CN115925644A - Method for preparing flame retardant by using amine waste mother liquor - Google Patents
Method for preparing flame retardant by using amine waste mother liquor Download PDFInfo
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- CN115925644A CN115925644A CN202211455622.4A CN202211455622A CN115925644A CN 115925644 A CN115925644 A CN 115925644A CN 202211455622 A CN202211455622 A CN 202211455622A CN 115925644 A CN115925644 A CN 115925644A
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- mother liquor
- melamine
- flame retardant
- cyanamide
- waste mother
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- 239000012452 mother liquor Substances 0.000 title claims abstract description 48
- 239000003063 flame retardant Substances 0.000 title claims abstract description 47
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 title claims abstract description 43
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- 238000000034 method Methods 0.000 title claims abstract description 39
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- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims abstract description 45
- ZQKXQUJXLSSJCH-UHFFFAOYSA-N melamine cyanurate Chemical compound NC1=NC(N)=NC(N)=N1.O=C1NC(=O)NC(=O)N1 ZQKXQUJXLSSJCH-UHFFFAOYSA-N 0.000 claims abstract description 37
- XZMCDFZZKTWFGF-UHFFFAOYSA-N Cyanamide Chemical compound NC#N XZMCDFZZKTWFGF-UHFFFAOYSA-N 0.000 claims abstract description 34
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- 239000000047 product Substances 0.000 claims description 22
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- 239000000706 filtrate Substances 0.000 claims description 20
- 239000007788 liquid Substances 0.000 claims description 18
- MYFXBBAEXORJNB-UHFFFAOYSA-N calcium cyanamide Chemical compound [Ca+2].[N-]=C=[N-] MYFXBBAEXORJNB-UHFFFAOYSA-N 0.000 claims description 16
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- 238000003828 vacuum filtration Methods 0.000 claims description 10
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- 239000000126 substance Substances 0.000 claims description 8
- MVXMNHYVCLMLDD-UHFFFAOYSA-N 4-methoxynaphthalene-1-carbaldehyde Chemical compound C1=CC=C2C(OC)=CC=C(C=O)C2=C1 MVXMNHYVCLMLDD-UHFFFAOYSA-N 0.000 claims description 7
- 239000004202 carbamide Substances 0.000 claims description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 6
- 230000002378 acidificating effect Effects 0.000 claims description 6
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- 238000010438 heat treatment Methods 0.000 claims description 4
- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 claims description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims 1
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- NDEMNVPZDAFUKN-UHFFFAOYSA-N guanidine;nitric acid Chemical compound NC(N)=N.O[N+]([O-])=O.O[N+]([O-])=O NDEMNVPZDAFUKN-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention discloses a method for preparing a flame retardant by using amine waste mother liquor, belonging to the technical field of melamine cyanurate flame retardants, and the preparation method comprises the following steps: generating cyanamide, melamine and a flame retardant; the method can realize the complete and effective recovery and utilization of products and materials in the waste mother liquor, reduces the discharge of waste water, has high yield of the recovered flame retardant melamine cyanurate, good quality, mild reaction conditions and easy operation of equipment, and the obtained product can be used for industrial application.
Description
Technical Field
The invention relates to the technical field of melamine cyanurate fire retardants, and in particular relates to a method for preparing a fire retardant by using amine waste mother liquor.
Background
Dicyandiamide, known as cyanoguanidine, also called dicyanodiamine, has the molecular formula C 2 H 4 N 4 . Dicyandiamide is a white crystal, has a melting point of 207-209 ℃, is stable in a dry product, and is dissolved in water and ethanol when heated.
The main uses of dicyandiamide are:
(1) Can be used as flocculant for water treatment;
(2) The epoxy resin is used as a dye color fixing agent and a latent curing agent of an epoxy resin adhesive to prepare a single-component epoxy adhesive;
(3) The fertilizer can be used as a chemical fertilizer, the activity of nitrobacteria can be controlled, the conversion speed of the nitrogen fertilizer in soil can be adjusted, the loss of nitrogen is reduced, and the use efficiency of the fertilizer is improved;
(4) As a fine chemical intermediate, the product can be used for preparing guanidine nitrate, sulfonamides and the like in medicine, and also can be used for preparing thiourea, cellulose nitrate stabilizers, rubber vulcanization accelerators, steel surface hardening agents, artificial leather fillers, adhesives and the like.
Melamine Cyanurate (MCA) is a typical halogen-free environment-friendly nitrogen-based flame retardant, and is white uniform particles or white flowable powder with a greasy feeling. Is hardly soluble in water, but is soluble in organic solvents such as ethanol and formaldehyde. MCA was initially used as a solid lubricant and was later gradually applied to rubber, polyamide, epoxy, polyamide, etc. materials as a flame retardant ingredient. The flame retardant has the advantages of high nitrogen content, good flame retardant effect, environmental friendliness, low price and the like, so the flame retardant is commonly used for flame retardant polyamide 6 (PA 6) and polyamide 66 (PA 66). The structural formula of MCA and the hydrogen-bonded crosslinked network are shown below:
at present, the traditional process for preparing dicyandiamide is a batch operation mode, the starting material is lime nitrogen (active ingredient calcium cyanamide), and the process can be divided into a three-step method and a four-step method according to operation steps. The three-step method comprises three stages of hydrolysis decalcification, polymerization and crystallization which are carried out in sequence; the four-step method comprises four stages of hydrolysis, decalcification, polymerization and crystallization, namely the four-step method separately carries out the two processes of hydrolysis and decalcification.
However, in any method, all steps related to product production all adopt water as a solvent, a large amount of mother liquor is generated in a cooling crystallization separation stage, and the mother liquor contains a large amount of impurities after being reused for many times, wherein the impurities comprise 5.5-8.5% (w/w) of urea, 0.5-1.0% (w/w) of melamine, 0.6-1.2% (w/w) of cyanamide, and 4.5-5.0% (w/w) of dicyanamide and other small amount of impurities. The impurity content in the mother liquor is high, so that the impurities are separated out along with the dicyandiamide in the crystallization process, the overproof of various impurities in the dicyandiamide is caused, and the quality index of the dicyandiamide is seriously influenced.
If the waste mother liquor is directly used for sewage treatment, resources are wasted, the sewage treatment cost of enterprises is increased, and the environmental pollution load is increased. With the development of the dicyandiamide industry and the expansion of the production scale, the yield of the waste mother liquor is gradually increased. How to effectively and properly treat the dicyandiamide waste mother liquor is a great difficulty for the sustainable development of the health of enterprises.
Therefore, there is a need to provide a new treatment method for amine wastewater mother liquor, which can overcome the disadvantages caused by sending the amine wastewater mother liquor to a sewage treatment plant for treatment, comprehensively recover and convert impurities in the amine wastewater mother liquor into other useful substances, create certain economic benefits, reduce the cost for sewage treatment, reduce the influence on the environment, and thus achieve the beneficial effects of improving the product quality and the product competitiveness.
Through retrieval, no public technology is available for recycling waste mother liquor generated in the amine production process.
The prior art describes the preparation of melamine cyanurate as follows:
chinese patent CN109438379A discloses a preparation method of melamine cyanurate, which comprises the following steps: (a) Adding melamine and cyanuric acid into a container, and stirring and grinding uniformly; (b) adding a chain extender into the container, and uniformly stirring; (c) Adding deionized water into the container, and adjusting the pH value to be neutral; (d) Stirring evenly, sealing and standing for 3-10 days at room temperature; (e) After the reaction is finished, the melamine cyanurate finished product is obtained through drying and grinding.
Chinese patent CN106749061A discloses a method for synthesizing melamine cyanurate fire retardant by a solid-phase synthesis method, i.e. under the condition of no water, melamine and cyanuric acid are synthesized into melamine cyanurate by using a specific mechanical device.
In the above-disclosed techniques, although melamine cyanurate can be obtained, the above-described techniques have problems of long reaction time (3 to 10 days), high equipment acquisition cost, low equipment utilization rate, high energy consumption, etc. due to the use of a chain extender, and are not suitable for industrial production.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for preparing a flame retardant by using an amine waste mother liquor, which can realize the complete and effective recovery and utilization of products and materials in the waste mother liquor, reduce the discharge of waste water, has the advantages of high yield, good quality, mild reaction conditions and easy operation of equipment of the recovered flame retardant melamine cyanurate, and the obtained product can be used for industrial application.
In order to solve the technical problem, the invention adopts the following technical scheme:
a method for preparing a flame retardant by using amine waste mother liquor comprises the following steps: to generate cyanamide, melamine and flame retardant.
Adding an acidic substance into the waste mother liquor to adjust the pH value to 7.0-8.0, stirring for 10min, carrying out vacuum filtration to obtain a filtrate, carrying out low-temperature negative pressure distillation on the filtrate, controlling the temperature in the low-temperature negative pressure distillation to be 40-45 ℃, controlling the negative pressure to be-0.085-0.10 MPa, and finishing the low-temperature negative pressure distillation to obtain a concentrated solution A; adding lime nitrogen into drinking water, keeping the temperature at 30-40 ℃, stirring for 30-60 min, introducing carbon dioxide at the speed of 5mL/min to adjust the pH value to be 7.0-8.0, and performing vacuum filtration to obtain filtrate B;
in the generated cyanamide, the waste mother liquor comprises the following components in percentage by mass: 1.2% of cyanamide, 4.6% of dicyandiamide, 0.8% of melamine, 7.1% of urea and 0.1% of other impurities;
in the generated cyanamide, the content of calcium cyanamide in the lime nitrogen is 61%;
in the generated cyanamide, the content of the cyanamide in the filtrate B is 3.1-3.4%;
in the generated cyanamide, the acidic substance is one of carbon dioxide or sulfuric acid, and when the acidic substance is carbon dioxide, the introduction speed of the carbon dioxide is 5mL/min;
in the generated cyanamide, the weight ratio of the waste mother liquor to the concentrated solution A is 600;
in the generated cyanamide, the weight ratio of drinking water to lime nitrogen is 200.
Sequentially putting the concentrated solution A and the filtrate B into a high-pressure container, adding drinking water and a catalyst for high-pressure polymerization, controlling the temperature of the high-pressure polymerization to be 125-135 ℃, the pressure to be 0.25-0.36 Mpa and the time to be 2-3 h, and obtaining feed liquid of melamine after the high-pressure polymerization is finished;
in the generated melamine, the content of the melamine in the feed liquid of the melamine is 6.4-6.6%;
the weight ratio of the concentrated solution A in the generated melamine to the lime nitrogen in the generated cyanamide is 300;
in the generated melamine, the mass-volume ratio of the concentrated solution A to the drinking water to the catalyst is 300g to 200mL;
in the melamine generation, the catalyst is one of aluminum oxide or aluminum silicate.
The flame retardant is generated, the material liquid of the melamine is continuously heated to 160-170 ℃ in a high-pressure container, the pressure in the high-pressure container is controlled to be 0.60-0.71 Mpa, the heat is preserved for 2.5-3.5 h to obtain the material liquid converted into the melamine cyanurate, then the temperature is reduced to 10-20 ℃, the heat is preserved for 0.5-1.5 h at 10-20 ℃, and then the melamine cyanurate product is obtained by suction filtration, hot water washing and drying;
in the generated flame retardant, the content of the melamine cyanurate in the melamine cyanurate product is 99.0-99.5%.
A method for preparing a flame retardant by using amine waste mother liquor comprises the following reaction route:
hydrolyzing calcium cyanamide to decalcify to generate cyanamide:
2CaCN 2 + 2H 2 O = Ca(HCN 2 ) 2 + Ca(OH) 2
Ca(HCN 2 ) 2 + CO 2 + H 2 O = H 2 CN 2 + CaCO 3 ↓
polymerizing cyanamide and dicyandiamide to generate melamine:
urea is pyrolyzed to generate cyanuric acid, and cyanuric acid and melamine hydrogen bond are subjected to composite reaction to generate melamine cyanurate:
compared with the prior art, the invention has the following beneficial effects:
(1) According to the method for preparing the flame retardant by using the amine waste mother liquor, a proper amount of lime nitrogen is added for directional reaction, and the distilled water and the final filtrate obtained in the treatment process are used for recycling the dicyandiamide product, so that the products and materials in the waste mother liquor are completely and effectively recycled, and the waste water discharge is reduced;
(2) According to the method for preparing the flame retardant by using the amine waste mother liquor, the melamine is finally subjected to hydrogen bond complex reaction to generate the melamine cyanurate product, the content of the melamine cyanurate in the obtained melamine cyanurate product can reach 99.0-99.5%, and the melamine cyanurate product can be continuously used for industrialization;
(3) The method for preparing the flame retardant by using the amine waste mother liquor has the advantage that the finally obtained melamine cyanurate flame retardant has high yield which can reach 81.1-85.0%.
Detailed Description
Example 1
A method for preparing a flame retardant by using amine waste mother liquor specifically comprises the following steps:
1. formation of cyanamide
Adding 600g of waste mother liquor into a dry three-necked bottle, introducing carbon dioxide at the speed of 5mL/min to adjust the pH to be 7.0, stirring for 10min, carrying out vacuum filtration, and carrying out low-temperature negative pressure distillation on the filtrate at the temperature of 40 ℃ and under the negative pressure of-0.085 to-0.090 MPa to obtain 300g of concentrated solution A;
the waste mother liquor comprises the following components in percentage by mass: 1.2% of cyanamide, 4.6% of dicyandiamide, 0.8% of melamine, 7.1% of urea and 0.1% of other impurities (mainly amine compounds);
adding 20g of lime nitrogen into 200g of drinking water, keeping the temperature at 30 ℃, stirring for 30min, introducing carbon dioxide at the speed of 5mL/min to adjust the pH to be 7.0, and performing vacuum filtration to obtain a filtrate B with the cyanamide content of 3.2%;
the content of calcium cyanamide in the lime nitrogen is 61%.
2. Formation of melamine
And (2) sequentially putting the concentrated solution A and the filtrate B obtained in the step (1) into an autoclave, adding 200ml of drinking water and 0.1g of aluminum oxide catalyst, and then carrying out high-pressure polymerization at 125 ℃ under 0.25Mpa for 2 hours to obtain a melamine feed liquid with the content of 6.5 percent.
3. Formation of flame retardant
And (2) continuously heating the melamine feed liquid in the step (2) in an autoclave to 160 ℃, controlling the pressure in the autoclave to be 0.60Mpa, preserving the heat for 2.5h to obtain the feed liquid converted into melamine cyanurate, cooling to 10 ℃, preserving the heat for 0.5h at 10 ℃, then carrying out suction filtration, hot water washing and drying to obtain 68.7g of melamine cyanurate product, wherein the yield is 82.1% (calculated by dicyandiamide), and the content of the melamine cyanurate in the melamine cyanurate product is 99.2% according to the detection of HG/T5341-2018.
Example 2
A method for preparing a flame retardant by using amine waste mother liquor specifically comprises the following steps:
1. formation of cyanamide
Adding 600g of waste mother liquor into a dry three-mouth bottle, introducing carbon dioxide at the speed of 5mL/min to adjust the pH value to be 7.5, stirring for 10min, carrying out vacuum filtration, and carrying out low-temperature negative pressure distillation on the filtrate at the temperature of 42 ℃ and under the negative pressure of-0.090-0.095 MPa to obtain 300g of concentrated solution A;
the waste mother liquor comprises the following components in percentage by mass: 1.2% of cyanamide, 4.6% of dicyandiamide, 0.8% of melamine, 7.1% of urea and 0.1% of other impurities (mainly amine compounds);
adding 20g of lime nitrogen into 200g of drinking water, keeping the temperature at 35 ℃, stirring for 45min, introducing carbon dioxide at the speed of 5mL/min to adjust the pH value to be =7.5, and performing vacuum filtration to obtain a filtrate B with the cyanamide content of 3.1%;
the content of calcium cyanamide in the lime nitrogen is 61%.
2. Formation of melamine
And (2) sequentially putting the concentrated solution A and the filtrate B obtained in the step (1) into a high-pressure kettle, adding 200ml of drinking water and 0.2g of aluminum oxide catalyst, and then carrying out high-pressure polymerization at the temperature of 130 ℃ under the pressure of 0.31MPa for 2.5h to obtain a melamine feed liquid with the content of 6.6% after the high-pressure polymerization is finished.
3. Formation of flame retardant
And (2) continuously heating the melamine feed liquid in the step 2 in an autoclave to 165 ℃, controlling the pressure in the autoclave to be 0.66Mpa, preserving the heat for 3.0h to obtain the feed liquid converted into melamine cyanurate, cooling to 15 ℃, preserving the heat for 1h at 15 ℃, carrying out suction filtration, hot water washing and drying to obtain 71.1g of melamine cyanurate product with the yield of 85.0 percent (calculated by dicyandiamide), and detecting according to HG/T5341-2018 that the content of the melamine cyanurate in the melamine cyanurate product is 99.5 percent.
Example 3
A method for preparing a flame retardant by using amine waste mother liquor specifically comprises the following steps:
1. formation of cyanamide
Adding 600g of waste mother liquor into a dry three-necked bottle, adjusting the pH value to be =8.0 by using sulfuric acid, stirring for 10min, performing vacuum filtration, and performing low-temperature negative pressure distillation on filtrate at the temperature of 45 ℃ and under the negative pressure of-0.095 to-0.10 MPa to obtain concentrated solution A with the weight of 300 g;
the waste mother liquor comprises the following components in percentage by mass: 1.2% of cyanamide, 4.6% of dicyandiamide, 0.8% of melamine, 7.1% of urea and 0.1% of other impurities (mainly amine compounds);
adding 20g of lime nitrogen into 200g of drinking water, keeping the temperature at 40 ℃, stirring for 60min, introducing carbon dioxide at the speed of 5mL/min to adjust the pH to be =8.0, and performing vacuum filtration to obtain a filtrate B with the cyanamide content of 3.4%;
the content of calcium cyanamide in the lime nitrogen is 61 percent.
2. Formation of melamine
And (2) sequentially putting the concentrated solution A and the filtrate B obtained in the step (1) into an autoclave, adding 200ml of drinking water and 0.2g of aluminum silicate catalyst, and then carrying out high-pressure polymerization at the temperature of 135 ℃, under the pressure of 0.36Mpa for 3 hours to obtain a melamine feed liquid with the content of 6.4 percent after the high-pressure polymerization is finished.
3. Formation of flame retardant
And (2) continuously heating the melamine feed liquid obtained in the step (2) in an autoclave to 170 ℃, controlling the pressure in the autoclave to be 0.71Mpa, preserving the heat for 3.5 hours to obtain the feed liquid converted into melamine cyanurate, cooling to 20 ℃, preserving the heat for 1.5 hours at 20 ℃, then carrying out suction filtration, hot water washing and drying to obtain 67.9g of melamine cyanurate product, wherein the yield is 81.1% (calculated by dicyandiamide), and the content of the melamine cyanurate in the melamine cyanurate product is 99.0% according to the detection of HG/T5341-2018.
From the results of the examples, it can be seen that the temperature of the autoclave is increased to 130 ℃ in the step 2 of melamine formation in example 2, and to 125 ℃ in the step 2 of melamine formation in example 1, and that the overall yield of example 2 is significantly higher than that of example 1, indicating that the preferred temperature in the step 2 of melamine formation is 130 ℃.
The temperature of the melamine feed liquid in the flame retardant forming step 3 in the example 3 is further increased to 170 ℃ in the autoclave, the temperature of the melamine feed liquid in the flame retardant forming step 3 in the example 1 is further increased to 160 ℃ in the autoclave, and the total yield of the example 1 is obviously higher than that of the example 3, which indicates that the preferable temperature in the flame retardant forming step 3 is 170 ℃.
Claims (10)
1. A method for preparing a flame retardant by using amine waste mother liquor is characterized by comprising the following steps: to generate cyanamide, melamine and flame retardant.
2. The method for preparing the flame retardant by using the amine waste mother liquor as claimed in claim 1, wherein the cyanamide is generated, the acidic substance is added into the waste mother liquor to adjust the pH value to 7.0-8.0, then the mixture is stirred for 10min, vacuum filtration is carried out to obtain filtrate, the filtrate is subjected to low-temperature negative pressure distillation, the temperature in the low-temperature negative pressure distillation is controlled to be 40-45 ℃, the negative pressure is controlled to be-0.085-0.10 MPa, and the low-temperature negative pressure distillation is finished to obtain concentrated solution A; adding lime nitrogen into drinking water, keeping the temperature and stirring, introducing carbon dioxide to regulate the pH to be 7.0-8.0, and performing vacuum filtration to obtain filtrate B.
3. The method for preparing flame retardant by using amine waste mother liquor according to claim 1, wherein the melamine is generated, the concentrated solution A and the filtrate B are sequentially put into a high-pressure vessel, drinking water and a catalyst are added for high-pressure polymerization, the temperature of the high-pressure polymerization is controlled to be 125-135 ℃, the pressure is controlled to be 0.25-0.36 MPa, the time is 2-3 hours, and the melamine feed liquid is obtained after the high-pressure polymerization is finished.
4. The method for preparing flame retardant by using amine waste mother liquor according to claim 1, wherein the step of generating the flame retardant comprises the steps of heating the melamine feed liquid in a high-pressure vessel to 160-170 ℃, controlling the pressure in the high-pressure vessel to 0.60-0.71 Mpa, keeping the temperature for 2.5-3.5 hours to obtain the melamine cyanurate-converted feed liquid, cooling to 10-20 ℃, keeping the temperature for 0.5-1.5 hours at 10-20 ℃, carrying out suction filtration, hot water washing and drying to obtain the melamine cyanurate product.
5. The method for preparing flame retardant by using amine waste mother liquor as claimed in claim 2, wherein the components and mass fractions of the waste mother liquor in the generation of the cyanamide are as follows: 1.2% of cyanamide, 4.6% of dicyandiamide, 0.8% of melamine, 7.1% of urea and 0.1% of other impurities;
in the generated cyanamide, the content of calcium cyanamide in the lime nitrogen is 61%;
in the generated cyanamide, the content of the cyanamide in the filtrate B is 3.1-3.4%.
6. The method for preparing flame retardant by using amine waste mother liquor according to claim 2, wherein in the generation of the cyanamide, the acidic substance is one of carbon dioxide or sulfuric acid, and when the acidic substance is carbon dioxide, the introduction rate of the carbon dioxide is 5mL/min.
7. The method for preparing flame retardant by using amine waste mother liquor according to claim 2, wherein in the generation of the cyanamide, the weight ratio of the waste mother liquor to the concentrated solution A is 600;
in the generated cyanamide, the weight ratio of drinking water to lime nitrogen is 200.
8. The method for preparing flame retardant by using amine waste mother liquor as claimed in claim 3, wherein the content of melamine in the melamine solution in the melamine production is 6.4-6.6%.
9. The method for preparing flame retardant by using amine waste mother liquor according to claim 3, wherein the weight ratio of concentrated solution A to lime nitrogen in the generated cyanamide is 300;
in the generated melamine, the mass-volume ratio of the concentrated solution A, the drinking water and the catalyst is 300g.
10. The method for preparing flame retardant by using amine waste mother liquor as claimed in claim 3, wherein in the formation of melamine, the catalyst is one of alumina or aluminum silicate.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102936211A (en) * | 2012-11-13 | 2013-02-20 | 宁夏宝马化工集团有限公司 | Method for continuously producing dicyandiamide |
| CN114751869A (en) * | 2022-04-21 | 2022-07-15 | 山东泰星新材料股份有限公司 | Preparation method of high-dispersion melamine cyanurate flame retardant |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102936211A (en) * | 2012-11-13 | 2013-02-20 | 宁夏宝马化工集团有限公司 | Method for continuously producing dicyandiamide |
| CN114751869A (en) * | 2022-04-21 | 2022-07-15 | 山东泰星新材料股份有限公司 | Preparation method of high-dispersion melamine cyanurate flame retardant |
Non-Patent Citations (1)
| Title |
|---|
| BARBARA JU¨RGENS等: "Melem (2, 5, 8-Triamino-tri-s-triazine), an Important Intermediate during Condensation of Melamine Rings to Graphitic Carbon Nitride: Synthesis, Structure Determination by X-ray Powder Diffractometry, Solid-State NMR, and Theoretical Studies", 《J. AM. CHEM. SOC.》, vol. 125, no. 34, pages 10288 - 10300, XP002438613, DOI: 10.1021/ja0357689 * |
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