阅读说明：本技术 一种环保型水滑石合成工艺 (Environment-friendly hydrotalcite synthesis process ) 是由 陶永玉 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种环保型水滑石合成工艺,属于无机化工技术领域。该工艺是将碱式碳酸镁和催化剂加入到反应釜中,加入水后搅拌,搅拌后将氢氧化铝加入到反应釜中加热进行反应,反应结束后降至室温,过滤分离获取滤液和滤饼；滤液回收作为反应用水,滤饼干燥后成品。本发明的母液可以进行循环使用,从而避免了大量废水的产生,能够节省大量的水资源。同时,利用碱式碳酸镁替代尿素作为反应原料,避免了氨的产生,进一步降低了企业的环保压力。(The invention discloses an environment-friendly hydrotalcite synthesis process, and belongs to the technical field of inorganic chemical industry. Adding basic magnesium carbonate and a catalyst into a reaction kettle, adding water, stirring, adding aluminum hydroxide into the reaction kettle after stirring, heating for reaction, cooling to room temperature after the reaction is finished, and filtering and separating to obtain filtrate and a filter cake; the filtrate is recovered as reaction water, and the filter cake is dried to obtain the finished product. The mother liquor of the invention can be recycled, thereby avoiding the generation of a large amount of waste water and saving a large amount of water resources. Meanwhile, the basic magnesium carbonate is used as a reaction raw material to replace urea, so that ammonia is avoided, and the environmental protection pressure of enterprises is further reduced.)

1. An environment-friendly hydrotalcite synthesis process is characterized in that basic magnesium carbonate and a catalyst are added into a reaction kettle, water is added into the reaction kettle, the reaction kettle is stirred, aluminum hydroxide is added into the reaction kettle after stirring, the reaction kettle is heated for reaction, the temperature is reduced to room temperature after the reaction is finished, and filtrate and filter cakes are obtained through filtration and separation; the filtrate is recovered as reaction water, and the filter cake is dried to obtain the finished product.

2. The process for synthesizing environment-friendly hydrotalcite according to claim 1, characterized by comprising the following steps:

(1) adding basic magnesium carbonate and a catalyst into a reaction kettle, adding reaction water, and uniformly stirring;

(2) adding aluminum hydroxide into the reaction kettle in the step (1), starting the reaction kettle, heating to 180-220 ℃, reacting for 2-5 hours, and cooling the reaction solution to room temperature after the reaction is finished;

(3) and (3) filtering the reaction liquid after the reaction in the step (2), separating out a filter cake and filtrate, recovering the filtrate, returning the filtrate to the step (1) for recycling, and removing the residual filter cake of the catalyst to obtain a finished product after drying.

3. The process for synthesizing environment-friendly hydrotalcite according to claim 2, wherein the catalyst in step (1) is prepared by immersing pumice in a ferrocene saturated trichloromethane solution for at least 2h, taking out and drying.

4. The process for synthesizing environment-friendly hydrotalcite according to claim 2, wherein the water in step (1) is prepared from the following raw materials in percentage by mass: catalyst: water was added at a ratio of 1: 10.

5. The process for synthesizing environment-friendly hydrotalcite according to claim 2, wherein the heating temperature in step (2) is 200 ℃ and the reaction time is 2.5 h.

6. The process of synthesizing environment-friendly hydrotalcite according to claim 2, wherein the drying in step (3) is to reduce the mass fraction of water in the filter cake to below 0.5%.

7. The process for synthesizing environment-friendly hydrotalcite according to claim 2, wherein the molar ratio of basic magnesium carbonate to aluminum hydroxide is: 1-10: 1.

Technical Field

The invention belongs to the technical field of inorganic chemical industry, and particularly relates to an environment-friendly hydrotalcite synthesis process.

Background

Hydrotalcite (LDH) is a layered structure mineral in which some or all of the trivalent metals in the composition may be replaced by tetravalent metals. The hydrotalcite can be used as an alkaline catalyst, an oxidation-reduction agent, a catalyst carrier, an ABS processing aid and the like, and meanwhile, the hydrotalcite compound can also be used as a medicament for treating gastropathy, for example, the hydrotalcite compound is used for preparing a pump for treating gastritis, gastric ulcer, duodenal ulcer and the like. LDHs are also widely used as ion exchangers or adsorbents in printing, paper making, electroplating, and nuclear wastewater treatment.

The existing hydrotalcite production method mainly comprises two types, namely a liquid phase method and a liquid-solid method. The liquid phase method reaction needs a large amount of water to participate in the reaction and washing, so that a large amount of industrial wastewater is generated, and the enterprises have great environmental protection pressure. The liquid-solid method is a method in which a compound of aluminum and a compound of magnesium are caused to react with urea in water to produce hydrotalcite. However, the liquid-solid method also has a problem of great environmental stress because the by-product ammonia of the reaction is difficult to treat. At the same time, the presence of ammonia also poses potential risks to safe production.

Disclosure of Invention

In order to solve the technical problems of large amount of wastewater and ammonia generated and high environmental pollution in the existing hydrotalcite preparation process, the invention provides an environment-friendly hydrotalcite synthesis process, which adopts the following technical scheme:

an environment-friendly hydrotalcite synthesis process comprises the steps of adding basic magnesium carbonate and a catalyst into a reaction kettle, adding water, stirring, adding aluminum hydroxide into the reaction kettle, heating for reaction, cooling to room temperature after the reaction is finished, and filtering and separating to obtain filtrate and a filter cake; the filtrate is recovered as reaction water, and the filter cake is dried to obtain the finished product.

Preferably, the hydrotalcite synthesis process comprises the following steps:

1) adding basic magnesium carbonate and a catalyst into a reaction kettle, adding reaction water, and uniformly stirring;

2) adding aluminum hydroxide into the reaction kettle in the step (1), starting the reaction kettle, heating to 180-220 ℃, reacting for 2-5 hours, and cooling the reaction solution to room temperature after the reaction is finished;

3) and (3) filtering the reaction liquid after the reaction in the step (2), separating out a filter cake and filtrate, recovering the filtrate, returning the filtrate to the step (1) for recycling, and removing the residual filter cake of the catalyst to obtain a finished product after drying.

Preferably, the catalyst in the step (1) is prepared by soaking pumice in a ferrocene saturated trichloromethane solution for at least 2h, taking out and drying.

Preferably, the water in the step (1) is prepared by mixing the following components in percentage by mass: catalyst: water was added at a ratio of 1: 10.

Preferably, the heating temperature of the step (2) is 200 ℃, and the reaction time is 2.5 h.

Preferably, the drying in the step (3) is to reduce the mass fraction of water in the filter cake to below 0.5%.

Preferably, the molar ratio of the basic magnesium carbonate to the aluminum hydroxide is: 1-10: 1.

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

the mother liquor of the invention can be recycled, thereby avoiding the generation of a large amount of waste water and saving a large amount of water resources. Meanwhile, the basic magnesium carbonate is used as a reaction raw material to replace urea, so that ammonia is avoided, and the environmental protection pressure and the safety production risk of enterprises are further reduced.

Detailed Description

The materials, methods and apparatus used in the following examples, which are not specifically illustrated, are conventional in the art and are commercially available to those of ordinary skill in the art.

In the following description of the present invention, it is noted that the terms "central", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and "upright" and the like indicate orientations or positional relationships and are used merely for convenience in describing the present invention and for simplicity in description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

In the following description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; the connection may be direct or indirect via an intermediate medium, or the connection may be internal to both components. To those of ordinary skill in the art, the specific meaning of the above-described terms in the present invention can be understood as a specific case.

In addition, in the following description of the present invention, the meaning of "plurality", and "plural" is two or more unless otherwise specified.

The reaction vessels used in the following examples are not exclusive common commercial products and are commercially available to those skilled in the art. The catalyst used in the following examples was a solid catalyst prepared by soaking pumice in a saturated solution of ferrocene in chloroform for 2 hours, taking it out and drying it. The purity of ferrocene is more than 99%.

The present invention is described in further detail below, but the following detailed description is not to be construed as limiting the invention.

Example 1

The embodiment provides an environment-friendly hydrotalcite synthesis process, which comprises the following specific steps:

(1) adding basic magnesium carbonate and pumice soaked in a ferrocene trichloromethane saturated solution into a reaction kettle, adding water with the mass 10 times that of the pumice, and stirring for 1 hour;

(2) according to the molar ratio of basic magnesium carbonate to aluminum hydroxide: weighing aluminum hydroxide according to the proportion of 1:1, adding the aluminum hydroxide into a reaction kettle, heating to 200 ℃, reacting for 2.5 hours, and cooling to room temperature after the reaction is finished;

(3) filtering the reaction solution obtained in the step (2) to obtain filtrate and filter cake, and recycling the filtrate as the water in the step (1) for recycling; drying to remove the filter cake of the pumice until the water content is lower than 0.5 percent to obtain the finished product of the hydrotalcite.

Example 2

The embodiment provides an environment-friendly hydrotalcite synthesis process, which comprises the following specific steps:

1) adding basic magnesium carbonate and pumice soaked in a ferrocene trichloromethane saturated solution into a reaction kettle, adding water with the mass 10 times that of the pumice, and stirring for 1 hour;

2) according to the molar ratio of basic magnesium carbonate to aluminum hydroxide: weighing aluminum hydroxide according to the ratio of 3:1, adding the aluminum hydroxide into a reaction kettle, heating to 180 ℃, reacting for 5 hours, and cooling to room temperature after the reaction is finished;

3) filtering the reaction solution obtained in the step (2) to obtain filtrate and filter cake, and recycling the filtrate as the water in the step (1) for recycling; drying to remove the filter cake of the pumice until the water content is lower than 0.5 percent to obtain the finished product of the hydrotalcite.

Example 3

The embodiment provides an environment-friendly hydrotalcite synthesis process, which comprises the following specific steps:

1) adding basic magnesium carbonate and pumice soaked in a ferrocene trichloromethane saturated solution into a reaction kettle, adding water with the mass 10 times that of the pumice, and stirring for 1 hour;

2) according to the molar ratio of basic magnesium carbonate to aluminum hydroxide: weighing aluminum hydroxide according to the proportion of 1:1, adding the aluminum hydroxide into a reaction kettle, heating to 220 ℃, reacting for 2.0h, and cooling to room temperature after the reaction is finished;

3) filtering the reaction solution obtained in the step (2) to obtain filtrate and filter cake, and recycling the filtrate as the water in the step (1) for recycling; drying to remove the filter cake of the pumice until the water content is lower than 0.5 percent to obtain the finished product of the hydrotalcite.

Example 4

The embodiment provides an environment-friendly hydrotalcite synthesis process, which comprises the following specific steps:

1) adding basic magnesium carbonate and pumice soaked in a ferrocene trichloromethane saturated solution into a reaction kettle, adding water with the mass 10 times that of the pumice, and stirring for 1 hour;

2) according to the molar ratio of basic magnesium carbonate to aluminum hydroxide: weighing aluminum hydroxide according to the proportion of 10:1, adding the aluminum hydroxide into a reaction kettle, heating to 200 ℃, reacting for 4.0h, and cooling to room temperature after the reaction is finished;

3) filtering the reaction solution obtained in the step (2) to obtain filtrate and filter cake, and recycling the filtrate as the water in the step (1) for recycling; drying to remove the filter cake of the pumice until the water content is lower than 0.5 percent to obtain the finished product of the hydrotalcite.

Example 5

The embodiment provides an environment-friendly hydrotalcite synthesis process, which comprises the following specific steps:

1) adding basic magnesium carbonate and pumice soaked in a ferrocene trichloromethane saturated solution into a reaction kettle, adding water with the mass 10 times that of the pumice, and stirring for 1 hour;

2) according to the molar ratio of basic magnesium carbonate to aluminum hydroxide: weighing aluminum hydroxide according to the ratio of 4:1, adding the aluminum hydroxide into a reaction kettle, heating to 200 ℃, reacting for 2.0h, and cooling to room temperature after the reaction is finished;

3) filtering the reaction solution obtained in the step (2) to obtain filtrate and filter cake, and recycling the filtrate as the water in the step (1) for recycling; drying to remove the filter cake of the pumice until the water content is lower than 0.5 percent to obtain the finished product of the hydrotalcite.

Example 6

The embodiment provides an environment-friendly hydrotalcite synthesis process, which comprises the following specific steps:

1) adding basic magnesium carbonate and pumice soaked in a ferrocene trichloromethane saturated solution into a reaction kettle, adding water with the mass 10 times that of the pumice, and stirring for 1 hour; the added water is the filtrate recovered in example 5, and the shortage is partly supplemented with fresh water;

2) according to the molar ratio of basic magnesium carbonate to aluminum hydroxide: weighing aluminum hydroxide according to the ratio of 4:1, adding the aluminum hydroxide into a reaction kettle, heating to 200 ℃, reacting for 2.0h, and cooling to room temperature after the reaction is finished;

3) filtering the reaction solution obtained in the step (2) to obtain filtrate and filter cake, and recycling the filtrate as the water in the step (1) for recycling; drying to remove the filter cake of the pumice until the water content is lower than 0.5 percent to obtain the finished product of the hydrotalcite.

Example 7

The embodiment provides an environment-friendly hydrotalcite synthesis process, which comprises the following specific steps:

1) adding basic magnesium carbonate and pumice soaked in a ferrocene trichloromethane saturated solution into a reaction kettle, adding water with the mass 10 times that of the pumice, and stirring for 1 hour; the added water is the filtrate recovered in example 6, and the shortage is partly supplemented with fresh water;

2) according to the molar ratio of basic magnesium carbonate to aluminum hydroxide: weighing aluminum hydroxide according to the ratio of 4:1, adding the aluminum hydroxide into a reaction kettle, heating to 200 ℃, reacting for 2.0h, and cooling to room temperature after the reaction is finished;

3) filtering the reaction solution obtained in the step (2) to obtain filtrate and filter cake, and recycling the filtrate as the water in the step (1) for recycling; drying to remove the filter cake of the pumice until the water content is lower than 0.5 percent to obtain the finished product of the hydrotalcite.

Example 8

The embodiment provides an environment-friendly hydrotalcite synthesis process, which comprises the following specific steps:

4) adding basic magnesium carbonate and pumice soaked in a ferrocene trichloromethane saturated solution into a reaction kettle, adding water with the mass 10 times that of the pumice, and stirring for 1 hour; the added water is filtrate which is recycled by more than 50 batches according to the method of the embodiment 7, and the shortage part is supplemented by fresh water;

5) according to the molar ratio of basic magnesium carbonate to aluminum hydroxide: weighing aluminum hydroxide according to the ratio of 4:1, adding the aluminum hydroxide into a reaction kettle, heating to 200 ℃, reacting for 2.0h, and cooling to room temperature after the reaction is finished;

6) filtering the reaction solution obtained in the step (2) to obtain filtrate and filter cake, and recycling the filtrate as the water in the step (1) for recycling; drying to remove the filter cake of the pumice until the water content is lower than 0.5 percent to obtain the finished product of the hydrotalcite.

Example 9

In this example, the hydrotalcites prepared in examples 1 to 8 were subjected to quality measurement, which was indicated by changes in appearance color, pH, whiteness, constant-weight moisture content, and magnesium-aluminum ratio. The results are shown in Table 1.

TABLE 1 quality of hydrotalcites prepared in examples 1 to 8

Sample (I)	Apparent color	pH	Whiteness degree	Dry constant weight water contentVariations in	Ratio of aluminum to magnesium
						Example 1	White colour	9.61	98.2	0.21％	2.1
Example 2	White colour	9.62	97.1	0.13％	2.2
						Example 3	White colour	9.65	97.3	0.41％	2.1
Example 4	White colour	9.62	98.7	0.32％	2.1
						Example 5	White colour	9.49	99.2	0.25％	2.2
Example 6	White colour	9.59	97.2	0.23％	2.1
						Example 7	White colour	9.88	95.6	0.41％	2.3
Example 8	Light yellow	9.91	90.1	0.84％	2.4

As can be seen from Table 1, the hydrotalcite prepared by the method has very stable quality index, the whiteness is more than 90, and the ratio of aluminum to magnesium is between 2.1 and 2.4. Meanwhile, the quality index of the hydrotalcite prepared by using more than 50 batches of filtrate is different from that of a product prepared by using fresh water, but still within the range of product delivery requirements. The hydrotalcite prepared by the method of the invention can save more than 90% of industrial water and reduce more than 99% of sewage discharge, and has extremely high environmental protection value.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.