CN112591774A - Method for preparing magnesium hydroxide by dry method - Google Patents
Method for preparing magnesium hydroxide by dry method Download PDFInfo
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- CN112591774A CN112591774A CN202011294193.8A CN202011294193A CN112591774A CN 112591774 A CN112591774 A CN 112591774A CN 202011294193 A CN202011294193 A CN 202011294193A CN 112591774 A CN112591774 A CN 112591774A
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F5/00—Compounds of magnesium
- C01F5/14—Magnesium hydroxide
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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Abstract
The invention discloses a method for preparing magnesium hydroxide by a dry method, which comprises the following steps: putting magnesium oxide into a hydration machine, adding a catalyst and water, and in the hydration process of the magnesium oxide, releasing a large amount of heat through catalysis, raising the temperature to 98-110 ℃, and reacting violently for 3-5 minutes; after the violent reaction, the temperature is slowly reduced, the mixture is kept at 96-98 ℃ for 30 minutes, then the formed magnesium hydroxide dry powder is conveyed to a curing bin, the materials are continuously cured, and the magnesium hydroxide dry powder is generated by air flow conveying, cooling and packaging. The method for preparing the magnesium hydroxide by the dry method has the advantages that the hydration rate is as high as 98 percent, no external energy is needed, and the effects of energy conservation, environmental protection, no waste water, waste residue, waste gas, simple process, simple equipment and cost saving are achieved; the whole process is carried out under normal pressure, is safe, and the time from feeding to completion of hydration to prepare the active magnesium hydroxide dry powder is 60 minutes.
Description
Technical Field
The invention relates to the technical field of preparation of magnesium hydroxide, in particular to a method for preparing magnesium hydroxide by a dry method.
Background
Magnesium hydroxide is an inorganic substance, namely caustic magnesite and light burnt magnesite, is soluble in dilute acid and ammonium salt solution and insoluble in water and alcohol, a suspension in water is called a magnesium hydroxide emulsion, a part soluble in water is completely ionized, and an aqueous solution is alkalescent and is almost insoluble in water. Heating to 350 deg.C to lose water to produce magnesium oxide and magnesium hydroxide, and can be used for preparing sugar and magnesium oxide.
The industrial reaction of sea water with cheap calcium hydroxide solution (lime milk) can obtain magnesium hydroxide precipitate, and its advantages are easily available raw material, simple process, difficult filtering and washing and low product quality. At present, no 'dry method' process for preparing magnesium hydroxide exists in China.
Disclosure of Invention
In view of the above technical problems in the related art, the present invention provides a method for preparing magnesium hydroxide by a dry process, which can overcome the above disadvantages in the prior art.
In order to achieve the technical purpose, the technical scheme of the invention is realized as follows:
a method for preparing magnesium hydroxide by a dry method comprises the following steps:
(1) putting magnesium oxide into a hydration machine, adding a catalyst with the weight of 0.3 percent of the magnesium oxide to excite the activity of the magnesium oxide, adding water with the weight of 50 to 55 percent of the magnesium oxide, wherein the adding amount of the water is determined according to the content of the magnesium oxide, and an atomizing nozzle of the hydration machine enables the magnesium oxide to be hydrated into magnesium hydroxide, so that the magnesium hydroxide is more uniform, and a large amount of heat is released by catalysis in the hydration process of the magnesium oxide, the temperature is raised to 98 to 110 ℃, and the magnesium oxide reacts violently for 3 to 5 minutes;
(2) after the violent reaction, the temperature is slowly reduced to about 98 ℃, the temperature is kept for 30 minutes at 96-98 ℃, then the formed magnesium hydroxide dry powder is conveyed to a curing bin, and the materials are continuously cured;
(3) after the material is cured, the material is conveyed by air flow, cooled and packaged to generate active magnesium hydroxide dry powder.
Further, the catalyst is hexamethylenetetramine or ammonium salt.
Further, the water in the step (1) is added through an atomizing nozzle of the hydration machine.
Further, the magnesium oxide hydration process in the step (1) generates dust, and the spray tower sprays water in time under the action of a draught fan to reduce the dust into water to form slurry with magnesium hydroxide content.
Further, the slurry is continuously recycled to participate in water and reaction.
Further, the slurry is subjected to three-level solid-liquid separation, the separated clear water enters a spray tower or a hydration machine for continuous recycling, and the separated solid is made into one of magnesium hydroxide suspension raw materials with different solid contents.
Further, the temperature of the curing silo is 95-98 ℃.
Further, after the material is cured in the step (3), screening the cured material through an ultrasonic vibration screen, and then packaging.
The invention has the beneficial effects that: the method for preparing the magnesium hydroxide by the dry method takes the light calcined powder calcined by magnesite with rich resources as a raw material, the hydration time is short, the hydration rate is as high as 98 percent, and the hydration conversion rate is high; the magnesium oxide hydration reaction is utilized to release heat energy, no external energy is needed, and the effects of energy conservation, environmental protection, no waste water, waste residue, waste gas, simple process, simple equipment, less equipment, digitalization, convenience in automation and cost saving are achieved; the whole process is carried out under normal pressure, is safe, and the time from feeding to completion of hydration to prepare the active magnesium hydroxide dry powder is 60 minutes; the temperature rises rapidly, water vapor and trace dust are generated, the spray tower sprays water in time under the action of a draught fan, the dust is reduced into water to form slurry with magnesium hydroxide content, the slurry can continuously participate in water and reaction recycling, the slurry can also be subjected to 3-level solid-liquid separation, separated clear water enters the spray tower or a hydration machine to be continuously recycled, and the solid can be made into one of magnesium hydroxide suspension raw materials with different solid contents.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a flow chart of a method for dry-process preparation of magnesium hydroxide according to an embodiment of the present invention;
figure 2 is an XRD spectrum of a magnesium hydroxide product according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
The raw material magnesia adopted in the following embodiments is light-burned magnesia which is generated by calcining Chinese Liaoning magnesite ore powder at the temperature of 800-1200 ℃, and the content is 93-95%.
Example 1
As shown in fig. 1, the method for preparing magnesium hydroxide by dry method comprises the following steps:
(1) putting magnesium oxide into a hydration machine, adding a catalyst (hexamethylenetetramine) with the weight of 0.3 percent of the magnesium oxide, exciting the activity of the magnesium oxide, adding water with the weight of 50 percent of the magnesium oxide through an atomizing nozzle of the hydration machine, and hydrating the magnesium oxide into magnesium hydroxide by the atomizing nozzle of the hydration machine, wherein a large amount of heat is released through catalysis in the hydration process of the magnesium oxide, the temperature is raised to 98-110 ℃, and the magnesium oxide reacts violently for 3-5 minutes; the method comprises the following steps that dust is generated in the hydration process of magnesium oxide, a spray tower sprays water in time under the action of a draught fan, the dust is reduced into water to form slurry with magnesium hydroxide content, the slurry is continuously recycled to participate in water and reaction, or through three-level solid-liquid separation, separated clear water enters the spray tower or a hydration machine to be continuously recycled, and separated solid is made into one of magnesium hydroxide suspension raw materials with different solid contents;
(2) after the violent reaction, the temperature is slowly reduced to about 98 ℃, the temperature is kept for 30 minutes at 96-98 ℃, then the formed magnesium hydroxide dry powder is conveyed to a curing bin, the materials are continuously cured, and the temperature of the curing bin is 95-98 ℃;
(3) after the material is cured, the material is conveyed by air flow and screened by an ultrasonic vibration screen, and then the material is cooled and packaged to generate active magnesium hydroxide dry powder.
Example 2
As shown in fig. 1, the method for preparing magnesium hydroxide by dry method comprises the following steps:
(1) putting magnesium oxide into a hydration machine, adding a catalyst (hexamethylenetetramine) with the weight of 0.3 percent of the magnesium oxide, exciting the activity of the magnesium oxide, adding water with the weight of 55 percent of the magnesium oxide through an atomizing nozzle of the hydration machine, and hydrating the magnesium oxide into magnesium hydroxide by the atomizing nozzle of the hydration machine, wherein a large amount of heat is released through catalysis in the hydration process of the magnesium oxide, the temperature is raised to 98-110 ℃, and the magnesium oxide reacts violently for 3-5 minutes; the method comprises the following steps that dust is generated in the hydration process of magnesium oxide, a spray tower sprays water in time under the action of a draught fan, the dust is reduced into water to form slurry with magnesium hydroxide content, the slurry is continuously recycled to participate in water and reaction, or through three-level solid-liquid separation, separated clear water enters the spray tower or a hydration machine to be continuously recycled, and separated solid is made into one of magnesium hydroxide suspension raw materials with different solid contents;
(2) after the violent reaction, the temperature is slowly reduced to about 98 ℃, the temperature is kept for 30 minutes at 96-98 ℃, then the formed magnesium hydroxide dry powder is conveyed to a curing bin, the materials are continuously cured, and the temperature of the curing bin is 95-98 ℃;
(3) after the material is cured, the material is conveyed by air flow and screened by an ultrasonic vibration screen, and then the material is cooled and packaged to generate active magnesium hydroxide dry powder.
As shown in FIG. 2, XRD analysis of the product prepared in example 1 was performed, and the XRD spectrum obtained was consistent with that of standard card JCPDS 44-1482, indicating that the product is magnesium hydroxide.
The indexes of the magnesium hydroxide synthesized in example 1 are shown in table 1:
TABLE 1 indexes of magnesium hydroxide
The above hydration reaction proceeds smoothly in the absence of a catalyst, and the addition of a catalyst accelerates the reaction, so that it is preferable to carry out dry hydration in the presence of a catalyst. The catalyst can be directly added into magnesium oxide or added into water to form a mixed solution with the water. A wide variety of catalysts are suitable, with hexamethylenetetramine or ammonium salts being commonly used.
In conclusion, by means of the technical scheme, the method for preparing magnesium hydroxide by the dry method takes the magnesite calcined light calcined powder with rich resources as the raw material, the hydration time is short, the hydration rate is as high as 98 percent, and the hydration conversion rate is high; the magnesium oxide hydration reaction is utilized to release heat energy, no external energy is needed, and the effects of energy conservation, environmental protection, no waste water, waste residue, waste gas, simple process, simple equipment, less equipment, digitalization, convenience in automation and cost saving are achieved; the whole process is carried out under normal pressure, is safe, and the time from feeding to completion of hydration to prepare the active magnesium hydroxide dry powder is 60 minutes; the temperature rises rapidly, water vapor and trace dust are generated, the spray tower sprays water in time under the action of a draught fan, the dust is reduced into water to form slurry with magnesium hydroxide content, the slurry can continuously participate in water and reaction recycling, the slurry can also be subjected to 3-level solid-liquid separation, separated clear water enters the spray tower or a hydration machine to be continuously recycled, and the solid can be made into one of magnesium hydroxide suspension raw materials with different solid contents.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. A method for preparing magnesium hydroxide by a dry method is characterized by comprising the following steps:
(1) putting magnesium oxide into a hydration machine, adding a catalyst with the weight of 0.3 percent of the magnesium oxide, and then adding water with the weight of 50 to 55 percent of the magnesium oxide, wherein during the hydration process of the magnesium oxide, a large amount of heat is released through catalysis, the temperature rises to 98 to 110 ℃, and the magnesium oxide reacts violently for 3 to 5 minutes;
(2) after the violent reaction, slowly reducing the temperature, keeping the temperature at 96-98 ℃ for 30 minutes, then conveying the formed magnesium hydroxide dry powder to a curing bin, and continuously curing the materials;
(3) after the material is cured, the material is conveyed by air flow, cooled and packaged to generate the magnesium hydroxide dry powder.
2. The method for preparing the magnesium hydroxide by the dry method according to claim 1, wherein the catalyst is hexamethylenetetramine or ammonium salt.
3. The dry process for preparing magnesium hydroxide according to claim 1, wherein the water in step (1) is added through an atomizer of a hydration machine.
4. The method for preparing the magnesium hydroxide by the dry method according to claim 1, wherein the magnesium oxide hydration process in the step (1) generates dust, and the spraying tower is matched with an induced draft fan to spray water in time to reduce the dust into water to form slurry with the magnesium hydroxide content.
5. The method for preparing the magnesium hydroxide by the dry method according to claim 4, wherein the slurry is continuously recycled to participate in water and reaction.
6. The method for preparing the magnesium hydroxide by the dry method according to claim 4, wherein the slurry is subjected to three-stage solid-liquid separation, the separated clear water enters a spray tower or a hydration machine for continuous recycling, and the separated solid is made into a magnesium hydroxide suspension raw material.
7. The method for dry-process preparation of magnesium hydroxide according to claim 1, wherein the temperature of the aging silo is 95-98 ℃.
8. The method for preparing magnesium hydroxide by a dry method according to claim 1, wherein the material in the step (3) is aged, sieved by an ultrasonic vibration sieve, and packaged.
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| CN202011294193.8A CN112591774A (en) | 2020-11-18 | 2020-11-18 | Method for preparing magnesium hydroxide by dry method |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101318672A (en) * | 2008-07-09 | 2008-12-10 | 中国科学院青海盐湖研究所 | Method for preparing magnesium hydroxide with catalysis hydration of organic acid ammonium salts |
| CN103159236A (en) * | 2011-12-08 | 2013-06-19 | 沈阳工业大学 | Production method of environmental-protective grade magnesium hydroxide |
| KR101462369B1 (en) * | 2014-04-08 | 2014-11-14 | 허재수 | Mg(oh)_2 manufacturing method |
| KR101722963B1 (en) * | 2016-03-08 | 2017-04-04 | 태경화학 주식회사 | Method For Producing Magnesium Hydroxide Powder By Semidry Process |
| CN108314335A (en) * | 2018-04-18 | 2018-07-24 | 镇江苏博特新材料有限公司 | A kind of light-burned MgO suspension kilns coproduction Mg (OH)2Production technology and device |
-
2020
- 2020-11-18 CN CN202011294193.8A patent/CN112591774A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101318672A (en) * | 2008-07-09 | 2008-12-10 | 中国科学院青海盐湖研究所 | Method for preparing magnesium hydroxide with catalysis hydration of organic acid ammonium salts |
| CN103159236A (en) * | 2011-12-08 | 2013-06-19 | 沈阳工业大学 | Production method of environmental-protective grade magnesium hydroxide |
| KR101462369B1 (en) * | 2014-04-08 | 2014-11-14 | 허재수 | Mg(oh)_2 manufacturing method |
| KR101722963B1 (en) * | 2016-03-08 | 2017-04-04 | 태경화학 주식회사 | Method For Producing Magnesium Hydroxide Powder By Semidry Process |
| CN108314335A (en) * | 2018-04-18 | 2018-07-24 | 镇江苏博特新材料有限公司 | A kind of light-burned MgO suspension kilns coproduction Mg (OH)2Production technology and device |
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