CN104163412A - Method for preparing aluminum hypophosphite via continuous reaction crystallization process - Google Patents
Method for preparing aluminum hypophosphite via continuous reaction crystallization process Download PDFInfo
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- CN104163412A CN104163412A CN201410387142.8A CN201410387142A CN104163412A CN 104163412 A CN104163412 A CN 104163412A CN 201410387142 A CN201410387142 A CN 201410387142A CN 104163412 A CN104163412 A CN 104163412A
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- hypo
- aluminum
- successive reaction
- aluminum orthophosphate
- salt
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Abstract
The invention relates to a method for preparing aluminum hypophosphite via a continuous reaction crystallization process. According to the technical scheme, the method comprises the following steps: continuously adding a 50-80wt% sodium hypophosphite solution and 50-60wt% soluble aluminum salt solution into a reaction crystallizer, controlling the average residence time of the materials in the continuous reaction crystallizer for 1 to 5 hours, further discharging a mother liquor I of aluminum hypophosphite from the bottom of the crystallizer and sending the mother liquor I of aluminum hypophosphite into an ager for aging 0 to 3 hours, then further discharging the mother liquor I from the bottom of the ager, and carrying out centrifugal separation, washing and drying so as to obtain an aluminum hypophosphite crystal with the purity greater than 99.0% and a crystallized mother liquor II; finally, evaporating and crystallizing the crystallized mother liquor II so as to obtain a coarse product sodium salt and a crystallized mother liquor III; returning the crystallized mother liquor III into the continuous reaction crystallizer for circulating. Based on the continuous reaction crystallization process, the method has the advantages of simple process, moderate operating condition, low energy consumption, stable aluminum hypophosphite quality and the like, and is easy to industrialize.
Description
Technical field
The invention belongs to fine chemicals preparing technical field, be specifically related to a kind of method that uses successive reaction crystallization process to prepare hypo-aluminum orthophosphate.
Background technology
Hypo-aluminum orthophosphate (Aluminium hypophosphite, Al (H
2pO
2)
3), be white powder solid/crystal, there is special odor, be slightly soluble in water, but be insoluble to alcohol.Hypo-aluminum orthophosphate is a kind of novel fire retardant, because its phosphorus content is high, has the advantages such as Heat stability is good, water-soluble little, fire-retardant effect be large.According to UL94 standard, thickness is 0. 7 mm, and its flame retardant grade is VO, and according to IEC61335-1 standard at 800 DEG C, thickness is greater than 0.8mm, has passed through GWIT test, all checks by various flame retardant ratings.
The preparation method of hypo-aluminum orthophosphate mainly divides two large classes: (1) is taking Hypophosporous Acid, 50 as raw material, based on acid-base neutralisation theoretical react with aluminium hydroxide generate hypo-aluminum orthophosphate (Li Qifei. hypophosphite fire retardant synthesize and fire-retardant Nylon 6 is studied. Northeast Forestry University, master thesis, 2011.); (2) be that Using Sodium Hypophosphite is raw material, the theoretical and aluminum soluble salt (AlCl based on replacement(metathesis)reaction
3, Al
2(SO
4)
3, Al (NO
3)
3deng) reaction generation hypo-aluminum orthophosphate (CN 102786041 A, CN103145110 A).The raw material Hypophosporous Acid, 50 of method (1) has volatility, and Hypophosporous Acid, 50 steam has very large harm to operator and environment; Method (2) is although solved the problem of the Hypophosporous Acid, 50 volatilization in method (1), but in current existing open source literature, method (1) is all to adopt batch technology with method (2), its level of automation is low, single covering device throughput is little, production cycle is long, unstable product quality, is unfavorable for the scale operation of hypo-aluminum orthophosphate.And in the preparation method of CN 102786041 A and the disclosed hypo-aluminum orthophosphate of CN103145110 A, the crystalline mother solution all it not being filtered out after hypo-aluminum orthophosphate is processed, and is rich in the by product Na of reaction in this crystalline mother solution
2sO
4and NaNO
3.
Summary of the invention
The present invention is intended to overcome prior art defect, and object is to provide a kind of method that uses successive reaction crystallization process to prepare hypo-aluminum orthophosphate, and the method has that technique is simple, mild condition, energy consumption are low, be easy to the advantages such as industrialization.
For achieving the above object, the concrete steps of the technical solution used in the present invention are:
Step 1, under the speed conditions of 30 ~ 90 DEG C and 200～500r/min, be mixed with by water-soluble sodium hypophosphite the sodium hypophosphite solution that concentration is 50 ~ 80wt%;
Step 2, under the speed conditions of 30 ~ 90 DEG C and 200～500r/min, be mixed with by water-soluble aluminum soluble salt the aluminum salt solution that concentration is 30 ~ 55wt%;
The aluminum salt solution that step 3, the sodium hypophosphite solution that is 50 ~ 80wt% by concentration and concentration are 30 ~ 55wt% joins in successive reaction crystallizer slowly, continuously, product mother liquid I is discharged continuously by crystallizer bottom, requiring control to add the stoichiometric ratio of sodium hypophosphite and aluminium salt is 1:(0.35 ~ 0.4), control 30 ~ 90 DEG C of temperature, mixing speed 200～500r/min in successive reaction crystallizer, material mean residence time in successive reaction crystallizer is 1 ~ 5h;
Step 4, product mother liquid I is delivered to digestion tank, control 30 ~ 90 DEG C of temperature, mixing speed 100～300r/min in digestion tank, material mean residence time in digestion tank is 0 ~ 3h, material after ageing finishes is discharged continuously by digestion tank bottom, obtains through centrifugation, washing, after dry hypo-aluminum orthophosphate crystal and the crystalline mother solution II that purity is greater than 99.0%;
Step 5, by crystalline mother solution II evaporate, crystallization, obtain crude product sodium salt and crystalline mother solution III, crystalline mother solution III is returned to successive reaction crystallizer and is circulated.
Described aluminium salt is AlCl
3, Al
2(SO
4)
3, Al (NO
3)
3in one.
Described stoichiometric ratio is mol ratio.
Described aluminium salt is selected AlCl
3time, crude product sodium salt is mainly the mixture of NaCl crystal and a small amount of hypo-aluminum orthophosphate, aluminum chloride; Described aluminium salt is selected Al
2(SO
4)
3time, crude product sodium salt is mainly Na
2sO
4the mixture of crystal and a small amount of hypo-aluminum orthophosphate, Tai-Ace S 150; Described aluminium salt is selected Al (NO
3)
3time, crude product sodium salt is mainly NaNO
3the mixture of crystal and a small amount of hypo-aluminum orthophosphate, aluminum nitrate.
Evaporation in described preparation process five adopts decompression operation, and its vacuum tightness is 0.02 ~ 0.08MPa, and then evaporative crystallization EO in the time that the crystal suspension density in its crystalline mother solution reaches 30 ~ 50wt% filters, is dried.
Owing to adopting technique scheme, the present invention compared with prior art has following positively effect:
(1) use successive reaction crystallization process involved in the present invention is prepared the method for hypo-aluminum orthophosphate, adopt successive reaction crystallization processes, by the residence time, temperature and the sodium hypophosphite solution of crystallization control process and the stream rate of acceleration of soluble aluminum salts solution, make that the reaction crystallization process of hypo-aluminum orthophosphate is constant to carry out under lower degree of supersaturation, thereby can obtain, median size is large, the hypo-aluminum orthophosphate crystal product of even particle size distribution; Intersect at traditional hypo-aluminum orthophosphate intermittent preparing process, successive reaction crystallization process has the advantages such as throughput is large, level of automation is high, constant product quality.
(2) use successive reaction crystallization process involved in the present invention is prepared the method for hypo-aluminum orthophosphate, and sodium hypophosphite and aluminum soluble salt reaction equation are as follows:
3NaH
2PO
2?+?Al
3+?---→?Al(H
2PO
2)
3↓?+?3Na
+
The hypo-aluminum orthophosphate generating due to reaction is slightly soluble in water, while adopting successive reaction crystallization process, can make the continuous crystallization of hypo-aluminum orthophosphate of generation, thereby allow above-mentioned reaction constantly carry out to positive reaction direction, improves the yield of product; Compared to traditional hypo-aluminum orthophosphate evaporative crystallization (or evaporation, concentrated after crystallisation by cooling again), successive reaction crystallization process involved in the present invention does not need evaporation concentration operation, operational condition milder, operation energy consumption is low, is easy to industrialization.
(3) use successive reaction crystallization process involved in the present invention is prepared the method for hypo-aluminum orthophosphate, there is no the generation of waste liquid.
Embodiment
Below in conjunction with embodiment, the invention will be further described, not the restriction to its protection domain.
embodiment 1
Use successive reaction crystallization process to prepare a method for hypo-aluminum orthophosphate, its concrete steps are:
Step 1, under the speed conditions of 30 ~ 90 DEG C and 200～500r/min, be mixed with by water-soluble sodium hypophosphite the sodium hypophosphite solution that concentration is 50 ~ 80wt%;
Step 2, under the speed conditions of 30 ~ 90 DEG C and 200～500r/min, be mixed with by water-soluble aluminum soluble salt the aluminum salt solution that concentration is 30 ~ 55wt%;
The aluminum salt solution that step 3, the sodium hypophosphite solution that is 50 ~ 80wt% by concentration and concentration are 30 ~ 55wt% joins in successive reaction crystallizer slowly, continuously, product mother liquid I is discharged continuously by crystallizer bottom, requiring control to add the stoichiometric ratio of sodium hypophosphite and aluminium salt is 1:(0.35 ~ 0.4), control 30 ~ 90 DEG C of temperature, mixing speed 200～500r/min in successive reaction crystallizer, material mean residence time in successive reaction crystallizer is 1 ~ 5h;
Step 4, product mother liquid I is delivered to digestion tank, control 30 ~ 90 DEG C of temperature, mixing speed 100～300r/min in digestion tank, material mean residence time in digestion tank is 0 ~ 3h, material after ageing finishes is discharged continuously by digestion tank bottom, obtains through centrifugation, washing, after dry hypo-aluminum orthophosphate crystal and the crystalline mother solution II that purity is greater than 99.0%;
Step 5, by crystalline mother solution II evaporate, crystallization, obtain crude product sodium salt and crystalline mother solution III, crystalline mother solution III is returned to successive reaction crystallizer and is circulated.
Described aluminium salt is AlCl
3.
Described stoichiometric ratio is mol ratio.
Described crude product sodium salt is mainly the mixture of NaCl crystal and a small amount of hypo-aluminum orthophosphate, aluminum chloride.
Evaporation in described preparation process five adopts decompression operation, and its vacuum tightness is 0.02 ~ 0.08MPa, and then evaporative crystallization EO in the time that the crystal suspension density in its crystalline mother solution reaches 30 ~ 50wt% filters, is dried.
embodiment 2
In the present embodiment except aluminium salt is Al
2(SO
4)
3, crude product sodium salt is mainly Na
2sO
4outside the mixture of crystal and a small amount of hypo-aluminum orthophosphate, Tai-Ace S 150, other are with embodiment 1.
embodiment 3
In the present embodiment except aluminium salt is Al (NO
3)
3, crude product sodium salt is mainly NaNO
3outside the mixture of crystal and a small amount of hypo-aluminum orthophosphate, Tai-Ace S 150, other are with embodiment 1.
Claims (6)
1. use successive reaction crystallization process to prepare a method for hypo-aluminum orthophosphate, it is characterized in that, specifically complete according to the following steps:
Step 1, under the speed conditions of 30 ~ 90 DEG C and 200～500r/min, be mixed with by water-soluble sodium hypophosphite the sodium hypophosphite solution that concentration is 50 ~ 80wt%;
Step 2, under the speed conditions of 30 ~ 90 DEG C and 200～500r/min, be mixed with by water-soluble aluminum soluble salt the aluminum salt solution that concentration is 30 ~ 55wt%;
The aluminum salt solution that step 3, the sodium hypophosphite solution that is 50 ~ 80wt% by concentration and concentration are 30 ~ 55wt% joins in successive reaction crystallizer slowly, continuously, product mother liquid I is discharged continuously by crystallizer bottom, requiring control to add the stoichiometric ratio of sodium hypophosphite and aluminium salt is 1:(0.35 ~ 0.4), control 30 ~ 90 DEG C of temperature, mixing speed 200～500r/min in successive reaction crystallizer, material mean residence time in successive reaction crystallizer is 1 ~ 5h;
Step 4, product mother liquid I is delivered to digestion tank, control 30 ~ 90 DEG C of temperature, mixing speed 100～300r/min in digestion tank, material mean residence time in digestion tank is 0 ~ 3h, material after ageing finishes is discharged continuously by digestion tank bottom, obtains hypo-aluminum orthophosphate crystal and crystalline mother solution II through centrifugation, washing, after dry;
Step 5, by crystalline mother solution II evaporate, crystallization, obtain crude product sodium salt and crystalline mother solution III, crystalline mother solution III is returned to successive reaction crystallizer and is circulated.
2. use successive reaction crystallization process according to claim 1 is prepared the method for hypo-aluminum orthophosphate, it is characterized in that, the purity of the described hypo-aluminum orthophosphate crystal preparing is greater than 99.0%.
3. use successive reaction crystallization process according to claim 1 is prepared the method for hypo-aluminum orthophosphate, it is characterized in that, described aluminium salt is AlCl
3, Al
2(SO
4)
3, Al (NO
3)
3in one.
4. use successive reaction crystallization process according to claim 1 is prepared the method for hypo-aluminum orthophosphate, it is characterized in that, described stoichiometric ratio is mol ratio.
5. use successive reaction crystallization process according to claim 1 is prepared the method for hypo-aluminum orthophosphate, it is characterized in that, described aluminium salt is selected AlCl
3time, crude product sodium salt is mainly the mixture of NaCl crystal and a small amount of hypo-aluminum orthophosphate, aluminum chloride; Described aluminium salt is selected Al
2(SO
4)
3time, crude product sodium salt is mainly Na
2sO
4the mixture of crystal and a small amount of hypo-aluminum orthophosphate, Tai-Ace S 150; Described aluminium salt is selected Al (NO
3)
3time, crude product sodium salt is mainly NaNO
3the mixture of crystal and a small amount of hypo-aluminum orthophosphate, aluminum nitrate.
6. use successive reaction crystallization process according to claim 1 is prepared the method for hypo-aluminum orthophosphate, it is characterized in that, evaporation in described preparation process five adopts decompression operation, its vacuum tightness is 0.02 ~ 0.08MPa, evaporative crystallization EO in the time that the crystal suspension density in its crystalline mother solution reaches 30 ~ 50wt%, then filters, is dried.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410387142.8A CN104163412A (en) | 2014-08-08 | 2014-08-08 | Method for preparing aluminum hypophosphite via continuous reaction crystallization process |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410387142.8A CN104163412A (en) | 2014-08-08 | 2014-08-08 | Method for preparing aluminum hypophosphite via continuous reaction crystallization process |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104860281A (en) * | 2015-06-01 | 2015-08-26 | 武汉理工大学 | Preparation method of aluminum hypophosphite |
| CN107337187A (en) * | 2017-07-21 | 2017-11-10 | 湖南工业大学 | A kind of preparation method of nanometer of hypo-aluminum orthophosphate |
-
2014
- 2014-08-08 CN CN201410387142.8A patent/CN104163412A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104860281A (en) * | 2015-06-01 | 2015-08-26 | 武汉理工大学 | Preparation method of aluminum hypophosphite |
| CN107337187A (en) * | 2017-07-21 | 2017-11-10 | 湖南工业大学 | A kind of preparation method of nanometer of hypo-aluminum orthophosphate |
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Application publication date: 20141126 |
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