阅读说明：本技术 一种拟薄水铝石的生产方法 (Method for producing pseudo-boehmite ) 是由 张华� 马晓宁 李卫涛 邹越路 郭翠红 夏青 于 2020-04-20 设计创作，主要内容包括：本发明公开了一种拟薄水铝石的生产方法,包括：使用拟薄水铝石洗涤过程中的二次洗液进行铝酸钠溶液的调配,获得符合预设指标的铝酸钠溶液；向铝酸钠溶液中通入二氧化碳,获得碳化后的拟薄水铝石浆液；对碳化后的拟薄水铝石浆液进行快速老化,获得老化后的拟薄水铝石浆液；对老化后的拟薄水铝石浆液进行洗涤、烘干,获得胶溶指数符合预设范围的拟薄水铝石成品；其中,在洗涤过程中回收二次洗液,以应用于下一批次的铝酸钠溶液的调配。通过采用二次洗液代替新水配料铝酸钠溶液,在显著降低水耗的同时保证了产品的质量,实现了拟薄水铝石生产过程中的二次洗液的循环综合利用。(The invention discloses a production method of pseudo-boehmite, which comprises the following steps: using a secondary washing liquid in the pseudo-boehmite washing process to prepare a sodium aluminate solution to obtain the sodium aluminate solution meeting the preset index; introducing carbon dioxide into the sodium aluminate solution to obtain carbonized pseudo-boehmite slurry; quickly aging the carbonized pseudo-boehmite slurry to obtain an aged pseudo-boehmite slurry; washing and drying the aged pseudo-boehmite slurry to obtain a pseudo-boehmite finished product with a peptization index meeting a preset range; wherein, the secondary washing liquid is recovered in the washing process so as to be applied to the preparation of the sodium aluminate solution of the next batch. The secondary washing liquid is adopted to replace new water for batching the sodium aluminate solution, so that the water consumption is obviously reduced, the product quality is ensured, and the cyclic comprehensive utilization of the secondary washing liquid in the pseudo-boehmite production process is realized.)

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

using a secondary washing liquid in the pseudo-boehmite washing process to prepare a sodium aluminate solution to obtain the sodium aluminate solution meeting the preset index;

introducing carbon dioxide into the sodium aluminate solution to obtain carbonized pseudo-boehmite slurry;

rapidly aging the carbonized pseudo-boehmite slurry to obtain an aged pseudo-boehmite slurry;

washing and drying the aged pseudo-boehmite slurry to obtain a pseudo-boehmite finished product with a peptization index meeting a preset range; wherein, the secondary washing liquid is recovered in the washing process so as to be applied to the preparation of the sodium aluminate solution of the next batch.

2. The production method according to claim 1, wherein the predetermined criteria include:

the sodium aluminate solution has a total alkali content of 45-55 g/L, an aluminum oxide content of 40-45 g/L and a caustic coefficient of α_k1.5 to 1.7.

3. The method of claim 1, wherein the predetermined range of peptization index is greater than 97%.

4. The production method according to claim 1, wherein before the preparing of the sodium aluminate solution by using the secondary washing liquid in the pseudo-boehmite washing process to obtain the sodium aluminate solution meeting the preset index, the method further comprises:

finely filtering the secondary washing liquid to obtain finely filtered secondary washing liquid;

the preparation of the sodium aluminate solution by using the secondary washing liquid in the pseudo-boehmite washing process specifically comprises the following steps:

and (4) blending the sodium aluminate solution by using the secondary washing liquid after the fine filtration.

5. The method according to claim 4, wherein after obtaining the secondary washing liquid after fine filtration and before preparing the sodium aluminate solution by using the secondary washing liquid after fine filtration, the method further comprises:

and reducing the temperature of the secondary washing liquid after fine filtration to below 30 ℃.

6. The production method according to claim 1, wherein the introducing of carbon dioxide into the sodium aluminate solution specifically comprises:

introducing 35-40% volume fraction and 0.85-0.9 kg/cm pressure into the sodium aluminate solution²Carbon dioxide gas of (2).

7. The production method according to claim 6, wherein the aeration time of the carbon dioxide gas is 9 to 11 minutes.

8. The production method according to claim 7, wherein the pH value of the gelling reaction is controlled to 8-12 during the introduction of carbon dioxide into the sodium aluminate solution.

9. The production method according to claim 1, wherein the rapid aging of the carbonized pseudo-boehmite slurry comprises:

and (3) rapidly heating the carbonized pseudo-boehmite slurry to more than 90 ℃, wherein the aging time is more than 2 hours.

10. Pseudoboehmite prepared by the production method of the pseudoboehmite according to any one of claims 1-9.

Technical Field

The application relates to the technical field of pseudo-boehmite, in particular to a production method of pseudo-boehmite.

Background

Pseudo boehmite, pseudo boehmite and pseudo boehmite are named as pseudo boehmite of pseudo boehmite in Chinese translation, are mainly used as a binder, a catalyst and a carrier thereof, and play a significant role in chemical alumina.

At present, a carbonization method is generally used for preparing the pseudoboehmite, carbon dioxide is introduced into a sodium metaaluminate solution for gelling reaction, and then the finished pseudoboehmite is obtained after aging and washing. In the production process, the aged product needs to be washed by a large amount of hot water, and particularly, the crystal alkali entering between crystals is more difficult to wash away. When the pseudoboehmite is industrially produced, the aged pseudoboehmite slurry needs to be sequentially subjected to three washing processes in a filter press, and a primary washing solution, a secondary washing solution and a tertiary washing solution are respectively and correspondingly generated after washing. Therefore, a large amount of water is consumed in the actual production process of the pseudoboehmite, and the generated washing liquid is directly discharged outside, thereby causing obvious environmental hazard.

At present, in the field of industrial production application, some solutions for reducing the consumption of new water in the production process of pseudo-boehmite exist. For example, in the literature "several ways to reduce the consumption of fresh water in the production of pseudo-boehmite", a solution is introduced to reduce the amount of fresh water added during the dosing process: the alkali content and the suspended matter content of the third washing liquid are both low, and the water temperature is close to the temperature of the sodium aluminate solution. Therefore, the washing liquid can replace fresh water to dilute and prepare ingredients, the utilization rate of the three washing liquids is improved, and the consumption of the fresh water is reduced. It can be seen that the prior art provides a solution for using the three wash liquor circulation dosing in the third wash process to reduce the consumption of fresh water. With increasingly strict environmental requirements, how to further reduce the consumption of new water in the production of the pseudo-boehmite and the environmental hazard caused by the discharge of washing liquor after washing becomes a difficult problem to be solved urgently.

Disclosure of Invention

The invention provides a production method of pseudo-boehmite, which aims to solve or partially solve the technical problems of further reducing the water consumption of the pseudo-boehmite production and the adverse effect of discharged washing liquid on the environment.

In order to solve the technical problem, the invention provides a production method of pseudo-boehmite, which comprises the following steps:

using a secondary washing liquid in the pseudo-boehmite washing process to prepare a sodium aluminate solution to obtain the sodium aluminate solution meeting the preset index;

introducing carbon dioxide into the sodium aluminate solution to obtain carbonized pseudo-boehmite slurry;

quickly aging the carbonized pseudo-boehmite slurry to obtain an aged pseudo-boehmite slurry;

washing and drying the aged pseudo-boehmite slurry to obtain a pseudo-boehmite finished product with a peptization index meeting a preset range; wherein, the secondary washing liquid is recovered in the washing process so as to be applied to the preparation of the sodium aluminate solution of the next batch.

Optionally, the preset index includes:

the sodium aluminate solution has a total alkali content of 45-55 g/L, an aluminum oxide content of 40-45 g/L and a caustic factor of α_k1.5 to 1.7.

Optionally, the predetermined range of peptization index is greater than 97%.

Optionally, before the secondary washing liquid in the pseudo-boehmite washing process is used for blending the sodium aluminate solution to obtain the sodium aluminate solution meeting the preset index, the method further comprises:

finely filtering the secondary washing liquid to obtain the secondary washing liquid after fine filtration;

the preparation of the sodium aluminate solution by using the secondary washing liquid in the pseudo-boehmite washing process comprises the following specific steps:

and (4) blending the sodium aluminate solution by using the secondary washing liquid after fine filtration.

Further, after obtaining the secondary washing liquid after the fine filtration and before using the secondary washing liquid after the fine filtration to prepare the sodium aluminate solution, the method further comprises the following steps:

and (3) reducing the temperature of the secondary washing liquid after fine filtration to below 30 ℃.

According to the technical scheme, the method for introducing carbon dioxide into the sodium aluminate solution specifically comprises the following steps:

introducing 35-40% volume fraction and 0.85-0.9 kg/cm pressure into sodium aluminate solution²Carbon dioxide gas of (2).

Furthermore, the aeration time of the carbon dioxide gas is 9-11 minutes.

Further, in the process of introducing carbon dioxide into the sodium aluminate solution, the pH value of the gelling reaction is controlled to be 8-12.

According to the technical scheme, the carbonized pseudo-boehmite slurry is subjected to rapid aging, and the method specifically comprises the following steps:

quickly heating the carbonized pseudo-boehmite slurry to more than 90 ℃, and aging for more than 2 hours.

Based on the same inventive concept of the technical scheme, the invention also provides the pseudoboehmite prepared by adopting any one production method of the pseudoboehmite in the technical scheme.

Through one or more technical schemes of the invention, the invention has the following beneficial effects or advantages:

the invention provides a production method of pseudo-boehmite, which adopts secondary washing liquid to replace new water for batching a sodium aluminate solution, realizes the cyclic comprehensive utilization of the secondary washing liquid while obviously reducing the water consumption, and avoids the adverse environmental influence caused by the direct discharge of the secondary washing liquid; and when the secondary washing liquor is used for batching, the sodium aluminate solution is controlled to reach the preset index, and finally the pseudo-boehmite with qualified quality and peptization index meeting the preset range can be obtained.

The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a flow chart showing a method for producing pseudoboehmite according to one embodiment of the present invention;

FIG. 2 is a process diagram illustrating a method for producing pseudoboehmite according to an embodiment of the present invention;

FIG. 3 shows a microscopic topography photograph of a pseudoboehmite product according to one embodiment of the invention.

Detailed Description

In order to make the present application more clearly understood by those skilled in the art to which the present application pertains, the following detailed description of the present application is made with reference to the accompanying drawings by way of specific embodiments.

Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Aiming at reducing the consumption of new water in the production of pseudo-boehmite, a method for preparing sodium aluminate solution by recycling three times of washing liquor and partially replacing the new water is provided at present. Although the third washing liquid is digested, the first washing liquid and the second washing liquid are not recycled, and the second washing liquid is taken as an example, because the alkali content is high, the components are complex, the cyclic washing cannot be performed, and the direct discharge is usually adopted, so that the environmental protection pressure is obviously increased while the water resource waste is caused. In order to realize the comprehensive utilization of the washing liquid as much as possible so as to achieve the invention purposes of reducing the consumption of new water and protecting the environment, the overall idea of the technical scheme provided in the embodiment of the invention is as follows:

in one aspect, an embodiment of the present invention provides a method for producing pseudo-boehmite, as shown in fig. 1, including:

s1: using a secondary washing liquid in the pseudo-boehmite washing process to prepare a sodium aluminate solution to obtain the sodium aluminate solution meeting the preset index;

the preset indexes are process parameters which are required to be met by the sodium aluminate solution obtained after the sodium aluminate solution is diluted and blended by using the secondary washing liquor so as to ensure the product performance of the pseudo-boehmite, and optionally, the preset indexes comprise the total alkali content of the sodium aluminate solution of 45-55 g/L, the aluminum oxygen content of 40-45 g/L and the caustic coefficient of α_k1.5 to 1.7. Mixing the prepared sodium aluminate solution with full alkali (Na)₂O_T) Content, aluminum oxide (Al)₂O₃) The content and caustic coefficient (caustic ratio) are controlled within the above range to overcome the adverse factors of high alkali and complex components of the secondary washing liquid, so as to ensure that the neutralization gelling reaction can be normally carried out when carbon dioxide is introduced subsequently, and the peptization index of the finally obtained pseudoboehmite product is good and not lower than that of the pseudoboehmite product obtained by the conventional process of diluting and batching by using fresh water_kThe control is 1.6 and 1.7, which is beneficial to improving the peptization index of the pseudo-boehmite product.

Optionally, before the secondary washing liquid in the pseudo-boehmite washing process is used for blending the sodium aluminate solution to obtain the sodium aluminate solution meeting the preset index, the method further comprises: finely filtering the secondary washing liquid to obtain the secondary washing liquid after fine filtration; and (4) blending the sodium aluminate solution by using the secondary washing liquid after fine filtration.

The secondary washing liquid is finely filtered before the ingredients are prepared, so that impurities such as suspended matters in the washing liquid can be removed.

Further, after obtaining the secondary washing liquid after the fine filtration and before using the secondary washing liquid after the fine filtration to prepare the sodium aluminate solution, the method further comprises the following steps: and (3) reducing the temperature of the secondary washing liquid after fine filtration to below 30 ℃.

The temperature of the secondary washing liquid is reduced as much as possible to meet the production control requirement of dilution and blending, and the production efficiency of the pseudo-boehmite is improved.

S2: introducing carbon dioxide into the sodium aluminate solution to obtain carbonized pseudo-boehmite slurry;

optionally, 35-40% of volume fraction is introduced into the sodium aluminate solution, and the pressure is 0.85-0.9 kg/cm²Carbon dioxide gas of (2).

Furthermore, the aeration time of the carbon dioxide gas is 9-11 minutes.

By controlling the content of carbon dioxide and the ventilation time within the above range and combining the control index (preset index) of the sodium aluminate solution, the carbonization gelling can be fully carried out, and the peptization index of the pseudo-boehmite product produced by using the secondary washing liquid is ensured to reach more than 97%. Further, in the process of introducing carbon dioxide into the sodium aluminate solution, the pH value of the gelling reaction is controlled to be 8-12.

S3: quickly aging the carbonized pseudo-boehmite slurry to obtain an aged pseudo-boehmite slurry;

optionally, the carbonized pseudo-boehmite slurry is rapidly heated to more than 90 ℃, and the aging time is more than 2 hours.

S4: washing and drying the aged pseudo-boehmite slurry to obtain a pseudo-boehmite finished product with a peptization index meeting a preset range; wherein, the secondary washing liquid is recovered in the washing process so as to be applied to the preparation of the sodium aluminate solution of the next batch.

The preset range is a peptization index range meeting the requirements of a control plan, and optionally, the preset range is more than 97%.

In summary, the method for producing pseudo-boehmite returns the secondary washing liquid in the washing process to the blending of the sodium aluminate solution, namely, when the refined sodium aluminate solution is diluted and blended (or cooled and diluted), the secondary washing liquid is used for replacing all or part of softened fresh water for blending. The secondary washing liquid is used for batching, the adverse effect of factors such as high alkali and complex components of the secondary washing liquid on the performance of the pseudo-boehmite product needs to be overcome, so that the index of the sodium aluminate solution needs to be controlled during dilution and blending, and then the pseudo-boehmite product with normal peptization index and meeting the quality control requirement is obtained through subsequent carbonization, high-temperature rapid aging, washing and drying. The process schematic of the whole production flow can be referred to fig. 2.

On the other hand, the embodiment of the invention also provides the pseudoboehmite, which is prepared by adopting the production method of the pseudoboehmite.

The technical solution of the present application will be further described with reference to specific examples.