CN100358808C - Method of producing high purity magnesium hydroxide by whisker selection method - Google Patents
Method of producing high purity magnesium hydroxide by whisker selection method Download PDFInfo
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- CN100358808C CN100358808C CNB2005100476714A CN200510047671A CN100358808C CN 100358808 C CN100358808 C CN 100358808C CN B2005100476714 A CNB2005100476714 A CN B2005100476714A CN 200510047671 A CN200510047671 A CN 200510047671A CN 100358808 C CN100358808 C CN 100358808C
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- magnesium hydroxide
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- whisker
- magnesium
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Abstract
The present invention relates to a method for producing highly pure magnesium hydroxide by a crystal whisker selection method. The method comprises the steps that (1) a water solution of magnesium sulfate or brine is used as raw materials, and insoluble impurities in the raw materials are removed; (2) the raw materials react with alkaline substances under the hydrothermal condition in a common reaction kettle of white steel or enamel; during the reaction, the water temperature ranges from 20 to 200 DEG C, the pressure ranges from 3 to 20 kgf, and the pressure maintaining time ranges from 0.5 to 6 hours; fibrous crystals or tabular crystals of magnesium salt as intermediates are generated after the reaction; (3) the obtained intermediates are washed and stirred at the speed of 5 to 80 rpm at the temperature of 20 to 98 DEG C so that the intermediates react with the alkaline substances; SO4<2> or Cl radicals are removed, and washing is carried out; consequently, magnesium hydroxide with high purity is obtained. When the technical method of the present invention is used, the common reaction kettle of white steel or enamel is used, and only little investment is required; the production of the fibrous crystals or the tabular crystals results in convenient separatint filtration of the products; the method also has the advantages of the use of pure water, the avoidance of the introduction of new impurities, high product purity, high yield, no generation of corrosive products in reactions, and suitability for industrial production.
Description
One, technical field: the present invention relates to a kind of is raw material with water-soluble magnesium sulfate salt or chlorination magnesium salts, produces the method for high purity magnesium hydroxide; Belong to inorganic field of fine chemical.
Two, background technology: magnesium hydroxide is a kind of applied range, nontoxic, tasteless basic chemical industry raw material, and it can be applied in the fire retardant that is used as low cigarette, Halogen, environment-friendly type in the plastic cement; In coating, make filler; Be used as good stopping composition in the paper industry; It in chemical industry is synthetic the industrial chemicals of making other magnesium compounds; And medicine, in the foodstuffs industry.That magnesium hydroxide has is natural, two kinds of chemosynthesis.Natural magnesium hydroxide claims brucite again, and the foreign matter content height can only use as low-grade product, and general content is 70～93%.Thereby chemical method synthetic magnesium hydroxide, to the flame retardant area of high request, especially the field of synthetic field of chemical industry and Insulation Material use is more and more important.Chemical synthesis is produced the general content of magnesium hydroxide and can be controlled in 98%, as the magnesium hydroxide that makes greater than 98% chemical method, because the viscosity of magnesium hydroxide itself is strong, not easily separated, so purity height, be the cost height of the product of magnesium hydroxide＞98%, and yield is low, this also is the difficult problem of the sector.
The production method of high purity magnesium hydroxide generally has following several:
(1) magnesium chloride-sodium hydroxide method claims bittern-soda processes again:
Chemical equation:
MgCl
2·6H
2O+2NaOH—Mg(OH)
2↓+2NaCl+6H
2O
This method is more original, and raw material is simple, but because magnesium chloride promptly contains multiple soluble impurity in the bittern, in addition, the magnesium hydroxide particle diameter of combination reaction is little, viscosity is big, filtration problem is difficult to solve, so be not suitable for producing highly purified magnesium hydroxide.
(2) bittern-continuous ammonia process:
Chemical equation:
MgCl
2·6H
2O+2NH
3·H
2O—Mg(OH)
2↓+2?NH
4Cl+6H
2O
This method is improving one's methods of method (1), used ammonia to replace sodium hydroxide, alkalescence a little less than, make to produce to be easy to control, make product viscosity controlled, but the cost height of ammonia in addition, must have ammonia recovery unit, facility investment is big, though the problem of filtration washing makes moderate progress, the production high purity, promptly the product of magnesium hydroxide＞98% acquires a certain degree of difficulty.
(3) calcining MgCl
2H
2The O method:
Chemical equation
MgCl
2·6H
2O+O
2→MgO+HCl↑+H
2O↑
MgO+H
2O→Mg(OH)
2
Advantage:
The Mg (OH) that this method is produced
2The purity height saved filtration, separating process, and product cut size is evenly distributed;
Weak point:
Facility investment is too big, and energy consumption is big, and the byproduct HCl hydrochloric acid that produces in the production process has serious corrosion to equipment, and the material of equipment is had particular requirement, causes production cost high.
Three, summary of the invention:
1, goal of the invention: the invention provides a kind of method of producing high purity magnesium hydroxide by whisker selection method, its objective is in the method for solution production magnesium hydroxide in the past, the cost of investment height, product is difficult to be separated, washs, to the problem of aspects such as equipment requirements height existence.
2, technical scheme: the present invention is achieved through the following technical solutions:
The object of the present invention is achieved like this:
A kind of method of producing high purity magnesium hydroxide by whisker selection method: it is characterized in that: this method is carried out as follows:
(1), get magnesium sulfate solution or bittern is raw material, remove the insoluble impurities in the raw material;
(2), in common white steel or enamel reaction still, raw material and alkaline substance are reacted under hydrothermal condition, and the water temperature during reaction is 20～200 ℃, and pressure is 3～20kgf, dwell time is 0.5～6 hour, and the reaction back generates the fibrous crystals or the tabular crystal of intermediate magnesium salts; Alkaline substance is selected from any in sodium hydroxide, potassium hydroxide or the aqua ammonia.
(3), the intermediate of gained after washing, temperature be 20～98 ℃ with 5～80rpm agitation condition under, with the alkaline substance reaction, remove SO
4 2-Or Cl
-Root promptly gets the high magnesium hydroxide of purity after washing.
The stirring velocity that raw material and alkaline substance generate intermediate is 80～120rpm.
In the entire reaction operating process, the water that uses is pure water.
The magnesium sulfate solution raw material choosing of using is with any aqueous solution in the sal epsom of 0～7 crystal water.
3, advantage and effect: by the enforcement of technical solution of the present invention, its objective is in the method for solution production magnesium hydroxide in the past, the cost of investment height, product is difficult to be separated, washs, the problem that aspects such as equipment requirements height exist.The invention provides a kind of novel method of producing high-purity magnesium hydroxide, make the purity height of the magnesium hydroxide that obtains, be easy to produce, convenient separation, washing.Adopt processing method of the present invention, can use common white steel or enamel reaction still, facility investment is little, through producd fibers shape or sheet magnesium salts crystal, it is very convenient that product separation is filtered, and drainability is strong, but repetitive scrubbing, in process of production, use pure water, avoided introducing new impurity, the product purity height, the yield height does not produce the product that is corrosive in the reaction, very suitable suitability for industrialized production.
Four, embodiment:
The present invention is a kind of method that adopts producing high purity magnesium hydroxide by whisker selection method, be raw material mainly with bittern or magnesium sulfate solution, through physics and the refining insoluble impurities of removing in the raw material of chemical process, at sodium hydroxide, in potassium hydroxide or the aqua ammonia under any effect, under hydrothermal condition, adopting and stirring appropriateness is that per minute 0～120 changes, water temperature during reaction is 20～200 ℃, pressure is 3～20kgf, dwell time is 0.5～6 hour, generate the reaction of intermediate magnesium salts crystalline, the crystal that generates is fibrous whisker, sheet or fibrous, sheet, fan-shaped crystalline miscellany, the type reaction formula when raw material is magnesium sulfate solution is:
MgSO
47H
2O+NaOH → MgSO
4Fibrous crystal palpus (or tabular crystal);
After the pure water washing, under 20～98 ℃ of agitation conditions that change with per minute 5～80, with alkaline substance, promptly SO is removed in a kind of reaction in sodium hydroxide, ammonia or the potassium hydroxide again
4 2-, the type reaction formula is:
MgSO
4Crystal+NaOH → Na
2SO
4+ Mg (OH)
2
Behind repetitive scrubbing, promptly get the high magnesium hydroxide of purity again.
Embodiment 1:
The present invention is a kind of method of producing high purity magnesium hydroxide by whisker selection method, getting magnesium sulfate solution is raw material, through physics and the refining insoluble impurities of removing in the magnesium sulfate solution of chemical process, in common white steel reactor, under the effect of sodium hydroxide, be under 190 ℃ the condition in water temperature, employing stirring speed is that per minute 90 changes, and pressure is 15kgf, and the dwell time is 3 hours, react, reaction formula is:
MgSO
47H
2O+NaOH → MgSO
4Fibrous crystal palpus (or tabular crystal);
MgSO
4Fibrous whisker or tabular crystal under 55 ℃ of agitation conditions that change with per minute 60, with the sodium hydroxide reaction, are removed SO again after the pure water washing
4 2-, reaction formula is:
MgSO
4Crystal+NaOH → Na
2SO
4+ Mg (OH)
2
Mg (OH)
2Behind repetitive scrubbing, promptly get the high magnesium hydroxide of purity again.
Embodiment 2:
The present invention is a kind of method of producing high purity magnesium hydroxide by whisker selection method, getting bittern is raw material, through physics and the refining insoluble impurities of removing in the bittern of chemical process, in common enamel reaction still, under the effect of potassium hydroxide, be under 180 ℃ the condition at hydrothermal temperature, adopting and stirring appropriateness is that per minute 80 changes, and pressure is 11kgf, and the dwell time is 3.5 hours, react, reaction formula is:
MgCl
25H
2O+KOH → MgCl
2Fibrous crystal palpus (or tabular crystal);
The MgCl of gained
2Fiber under 60 ℃ of agitation conditions that change with per minute 65, with the potassium hydroxide reaction, is removed Cl again after the pure water washing
-And SO
4 2-, reaction formula is:
MgCl
2Crystal+KOH → KCl+Mg (OH)
2
Mg (OH)
2Behind repetitive scrubbing, get final product again the high magnesium hydroxide of purity.
Embodiment 3:
In like manner, when alkaline substance adopted aqua ammonia, reaction conditions was the same, also can obtain the higher magnesium hydroxide of purity.
The magnesium hydroxide that the foregoing description 1,2 and 3 obtains after testing, every index is as follows:
Outward appearance: the mobile powder of white;
Whiteness: 〉=95; Content: 〉=99.5%; Density: ≈ 2.36g/cm
3
Decomposition temperature: 340 ℃; Water content:＜0.5%; Heap proportion: 450～600g/L;
Particle diameter: 2～10 μ m; Ignition loss (1200 ℃): 31%; Specific refractory power: 1.56～1.58;
Other general data:
Cl
-：＜0.01％； Fe
2O
3：＜0.03％； CaO：＜0.8％；
B
2O
3:＜0.001%; SO
4 2-:＜1.0%; Heavy metal:＜0.002%;
More than every detection index result all meet or surpass the standard of high purity magnesium hydrate.
Claims (3)
1, a kind of method of producing high purity magnesium hydroxide by whisker selection method is characterized in that: this method is carried out as follows:
(1), get magnesium sulfate solution or bittern is raw material, remove the insoluble impurities in the raw material;
(2), in common white steel or enamel reaction still, raw material and alkaline substance are reacted under hydrothermal condition, water temperature during reaction is 180～200 ℃, pressure is 3～20kgf, dwell time is 0.5～6 hour, and the stirring velocity that raw material and alkaline substance generate intermediate is fibrous crystals or the tabular crystal that 80～120rpm reaction back generates the intermediate magnesium salts; Alkaline substance is selected from any in sodium hydroxide, potassium hydroxide or the aqua ammonia;
(3), the intermediate of gained after washing, temperature be 20～98 ℃ with 5～80rpm agitation condition under, with the alkaline substance reaction, remove SO
4 2-Or Cl
-Root promptly gets the high magnesium hydroxide of purity after washing.
2, according to the method for a kind of producing high purity magnesium hydroxide by whisker selection method described in the claim 1, it is characterized in that: in the entire reaction operating process, the water that uses is pure water.
3, according to the method for a kind of producing high purity magnesium hydroxide by whisker selection method described in the claim 1, it is characterized in that: the choosing of the magnesium sulfate solution raw material of use is with any aqueous solution in the sal epsom of 0～7 crystal water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100476714A CN100358808C (en) | 2005-11-10 | 2005-11-10 | Method of producing high purity magnesium hydroxide by whisker selection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100476714A CN100358808C (en) | 2005-11-10 | 2005-11-10 | Method of producing high purity magnesium hydroxide by whisker selection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1752004A CN1752004A (en) | 2006-03-29 |
| CN100358808C true CN100358808C (en) | 2008-01-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100476714A Expired - Fee Related CN100358808C (en) | 2005-11-10 | 2005-11-10 | Method of producing high purity magnesium hydroxide by whisker selection method |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102502728B (en) * | 2011-10-12 | 2014-07-23 | 江苏艾特克阻燃材料有限公司 | Magnesium hydroxide flame retardant and preparation method thereof |
| CN104153002A (en) * | 2014-08-22 | 2014-11-19 | 瓮福（集团）有限责任公司 | Method for preparing magnesium hydroxide crystal whiskers by utilizing magnesium-containing waste liquid |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4246254A (en) * | 1978-02-22 | 1981-01-20 | Kyowa Chemical Industry Co., Ltd. | Fibrous magnesium hydroxide and process for production thereof |
| US5264284A (en) * | 1991-06-06 | 1993-11-23 | Kabushiki Kaisha Kaisui Kagaku Kenkyujo | Fibrous composite metal hydroxide and process for the production thereof |
| CN1270143A (en) * | 1999-04-13 | 2000-10-18 | 德拉沃石灰有限公司 | High purity magnesium hydrate and preparation thereof |
| CN1458066A (en) * | 2002-05-17 | 2003-11-26 | 隗学礼 | Process for preparing magnesium hydroxide whisker |
-
2005
- 2005-11-10 CN CNB2005100476714A patent/CN100358808C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4246254A (en) * | 1978-02-22 | 1981-01-20 | Kyowa Chemical Industry Co., Ltd. | Fibrous magnesium hydroxide and process for production thereof |
| US5264284A (en) * | 1991-06-06 | 1993-11-23 | Kabushiki Kaisha Kaisui Kagaku Kenkyujo | Fibrous composite metal hydroxide and process for the production thereof |
| CN1270143A (en) * | 1999-04-13 | 2000-10-18 | 德拉沃石灰有限公司 | High purity magnesium hydrate and preparation thereof |
| CN1458066A (en) * | 2002-05-17 | 2003-11-26 | 隗学礼 | Process for preparing magnesium hydroxide whisker |
Non-Patent Citations (3)
| Title |
|---|
| 水热处理氢氧化镁微晶性质研究. 郑遗凡等.无机化学学报，第19卷第6期. 2003 * |
| 高纯微细氢氧化镁的水热法制备. 吴会军等.华南理工大学学报(自然科学版)，第31卷第6期. 2003 * |
| 高纯氢氧化镁及其水热处理技术评述. 许荣辉等.盐湖研究，第12卷第2期. 2004 * |
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| CN1752004A (en) | 2006-03-29 |
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| PB01 | Publication | ||
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| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Assignee: Yingkou city Weisike Chemical Co. Ltd. Assignor: Zhao Xingli Contract record no.: 2011210000014 Denomination of invention: Method of producing high purity magnesium hydroxide by whisker selection method Granted publication date: 20080102 License type: Exclusive License Open date: 20060329 Record date: 20110222 |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20080102 Termination date: 20111110 |