Oxygen uptake type coal gangue porous material for preventing and treating combustion in goaf and preparation method of oxygen uptake type coal gangue porous material

Abstract

The invention discloses an oxygen uptake type coal gangue porous material for preventing and treating coal combustion in a goaf and a preparation method thereof, the preparation method comprises the following steps: firstly, preparing coal gangue into a porous material by a template method, and then endowing the porous material with an oxygen uptake function by a doping modification method, so as to obtain the oxygen uptake type coal gangue porous material. The coal mine solid waste is mainly prepared into the fire preventing and extinguishing material with high economic value, effective utilization of the solid waste is achieved, meanwhile, the solid waste is wide in source and quite low in cost, and the manufacturing method is simple; after the prepared porous material is injected into a goaf along with slurry, an inerting isolation belt is formed; meanwhile, existing oxygen in a goaf is absorbed, a completely oxygen-free suffocation zone is formed, spontaneous combustion of coal is inhibited, in addition, the high-strength property of the porous material can achieve longitudinal accumulation of slurry, the slurry is not prone to being broken, high-position cracks can be completely blocked, and wide application prospects are achieved in the field of mine fire prevention and control.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine fire prevention and extinguishing, and in particular to an oxygen-absorbing coal gangue porous material for preventing and controlling goaf area combustion and a preparation method thereof. Background Art

[0002] Spontaneous combustion of coal has always been a major disaster in the production process of coal mines, especially for goafs. After the roof collapses, complex cracks are formed, and air leakage is serious, causing spontaneous combustion of the coal in the goaf, and even causing accidents such as gas and dust explosions. Therefore, plugging leaks has become one of the basic measures to prevent and control spontaneous combustion of coal. Commonly used plugging materials include yellow mud, cement slurry, concrete, polyurethane, etc. However, the mud has strong fluidity during the injection process, and it is difficult to achieve precise sealing at high positions. At the same time, after the water evaporates, the mud shrinks and deforms, re-forming an air leakage channel, which is easy to cause the coal to reignite. Although the performance of polyurethane is relatively excellent, it has disadvantages such as high cost, large heat release during the reaction process, and single performance.

[0003] Coal gangue is a byproduct of coal production and washing, and is an industrial waste. At present, the total amount of coal gangue stockpiled in my country has exceeded 7 billion tons, and it continues to grow every year. At present, the application of coal gangue in coal mines is mainly used for underground filling. For example, the patent with publication number CN118084448A discloses a high-concentration filling slurry of coal gangue and its preparation method. The slurry is easy to solidify, does not bleed water, and is convenient for pipeline transportation; the patent with publication number CN118255565A discloses a mine water solidification filling material containing CSH gel. The prepared gel absorbs the anions and cations in the mine water and then solidifies on the surface of the coal gangue aggregate particles or fills the gaps between the particles, and is sealed in the coal mine goaf. However, there is no literature report on making coal gangue into oxygen-absorbing fire-proof and extinguishing materials. Summary of the invention

[0004] The purpose of the present invention is to provide an oxygen-absorbing coal gangue porous material for preventing and controlling combustion in goaf areas and a preparation method thereof. The raw material coal gangue used in the method is widely available, low in cost, and has a simple and easy manufacturing process. The prepared porous material can effectively seal the goaf and remove oxygen from the enclosed space to form an oxygen-free asphyxiation space, thereby preventing and controlling spontaneous combustion of coal.

[0005] To achieve the above object, the present invention is implemented by the following technical solutions:

[0006] A method for preparing an oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion comprises the following steps:

[0007] S1. preparing coal gangue porous material;

[0008] S1-1, adding coal gangue powder crushed to 200 mesh or more into excess dilute hydrochloric acid, stirring thoroughly and evenly for 10-15 minutes, and then filtering to obtain acid-washed coal gangue;

[0009] S1-2, mixing the acid-washed coal gangue with distilled water in a certain proportion, and stirring evenly for 15-20 minutes to obtain a 5-10wt% coal gangue suspension;

[0010] S1-3, adding 1.5-5wt% of dispersant to the gangue suspension, and stirring evenly for 5-10 minutes in a 50-60°C water bath to obtain a gangue sol;

[0011] S1-4, mixing the template with distilled water in a certain proportion, and stirring evenly for 10-15 minutes to obtain a 10-20 wt% template suspension;

[0012] S1-5, adding the template suspension prepared in step S1-4 dropwise into the gangue sol prepared in step S1-3 at a mass ratio of 1:(5-10), and stirring evenly for 60-90 minutes under heating in a water bath at 40-60°C to obtain a porous material precursor;

[0013] S1-6, soaking the porous material precursor in an organic solvent, stirring evenly for 10-30 minutes and filtering, washing the filtered sample with distilled water for 3-5 times, and obtaining a coal gangue porous material;

[0014] S2. Mix a certain proportion of the adsorbent and distilled water, and stir evenly for 3-10 minutes to obtain a 20-40 wt% adsorption liquid;

[0015] S3, mixing the coal gangue porous material prepared in step S1 with the adsorption liquid prepared in step S2, adding ammonia water slowly and evenly while stirring continuously, and controlling the pH value of the solution to 8-10 to obtain a precipitate;

[0016] S4. Wash the precipitate with deionized water for 3-5 times, and heat treat it at 400-600° C. for 120-150 min to obtain an oxygen-absorbing coal gangue porous material.

[0017] Preferably, in step S1-1, the concentration of the dilute hydrochloric acid is 1-2M.

[0018] Preferably, in step S1-3, the dispersant is polyvinyl pyrrolidone.

[0019] Preferably, in step S1-4, the template is one of polyacrylic acid microspheres, polymethyl methacrylate microspheres or polystyrene microspheres.

[0020] Preferably, in step S1-5, the titration rate of the template suspension is 2 s / drop.

[0021] Preferably, in step S1-6, the organic solvent is one of dichloromethane, toluene and tetrahydrofuran.

[0022] Preferably, in step S2, the adsorbent is one of cobalt nitrate, nickel nitrate and cerium nitrate.

[0023] Preferably, in step S3, the concentration of aqueous ammonia is 1-2M.

[0024] Preferably, the stirring is magnetic stirring, and the stirring speed is 500-1000 rpm.

[0025] In order to achieve the above-mentioned purpose of the invention, the present invention also provides an oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion, which is prepared by the above-mentioned preparation method.

[0026] In the preparation process of the present invention, impurities in the coal gangue are first removed by pickling to improve its reaction activity; then the dispersion and stability of the material are improved by preparing a coal gangue suspension and adding a dispersant, and at the same time, a precursor of a porous material is formed by introducing a template and controlling temperature and time, thereby optimizing the pore structure of the porous material and providing abundant attachment sites for oxygen adsorption. The porous material prepared by the present invention can effectively remove oxygen in the blocked space, form an anaerobic asphyxiation environment, and inhibit the occurrence of coal spontaneous combustion.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) The present invention uses coal gangue as a porous material and endows it with oxygen absorption function by a doping modification method. The prepared oxygen-absorbing coal gangue porous material can effectively block the air leakage channel in the goaf and absorb the oxygen in the goaf, so that the enclosed space forms a completely oxygen-free isolation space, thereby inhibiting the occurrence of coal spontaneous combustion;

[0029] (2) The oxygen-absorbing coal gangue porous material prepared by the present invention realizes the longitudinal accumulation of slurry during the grouting process, thereby blocking high-position fracture channels;

[0030] (3) The raw material coal gangue used in the present invention is widely available and low in cost. The production process is simple and easy, and effective treatment of solid waste is achieved. It has good application prospects. The prepared porous material can be effectively used for the prevention and control of spontaneous combustion in coal mine goaf areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 1 and 2 are adsorption isotherms of four embodiments of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Embodiment 1

[0034] A method for preparing an oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion comprises the following steps:

[0035] S1. Preparation of porous coal gangue materials:

[0036] S1-1, crush 10g of coal gangue into powder with a size of more than 200 mesh, add it into an excess of 1M dilute hydrochloric acid, stir evenly for 10 minutes, and then filter to obtain acid-washed coal gangue;

[0037] S1-2, 5 g of acid-washed coal gangue was mixed with 45 g of distilled water, and stirred evenly for 15 min to obtain a coal gangue suspension;

[0038] S1-3, adding 1 g of polyvinyl pyrrolidone to the gangue suspension, and stirring evenly for 10 min in a 50° C. water bath to obtain a gangue sol;

[0039] S1-4, 10 g of polyacrylic acid microspheres were mixed with 90 g of distilled water, and stirred evenly for 10 min to obtain a template suspension;

[0040] S1-5, adding 50 g of the template suspension dropwise into the gangue sol at a dropping speed of 2 s / drop, and stirring evenly for 60 min under heating in a 40° C. water bath to obtain a porous material precursor;

[0041] S1-6, soaking the porous material precursor in dichloromethane, stirring evenly for 10 minutes, and washing the filtered sample with distilled water for 5 times to obtain a coal gangue porous material;

[0042] S2, 10g of cobalt nitrate and 40g of distilled water were mixed and stirred evenly for 3min to obtain an adsorption solution;

[0043] S3, mixing the coal gangue porous material with the adsorption liquid, stirring evenly and slowly adding 1M ammonia water, and controlling the pH of the solution to 8 to obtain a precipitate;

[0044] S4. Wash the precipitate with deionized water for 5 times and heat treat it at 400° C. for 120 min to obtain an oxygen-absorbing coal gangue porous material.

[0045] Embodiment 2

[0046] A method for preparing an oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion comprises the following steps:

[0047] S1. Preparation of porous coal gangue materials:

[0048] S1-1, crush 10g of coal gangue into powder with a size of more than 200 mesh, add it into excess 1M dilute hydrochloric acid, stir evenly for 10 minutes, and then filter to obtain acid-washed coal gangue;

[0049] S1-2, 5 g of acid-washed coal gangue was mixed with 55 g of distilled water in a certain proportion, and stirred evenly for 20 min to obtain a coal gangue suspension;

[0050] S1-3, adding 1.5 g of polyvinyl pyrrolidone to the gangue suspension, and stirring evenly for 5 min in a 55° C. water bath to obtain a gangue sol;

[0051] S1-4, 10 g of polymethyl methacrylate microspheres were mixed with 80 g of distilled water, and stirred evenly for 10 min to obtain a template suspension;

[0052] S1-5, adding 20 g of the template suspension dropwise into the gangue sol at a dropping speed of 2 s / drop, and stirring evenly for 80 min under heating in a 50° C. water bath to obtain a porous material precursor;

[0053] S1-6, soaking the porous material precursor in toluene, stirring evenly for 10 minutes, and washing the filtered sample with distilled water for 5 times to obtain a coal gangue porous material;

[0054] S2, 10g nickel nitrate and 20g distilled water were mixed and stirred evenly for 5min to obtain an adsorption solution;

[0055] S3, mixing the coal gangue porous material with the adsorption liquid, adding 2M ammonia water slowly and evenly while stirring continuously, and controlling the pH of the solution to 10 to obtain a precipitate;

[0056] S4. Wash the precipitate with deionized water for three times and heat treat it at 600° C. for 140 min to obtain an oxygen-absorbing coal gangue porous material.

[0057] Embodiment 3

[0058] A method for preparing an oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion comprises the following steps:

[0059] S1. Preparation of porous coal gangue materials:

[0060] S1-1, crush 10g of coal gangue into powder with a size of more than 200 mesh, add it into excess 2M dilute hydrochloric acid, stir evenly for 10 minutes, and then filter to obtain acid-washed coal gangue;

[0061] S1-2, 5 g of acid-washed coal gangue was mixed with 95 g of distilled water in a certain proportion, and stirred evenly for 18 min to obtain a coal gangue suspension;

[0062] S1-3, adding 5 g of polyvinyl pyrrolidone to the gangue suspension, and stirring evenly for 8 min in a 60° C. water bath to obtain a gangue sol;

[0063] S1-4, 10 g of polystyrene microspheres were mixed with 40 g of distilled water, and stirred evenly for 14 min to obtain a template suspension;

[0064] S1-5, adding 20 g of the template suspension dropwise into the gangue sol at a dropping speed of 2 s / drop, and stirring evenly for 80 min under heating in a 50° C. water bath to obtain a porous material precursor;

[0065] S1-6, soaking the porous material precursor in tetrahydrofuran, stirring evenly for 25 minutes, and washing the filtered sample with distilled water for 5 times to obtain a coal gangue porous material;

[0066] S2, 10g of cerium nitrate and 15g of distilled water were mixed and stirred evenly for 8min to obtain an adsorption solution;

[0067] S3, mixing the coal gangue porous material with the adsorption liquid, adding 1M ammonia water slowly and evenly while stirring continuously, and controlling the pH of the solution to 9 to obtain a precipitate;

[0068] S4. Wash the precipitate with deionized water for three times and heat treat it at 600° C. for 150 min to obtain an oxygen-absorbing coal gangue porous material.

[0069] Embodiment 4

[0070] A method for preparing an oxygen-absorbing coal gangue porous material for preventing and controlling combustion in goaf areas comprises the following steps:

[0071] S1. Preparation of porous coal gangue materials:

[0072] S1-1, crush 10g of coal gangue into powder with a size of more than 200 mesh, add it into excess 1M dilute hydrochloric acid, stir evenly for 10 minutes, and then filter to obtain acid-washed coal gangue;

[0073] S1-2, 5 g of acid-washed coal gangue was mixed with 60 g of distilled water in a certain proportion, and stirred evenly for 20 min to obtain a coal gangue suspension;

[0074] S1-3, adding 1 g of polyvinyl pyrrolidone to the gangue suspension, and stirring evenly for 10 min in a 50° C. water bath to obtain a gangue sol;

[0075] S1-4, 10 g of polyacrylic acid microspheres were mixed with 60 g of distilled water, and stirred evenly for 15 min to obtain a template suspension;

[0076] S1-5, adding 15 g of template suspension into the gangue sol dropwise at a dropping speed of 2 s / drop, and stirring evenly for 60 min under heating in a 40° C. water bath to obtain a porous material precursor;

[0077] S1-6, soaking the porous material precursor in dichloromethane, stirring evenly for 10 minutes, and washing the filtered sample with distilled water for 5 times to obtain a coal gangue porous material;

[0078] S2, 8g of cobalt nitrate and 40g of distilled water were mixed and stirred evenly for 10min to obtain an adsorption solution;

[0079] S3, mixing the coal gangue porous material with the adsorption liquid, adding 2M ammonia water slowly and evenly, and controlling the pH of the solution to 8 to obtain a precipitate;

[0080] S4. Wash the precipitate with deionized water for 5 times and heat treat it at 400° C. for 120 min to obtain an oxygen-absorbing coal gangue porous material.

[0081] The strength and oxygen adsorption capacity of the oxygen-type coal gangue porous materials prepared in Examples 1 to 4 were tested. The performance of the porous materials was tested using a press and a fully automatic specific surface area and pore size analyzer. The test results are shown in Tables 1 and Figure 1 shown.

[0082] Table 1 Compressive strength of porous materials prepared in various embodiments

[0083] sample Compressive strength(MPa) Embodiment 1 31 Embodiment 2 30 Embodiment 3 32 Embodiment 4 34

[0084] It can be seen from Table 1 that the compressive strength of the coal gangue porous material prepared in the above embodiment is relatively high. When the slurry is injected or deposited on the material, the coal gangue porous material can effectively support the weight of the slurry and prevent it from collapsing or leaking due to its own weight or external force. The porous structure not only gives the material good mechanical properties, but also provides excellent permeability and adsorption, so that the slurry can be evenly distributed.

[0085] from Figure 1 It can be seen that the porous material of coal gangue has good oxygen absorption properties. After high-temperature treatment, the nitrate adsorbent is transformed into an oxide, which can undergo redox reaction with oxygen. At the same time, there are a large number of oxygen vacancies on the surface of the adsorbent, which can capture and adsorb oxygen molecules, further increasing its adsorption capacity. The oxygen absorption capacity of Example 3 is significantly higher than that of other examples. This is because cerium oxide can absorb oxygen in Ce 4 + and Ce 3+, this variability in valence enables it to effectively adsorb oxygen during the reaction, and at the same time, a large number of oxygen vacancies in cerium oxide can adsorb oxygen and form active oxygen species, thereby improving the oxygen absorption capacity. In addition, the adsorbent concentration in Example 3 is relatively high, which further enhances the adsorption capacity.

[0086] The above test results show that the present invention uses low-cost coal gangue to make oxygen-absorbing coal gangue porous materials for preventing and controlling goaf combustion. The process is simple, and waste utilization is achieved. The porous material has good oxygen absorption properties, and removes the existing oxygen in the goaf while achieving plugging, greatly reducing the risk of spontaneous combustion of coal in the goaf. At the same time, the good strength of the porous material can achieve the accumulation of slurry and better plug high-position fissure channels to meet the plugging of different conditions in coal mines.

Claims

1. A method for preparing oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion, characterized in that: The steps include: S1. preparing coal gangue porous material; S1-1, adding coal gangue powder crushed to 200 mesh or more into excess dilute hydrochloric acid, stirring thoroughly and evenly for 10-15 minutes, and then filtering to obtain acid-washed coal gangue; S1-2, mixing the acid-washed coal gangue with distilled water in a certain proportion, and stirring evenly for 15-20 minutes to obtain a 5-10wt% coal gangue suspension; S1-3, adding 1.5-5wt% of dispersant to the gangue suspension, and stirring evenly for 5-10 minutes in a 50-60°C water bath to obtain a gangue sol; S1-4, mixing the template agent with distilled water in a certain proportion, and stirring evenly for 10-15 minutes to obtain a 10-20wt% template suspension; S1-5, adding the template suspension prepared in step S1-4 dropwise into the gangue sol prepared in step S1-3 at a mass ratio of 1:(1-5), and stirring evenly for 60-90 minutes under heating in a water bath at 40-60°C to obtain a porous material precursor; S1-6, soaking the porous material precursor in an organic solvent, stirring evenly for 10-30 minutes and filtering, washing the filtered sample with distilled water for 3-5 times, and obtaining a coal gangue porous material; S2. Mix a certain proportion of the adsorbent and distilled water, and stir evenly for 3-10 minutes to obtain a 20-40 wt% adsorption liquid; S3, mixing the coal gangue porous material prepared in step S1 with the adsorption liquid prepared in step S2, adding ammonia water slowly and evenly while stirring continuously, and controlling the pH value of the solution to 8-10 to obtain a precipitate; S4. Wash the precipitate with deionized water for 3-5 times, and heat treat it at 400-600° C. for 120-150 min to obtain an oxygen-absorbing coal gangue porous material.

2. The method for preparing the oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion according to claim 1, characterized in that: In step S1-1, the concentration of the dilute hydrochloric acid is 1-2M.

3. The method for preparing the oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion according to claim 1 or 2, characterized in that: In step S1-3, the dispersant is polyvinyl pyrrolidone.

4. The method for preparing the oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion according to claim 1 or 2, characterized in that: In step S1-4, the template is one of polyacrylic acid microspheres, polymethyl methacrylate microspheres, and polystyrene microspheres.

5. The method for preparing the oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion according to claim 1 or 2, characterized in that: In step S1-5, the titration rate of the template suspension is 2 s / drop.

6. The method for preparing the oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion according to claim 1 or 2, characterized in that: In step S1-6, the organic solvent is one of dichloromethane, toluene and tetrahydrofuran.

7. The method for preparing the oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion according to claim 1 or 2, characterized in that: In step S2, the adsorbent is one of cobalt nitrate, nickel nitrate and cerium nitrate.

8. The method for preparing the oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion according to claim 1 or 2, characterized in that: In step S3, the concentration of aqueous ammonia is 1-2M.

9. The method for preparing the oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion according to claim 1 or 2, characterized in that: The stirring is magnetic stirring, and the stirring speed is 500-1000rmp.

10. The oxygen-absorbing coal gangue porous material for preventing and controlling goaf combustion prepared by the preparation method according to any one of claims 1 to 9.

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