An Expandable Phosphorus-Boron Composite Inhibitor and Its Application in Suppressing Aluminum Dust Explosion

Abstract

Preparation method of an expandable phosphorus-boron composite inhibitor and its application in suppressing aluminum dust explosion, belonging to the field of dust explosion safety protection. The dispersibility of ammonium polyphosphate is increased by 3-aminopropyltriethoxysilane, and expandable graphite is introduced to enhance the barrier performance against oxidants, obtaining 5KAPP expandable phosphorus-containing inhibitor. The neutralization reaction between boric acid and zinc oxide is regulated, and Al(OH)3 is introduced to improve the heat barrier capacity of the decomposition products of zinc borate, obtaining B1A1 boron-containing synergistic inhibitor. Then 5KAPP and B1A1 are mechanically compounded to finally prepare P1B2 expandable phosphorus-boron composite inhibitor, whose initial decomposition temperature is reduced to 75 °C, the heat absorption per unit increases to 698 J / g, and the physical coating layer covering the combustible medium can be expanded up to 520 times at most; the critical inhibition concentration for 30-μm aluminum dust explosion is reduced to 400 g / m³, and the efficient suppression of the explosion flame and overpressure of aluminum dust can be achieved.

Description

Technical Field

[0001] The present invention relates to a preparation method of a P1B2 expandable phosphorus-boron composite inhibitor and its application in suppressing aluminum dust explosion, belonging to the technical field of dust explosion safety protection. Background Art

[0002] Aluminum has a high energy density and excellent chemical reactivity, and is widely used in many important fields such as automobiles, aerospace, and fuels. However, during the surface treatment processes of aluminum products such as cutting, polishing, and grinding, a large amount of suspended aluminum dust will be generated. Once encountering an ignition source, serious aluminum dust explosion accidents will occur, resulting in incalculable accident consequences. Therefore, it is urgent to carry out research on aluminum dust explosion safety protection technology.

[0003] Explosion suppression technology can achieve efficient protection in the initial stage of explosion. Solid inhibitors are widely used due to their relatively excellent and stable performance, environmental protection and pollution-free, convenient use, and economic benefits. However, due to the complex process and high explosion intensity of aluminum dust explosion, the critical suppression concentration of existing solid inhibitors for aluminum dust explosion (the critical suppression concentration is the concentration of inhibitor required to completely suppress aluminum dust explosion) is relatively high, and the suppression efficiency is low. Although the critical suppression concentration of phosphorus-containing inhibitors in solid inhibitors is relatively low, there will be a phenomenon of increased explosion intensity when the concentration is low, resulting in more serious accident consequences. Therefore, developing an efficient solid inhibitor for aluminum dust explosion has become a key problem to be solved urgently, which is of great significance for preventing aluminum dust explosion accidents. Summary of the Invention

[0004] To solve the problems of high inhibition concentration and low efficiency of existing solid inhibitors for aluminum dust explosion, a preparation method of a P1B2 expandable phosphorus-boron composite inhibitor and its application in suppressing aluminum dust explosion are provided to achieve the purpose of efficiently suppressing aluminum dust explosion flame and overpressure.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A preparation method of an expandable phosphorus-boron composite inhibitor, the preparation method comprising the following steps:

[0007] Step S1: Add 3-aminopropyltriethoxysilane to deionized water for hydrolysis, adjust the pH value of the solution to 5 with hydrochloric acid to obtain a 3-aminopropyltriethoxysilane solution; add ammonium polyphosphate to absolute ethanol for hydrolysis to obtain an ammonium polyphosphate solution;

[0008] Add the ammonium polyphosphate solution to the 3-aminopropyltriethoxysilane solution for reaction, then add expandable graphite, and after the reaction is completed, wash and dry to obtain a 5EGAPP expandable phosphorus-containing inhibitor;

[0009] The mass ratio of the 3-aminopropyltriethoxysilane: ammonium polyphosphate: expandable graphite is 1: (30 - 50): (1 - 3);

[0010] Step S2: After reacting the boric acid solution and zinc oxide in a water bath, the product is washed and filtered by suction to obtain the NZB inhibitor, and Al(OH)3 is compounded in a ball mill, and then dried to obtain the boron-containing synergistic inhibitor B1A1;

[0011] The mass ratio of the boric acid to the zinc oxide is (3 - 5): 1, and the mass ratio of the NZB inhibitor to Al(OH)3 is 1:1;

[0012] Step S3: Compounding the 5EGAPP expandable phosphorus-containing inhibitor and the boron-containing synergistic inhibitor B1A1 in a ball mill, and then drying to obtain the P1B2 expandable phosphorus-boron composite inhibitor; the mass ratio of the 5EGAPP expandable phosphorus-containing inhibitor to the boron-containing synergistic inhibitor B1A1 is 1:2 - 2:1.

[0013] The concentration of the 3-aminopropyltriethoxysilane solution is 0.04 - 0.06 g / ml; the concentration of the ammonium polyphosphate solution is 0.4 - 0.6 g / ml; the concentration of the boric acid solution is 0.2 - 0.4 g / ml.

[0014] The preparation of the 3-aminopropyltriethoxysilane solution in Step S1: adding 3-aminopropyltriethoxysilane to deionized water for hydrolysis, adjusting the pH, stirring at room temperature for 20 - 40 min, and then heating to 70 - 90 °C for reaction for 1 - 2 h; the preparation of the ammonium polyphosphate solution: adding ammonium polyphosphate to absolute ethanol for hydrolysis, and stirring at room temperature for 20 - 40 min.

[0015] In Step S1, adding the ammonium polyphosphate solution to the 3-aminopropyltriethoxysilane solution for reaction, the reaction temperature is 50 - 70 °C, and the reaction time is 1 - 3 h.

[0016] In Step S1, after adding the expandable graphite, the reaction temperature is 50 - 70 °C, and the reaction time is 1 - 3 h.

[0017] In Step S2, after adding the boric acid solution to the zinc oxide, the reaction temperature is 90 - 100 °C, and the reaction time is 3 - 5 h.

[0018] An expandable phosphorus-boron composite inhibitor, which is prepared by the above preparation method.

[0019] Furthermore, a preparation method of a P1B2 expandable phosphorus-boron composite inhibitor, the preparation method comprising the following steps:

[0020] Step S1: Wash, filter by suction, and dry the product of the water bath reaction of APP (ammonium polyphosphate), KH550 (3-aminopropyltriethoxysilane), EG (expandable graphite), hydrochloric acid, deionized water, and absolute ethanol to obtain 5EGAPP expandable phosphorus-containing inhibitor;

[0021] Among them, the concentration of the KH550 solution is 2.5 g / 50 ml (deionized water), and the pH value of the solution is adjusted to about 5.0 with hydrochloric acid; the concentration of the APP solution is 100 g / 200 ml (absolute ethanol); 5 g of EG is added to the 5KAPP solution;

[0022] Step S2: Wash and filter by suction the product of the water bath reaction of boric acid and zinc oxide to obtain NZB, compound it with Al(OH)3 in a ball mill, and dry to obtain B1A1 boron-containing synergistic inhibitor;

[0023] Among them, the concentration of the boric acid solution is 15 g / 50 ml (deionized water), and the mass of zinc oxide is 4.86 g;

[0024] Step S3: Compound 5EGAPP expandable phosphorus-containing inhibitor and B1A1 boron-containing synergistic inhibitor in a ball mill and dry to obtain P1B2 expandable phosphorus-boron composite inhibitor;

[0025] In the step S1, the magnetic stirring time of the hydrolyzed KH550 solution is 30 min, and then the stirring speed is 300 rpm, the heating temperature is 80 °C, and the reaction time is 1 h;

[0026] In the step S1, the magnetic stirring time of the APP solution is 30 min, the reaction system temperature of the KH550 solution and the APP solution is 60 °C, and the reaction time is 2 h;

[0027] In the step S1, the reaction system temperature of adding EG to the 5KAPP solution is 60 °C, and the reaction time is 1 h; dry in an air atmosphere at 60 °C for 12 h;

[0028] In the step S2, the magnetic stirring time of the boric acid solution is 30 min, transfer it to an oil bath with a heating temperature of 95 °C, the stirring speed after adding zinc oxide is 150 rpm, the heating temperature is 95 °C, and the reaction time is 4 h; dry in an air atmosphere at 80 °C for 12 h;

[0029] In the step S2, the mass ratio of NZB to Al(OH)3 is 1:1, the rotation speed is 300 rpm, and the reaction time is 60 min; dry in an air atmosphere at 45 °C for 24 h;

[0030] In the step S3, the mass ratio of 5EGAPP to B1A1 is 1:2, the rotation speed is 300 rpm, and the reaction time is 60 min; dry in an air atmosphere at 45 °C for 24 h;

[0031] A P1B2 expandable phosphorus-boron composite inhibitor is prepared by the above preparation method.

[0032] An application of a P1B2 expandable phosphorus-boron composite inhibitor, wherein the inhibitor is applied to inhibit the explosion of aluminum dust.

[0033] Mix the above P1B2 expandable phosphorus-boron composite inhibitor with aluminum dust, and through the aluminum dust explosion inhibition experimental system and the aluminum dust explosion flame structure observation system, obtain the influence law of the inhibitor on the aluminum dust explosion flame and overpressure.

[0034] Preferably, in step S2, the set reaction temperature for the reaction of boric acid and zinc oxide solution is 95 °C, the reaction time is 4 h, n(boric acid) / n(zinc oxide) is 4:1, m(boric acid) / V(deionized water) is 7.5 g / 25 mL, and n(ZnO) is 0.04. The beneficial effects of the present invention are as follows:

[0035] The P1B2 phosphorus-boron composite inhibitor provided by the present invention is based on the surface modification mechanism of APP by silane coupling agent and the oxidant barrier characteristics of expandable inhibitors. KH550 and EG are introduced to improve the dispersion performance and oxidant barrier performance of APP. Further combined with the characteristics of low initial decomposition temperature and strong heat barrier performance of the B1A1 boron-containing synergistic inhibitor, a P1B2 expandable phosphorus-boron composite inhibitor is prepared by mechanochemical technology. The initial decomposition temperature of P1B2 is reduced to 75 °C, the unit heat absorption increases to 698 J / g, and the maximum expandability of the physical coating layer covering the combustible medium can reach 520 times. The inhibition effect of P1B2 on the explosion of aluminum dust includes physical inhibition and chemical inhibition. In terms of physical inhibition, first of all, the decomposition of P1B2 at a lower temperature is an endothermic reaction, and the evaporation of H2O, the expansion of EG, and the gasification of B2O3 to produce BO2 are also endothermic processes, all of which can effectively absorb the heat of the combustion reaction and reduce the combustion rate of aluminum particles. Then, the solid products generated by the decomposition of P1B2, including phosphoric acid, pyrophosphoric acid, P2O5, B2O3, Al2O3, and aluminum borate, etc., can coat the surface of aluminum particles to form a solid physical barrier layer, hindering the heat transfer between the burned aluminum particles and the unburned aluminum particles. At the same time, the expanded EG can fully limit the contact between aluminum particles and the oxidant, interrupting the mass transfer process. Finally, NH3 and water vapor in the decomposition products can dilute the concentration of oxygen and cause a change in the ambient atmosphere, thereby reducing the adiabatic flame temperature of aluminum particles. Since the combustion heat of NH3 is much lower than that of aluminum particles, the competitive effect of NH3 and aluminum particles on oxygen can reduce the heat release of the entire combustion system when the oxygen content is certain. In addition, gaseous ZnO and Zn(OH)2 can enter the gas-phase reaction and can also dilute the oxygen concentration and limit the propagation of the aluminum powder gas-phase flame.

[0036] In terms of chemical inhibition, adding inhibitors can reduce the concentrations of key free radicals O and AlO during the gas-phase combustion process of aluminum dust, thereby blocking the development of the aluminum dust combustion chain reaction and gas-phase reactions. On the one hand, elementary reactions (HOPO + O <=> OH + PO2, HPO3 + O <=> OH + PO3, PO + O2 <=> PO2 + O, PO2 + O2 <=> O + PO3) can capture and remove O free radicals. On the other hand, adding inhibitors can reduce the sensitivity coefficients of the forward elementary reactions that promote the generation of O and AlO free radicals, and the reverse elementary reactions (PO2 + OH + M <=> HPO3 + M, BO2 + OH <=> HOBO + O, HBO + O2 <=> BO2 + OH) can also inhibit the generation of O and AlO free radicals.

[0037] In addition, as the concentration of P1B2 increases, the sensitivity coefficients of the elementary reactions that promote temperature increase decrease, and the absolute values of the sensitivity coefficients of the elementary reactions that inhibit temperature increase increase, indicating that P1B2 can inhibit the increase in the gas-phase flame temperature. Adding P1B2 can reduce the heat release of aluminum particle melting and slow down the melting rate, thereby reducing the possibility of the reaction between H2O and high-temperature molten aluminum particles. In addition, the process of P1B2 decomposition to produce H2O absorbs the heat of the combustion reaction, all of which play a positive inhibitory role in the aluminum dust explosion and can offset the negative inhibitory effect of the increased explosion intensity caused by the reaction between H2O and aluminum particles. Generally speaking, P1B2 achieves efficient inhibition of the aluminum dust explosion flame and overpressure by enhancing physical and chemical inhibition effects. Description of the Drawings

[0038] Figure 1 shows the pyrolysis characteristics of P1B2 in an air atmosphere.

[0039] Figure 2 shows the pyrolysis characteristics of the P1B2 / aluminum powder mixture in an air atmosphere.

[0040] Figure 3 shows the influence law of P1B2 on the flame propagation behavior of aluminum dust explosion.

[0041] Figure 4 shows the influence law of P1B2 on the flame structure of aluminum dust explosion.

[0042] Figure 5 shows the influence law of P1B2 on the flame propagation speed of aluminum dust explosion.

[0043] Figure 6 shows the influence law of P1B2 on the explosion intensity of aluminum dust. Detailed Implementation Modes

[0044] The following further describes in detail the specific implementation manners of the present invention in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts all fall within the protection scope of the present invention.

[0045] The names and symbols used in the present invention are all common names and symbols in the art.

[0046] The preparation method of the P1B2 expandable phosphorus-boron composite inhibitor of the present invention includes the following steps:

[0047] Step S1: Hydrolyze KH550 (3-aminopropyltriethoxysilane) under magnetic stirring with deionized water added, and add hydrochloric acid to adjust the pH of the solution. Transfer the hydrolyzed KH550 to a three-necked flask, stir and heat up with an oil bath.

[0048] Step S2: Disperse APP (ammonium polyphosphate) in absolute ethanol under magnetic stirring, and add the absolute ethanol solution of APP to the hydrolyzed KH550 solution prepared in Step S1. Stir and heat up with an oil bath. Then continue to add EG (expandable graphite) to the solution, stir and heat up with an oil bath. Wash the product three times with absolute ethanol and perform a drying treatment to obtain a 5EGAPP expandable phosphorus-containing inhibitor.

[0049] Step S3: Disperse boric acid in deionized water under magnetic stirring, and transfer the high-concentration boric acid solution to a three-necked flask. Stir and heat up with an oil bath. Then continue to add zinc oxide to the solution, stir and heat up with an oil bath. Wash the product three times with absolute ethanol and perform a drying treatment to obtain an NZB inhibitor.

[0050] Step S4: Mechanically compound the NZB inhibitor prepared in Step S3 with Al(OH)3 in a ball mill, and perform a drying treatment to obtain a B1A1 boron-containing synergistic inhibitor.

[0051] Step S5: Mechanically compound the 5EGAPP expandable phosphorus-containing inhibitor obtained in Step S2 and the B1A1 boron-containing synergistic inhibitor in a ball mill, and perform a drying treatment to obtain a P1B2 expandable phosphorus-boron composite inhibitor.

[0052] In Step S1, the concentration of the KH550 solution is 2.5 g / 50 ml (deionized water), the pH value of the solution is adjusted to about 5.0 with hydrochloric acid, the stirring speed is 300 rpm, the heating temperature is 80 °C, and the heating time is 1 h.

[0053] In Step S2, the concentration of the APP solution is 100 g / 200 ml (absolute ethanol), the magnetic stirring time is 30 min, the heating temperature is 60 °C, and the heating time is 2 h.

[0054] In step S2, 5 g of EG is added to the solution, the heating temperature is 60 °C, and the heating time is 1 h;

[0055] In step S2, the drying temperature is 60 °C and the drying time is 12 h;

[0056] In step S3, the concentration of the boric acid solution is 15 g / 50 ml (deionized water), the magnetic stirring time is 30 min, 4.86 g of zinc oxide is added, the stirring speed is 150 rpm, the heating temperature is 95 °C, the heating time is 4 h, and the drying temperature of the product is 80 °C and the drying time is 12 h;

[0057] In step S4: The mass ratio of the NZB inhibitor to Al(OH)3 is 1:1, the grinding time in the ball mill is 60 min, the rotation speed is 300 rpm, the drying temperature of the product is 45 °C, and the drying time is 24 h;

[0058] In step S5, the mass ratio of the 5EGAPP expandable phosphorus-containing inhibitor to the B1A1 boron-containing synergistic inhibitor is 1:2, the grinding time in the ball mill is 60 min, the rotation speed is 300 rpm, and the drying temperature of the product is 24 h;

[0059] The application of the P1B2 expandable phosphorus-boron composite inhibitor described in the present invention in suppressing aluminum dust explosion can effectively suppress the explosion flame and overpressure of aluminum dust.

[0060] The present invention will be further described below in conjunction with specific embodiments. Example 1

[0061] The preparation method of the P1B2 expandable phosphorus-boron composite inhibitor in this example specifically includes the following steps:

[0062] S1. Hydrolyze 2.5 g of KH550 (3-aminopropyltriethoxysilane) in 50 ml of deionized water, adjust the pH of the solution to 5.0 with hydrochloric acid, magnetically stir at room temperature for 30 min, and transfer it to a three-necked flask for oil bath heating to 80 °C for reaction for 1 h;

[0063] S2. Hydrolyze 100 g of APP (ammonium polyphosphate) in 200 ml of absolute ethanol, magnetically stir at room temperature for 30 min, and add the absolute ethanol solution of APP to the solution formed in step S1, and heat it in an oil bath to 60 °C for reaction for 2 h;

[0064] S3. Add 5 g of EG (expandable graphite) to the solution formed in step S2, keep heating in an oil bath at 60 °C for reaction for 1 h, wash the product three times with absolute ethanol, and dry it at 60 °C for 12 h to obtain the 5EGAPP expandable phosphorus-containing inhibitor;

[0065] S4. 15 g of boric acid was hydrolyzed in 50 ml of deionized water, magnetically stirred at room temperature for 30 min, and transferred to a three-necked flask. 4.86 g of zinc oxide was added at the same time, and the oil bath was heated to 95 ° C for 4 h. The product was washed three times with anhydrous ethanol and dried at 80 ° C for 12 h to obtain NZB inhibitor;

[0066] S5. NZB and Al(OH)3 were placed in a ball mill at a mass ratio of 1:1 and fully ground for 60 min at a speed of 300 rpm. The product was dried at 45°C for 24 h to obtain B1A1 boron-containing synergistic inhibitor;

[0067] S6. The 5EGAPP obtained in step S3 and the B1A1 obtained in step S5 were put into a ball mill in a mass ratio of 1:2 and fully ground for 60 min at a speed of 300 rpm. The product was dried at 45° C. for 24 h to finally obtain a P1B2 expandable phosphorus-boron composite inhibitor;

[0068] The critical inhibition concentration of the inhibitor for aluminum dust explosion is 400g / m³ when the aluminum dust concentration is 1000g / m³.

[0069] The performance test results of the above embodiment are as follows:

[0070] The pyrolysis performance of P1B2 and P1B2 / aluminum powder mixture in air atmosphere was tested using a synchronous thermal analyzer (TGA / DSC3+) manufactured by Mettler Toledo, Switzerland. Figure 1 The pyrolysis characteristics of the P1B2 expandable phosphorus-boron composite inhibitor prepared in the embodiment of the present invention under air atmosphere are as follows: Figure 1 It can be seen that the initial decomposition temperature of P1B2 is about 75℃. When the temperature increases to 1200℃, the decomposition residue is about 57.4%. The DSC curve shows that the unit heat absorption of P1B2 at 214-345℃ is about 698J / g. Figure 2 As is known, the addition of P1B2 can reduce the melting rate of aluminum particles, and there is a large endothermic peak in the range of 928-1197°C, with a unit endothermic heat of about 1920 J / g.

[0071] The aluminum dust explosion suppression experimental system designed and built independently was used for testing. In order to explore the influence of P1B2 on the flame propagation behavior of aluminum dust explosion, when the aluminum dust concentration was 1000g / m³, P1B2 was mixed with aluminum dust at mass ratios (mass ratio is the mass of the inhibitor / mass of aluminum powder) of 0.05, 0.1, 0.2, 0.3 and 0.35, respectively, and the influence of P1B2 on the flame propagation behavior of aluminum dust explosion was recorded by a high-speed photography system. Figure 3 The influence of P1B2 on the flame propagation behavior of aluminum dust explosion is given by Figure 3It can be seen that as the mass ratio of P1B2 increases from 0.05 to 0.35, the leading edge of the aluminum dust explosion flame gradually becomes discrete and irregular, and the time for the flame to propagate to the top of the chamber gradually increases. When the mass ratio increases to 0.4, the aluminum explosion flame is completely suppressed.

[0072] Tests were carried out using an observation system for the structure of the aluminum dust explosion flame designed and built independently. To explore the influence law of P1B2 on the structure and propagation speed of the aluminum dust explosion flame, when the aluminum dust concentration was 1000 g / m³, P1B2 with mass ratios of 0.05, 0.1, 0.2, 0.3, and 0.35 was mixed with the aluminum dust respectively, and the influence law of P1B2 on the structure and propagation speed of the aluminum dust explosion flame was recorded through a high-speed photography system. Figure 4 and Figure 5 are respectively the influence laws of P1B2 on the structure and propagation speed of the aluminum dust explosion flame. It can be seen from Figure 4 and Figure 5 that as the mass ratio of P1B2 increases from 0.05 to 0.35, the leading edge of the aluminum dust explosion flame gradually changes from yellow to blue-green, and the average flame propagation speeds are reduced by 20.3%, 45.5%, 61.8%, 82.0%, and 90.4% respectively.

[0073] Tests were carried out using an experimental system for suppressing aluminum dust explosion designed and built independently. To explore the influence law of P1B2 on the explosion intensity of aluminum dust, when the aluminum dust concentration was 1000 g / m³, P1B2 with mass ratios of 0.05, 0.1, 0.2, 0.3, and 0.35 was mixed with the aluminum dust respectively, and the influence law of P1B2 on the explosion intensity of aluminum dust was recorded through a pressure measurement unit and a collection and control unit. Figure 6 is the influence law of P1B2 on the explosion intensity of aluminum dust. As the mass ratio of P1B2 increases from 0.05 to 0.35, compared with the pure aluminum dust explosion, the maximum pressures are reduced by 16.2%, 26.3%, 40.4%, 63.5%, and 86.2% respectively, and the maximum pressure rise rates are reduced by 23.4%, 45.7%, 65.9%, 74.1%, and 92.0% respectively. Comprehensive Figures 3 to 6 experimental results show that the expandable phosphorus-boron composite inhibitor P1B2 can effectively inhibit the aluminum dust explosion flame and overpressure, and the critical inhibition concentration of P1B2 for aluminum dust explosion is 400 g / m³. Example 2

[0074] The expandable phosphorus-boron composite inhibitor P1B1 of this comparative example is prepared by the following specific steps:

[0075] S1. Hydrolyze 2.5 g KH550 in 50 ml deionized water, add hydrochloric acid to adjust the solution pH to 5.0, stir magnetically at room temperature for 30 min, transfer to a three-necked flask and heat to 80 ° C in an oil bath for 1 h;

[0076] S2. 100 g of APP was hydrolyzed in 200 ml of anhydrous ethanol, and magnetic stirring was performed at room temperature for 30 min. The anhydrous ethanol solution of APP was added to the solution formed in step S1, and the oil bath was heated to 60 ° C for 2 h;

[0077] S3. Add 5 g EG to the solution formed in step S2, heat in an oil bath and keep the reaction at 60 ° C for 1 h, wash the product three times with anhydrous ethanol, and dry at 60 ° C for 12 h to obtain 5EGAPP expandable phosphorus inhibitor;

[0078] S4. 15 g of boric acid was hydrolyzed in 50 ml of deionized water, magnetically stirred at room temperature for 30 min, and transferred to a three-necked flask. 4.86 g of zinc oxide was added at the same time, and the oil bath was heated to 95 ° C for 4 h. The product was washed three times with anhydrous ethanol and dried at 80 ° C for 12 h to obtain NZB inhibitor;

[0079] S5. NZB and Al(OH)3 were placed in a ball mill at a mass ratio of 1:1 and fully ground for 60 min at a speed of 300 rpm. The product was dried at 45°C for 24 h to obtain B1A1 boron-containing synergistic inhibitor;

[0080] S6. The 5EGAPP obtained in step S3 and the B1A1 obtained in step S5 were put into a ball mill in a mass ratio of 1:1 and fully ground for 60 minutes at a rotation speed of 300 rpm. The product was dried at 45° C. for 24 hours to finally obtain the P1B1 expandable phosphorus-boron composite inhibitor.

[0081] The critical inhibition concentration of the inhibitor for aluminum dust explosion is 450g / m³. Example 3

[0082] The preparation method of the P2B1 expandable phosphorus-boron composite inhibitor of this comparative example specifically comprises the following steps:

[0083] S1. Hydrolyze 2.5 g KH550 in 50 ml deionized water, add hydrochloric acid to adjust the solution pH to 5.0, stir magnetically at room temperature for 30 min, transfer to a three-necked flask and heat to 80 ° C in an oil bath for 1 h;

[0084] S2. 100 g of APP was hydrolyzed in 200 ml of anhydrous ethanol, and magnetic stirring was performed at room temperature for 30 min. The anhydrous ethanol solution of APP was added to the solution formed in step S1, and the oil bath was heated to 60 ° C for 2 h;

[0085] S3. Add 5 g EG to the solution formed in step S2, heat in an oil bath and keep the reaction at 60 ° C for 1 h, wash the product three times with anhydrous ethanol, and dry at 60 ° C for 12 h to obtain 5EGAPP expandable phosphorus inhibitor;

[0086] S4. 15 g of boric acid was hydrolyzed in 50 ml of deionized water, magnetically stirred at room temperature for 30 min, and transferred to a three-necked flask. 4.86 g of zinc oxide was added at the same time, and the oil bath was heated to 95 ° C for 4 h. The product was washed three times with anhydrous ethanol and dried at 80 ° C for 12 h to obtain NZB inhibitor;

[0087] S5. NZB and Al(OH)3 were placed in a ball mill at a mass ratio of 1:1 and fully ground for 60 min at a speed of 300 rpm. The product was dried at 45°C for 24 h to obtain B1A1 boron-containing synergistic inhibitor;

[0088] S6. The 5EGAPP obtained in step S3 and the B1A1 obtained in step S5 were put into a ball mill in a mass ratio of 2:1 and fully ground for 60 minutes at a rotation speed of 300 rpm. The product was dried at 45° C. for 24 hours to finally obtain the P2B1 expandable phosphorus-boron composite inhibitor.

[0089] The critical inhibition concentration of the inhibitor for aluminum dust explosion is 550g / m³.

[0090] Summary: With the increase of the mass ratio of boron-containing substances, the inhibitory performance of the inhibitor gradually improves. The critical inhibition concentrations of expandable phosphorus-boron composite inhibitors P1B2, P1B1 and P2B1 on aluminum dust explosion are 400g / m³, 450g / m³ and 550g / m³, respectively. The inhibitory performance of P1B2 on aluminum dust explosion is better than that of P1B1 and P2B1 inhibitors.

[0091] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. An application of an expandable phosphorus-boron composite inhibitor, characterized in that: The inhibitor is used to suppress aluminum dust explosion; The preparation method of the inhibitor comprises the following steps: Step S1: adding 3-aminopropyltriethoxysilane to deionized water for hydrolysis, adjusting the pH value of the solution to 5 with hydrochloric acid, and obtaining a 3-aminopropyltriethoxysilane solution; adding ammonium polyphosphate to anhydrous ethanol for hydrolysis, and obtaining an ammonium polyphosphate solution; The ammonium polyphosphate solution is added to the 3-aminopropyltriethoxysilane solution for reaction, and then expandable graphite is added. After the reaction is completed, the solution is washed and dried to obtain a 5EGAPP expandable phosphorus-containing inhibitor; The mass ratio of 3-aminopropyltriethoxysilane: ammonium polyphosphate: expandable graphite is 2.5g: 100g: 5g; Step S2: After the boric acid solution and zinc oxide are reacted in a water bath, the product is washed and filtered to obtain the NZB inhibitor, and then compounded with Al(OH)3 in a ball mill and dried to obtain the B1A1 boron-containing synergistic inhibitor; The mass ratio of boric acid to zinc oxide is 15 g:4.86 g, and the mass ratio of NZB inhibitor to Al(OH)3 is 1:1; Step S3: compounding a 5EGAPP expandable phosphorus-containing inhibitor and a B1A1 boron-containing synergistic inhibitor in a ball mill, and drying to obtain a P1B2 expandable phosphorus-boron composite inhibitor; the mass ratio of the 5EGAPP expandable phosphorus-containing inhibitor to the B1A1 boron-containing synergistic inhibitor is 1:2; The concentration of the 3-aminopropyltriethoxysilane solution is 0.05 g / ml; the concentration of the ammonium polyphosphate solution is 0.5 g / ml; and the concentration of the boric acid solution is 0.3 g / ml.

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