CN111748249A

CN111748249A - Silicon-phosphorus synergistic coal flame-retardant dust suppressant and preparation method thereof

Info

Publication number: CN111748249A
Application number: CN202010745724.4A
Authority: CN
Inventors: 来水利; 陈功; 杨欣; 李晨辉
Original assignee: Shaanxi University of Science and Technology
Current assignee: Shaanxi University of Science and Technology
Priority date: 2020-07-29
Filing date: 2020-07-29
Publication date: 2020-10-09
Anticipated expiration: 2040-07-29
Also published as: CN111748249B

Abstract

The invention belongs to the field of coal flame-retardant dust suppressant, and particularly discloses a silicon-phosphorus synergistic coal flame-retardant dust suppressant and a preparation method thereof, wherein the silicon-phosphorus synergistic coal flame-retardant dust suppressant comprises the following raw materials in parts by mass: 0.10-0.30 part of phosphorus flame retardant, 0.15-0.30 part of silane coupling agent, 0.008-0.018 part of catalyst, 80.0-160.0 parts of solvent, 0.10-0.40 part of silicon flame retardant, 0.1-0.4 part of pH regulator, 83.0-125.0 parts of deionized water, 57.0-95.0 parts of alcohol compound, 1.0-2.0 parts of natural polymer, 10.0-20.0 parts of monomer, 4.0-8.0 parts of pH buffer, 0.1-0.4 part of initiator, 0.02-0.08 part of cross-linking agent, 0.2-0.4 part of surfactant and 0.2-1.0 part of plasticizer. The flame-retardant dust suppressant introduces silicon and phosphorus elements, is an efficient silicon-phosphorus synergistic flame-retardant system, can overcome the defects of low flame-retardant level and small limiting oxygen index of a single flame retardant, and has excellent flame-retardant performance. The polymer film formed after spraying can not only prevent the coal dust from blowing away, reduce the coal dust pollution; but also has the effect of isolating oxygen, thereby preventing the spontaneous combustion of coal.

Description

Silicon-phosphorus synergistic coal flame-retardant dust suppressant and preparation method thereof

Technical Field

The invention belongs to the technical field of coal flame-retardant dust suppressant, and particularly relates to a silicon-phosphorus synergistic coal flame-retardant dust suppressant and a preparation method thereof.

Background

Along with the rapid development of economy in China, the energy demand is larger and larger, and the mining, transportation and storage capacity of coal serving as a main energy source is increased year by year. At present, coal in China is mainly transported by railways, dust is easily generated due to airflow disturbance in the transportation process, not only can coal resources be seriously wasted, but also the surrounding air can be greatly polluted, and the health of people is seriously harmed. Meanwhile, the spontaneous combustion of coal also threatens the life of operators and the safety of mining equipment in the mining and storage of coal, and causes a great deal of economic loss and resource waste.

The traditional dust suppression methods comprise a sprinkling wetting method, a tarpaulin covering method, a wind-shield wall isolating method and the like, and have the problems of large water consumption, complex operation, low dust suppression efficiency and the like. With the emergence of chemical dust depressors, the chemical dust suppression method has received extensive attention and research due to its good dust suppression effect. The traditional dust suppressant mainly comprises wetting type, bonding type, condensation type and composite type. In recent years, chemical dust depressors gradually develop towards environmental protection, low price, high efficiency, wide application, multifunction and the like.

The flame retardant may be classified into a halogen-containing flame retardant, a phosphorus-containing flame retardant, a nitrogen-containing flame retardant, a silicon-containing flame retardant, an aluminum-magnesium-containing flame retardant, a nitrogen-phosphorus-containing flame retardant, and the like, depending on the kind of the element added. However, the smoke toxicity and environmental problems caused by halogen flame retardants are prominent, and the halogen-free or low-halogen flame retardant products are limited by the use of multiple industries, and are becoming the development trend of the industries. The single flame retardant has the defects of low flame retardant grade, small limiting oxygen index and large addition amount.

At present, most of China uses a dust suppressant and a flame retardant in a compounding way, and most of the flame retardants rely on imports and are high in cost. In addition, the hard shell type dust suppressant in the market is applied more and has poor pressure resistance, a cured layer of the product after being sprayed is brittle and is easy to crack after being vibrated and wind power in transportation, so that the dust suppression effect is lost, and the cost is high due to the fact that a large amount of dust suppressant needs to be sprayed repeatedly.

Disclosure of Invention

The invention aims to provide a silicon-phosphorus synergistic coal flame-retardant dust suppressant and a preparation method thereof, and the flame-retardant dust suppressant has the characteristics of flame retardance and dust suppression, strong flame-retardant dust suppression capability, flexible film forming, low cost, greenness and environmental friendliness.

The invention is realized by the following technical scheme:

the silicon-phosphorus synergistic coal flame-retardant dust suppressant comprises the following raw materials in parts by mass:

0.10-0.30 part of phosphorus flame retardant, 0.15-0.30 part of silane coupling agent, 0.008-0.018 part of catalyst, 80.0-160.0 parts of solvent, 0.10-0.40 part of silicon flame retardant, 0.1-0.4 part of pH regulator, 83.0-125.0 parts of deionized water, 57.0-95.0 parts of alcohol compound, 1.0-2.0 parts of natural polymer, 10.0-20.0 parts of monomer, 4.0-8.0 parts of pH buffer, 0.1-0.4 part of initiator, 0.02-0.08 part of cross-linking agent, 0.2-0.4 part of surfactant and 0.2-1.0 part of plasticizer.

Further, the phosphorus flame retardant is DOPO.

Further, the silane coupling agent is at least one of gamma-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane.

Further, the catalyst is at least one of azobisisobutyronitrile, azobisisoheptonitrile and dimethyl azobisisobutyrate.

Further, the silicon flame retardant is nano SiO₂At least one of kaolin, diatomaceous earth, montmorillonite and attapulgite.

Further, the natural polymer is at least one of sodium alginate, starch and derivatives thereof, cellulose and derivatives thereof, and chitosan.

Further, the solvent is at least one of absolute ethyl alcohol, benzene, toluene, chloroform, acetone, cyclohexane and tetrahydrofuran;

the pH regulator is at least one of acetic acid and hydrochloric acid;

the pH buffering agent is sodium hydroxide;

the alcohol compound is at least one of methanol and ethanol; the monomer is at least one of acrylic acid, acrylamide and 2-acrylamide-2-methylpropanesulfonic acid;

the initiator is potassium persulfate and sodium bisulfite, or ammonium persulfate and sodium bisulfite;

the cross-linking agent is at least one of N, N' -methylene-bisacrylamide and dimethyldiallylammonium chloride;

the surfactant is at least one of sodium dodecyl benzene sulfonate and sodium dodecyl sulfate;

the plasticizer is glycerol.

The invention also discloses a preparation method of the silicon-phosphorus synergistic coal flame-retardant dust suppressant, which comprises the following steps:

(1) mixing 0.10-0.30 part of phosphorus flame retardant, 0.15-0.30 part of silane coupling agent and 20.0-50.0 parts of solvent to obtain solution A;

dissolving 0.008-0.018 parts of catalyst by 10.0 parts of solvent to obtain solution B;

dropwise adding the solution B into the solution A, reacting at 60-120 ℃ for 5-12h to obtain a crude product, removing the solvent by rotary evaporation, and drying for 8-24h to obtain a flame-retardant intermediate;

(2) adding 57.0-95.0 parts of alcohol compound and 3.0-5.0 parts of deionized water into the flame-retardant intermediate, then adding a pH regulator to adjust the pH to 3.0-4.0, and performing ultrasonic hydrolysis for 1-2 hours to obtain a solution C;

adding 50.0-100.0 parts of solvent and 0.10-0.40 part of silicon flame retardant into the solution C, reacting at 70-120 ℃ for 8-24h, washing, performing suction filtration, and drying at 60-80 ℃ for 8-12h to obtain the flame retardant;

(3) mixing 1-2 parts of natural polymer, 0.2-0.8 part of flame retardant and 40-80 parts of deionized water to obtain a solution D;

mixing 10.0-20.0 parts of monomer, 4.0-8.0 parts of pH buffer, 20.0-40.0 parts of deionized water and 0.02-0.08 part of cross-linking agent to obtain solution E;

mixing 0.1-0.4 part of initiator and 10.0-20.0 parts of deionized water to obtain a solution F;

introducing inert gas into the solution D, simultaneously dropwise adding the solution E and the solution F into the solution D, and preserving heat for 4-6h at the temperature of 50-60 ℃ to obtain a solution G;

(4) and then adding 0.2-0.4 part of surfactant and 0.2-1.0 part of plasticizer into the solution G, and uniformly stirring to obtain light yellow transparent viscous liquid, namely the silicon-phosphorus synergistic coal flame-retardant dust suppressant.

Further, in the step (1), preparing a solution A under the protection of inert gas;

in the step (3), the preparation of the solution E is carried out under the ice-water bath condition.

Further, in the step (2), the mass ratio of the alcohol compound to the deionized water is 19: 1.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention discloses a silicon-phosphorus synergistic coal flame-retardant dust suppressant, which comprises a phosphorus flame retardant, a silane coupling agent, a catalyst, a solvent, a silicon flame retardant, a pH regulator, deionized water, an alcohol compound, a natural polymer, a monomer, a pH buffering agent, an initiator, a cross-linking agent, a surfactant and a plasticizer. The phosphorus flame retardant and the silane coupling agent are combined through free radical addition reaction to obtain a flame retardant intermediate, then the flame retardant intermediate is hydrolyzed to obtain a silanol group, the silanol group is dehydrated and combined with hydroxyl on the silicon flame retardant to obtain a silicon-phosphorus synergistic flame retardant, and finally the silicon-phosphorus synergistic coal flame retardant dust suppressant is combined with natural polymers, monomers, surfactants, plasticizers and other dust suppression components through free radical polymerization reaction to obtain the silicon-phosphorus synergistic coal flame retardant dust suppressant with both flame retardant and dust suppression performances. The flame-retardant dust suppressant has the functions of wetting, bonding, condensing, retaining water and the like, can condense and bond coal dust particles quickly after being sprayed, enhances the capture capacity of water to the coal dust due to good wettability, and achieves the effect of quickly reducing dust. After spraying, a layer of soft and compact polymer film is formed on the surface of the pulverized coal, and the pulverized coal has excellent mechanical property, flexibility, anti-vibration property and anti-wind erosion property, and is not easy to break due to wind erosion and vibration. Not only can play the effect of preventing coal dust from floating, but also can effectively slow down the evaporation of water to achieve the purpose of locking water, thereby greatly prolonging the dust suppression period. The flame-retardant dust suppressant introduces silicon and phosphorus elements, is an efficient silicon-phosphorus synergistic flame-retardant system, can overcome the defects of low flame-retardant level and small limiting oxygen index of a single flame retardant, can fully exert respective performances by synergistic use of multiple flame retardants, reduces the cost, and simultaneously improves the flame-retardant performance of the material. And the macromolecular film formed after spraying can play the effect of isolating oxygen, thereby preventing the spontaneous combustion of coal. The flame-retardant dust suppressant is made of an environment-friendly degradable material, and does not generate toxic and harmful gases when coal is combusted. The coal dust can be effectively slowed down and the coal can be prevented from spontaneous combustion in the processes of coal mining, storage, transportation and combustion, so that the air pollution and the waste of coal resources are reduced, and the method has great practical significance and application prospect.

Furthermore, the materials adopted by the natural polymer and the silicon flame retardant are from nature, have rich resources, low price, no pollution to the environment and good biocompatibility.

The invention also discloses a preparation method of the silicon-phosphorus synergistic coal flame-retardant dust suppressant, active hydrogen on the phosphorus flame retardant can generate free radical addition reaction with double bonds on the silane coupling agent, a catalyst is added to accelerate the reaction, and a flame-retardant intermediate is obtained through the reaction; then hydrolyzing the flame-retardant intermediate to obtain a silanol group, and dehydrating and combining the silanol group with hydroxyl on the silicon flame retardant to obtain the silicon-phosphorus synergistic flame retardant; and finally, combining the flame retardant with natural high molecules, monomers, a surfactant, a plasticizer and other dust suppression components through free radical polymerization to obtain the silicon-phosphorus synergistic coal flame-retardant dust suppressant with flame retardance and dust suppression simultaneously. The flame retardant is prepared by reacting several flame retardant components to obtain a flame retardant intermediate and finally preparing the flame retardant, and has better compatibility with materials.

Further, when the solution A is prepared, the inert gas is introduced to exhaust air, so that the condition that the subsequent reaction is influenced by the oxidation of free radicals generated in the reaction process of double bonds on the silane coupling agent and the phosphorus flame retardant by oxygen is prevented;

the monomer is easy to volatilize due to a large amount of heat generated during neutralization, so that the monomer can be prevented from volatilizing during neutralization in an ice-water bath.

Further, when the solution C is prepared, the mass ratio of the alcohol compound to the deionized water is 19:1, and the hydrolysis reaction is faster at the ratio, so that the hydrolysis is facilitated.

Drawings

FIG. 1 is a reaction scheme of the flame retardant dust suppressant of the present invention;

FIG. 2 is an infrared spectrum of KH570-DOPO and DOPO as flame retardant intermediates;

FIG. 3 is an XRD pattern of the flame retardant intermediates KH570-DOPO and DOPO;

FIG. 4 is an infrared spectrum of the flame retardant dust suppressant;

FIG. 5 is an XRD pattern of the flame retardant dust suppressant;

FIG. 6 shows the surface morphology of the pulverized coal after spraying water (a) and the flame retardant and dust suppressant (b), respectively;

FIG. 7 shows the results of the flame retardant performance test of the flame retardant dust suppressant.

Detailed Description

The invention discloses a silicon-phosphorus synergistic coal flame-retardant dust suppressant, which comprises the following raw materials in parts by mass:

Specifically, the phosphorus flame retardant is 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO).

Specifically, the silane coupling agent is at least one of gamma-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane.

Specifically, the catalyst is at least one of Azobisisobutyronitrile (AIBN), azobisisoheptonitrile, and dimethyl azobisisobutyrate.

Specifically, the silicon-based flame retardant is nano SiO₂At least one of kaolin, diatomaceous earth, montmorillonite and attapulgite.

Specifically, the solvent is at least one of absolute ethyl alcohol, benzene, toluene, chloroform, acetone, cyclohexane and tetrahydrofuran.

Specifically, the pH regulator is at least one of acetic acid and hydrochloric acid.

Specifically, the pH buffer is sodium hydroxide.

Specifically, the alcohol compound is at least one of methanol and ethanol.

Specifically, the natural polymer is at least one of sodium alginate, starch and derivatives thereof, cellulose and derivatives thereof, and chitosan.

Specifically, the monomer is at least one of acrylic acid, acrylamide and 2-acrylamide-2-methylpropanesulfonic acid.

Specifically, the initiator is potassium persulfate and sodium bisulfite, or ammonium persulfate and sodium bisulfite.

Specifically, the crosslinking agent is at least one of N, N' -methylene bisacrylamide and dimethyldiallylammonium chloride.

Specifically, the surfactant is at least one of sodium dodecyl benzene sulfonate and sodium dodecyl sulfate.

Specifically, the plasticizer is glycerol.

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

Example 1

A preparation method of a silicon-phosphorus synergistic coal flame-retardant dust suppressant comprises the following steps:

(1) adding 0.20g of DOPO, 0.25g of KH570 and 30.0g of absolute ethanol into a three-neck flask filled with inert gas to obtain a solution A;

dissolving 0.014g of azobisisobutyronitrile in 10.0g of absolute ethyl alcohol to obtain a solution B;

and dropwise adding the solution B into the solution A for 30min, reacting in an oil bath at 75 ℃ for 12h to obtain a crude product, removing the solvent by rotary evaporation, and drying for 24h to obtain the flame-retardant intermediate.

The reaction scheme is shown in figure 1, active hydrogen on DOPO can generate free radical addition reaction with double bonds on KH570, a catalyst of azobisisobutyronitrile is added to accelerate the reaction, and the flame-retardant intermediate is obtained through the reaction. The catalyst cannot be added too quickly or slag is easily blown up.

(2) Adding a flame-retardant intermediate into a beaker, adding 57.0g of ethanol and 3.0g of deionized water into the flame-retardant intermediate, adding 0.12g of acetic acid to adjust the pH value to 4.0, and performing ultrasonic hydrolysis for 2 hours to obtain a solution C;

then transferred into a three-neck flask filled with inert gas, and added with 50.0g of absolute ethyl alcohol and 0.20g of nano SiO₂And carrying out reflux reaction at 78 ℃ for 8h, washing with ethanol for three times to remove unreacted substances, carrying out suction filtration, and drying at 60 ℃ for 12h to obtain the flame retardant.

And (3) carrying out ultrasonic hydrolysis on the flame-retardant intermediate to obtain a silanol group, so that the silanol group is conveniently dehydrated and combined with hydroxyl on the silicon flame retardant to obtain the silicon-phosphorus flame retardant.

(3) Adding 2g of sodium alginate, 0.2g of flame retardant and 60g of deionized water into a three-neck flask, and stirring at room temperature to fully dissolve to obtain a solution D for later use;

stirring and dissolving 20.0g of acrylic acid, 6.66g of sodium hydroxide, 30.0g of deionized water and 0.04g N, N' -methylenebisacrylamide in an ice-water bath to obtain a solution E;

dissolving 0.2g of potassium persulfate, 0.074g of sodium bisulfite and 10.0g of deionized water to obtain a solution F;

and introducing inert gas into the three-neck flask, putting the three-neck flask into a water bath at 60 ℃, slowly dropwise adding the solution E and the solution F into the solution D for 40min, and preserving the temperature for 5h to obtain a solution G.

Flame retardant, natural polymer, monomer and the like are reacted and combined with flame retardant and dust suppression components by a free radical polymerization method to obtain the flame retardant dust suppression agent.

(4) And then adding 0.2G of sodium dodecyl benzene sulfonate and 0.5G of glycerol into the solution G, and uniformly stirring to obtain a light yellow transparent viscous liquid, namely the silicon-phosphorus synergistic coal flame-retardant dust suppressant.

Example 2

(1) adding 0.20g of DOPO, 0.30g of KH570 and 50.0g of toluene into a three-neck flask filled with inert gas to obtain a solution A;

0.015g of azobisisobutyronitrile was dissolved in 10.0g of toluene to obtain a solution B;

dropwise adding the solution B into the solution A for 40min, then reacting in an oil bath at 120 ℃ for 12h to obtain a crude product, removing the solvent by rotary evaporation, and then drying for 24h to obtain a flame-retardant intermediate;

then transferred into a three-neck flask filled with inert gas, and added with 50.0g of absolute ethyl alcohol and 0.20g of nano SiO₂Carrying out reflux reaction at 78 ℃ for 8h, washing with ethanol for three times to remove unreacted substances, carrying out suction filtration, and drying at 60 ℃ for 12h to obtain the flame retardant;

(3) adding 1g of sodium alginate, 0.2g of flame retardant and 60g of deionized water into a three-neck flask, and stirring at room temperature to fully dissolve to obtain a solution D for later use;

stirring and dissolving 10.0g of acrylic acid, 3.33g of sodium hydroxide, 30.0g of deionized water and 0.02g N, N' -methylene bisacrylamide in an ice-water bath to obtain a solution E;

dissolving 0.1g of potassium persulfate, 0.037g of sodium bisulfite and 10.0g of deionized water to obtain a solution F;

introducing inert gas into a three-neck flask, putting the three-neck flask into a water bath at 60 ℃, slowly dropwise adding the solution E and the solution F for 30min into the solution D, and preserving heat for 5h to obtain a solution G;

Example 3

(1) adding 0.15g of DOPO, 0.20g of KH570 and 50.0g of toluene into a three-neck flask filled with inert gas to obtain a solution A;

dissolving 0.011g of azobisisobutyronitrile in 10.0g of toluene to obtain a solution B;

then transferring the mixture into a three-neck flask filled with inert gas, adding 50.0g of absolute ethyl alcohol and 0.20g of kaolin, carrying out reflux reaction at 78 ℃ for 8 hours, washing the mixture with ethyl alcohol for three times to remove unreacted substances, carrying out suction filtration, and drying at 60 ℃ for 12 hours to obtain the flame retardant;

(3) adding 2g of sodium alginate, 0.4g of flame retardant and 60g of deionized water into a three-neck flask, and stirring at room temperature to fully dissolve to obtain a solution D for later use;

stirring and dissolving 20.0g of acrylic acid, 6.66g of sodium hydroxide, 30.0g of deionized water and 0.04g N, N' -methylene bisacrylamide in an ice-water bath to obtain a solution E; ,

introducing inert gas into a three-neck flask, putting the three-neck flask into a water bath at 60 ℃, slowly dropwise adding the solution E and the solution F for 40min into the solution D, and preserving heat for 5h to obtain a solution G;

Example 4

(1) adding 0.20g of DOPO, 0.25g of 0.25g A171 and 30.0g of absolute ethanol into a three-necked flask filled with inert gas to obtain a solution A;

dropwise adding the solution B into the solution A for 30min, reacting in an oil bath at 75 ℃ for 12h to obtain a crude product, removing the solvent by rotary evaporation, and drying for 24h to obtain a flame-retardant intermediate;

(2) adding a flame-retardant intermediate into a beaker, adding 76.0g of ethanol and 4.0g of deionized water into the flame-retardant intermediate, adding 0.16g of acetic acid to adjust the pH value to 4.0, and performing ultrasonic hydrolysis for 2 hours to obtain a solution C;

then transferring the mixture into a three-neck flask filled with inert gas, adding 50.0g of absolute ethyl alcohol and 0.20g of diatomite, carrying out reflux reaction at 78 ℃ for 8 hours, washing the mixture with ethyl alcohol for three times to remove unreacted substances, carrying out suction filtration, and drying at 60 ℃ for 12 hours to obtain the flame retardant;

(3) adding 2g of sodium alginate, 0.8g of flame retardant and 60g of deionized water into a three-neck flask, and stirring at room temperature to fully dissolve to obtain a solution D for later use;

mixing 20.0g of acrylic acid, 6.66g of sodium hydroxide, 30.0g of deionized water and 0.04g N, N' -methylenebisacrylamide in an ice-water bath, and stirring to dissolve to obtain a solution E;

mixing 0.2g of ammonium persulfate, 0.074g of sodium bisulfite and 10.0g of deionized water, and dissolving to obtain a solution F;

introducing inert gas into the three-neck flask, putting the three-neck flask into a water bath at 60 ℃, slowly dropwise adding the solution E and the solution F into the solution D for 40min, and preserving heat for 5h to obtain a solution G;

Example 5

(1) adding 0.25g of DOPO, 0.30g A151 and 50.0g of absolute ethanol into a three-neck flask filled with inert gas to obtain a solution A;

dissolving 0.017g of azobisisobutyronitrile in 10.0g of absolute ethyl alcohol to obtain a solution B;

dropwise adding the solution B into the solution A, dropwise adding for 40min, reacting in an oil bath at 75 ℃ for 12h to obtain a crude product, removing the solvent by rotary evaporation, and drying for 24h to obtain a flame-retardant intermediate;

(3) adding 1g of carboxymethyl cellulose, 0.6g of flame retardant and 60g of deionized water into a three-neck flask, and stirring at room temperature to fully dissolve to obtain a solution D for later use;

mixing 10.0g of acrylic acid, 3.33g of sodium hydroxide, 30.0g of deionized water, 1g of acrylamide and 0.03g of N, N' -methylene-bisacrylamide in an ice-water bath, and stirring to dissolve to obtain a solution E;

mixing 0.1g of potassium persulfate, 0.037g of sodium bisulfite and 10.0g of deionized water, and stirring to dissolve to obtain a solution F;

introducing inert gas into the three-neck flask, putting the three-neck flask into a water bath at 60 ℃, slowly dropwise adding the solution E and the solution F into the solution D for 30min, and preserving heat for 5h to obtain a solution G;

(4) and then adding 0.2G of sodium dodecyl benzene sulfonate and 1.0G of glycerol into the solution G, and uniformly stirring to obtain a light yellow transparent viscous liquid, namely the silicon-phosphorus synergistic coal flame-retardant dust suppressant.

The flame-retardant intermediate and the flame-retardant dust suppressant obtained in examples 1 to 5 were subjected to structural characterization and performance tests, and the results are shown in fig. 2 to 6.

FIG. 2 is a FT-IR curve of KH570-DOPO as the flame-retardant intermediate and DOPO as the starting material, and it can be seen from FIG. 2 that 3057cm after the reaction^-1The absorption peak of unsaturated carbon-hydrogen bond on benzene ring is obviously weakened, and is 2945cm^-1Saturated carbon-hydrogen bond absorption occursCollecting peaks; 2436cm^-1The absorption peak of P-H bond disappears; 1726cm^-1The absorption peak of C ═ O bond appears; 1048cm^-1A clear Si-O bond absorption peak appears. FIG. 3 is XRD curves of KH570-DOPO as the flame-retardant intermediate and DOPO as the raw material, and it can be seen from FIG. 3 that DOPO has many sharp crystalline peaks before reaction, while KH570-DOPO has only a broad steamed bun-like dispersion peak and is changed into an amorphous structure. Therefore, the flame-retardant intermediate KH570-DOPO can be successfully synthesized by the DOPO reaction.

Fig. 4 and 5 are respectively an FT-IR curve and an XRD curve of the flame-retardant dust suppressant. The non-flame retardant dust suppressant in FIG. 4 (b) represents the product obtained by reacting several dust suppressing components, i.e., natural polymer, monomer, pH buffer, initiator, crosslinking agent, surfactant and plasticizer, without adding a flame retardant. It can be seen from FIG. 4 that 3616cm after the reaction^-1The absorption peak of sodium alginate-OH is obviously disappeared by 1605cm^-1-COO in sodium alginate^-The absorption peak shifts to 1553cm^-1At least one of (1) and (b); at 1218cm^-1Shows an absorption peak of the P ═ O bond, 1045cm^-1An Si-O bond absorption peak appears. As can be seen from fig. 5, the diffraction peak at 2 θ ═ 14.3 ° after the reaction disappeared, and a broad amorphous dispersion peak appeared at around 30 °; a diffraction peak of DOPO group appears at 12.8 °, and a diffraction peak of nano-silica appears at 21.2 °. From the results, the sodium alginate, the acrylic acid and the flame retardant are successfully reacted to obtain the flame-retardant dust suppressant.

Fig. 6(a) and (b) are the surface appearances of the pulverized coal after being sprayed with water and dried with 5% of the flame retardant dust suppressant, respectively. As can be seen from fig. 6(a), the coal powder has uneven surface and loose arrangement after being sprayed with water, almost no adhesion between the coal powders, and is easy to fly due to wind erosion and vibration; and after the flame-retardant dust suppressant is sprayed in the figure 6(b), a layer of compact film is formed on the surface of the coal powder to cover the surface of the coal powder, and the coal powder is tightly bonded together, so that the coal powder can be effectively prevented from floating around under the action of external force to cause air pollution and resource waste, and the film can also reduce the contact between the coal powder and oxygen and reduce the risk of spontaneous combustion of coal.

The invention also makes the following performance tests:

TB/T3210.1-2009 dust suppression technical conditions for railway coal transportation part 1: the dust suppressant specifies the product performance requirements of the dust suppressant for railway coal transportation, wherein the spraying amount is required to be not less than 1.5L/m²Time, wind erosion rate<1% and the cured layer thickness is not less than 10 mm. The weathering resistance and the cured layer thickness of the flame-retardant dust suppressant were tested according to the specified test methods.

1. Test of resistance to weathering

Selecting 10-30 mesh coal sample, oven drying at 50 deg.C for 300min, removing water, respectively placing appropriate amount of coal in 2 (300mm × 210mm × 30mm) enamel trays to make coal layer surface level with the trays, and weighing respectively, wherein the coal mass is M₁. Spraying 2% flame retardant dust suppressant (spraying amount is 1.5L/m) on the two trays respectively²) Drying in a drying oven at 50 deg.C for 120min, respectively blowing for 5min at the surface wind speed of 30M/s, weighing respectively, and weighing the rest coal₂. Then, the wind erosion rate of the sample is respectively calculated according to the following formula:

in the formula:

e-sample wind erosion rate,%;

M₁-mass of coal dust before erosion blowing, g;

M₂mass of coal fines after erosion, g.

The weathering rate of sample 1 was found to be E₁The weathering rate of sample 2 was E₂And taking the average value.

2. Thickness test of cured layer

The thickness of the cured layer at 4 points was measured with a scale, and the average value was taken.

After the flame-retardant dust suppressant with the mass fraction of 2% is sprayed and dried, the surface of the coal seam is blown and eroded for 5min at the wind speed of 30m/s, the wind erosion rate is only 0.61%, and the thickness of the cured layer is 1.35cm, so that the requirement of TB/T3210.1-2009 on dust suppression performance is met.

3. Test for flame retardancy

Taking 2 parts of 30g of coal powder, respectively treating the coal powder by using a flame-retardant dust suppressant solution with the mass fraction of 2% and water (both 30g), drying, putting the coal powder into 2 three-neck flasks, connecting the flasks with an air suction pump, putting the flasks into a thermometer, setting the gas flow rate at 250mL/min, putting the flasks into an 80 ℃ oil bath kettle, detecting the CO concentration by using a CO gas detector, continuously increasing the temperature to 150 ℃, and respectively recording the CO concentrations at different temperatures. And analyzing and comparing the concentration difference of CO in the flame-retardant treatment and the water treatment to determine the flame-retardant effect, wherein the smaller the concentration of CO is, the better the flame-retardant effect is. The formula for calculating the resistivity is as follows:

in the formula:

z-inhibition ratio,%;

S₁-the concentration of CO emitted from the water treated coal sample, g/L;

S₂and treating the coal sample by using the flame-retardant dust suppressant to obtain the concentration of CO discharged by the coal sample in g/L.

The test result is shown in fig. 7, and it can be seen from the figure that the inhibition rate of the coal sample treated by the flame-retardant dust suppressant with a mass fraction of 2% at 150 ℃ can reach 51.61%, which indicates that the flame-retardant dust suppressant can prevent spontaneous combustion of coal to a certain extent. The phosphorus flame retardant acts with oxygen to form a protective layer such as phosphoric acid and polyphosphoric acid, so that the phosphorus flame retardant has the effects of isolating oxygen and reducing the release of carbon monoxide, can release PO & free radicals to capture H & free radicals and HO & free radicals released during combustion, and achieves the flame retardant effect; the silicon flame retardant is mainly used for transferring the flame retardant to the surface of coal powder during combustion, and enriching the flame retardant on the surface, so that the effect of reducing the contact of oxygen and combustible gas is achieved, and the flame retardant effect is achieved.

Claims

1. The silicon-phosphorus synergistic coal flame-retardant dust suppressant is characterized by comprising the following raw materials in parts by mass:

2. The silicon-phosphorus synergistic coal flame-retardant dust suppressant according to claim 1, wherein the phosphorus flame retardant is DOPO.

3. The silicon-phosphorus synergistic coal flame retardant and dust suppression agent as claimed in claim 1, wherein the silane coupling agent is at least one of gamma-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane.

4. The silicon-phosphorus synergistic coal fire-retardant dust suppressant according to claim 1, wherein the catalyst is at least one of azobisisobutyronitrile, azobisisoheptonitrile and dimethyl azobisisobutyrate.

5. The silicon-phosphorus synergistic coal flame-retardant dust suppressant according to claim 1, wherein the silicon-based flame retardant is nano SiO₂At least one of kaolin, diatomaceous earth, montmorillonite and attapulgite.

6. The silicon-phosphorus synergistic coal flame-retardant dust suppressant according to claim 1, wherein the natural polymer is at least one of sodium alginate, starch and derivatives thereof, cellulose and derivatives thereof and chitosan.

7. The silicon-phosphorus synergistic coal flame-retardant dust suppressant according to claim 1, wherein the solvent is at least one of absolute ethyl alcohol, benzene, toluene, chloroform, acetone, cyclohexane and tetrahydrofuran;

the pH regulator is at least one of acetic acid and hydrochloric acid;

the pH buffering agent is sodium hydroxide;

the plasticizer is glycerol.

8. A preparation method of a silicon-phosphorus synergistic coal flame-retardant dust suppressant is characterized by comprising the following steps:

9. The preparation method of the silicon-phosphorus synergistic coal flame-retardant dust suppressant according to claim 8, wherein in the step (1), the solution A is prepared under the protection of inert gas;

10. The preparation method of the silicon-phosphorus synergistic coal flame-retardant dust suppressant according to claim 8, wherein in the step (2), the mass ratio of the alcohol compound to the deionized water is 19: 1.