Preparation method of potassium oxalate-potassium montmorillonite nanocomposite explosion suppression powder explosion suppression agent

Abstract

This invention relates to a method for preparing a potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant powder (OA-MMT), belonging to the field of explosion suppressant preparation technology. The invention first uses montmorillonite, which has strong adsorption capacity and cation exchange performance, as a matrix. Montmorillonite is mixed with deionized water and stirred to obtain a montmorillonite suspension. Then, hydrochloric acid and potassium carbonate are added to the suspension, followed by acidification activation and potassium ion exchange modification to obtain potassium montmorillonite. Oxalic acid is then incorporated into the potassium montmorillonite matrix, and the mixture is treated with ultrasound, drying, and grinding to finally obtain a novel powder explosion suppressant with highly efficient physical and chemical synergistic explosion suppressing effects. The powder explosion suppressant prepared by this invention has advantages such as easy storage, good explosion-proof performance, and extremely strong adsorption capacity for explosion energy, and has broad application prospects.

Description

Technical Field

[0001] This invention relates to a method for preparing a potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant powder, belonging to the field of explosion suppressant preparation technology. Background Technology

[0002] With the rapid development of modern industry, many sectors such as agriculture, forestry, chemicals, and light industry use powders as raw materials for processing and production. Some intermediates or products are also powders. Therefore, the types of powders are numerous and their usage has greatly increased. Simultaneously, powder-related industries are developing towards mechanization and large-scale production, significantly increasing the possibility of dust explosion accidents. The dust explosion process is extremely complex, involving the combustion of heterogeneous systems containing solid particles, pyrolysis-gasified combustible gases, and liquefied particles, accompanied by transient turbulent multiphase flow dynamics under high temperature and overpressure. This involves numerous disciplines such as chemical thermodynamics, reaction kinetics, heat and mass transfer processes, multiphase combustion fluid mechanics, and gas dynamics, making the understanding and research of dust explosion mechanisms extremely challenging. How to prevent nanoparticle dust explosion accidents, reduce their hazards, and ensure the safety of people's production and lives has become an urgent problem to be solved.

[0003] To address the above issues, and taking into full account the synergistic physical and chemical explosion-suppressing properties of explosion-suppressing powders, a novel potassium oxalate-potassium montmorillonite nanocomposite explosion-suppressing powder has been developed. This powder can decompose more quickly and effectively, dilute the concentration of reactants more efficiently, absorb more heat, and rapidly capture and consume more reactive free radicals in the explosion and combustion reaction during an explosion. This allows for a faster and more efficient interruption of the combustion reaction and suppression of the explosion's development, which is of positive significance to the field of explosion suppressant preparation technology. Summary of the Invention

[0004] The main technical problem addressed by this invention is the preparation method of a novel potassium oxalate-potassium montmorillonite nanocomposite explosion-suppressing powder, which possesses a highly efficient synergistic physical and chemical explosion-suppressing effect, targeting the characteristics of high intensity, high destructive power, and wide impact range of dust explosions. The preparation steps of the potassium oxalate-potassium montmorillonite nanocomposite explosion-suppressing powder are as follows:

[0005] Step 1: Grind and sieve the blocky montmorillonite and mix it with deionized water at a mass ratio of 1:(10-35). Stir magnetically for 30 minutes to obtain a natural montmorillonite suspension.

[0006] Step 2: Acidify the above-mentioned natural montmorillonite suspension with hydrochloric acid to obtain acid-purified montmorillonite suspension;

[0007] Step 3: Add 8-40 parts of potassium carbonate to the acid-purified montmorillonite suspension obtained in Step 2, react at 55℃-75℃ for 5-6 hours, and let stand for 16-24 hours to obtain potassium-based nano-sized montmorillonite suspension.

[0008] Step 4: Add oxalic acid to the potassium-based montmorillonite suspension in small amounts several times, perform ultrasonic treatment for 10-30 minutes, let stand for 16 hours, dry and grind to obtain potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant powder (OA-MMT).

[0009] Furthermore, in step one, the montmorillonite is pulverized to a particle size of 38 μm using a ball mill, and the magnetic stirring temperature is 60℃~100℃.

[0010] Furthermore, the method for preparing the acid-purified montmorillonite suspension by acidifying the natural montmorillonite suspension with hydrochloric acid in step two includes:

[0011] (1) Add hydrochloric acid dropwise to the natural montmorillonite suspension until the pH of the liquid is 1.5 to 3.5.

[0012] (2) Separate with a centrifuge, rinse the filter cake repeatedly with purified water until the pH value of the solution is neutral, then use plate and frame filter press to collect the solid material and dry it, crush it through a 400-mesh sieve to obtain acid-purified montmorillonite powder.

[0013] (3) Soak the acid-purified montmorillonite powder obtained in step (2) in deionized water for 1-2 hours, and then sonicate it for 10-30 minutes with stirring; continue stirring for 1-2 hours to obtain an acid-purified montmorillonite suspension.

[0014] Furthermore, the ultrasonic treatment described in step four uses ultrasonic frequencies of 30–45 kHz.

[0015] The beneficial effects of this invention are:

[0016] (1) This invention first uses montmorillonite, which has strong adsorption capacity and cation exchange capacity, as a template. It is mixed with deionized water and stirred to obtain a montmorillonite suspension. Then, hydrochloric acid and potassium carbonate are added to the suspension. After acidification activation and potassium modification, potassium montmorillonite is obtained. Oxalic acid is then added to the potassium montmorillonite matrix to finally obtain a powder explosion suppressant. The temperature of the explosion suppressant obtained by this invention increases with the increase of the explosion environment temperature. When the temperature reaches a certain value, the interlayer water and structural water of the potassium montmorillonite matrix escape, the surface-loaded nano potassium oxalate crystal water escapes, and the potassium oxalate gradually decomposes thermally. During this pyrolysis process, a large amount of energy is consumed and absorbed to generate water vapor. After the crystal water is vaporized at high temperature, its volume increases by thousands of times, effectively diluting the oxygen and volatile concentration in the explosion system and playing a physical suppression role in dust explosion.

[0017] (2) During the explosion, a large amount of K adsorbed between the crystals of the potassium montmorillonite matrix... +It undergoes ion exchange with the reactive free radical H· during combustion, resulting in the adsorption of a large amount of H· between the crystals. Furthermore, at high temperatures, the hydroxyl groups of potassium montmorillonite consume H· endothermically to remove hydroxyl water, reducing the concentration of reactive free radicals and the temperature. On the other hand, K· released from the interlayer ion exchange of the potassium montmorillonite matrix... + and potassium oxalate in K + and C2O4 2- It can efficiently capture and consume the active free radicals H· and OH· in the explosive combustion chain reaction, exerting a synergistic physicochemical explosion suppression effect. The explosion suppression principle is as follows: Figure 3 As shown.

[0018] (3) Compared with other explosion suppressants loaded on the carrier, the potassium oxalate (K2C2O4·H2O) selected in this invention not only has the effect of rapid physical cooling, but also has potassium ions and oxalate ions with a higher ability to capture free radicals than other ions. It can quickly capture combustion reaction free radicals and thus interrupt the chain reaction; and the CO2 and other gases generated by its thermal decomposition can effectively dilute the concentration of reactants and affect the rate of explosion combustion chain reaction.

[0019] (4) The potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant prepared by the present invention has a simple process, is suitable for industrial production, and has strong stability, good hydrophobicity, and is easy to store. Attached Figure Description

[0020] Figure 1 Scanning electron microscopy images of natural potassium oxalate and potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant powder.

[0021] Figure 2 XRD characterization diagrams of potassium oxalate and potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant powders.

[0022] Figure 3 This is a schematic diagram illustrating the explosion suppression principle of potassium oxalate-potassium montmorillonite nanocomposite explosion suppression powder.

[0023] Figure 4 This is a comparison chart showing the experimental results of the product provided by this invention in inhibiting the explosion of aluminum powder, PMMA powder, and lauric acid powder. Detailed Implementation

[0024] To address the problems existing in the prior art, this invention provides a method for preparing and applying a potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant powder. The invention will be described in detail below with reference to the accompanying drawings.

[0025] Figure 1 The electron micrograph of the product obtained by this invention shows that the montmorillonite powder particles exhibit good dispersibility, are flaky particles, and do not agglomerate; due to the loading of potassium oxalate particles, the composite explosion suppressant powder particles no longer appear as flaky particles, but as irregular particles.

[0026] Figure 2 The XRD characterization pattern of this product is shown in the figure. The characteristic diffraction peaks of potassium oxalate are 17.89, 31.95, 36.05, 36.83, and 44.84, which are present in the potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant powder with a loading of 40%. After modification, the MMT characteristic peaks are weakened. The XRD diffraction pattern confirms that the composite explosion suppressant powder contains montmorillonite and potassium oxalate.

[0027] To further illustrate the effect of the potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant powder provided by the present invention, explosion suppression experiments on aluminum dust, PMMA dust and lauric acid dust were conducted to demonstrate its effectiveness.

[0028] Example 1:

[0029] A potassium oxalate-potassium montmorillonite nanocomposite powder explosion suppressant formulation for inhibiting the explosion of aluminum dust, PMMA dust and lauric acid dust: by mass fraction, 79% blocky montmorillonite, 12% potassium carbonate, and 9% oxalic acid.

[0030] The maximum explosion pressure (P0) of aluminum dust, PMMA dust, and lauric acid dust under the intervention of the above-mentioned composite powders was determined using a standard 20L explosion canister. max and the maximum explosion pressure rise rate (dP / dt) max The minimum dosage of this product required to suppress explosions of aluminum dust, PMMA dust, and lauric acid dust was determined. The experimental results are shown in [link to experimental results]. Figure 4 .like Figure 4 As shown, the minimum amounts of the powder explosion suppressant required to suppress the explosions of aluminum dust, PMMA dust, and lauric acid dust at this mass fraction are 180%, 60%, and 150%, respectively.

[0031] Example 2:

[0032] The difference from Example 1 lies in the formulation of the potassium oxalate-potassium montmorillonite nanocomposite powder explosion suppressant for inhibiting the explosion of aluminum dust, PMMA dust, and lauric acid dust: by mass fraction, 65% blocky montmorillonite, 21% potassium carbonate, and 14% oxalic acid. Experimental results are shown below. Figure 4 .like Figure 4 As shown, the minimum amounts of the powder explosion suppressant required to suppress the explosions of aluminum dust, PMMA dust, and lauric acid dust at this mass fraction are 200%, 40%, and 60%, respectively.

[0033] Example 3:

[0034] The difference from Example 1 lies in the formulation of the potassium oxalate-potassium montmorillonite nanocomposite powder explosion suppressant for inhibiting the explosion of aluminum dust, PMMA dust, and lauric acid dust: by mass fraction, 52% blocky montmorillonite, 25% potassium carbonate, and 23% oxalic acid. Experimental results are shown below. Figure 4.like Figure 4 As shown, the minimum amounts of the powder explosion suppressant required to suppress the explosions of aluminum dust, PMMA dust, and lauric acid dust at this mass fraction are 160%, 20%, and 40%, respectively.

[0035] In addition, a comparative experiment was conducted using sodium bicarbonate, a traditional explosion suppressant, to determine the minimum amount of sodium bicarbonate required for explosions of aluminum dust, PMMA dust, and lauric acid dust. The comparison results are shown below. Figure 4 .like Figure 4 As shown, the minimum amounts of sodium bicarbonate required to suppress explosions of aluminum dust, PMMA dust, and lauric acid dust are 320%, 280%, and 200%, respectively.

[0036] Figure 4 The results of Examples 1 to 3 and the control experiment are shown in the comparative graph. It was determined that the products prepared in Examples 1 to 3 have a significant inhibitory effect on dust explosions, and the minimum dosage required to inhibit the explosions of aluminum dust, PMMA dust, and lauric acid dust is lower than the minimum dosage of the traditional explosion suppressant sodium bicarbonate. This inhibits the release of K+ ions from the interlayer ion exchange of the potassium montmorillonite matrix after an explosion. + and potassium oxalate in K + and C2O4 2- It efficiently captures and consumes the active free radicals H· and OH· in the explosive combustion chain reaction, exerting a synergistic physicochemical explosion suppression effect.

Claims

1. A method for preparing a potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant powder, characterized in that, The explosion suppressant powder, by weight, is composed of 50-100 parts of montmorillonite (MMT), 9-30 parts of potassium carbonate (K2CO3), and 5-26 parts of oxalic acid (H2C2O4). The preparation steps of the explosion-suppressing powder include: (1) The blocky montmorillonite is ground, sieved and mixed with deionized water at a mass ratio of 1: (10-35), and magnetically stirred for 30 minutes to obtain a natural montmorillonite suspension. (2) The above natural montmorillonite suspension was acidified with hydrochloric acid to obtain acid-purified montmorillonite suspension. (3) Add 8 to 40 parts of potassium carbonate to the acid-purified montmorillonite suspension obtained in step (2), react at 55℃ to 75℃ for 5 to 6 hours, and let stand for 16 to 24 hours to obtain potassium-based nano-sized montmorillonite suspension. (4) Oxalic acid is added to the potassium-based montmorillonite suspension in small amounts and multiple times, and ultrasonic treatment is performed for 10 to 30 minutes. After standing for 16 hours, it is dried and ground to obtain potassium oxalate-potassium montmorillonite nanocomposite explosion suppressant powder (OA-MMT).

2. The method for preparing the explosion-suppressing powder according to claim 1, characterized in that: In step (1), montmorillonite is pulverized to a particle size of 38 μm using a ball mill, and the magnetic stirring temperature is 60℃~100℃.

3. The method for preparing the explosion-suppressing powder according to claim 1, characterized in that: The preparation method of acid-purified montmorillonite suspension obtained by acidifying the natural montmorillonite suspension with hydrochloric acid in step (2) includes: (1) Add hydrochloric acid dropwise to the natural montmorillonite suspension until the pH of the liquid is 1.5 to 3.5; (2) Separate with a centrifuge, rinse the filter cake repeatedly with purified water until the pH value of the solution is neutral, then use plate and frame filter press to collect the solid material and dry it, crush it through a 400-mesh sieve to obtain acid-purified montmorillonite powder. (3) Soak the acid-purified montmorillonite powder obtained in step (2) in deionized water for 1-2 hours, and then sonicate it for 10-30 minutes with stirring; continue stirring for 1-2 hours to obtain an acid-purified montmorillonite suspension.

4. The method for preparing the explosion-suppressing powder according to claim 1, characterized in that: The ultrasonic treatment described in step (4) uses ultrasonic frequencies of 30–45 kHz.

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