CN116081616A - Low-sulfur high-expansion-temperature expandable graphite and preparation method and application thereof - Google Patents
Low-sulfur high-expansion-temperature expandable graphite and preparation method and application thereof Download PDFInfo
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 90
- 239000010439 graphite Substances 0.000 title claims abstract description 79
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 79
- 229910052717 sulfur Inorganic materials 0.000 title claims abstract description 47
- 239000011593 sulfur Substances 0.000 title claims abstract description 47
- 238000002360 preparation method Methods 0.000 title claims abstract description 9
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 30
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 23
- 239000013067 intermediate product Substances 0.000 claims abstract description 22
- 238000003756 stirring Methods 0.000 claims abstract description 22
- 239000012065 filter cake Substances 0.000 claims abstract description 21
- 238000001914 filtration Methods 0.000 claims abstract description 21
- 238000005406 washing Methods 0.000 claims abstract description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 21
- 238000001035 drying Methods 0.000 claims abstract description 12
- 238000000034 method Methods 0.000 claims abstract description 12
- 238000002156 mixing Methods 0.000 claims abstract description 12
- 238000009830 intercalation Methods 0.000 claims abstract description 10
- 230000002687 intercalation Effects 0.000 claims abstract description 10
- 239000000654 additive Substances 0.000 claims abstract description 9
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 9
- 238000002791 soaking Methods 0.000 claims abstract description 9
- 239000007800 oxidant agent Substances 0.000 claims abstract description 8
- 230000001590 oxidative effect Effects 0.000 claims abstract description 6
- 238000004519 manufacturing process Methods 0.000 claims abstract description 5
- 229910052799 carbon Inorganic materials 0.000 claims description 11
- 239000008367 deionised water Substances 0.000 claims description 10
- 229910021641 deionized water Inorganic materials 0.000 claims description 10
- 238000007865 diluting Methods 0.000 claims description 10
- 239000012286 potassium permanganate Substances 0.000 claims description 9
- BAERPNBPLZWCES-UHFFFAOYSA-N (2-hydroxy-1-phosphonoethyl)phosphonic acid Chemical group OCC(P(O)(O)=O)P(O)(O)=O BAERPNBPLZWCES-UHFFFAOYSA-N 0.000 claims description 6
- NTYJJOPFIAHURM-UHFFFAOYSA-N Histamine Chemical compound NCCC1=CN=CN1 NTYJJOPFIAHURM-UHFFFAOYSA-N 0.000 claims description 6
- 230000000996 additive effect Effects 0.000 claims description 5
- DBVJJBKOTRCVKF-UHFFFAOYSA-N Etidronic acid Chemical compound OP(=O)(O)C(O)(C)P(O)(O)=O DBVJJBKOTRCVKF-UHFFFAOYSA-N 0.000 claims description 4
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 4
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 4
- 229910019142 PO4 Inorganic materials 0.000 claims description 3
- 229960001340 histamine Drugs 0.000 claims description 3
- 239000010452 phosphate Substances 0.000 claims description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 3
- 229920006351 engineering plastic Polymers 0.000 claims description 2
- 239000000138 intercalating agent Substances 0.000 claims description 2
- 239000002245 particle Substances 0.000 claims 1
- 230000000979 retarding effect Effects 0.000 claims 1
- 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 description 8
- 238000006243 chemical reaction Methods 0.000 description 8
- 239000003063 flame retardant Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000000047 product Substances 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000012467 final product Substances 0.000 description 2
- 239000011229 interlayer Substances 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000012805 post-processing Methods 0.000 description 2
- ABLZXFCXXLZCGV-UHFFFAOYSA-N Phosphorous acid Chemical compound OP(O)=O ABLZXFCXXLZCGV-UHFFFAOYSA-N 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 150000001868 cobalt Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 150000005837 radical ions Chemical class 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K7/00—Use of ingredients characterised by shape
- C08K7/22—Expanded, porous or hollow particles
- C08K7/24—Expanded, porous or hollow particles inorganic
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/21—After-treatment
- C01B32/22—Intercalation
- C01B32/225—Expansion; Exfoliation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The invention provides expandable graphite with low sulfur and high expansion temperature, a preparation method and application thereof, wherein the method comprises the following steps: (1) Mixing concentrated sulfuric acid, natural crystalline flake graphite and auxiliary intercalation agent at 5-40 ℃, stirring for 30-100 minutes, adding oxidant at 20-50 ℃ and continuously stirring for 60-300 minutes, and standing for 2-6 hours to obtain an intermediate product; (2) Mixing the intermediate product of the step (1), water and additives, soaking for 30-100 minutes, filtering, repeatedly washing a filter cake, and drying at 50-80 ℃ to obtain the low-sulfur high-expansion-temperature expandable graphite; the expansion ratio and initial expansion temperature of the low-sulfur high-expansion-temperature expandable graphite prepared by the production process are extremely high, the sulfur content of the low-sulfur high-expansion-temperature expandable graphite is extremely low, the sulfur content of the low-sulfur high-expansion-temperature expandable graphite is less than or equal to 300ppm, the expansion ratio is 270-310m L/g, and the initial expansion temperature is 280-320 ℃.
Description
Technical Field
The invention relates to the technical field of expandable graphite, in particular to low-sulfur high-expansion-temperature expandable graphite, and a preparation method and application thereof.
Background
The expandable graphite is a typical physical expansion type flame retardant, has the advantages of no drop, strong instant expansion force, capability of extinguishing flame in a short time, and the like, is mature in modern innovative scientific research, and has quite wide application field. The flame-retardant mechanism of expandable graphite belongs to a solidification phase flame-retardant mechanism, and achieves the aim of flame retardance by delaying or interrupting the generation of combustible substances from solid substances. The expandable graphite begins to expand after being heated to a certain degree, and the state of the expanded graphite is changed from the original scaly shape to a worm shape with low density, so that a good heat insulation layer is formed; moreover, the expanded graphite flake becomes a carbon source in an expansion system, and can effectively insulate heat, delay and terminate the decomposition of the polymer; in addition, a large amount of heat absorption can be generated in the expansion process of the expandable graphite, the system temperature can be reduced, and acid radical ions in the interlayer can be released in the expansion process of the expandable graphite, so that dehydration and carbonization are promoted.
However, the expandable graphite prepared by the single sulfuric acid intercalation agent has low expansion volume, and the mechanical strength of a carbon layer formed during combustion expansion is obviously low, so that the flame retardant effect is affected. Therefore, although the product has excellent flame retardant property, the flame retardant property is still obviously insufficient when the product is used alone, the generation of molten drops and smoke cannot be effectively inhibited, and the sulfur content of the expandable graphite prepared by the sulfuric acid intercalation agent is high, so that the application of the expandable graphite product in the high-end field is limited. Therefore, it is very important to develop a process for preparing expandable graphite having a low sulfur and a high expansion temperature.
Disclosure of Invention
In order to solve the problems of low expansion rate, high sulfur content and low initial expansion of the expandable graphite in the prior art, the invention provides the expandable graphite with low sulfur content and high expansion temperature, and the preparation method and the application thereof, wherein the sulfur content of the expandable graphite with low sulfur content and high expansion temperature is less than or equal to 300ppm, the expansion rate is 270-310mL/g, and the initial expansion temperature is 280-320 ℃.
The invention aims at realizing the following technical scheme:
a method of preparing low sulfur, high expansion temperature expandable graphite, the method comprising the steps of:
(1) Mixing concentrated sulfuric acid, natural crystalline flake graphite and auxiliary intercalation agent at 5-40 ℃, stirring for 30-100 minutes, adding oxidant at 20-50 ℃ and continuously stirring for 60-300 minutes, and standing for 2-6 hours to obtain an intermediate product;
(2) Mixing the intermediate product of the step (1), water and additives, soaking for 30-100 minutes, filtering, repeatedly washing a filter cake, and drying at 50-80 ℃ to obtain the low-sulfur high-expansion-temperature expandable graphite;
in step (2), the additive is selected from hydroxyethylidene diphosphonic acid (C) 2 H 8 O 7 P 2 ) (1-hydroxyethylidene) bisphosphonic acid, histamine (C) phosphate 5 H 15 N 3 O 8 P 2 ) At least one of them.
According to the embodiment of the invention, in the step (1), the carbon content of the natural crystalline flake graphite is more than or equal to 80%, and the granularity of the natural crystalline flake graphite is 30-100 meshes.
According to an embodiment of the present invention, in the step (1), the concentration of the concentrated sulfuric acid is 60% to 85%.
According to an embodiment of the present invention, in step (1), the auxiliary intercalator is selected from CuSO 4 And CoSO 4 At least one of them.
According to an embodiment of the present invention, in the step (1), the oxidizing agent is one or more selected from potassium permanganate, hydrogen peroxide and potassium dichromate.
According to an embodiment of the invention, in the step (1), the mass ratio of the natural crystalline flake graphite to the concentrated sulfuric acid is 1 (3-15), for example, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14 or 1:15.
According to an embodiment of the invention, in step (1), the mass ratio of the oxidizing agent to the natural crystalline flake graphite is 1 (0.8-1.2), for example 1:0.8, 1:0.9, 1:1, 1:1.1 or 1:1.2.
According to an embodiment of the invention, in step (1), the mass ratio of the auxiliary intercalation agent to the natural crystalline flake graphite is (0.01-0.1): 1, for example 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1 or 0.1:1.
According to an embodiment of the present invention, in step (1), a post-treatment step is further included, the post-treatment step including: diluting with deionized water, filtering, and repeatedly washing the filter cake until the pH=6+ -0.5.
According to an embodiment of the invention, in step (2), the mass ratio of the intermediate product and the additive of step (1) is 1 (0.1-0.5), for example 1:0.1, 1:0.2, 1:0.3, 1:0.4 or 1:0.5.
According to an embodiment of the invention, in step (2), the mass ratio of the intermediate product of step (1) to water is 1 (0.8-1.2), for example 1:0.8, 1:0.9, 1:1, 1:1.1 or 1:1.2.
According to an embodiment of the present invention, in step (2), a post-processing step is further included, the post-processing step including: filtering, repeatedly washing the filter cake, and drying at 50-80deg.C.
According to an embodiment of the invention, the method comprises the steps of:
(1) Adding concentrated sulfuric acid, natural crystalline flake graphite and an auxiliary intercalation agent into a reaction kettle in proportion at the temperature of 5-40 ℃, stirring for 30-100 minutes, adding an oxidant at the temperature of 20-50 ℃ for continuously stirring for 60-300 minutes, standing for 2-6 hours, finally diluting with deionized water, filtering, and repeatedly washing a filter cake until the pH value is=6+/-0.5 to obtain an intermediate product;
(2) Mixing the intermediate product of the step (1), water and additives in proportion, soaking for 30-100 minutes, filtering, repeatedly washing a filter cake, and drying at 50-80 ℃ to obtain the low-sulfur high-expansion-temperature expandable graphite;
in step (2), the additive is selected from hydroxyethylidene diphosphonic acid (C) 2 H 8 O 7 P 2 ) (1-hydroxyethylidene) bisphosphonic acid, histamine (C) phosphate 5 H 15 N 3 O 8 P 2 ) At least one of them.
The invention also provides the expandable graphite with low sulfur and high expansion temperature prepared by the method.
According to the embodiment of the invention, the sulfur content of the expandable graphite with low sulfur and high expansion temperature is less than or equal to 300ppm, the expansion ratio is 270-310m L/g, and the initial expansion temperature is 280-320 ℃.
The invention also provides application of the low-sulfur high-expansion-temperature expandable graphite in engineering plastics, rubber flame retardance and the like.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) Solves the problems of low expansion performance, poor initial expansion temperature controllability, substrate corrosion and SO release in the combustion process of the expandable graphite prepared by single sulfuric acid intercalation 2 Harmful gas, etc. The copper salt and/or cobalt salt is used as auxiliary intercalation agent, so that the sulfur content can be reduced by replacing part of sulfuric acid, and simultaneously, the expansion performance of the final product can be improved, and the initial expansion temperature of the final product can be improved, thereby obtaining more excellent flame retardant effect.
(2) The invention uses the strong adsorptivity of the surface and interlayer active points of the expandable graphite, can firmly adsorb the organic phosphonic acid, exchanges substances with sulfide on the surface of the expandable graphite through concentration difference, diffuses the substances between more graphite sheets, greatly reduces the sulfur content of the expandable graphite, and can further improve the expansion rate and flame retardant property of the expandable graphite.
(3) The expansion ratio and initial expansion temperature of the low-sulfur high-expansion-temperature expandable graphite prepared by the production process are extremely high, the sulfur content of the low-sulfur high-expansion-temperature expandable graphite is extremely low, the sulfur content of the low-sulfur high-expansion-temperature expandable graphite is less than or equal to 300ppm, the expansion ratio is 270-310m L/g, and the initial expansion temperature is 280-320 ℃.
Detailed Description
The preparation method of the present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are illustrative only and are not to be construed as limiting the scope of the invention. All techniques implemented based on the above description of the invention are intended to be included within the scope of the invention.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; the reagents, materials, etc. used in the examples described below are commercially available unless otherwise specified.
Example 1
(1) 50g of 65% concentrated sulfuric acid and 0.3g of CuSO are added at 10 DEG C 4 Sequentially adding 10g of natural crystalline flake graphite (carbon content: 94%,50 mesh) into a reaction kettle, stirring for 40 min, adding 10g of potassium permanganate at 30 ℃ for continuous stirring for 100 min, standing for 3 h, finally diluting with deionized water, filtering, and repeatedly washing a filter cake until the pH value is=6.5 to obtain an intermediate product;
(2) Mixing 1g of the intermediate product in the step (1), 1g of water and 0.1g of hydroxyethylidene diphosphonic acid, soaking for 40 minutes, filtering, repeatedly washing a filter cake, and drying at 50 ℃ to obtain low-sulfur high-expansion-temperature expandable graphite; the expansion ratio of the expandable graphite was 276m L/g, the sulfur content was 200ppm, and the initial expansion temperature was 287 ℃.
Example 2
(1) 70g of 70% concentrated sulfuric acid and 0.5g of CuSO at 20 DEG C 4 Sequentially adding 10g of natural crystalline flake graphite (carbon content: 90%,80 mesh) into a reaction kettle, stirring for 60 minutes, then adding 10g of potassium permanganate at 30 ℃ for continuously stirring for 160 minutes, standing for 4 hours, finally diluting with deionized water, filtering, and repeatedly washing a filter cake until the pH value is=6.0 to obtain an intermediate product;
(2) Mixing 1g of the intermediate product in the step (1), 1g of water and 0.3g of hydroxyethylidene diphosphonic acid, soaking for 70 minutes, filtering, repeatedly washing a filter cake, and drying at 60 ℃ to obtain low-sulfur high-expansion-temperature expandable graphite; the expansion ratio of the expandable graphite was 285m L/g, the sulfur content was 240ppm and the initial expansion temperature was 292 ℃.
Example 3
(1) 100g of 85% concentrated sulfuric acid and 1g of CuSO are added at 40 DEG C 4 Sequentially adding 10g of natural crystalline flake graphite (carbon content: 86%,30 meshes) into a reaction kettle, stirring for 80 minutes, then adding 10g of potassium permanganate at 50 ℃ for continuously stirring for 280 minutes, standing for 6 hours, finally diluting with deionized water, filtering, and repeatedly washing a filter cake until the pH value is=5.5 to obtain an intermediate product;
(2) Mixing 1g of the intermediate product obtained in the step (1), 1g of water and 0.5g of (1-hydroxyethylidene) diphosphonic acid, soaking for 100 minutes, filtering, repeatedly washing a filter cake, and drying at 80 ℃ to obtain low-sulfur high-expansion-temperature expandable graphite; the expansion ratio of the expandable graphite was 306m L/g, the sulfur content was 300ppm, and the initial expansion temperature was 310 ℃.
Comparative example 1
(1) Sequentially adding 50g of 65% concentrated sulfuric acid and 10g of natural crystalline flake graphite (carbon content: 94%,50 meshes) into a reaction kettle at 10 ℃, stirring for 40 minutes, then adding 10g of potassium permanganate at 30 ℃ for continuously stirring for 100 minutes, standing for 3 hours, finally diluting with deionized water, filtering, and repeatedly washing a filter cake until the pH=6.5 to obtain expandable graphite;
the expansion ratio of the expandable graphite was 220m L/g, the sulfur content was 1000ppm and the initial expansion temperature was 130 ℃.
Comparative example 2
(1) Sequentially adding 50g of 65% concentrated sulfuric acid and 10g of natural crystalline flake graphite (carbon content: 94%,50 meshes) into a reaction kettle at 10 ℃, stirring for 40 minutes, then adding 10g of potassium permanganate at 30 ℃ for continuous stirring for 100 minutes, standing for 3 hours, finally diluting with deionized water, filtering, and repeatedly washing a filter cake to pH=6.5 to obtain an intermediate product;
(2) Mixing 1g of the intermediate product in the step (1), 1g of water and 0.1g of hydroxyethylidene diphosphonic acid, soaking for 40 minutes, filtering, repeatedly washing a filter cake, and drying at 50 ℃ to obtain expandable graphite; the expansion ratio of the expandable graphite was 266m L/g, the sulfur content was 420ppm, and the initial expansion temperature was 270 ℃.
Comparative example 3
(1) 50g of 65% concentrated sulfuric acid and 0.3g of CuSO are added at 10 DEG C 4 Sequentially adding 10g of natural crystalline flake graphite (carbon content: 94%,50 mesh) into a reaction kettle, stirring for 40 minutes, then adding 10g of potassium permanganate at 30 ℃ for continuously stirring for 100 minutes, standing for 3 hours, finally diluting with deionized water, filtering, repeatedly washing a filter cake to pH=6.5, and then drying at 50 ℃ to obtain expandable graphite;
the expansion ratio of the expandable graphite was 230m L/g, the sulfur content was 910ppm, and the initial expansion temperature was 140 ℃.
Comparative example 4
(1) 50g of 65% concentrated sulfuric acid and 0.3g of CuSO are added at 10 DEG C 4 Sequentially adding 10g of natural crystalline flake graphite (carbon content: 94%,50 mesh) into a reaction kettle, stirring for 40 min, adding 10g of potassium permanganate at 30 ℃ for continuous stirring for 100 min, standing for 3 h, finally diluting with deionized water, filtering, and repeatedly washing a filter cake until the pH value is=6.5 to obtain an intermediate product;
(2) Mixing 1g of the intermediate product in the step (1), 1g of water and 0.1g of phosphoric acid, soaking for 40 minutes, filtering, repeatedly washing a filter cake, and drying at 50 ℃ to obtain expandable graphite; the expansion ratio of the expandable graphite was 240m L/g, the sulfur content was 800ppm, and the initial expansion temperature was 160 ℃.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method of preparing low sulfur, high expansion temperature expandable graphite, the method comprising the steps of:
(1) Mixing concentrated sulfuric acid, natural crystalline flake graphite and auxiliary intercalation agent at 5-40 ℃, stirring for 30-100 minutes, adding oxidant at 20-50 ℃ and continuously stirring for 60-300 minutes, and standing for 2-6 hours to obtain an intermediate product;
(2) Mixing the intermediate product of the step (1), water and additives, soaking for 30-100 minutes, filtering, repeatedly washing a filter cake, and drying at 50-80 ℃ to obtain the low-sulfur high-expansion-temperature expandable graphite;
in step (2), the additive is selected from hydroxyethylidene diphosphonic acid (C) 2 H 8 O 7 P 2 ) (1-hydroxyethylidene) bisphosphonic acid, histamine (C) phosphate 5 H 15 N 3 O 8 P 2 ) At least one of them.
2. The preparation method according to claim 1, wherein in the step (1), the carbon content of the natural crystalline flake graphite is not less than 80%, and the particle size of the natural crystalline flake graphite is 30-100 mesh;
and/or, in the step (1), the concentration of the concentrated sulfuric acid is 60% -85%;
and/or in the step (1), the oxidant is selected from one or more than two of potassium permanganate, hydrogen peroxide and potassium dichromate.
3. The process according to claim 1, wherein in step (1), the auxiliary intercalating agent is selected from CuSO 4 And CoSO 4 At least one of them.
4. The preparation method according to claim 1, wherein in the step (1), the mass ratio of the natural crystalline flake graphite to the concentrated sulfuric acid is 1 (3-15);
and/or, in the step (1), the mass ratio of the oxidant to the natural crystalline flake graphite is 1 (0.8-1.2);
and/or, in the step (1), the mass ratio of the auxiliary intercalation agent to the natural crystalline flake graphite is (0.01-0.1): 1.
5. The production method according to claim 1, wherein in step (1), a post-treatment step is further included, the post-treatment step comprising: diluting with deionized water, filtering, and repeatedly washing the filter cake until the pH=6+ -0.5.
6. The preparation method according to claim 1, wherein in the step (2), the mass ratio of the intermediate product and the additive in the step (1) is 1 (0.1-0.5);
and/or in the step (2), the mass ratio of the intermediate product of the step (1) to water is 1 (0.8-1.2).
7. The production method according to claim 1, wherein in step (2), a post-treatment step is further included, the post-treatment step comprising: filtering, repeatedly washing the filter cake, and drying at 50-80deg.C.
8. The low sulfur, high expansion temperature expandable graphite produced by the process of any one of claims 1-7.
9. The low sulfur, high expansion temperature expandable graphite of claim 8, wherein said low sulfur, high expansion temperature expandable graphite has a sulfur content of 300ppm or less, an expansion ratio of 270-310m L/g, and an initial expansion temperature of 280-320 ℃.
10. Use of the expandable graphite with low sulfur and high expansion temperature as claimed in claim 8 or 9 in flame retarding engineering plastics and rubber.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211735660.5A CN116081616B (en) | 2022-12-30 | 2022-12-30 | Low-sulfur high-expansion-temperature expandable graphite and preparation method and application thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211735660.5A CN116081616B (en) | 2022-12-30 | 2022-12-30 | Low-sulfur high-expansion-temperature expandable graphite and preparation method and application thereof |
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| Publication Number | Publication Date |
|---|---|
| CN116081616A true CN116081616A (en) | 2023-05-09 |
| CN116081616B CN116081616B (en) | 2024-06-11 |
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