the system will increase.

[0048] In actual production, it is found that if the stirring rate is lower than 300r / min, the acidic components will be unevenly dispersed in the system; if the stirring rate is higher than 500r / min, the slurry will splash and stick to the wall.

[0049] In some embodiments of the present application, the acid agent is a mixed acid of nitric acid, hydrochloric acid, and acetic acid.

[0050] In actual production, it is found that using a mixed acid of nitric acid, hydrochloric acid, and acetic acid as an acid agent can increase the dispersion effect of the colloidal solution and increase the stability of the colloidal solution and nano-alumina sol.

[0051] In some embodiments of the present application, the acid agent is obtained by compounding 35-38% hydrochloric acid, 34-36% nitric acid, and 34-36% acetic acid in a mass ratio of 1:1:1.

[0052] In some embodiments of the present application, the acid agent is introduced into the slurry in the form of a spray, and the spray is introduced intermittently at a time interval of 5-10 minutes.

[0053] The purpose of intermittently introducing the slurry by spraying is to increase the reaction time and make the reaction more uniform.

[0054] In actual production, it is found that when the time interval is less than 5 minutes, it is easy to cause the sol to transform into gel; when the time interval is too long, it is not conducive to improving production efficiency.

[0055] In some embodiments of the present application, the pH of the nano-alumina sol is controlled to be 5.5-6.6.

[0056] In some embodiments of the present application, the temperature of the hydrothermal treatment is 110-130° C., and the time is 1-3 hours.

[0057] In actual production, it is found that if the hydrothermal treatment temperature is lower than 110°C or the time is less than 1h, the hydrothermal treatment effect will be unobvious; if the hydrothermal treatment temperature is higher than 130°C, it will easily lead to excessively large micelles.

[0058] In some embodiments of the present application, the step of maintaining the slurry at a predetermined temperature and stirring is always performed in an ultrasonic environment.

[0059] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application only and are not intended to limit the scope of the present application. The experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national standards. If there are no corresponding national standards, then the methods are carried out in accordance with general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0060] Example 1

[0061] This embodiment provides a method for preparing nano-alumina sol, which is as follows:

[0062] High-viscosity pseudo-boehmite with an alumina content of 65% was crushed, ground and sieved at 180 mesh to obtain the bottom material. Distilled water was added to the bottom material to prepare a slurry with a solid content of 30% wt. The total slurry was 5 kg, kept warm at 35°C, and ultrasonically dispersed. Acid mist of 0.3% of the total weight of the slurry was injected every 10 minutes. The mixture was stirred at 400 r / min. After the system was clarified and free of insoluble matter, it was taken out and hydrothermally treated at 120°C for 3 hours to obtain a nano-alumina sol.

[0063] Example 2

[0064] This embodiment provides a method for preparing nano-alumina sol, which is as follows:

[0065] High-viscosity pseudo-boehmite with an alumina content of 60% was crushed, ground and sieved at 200 mesh to obtain the bottom material. Distilled water was added to the bottom material to prepare a slurry with a solid content of 35% wt. The total slurry was 5 kg, kept warm at 40°C, and ultrasonically dispersed. Acid mist of 0.3% of the total weight of the slurry was injected every 10 minutes. The mixture was stirred at 500 r / min. After the system was clarified and free of insoluble matter, it was taken out and hydrothermally treated at 110°C for 3 hours to obtain a nano-alumina sol.

[0066] Example 3

[0067] This embodiment provides a method for preparing nano-alumina sol, which is as follows:

[0068] High-viscosity pseudo-boehmite with an alumina content of 80% was crushed, ground and sieved at 120 mesh to obtain the bottom material. Distilled water was added to the bottom material to prepare a slurry with a solid content of 20% wt. The total slurry was 5 kg, kept warm at 20°C, and ultrasonically dispersed. Acid mist of 0.1% of the total weight of the slurry was injected every 5 minutes. The mixture was stirred at 300 r / min. After the system was clarified and free of insoluble matter, it was taken out and hydrothermally treated at 130°C for 1 hour to obtain a nano-alumina sol.

[0069] The properties of the nano-alumina sol obtained in Examples 1-3 are as follows:

[0070]

[0071] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a hard limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numbers within the range. For example, the description of a range from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0072] In this application, unless otherwise indicated, directional terms such as "upper" and "lower" refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of this application specification, the terms "include", "comprise", etc. mean "including but not limited to". Moreover, the terms "include", "comprises", or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article, or device. In the absence of further restrictions, the elements defined by the phrase "include..." do not exclude the presence of other identical elements in the process, method, article, or device comprising the elements. In this document, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. In this document, "and / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone. For the association relationship of more than three associated objects described with "and / or", it means that any one of these three associated objects can exist alone, or any at least two of them exist at the same time. For example, for A, and / or B, and / or C, it can be represented that any one of A, B, and C exists alone, or any two of them exist at the same time, or three of them exist at the same time. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single item (individual) or plural items (individual). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc or abc, where a, b, c can be single or multiple, respectively.

[0073] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A method for preparing nano-alumina sol, characterized in that: The preparation method of the nano alumina sol comprises the following steps: Providing pseudo-boehmite powder, and mixing the pseudo-boehmite powder with water to form a slurry; introducing an acid agent into the slurry in the form of a spray, and maintaining the slurry under stirring at a predetermined temperature until a clear colloidal solution is obtained; performing hydrothermal treatment on the colloidal solution to obtain nano-alumina sol; The acid agent is prepared by mixing 35-38% hydrochloric acid, 34-36% nitric acid, and 34-36% acetic acid in a mass ratio of 1:1:1; The acid agent is introduced into the slurry in the form of a spray, and 0.3% of the total weight of the slurry is injected into the acid mist every 10 minutes; The hydrothermal treatment temperature is 110-130°C and the time is 1-3h; The pH of the nano-alumina sol is controlled to be 5.5-6.6, and the particle size of the colloid is 30-50 nm.

2. The method for preparing nano-alumina sol according to claim 1, wherein Providing pseudo-boehmite powder comprises the following steps: Providing pseudo-boehmite, and grinding the pseudo-boehmite to obtain a powder; The powder is sieved, and the material at the bottom of the 120-200 mesh sieve is the pseudo-boehmite powder.

3. The method for preparing nano-alumina sol according to claim 2, wherein: The alumina concentration of the pseudo-boehmite is 60-80%, and the peptization index is 95-98%.

4. The method for preparing nano-alumina sol according to claim 1, wherein The pseudo-boehmite powder is mixed with water to form a slurry, and the solid content of the obtained slurry is 20-35%.

5. The method for preparing nano-alumina sol according to claim 1, wherein: The predetermined temperature is 20-40°C; and / or, The stirring speed is 300-500 r / min.

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