FLY ASH-BASED FIRE-PREVENTION AND EXTINGUISHING MATERIAL WITH CARBON DIOXIDE MINERALIZED AND STORED, AND PREPARATION METHOD THEREOF

Abstract

A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored, and a preparation method thereof are provided. The preparation method includes: separately weighing 100 parts to 120 parts of water, 1 part to 3 parts of a solid strong alkali, and 20 parts to 40 parts of a fly ash as raw materials, pouring the raw materials into a reactor successively to obtain a resulting mixture, and stirring the resulting mixture at a high rotational speed; adding 10 parts to 20 parts of a solubilizing agent to the reactor, sealing the reactor, introducing carbon dioxide to the reactor at room temperature to maintain a carbon dioxide pressure to obtain a resulting slurry, and stirring the resulting slurry at a high rotational speed; and further introducing carbon dioxide into the reactor to increase the carbon dioxide pressure, and stirring the resulting slurry at a low rotational speed.

Claims

1. A preparation method of a fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored, comprising the following steps: step 1: separately weighing 100 parts to 120 parts of water, 1 part to 3 parts of a solid strong alkali, and 20 parts to 40 parts of a fly ash as raw materials, pouring the raw materials into a reactor successively to obtain a resulting mixture, and stirring the resulting mixture at a rotational speed of 600 rpm to 1,200 rpm for 3 min to 5 min, wherein a mass of an ash with a particle size less than or equal to 100 ?m in the fly ash accounts for 80% or more of a total mass of the fly ash; and in the fly ash, a silica content is 30% or more and a calcium oxide content is 10% or more; step 2: adding 10 parts to 20 parts of a solubilizing agent to the reactor, sealing the reactor, introducing carbon dioxide into the reactor at room temperature to maintain a carbon dioxide pressure in the reactor at 1 bar to 3 bar to obtain a first resulting slurry, and stirring the first resulting slurry at a rotational speed of 600 rpm to 1,200 rpm for 3 min to 5 min, wherein the solubilizing agent is one or more selected from a group consisting of polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monolaurate sorbate, polyoxyethylene laurate, polyglyceryl fatty acid ester, fatty alcohol polyoxyethylene ether, and polyoxyethylene-polyoxypropylene block copolymer, and a concentration of the solubilizing agent is 3 wt %; and step 3: further introducing the carbon dioxide into the reactor to allow the carbon dioxide pressure in the reactor to reach 10 bar or more to obtain a second resulting slurry, and stirring the second resulting slurry at a rotational speed of 60 rpm to 100 rpm for 10 min to 15 min to obtain the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored.

2. The preparation method of the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored according to claim 1, wherein a ratio of the raw materials is 120 parts of the water, 3 parts of the solid strong alkali, 20 parts of the fly ash, and 20 parts of the solubilizing agent.

3. The preparation method of the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored according to claim 2, wherein in the step 1, the solid strong alkali is at least one of sodium hydroxide and potassium hydroxide.

4. The preparation method of the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored according to claim 1, wherein in the step 1, the solid strong alkali is at least one of sodium hydroxide and potassium hydroxide.

5. A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored prepared by the preparation method according to claim 1.

6. A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored prepared by the preparation method according to claim 2.

7. A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored prepared by the preparation method according to claim 3.

8. A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored prepared by the preparation method according to claim 4.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1s a flow chart of preparation of a CSH gel with a fly ash.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The present disclosure is further introduced below in conjunction with specific examples, but a claimed protection scope of the present disclosure is not limited thereto.

Example 1

[0028] A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored was provided, and the slurry was prepared from the following raw materials in parts by mass: water: 120 parts, fly ash: 40 parts, solubilizing agent: 20 parts, and solid strong alkali: 3 parts.

[0029] A mass of an ash with a particle size less than or equal to 100 ?m in the fly ash accounted for 80% or more of a total mass of the fly ash; in the fly ash, a silica content was 35.5% and a calcium oxide content was 24.5%; the solubilizing agent was polyoxyethylene sorbitan monolaurate, and a concentration of the solubilizing agent was 3 wt %; and the solid strong alkali was sodium hydroxide.

[0030] A preparation method of the fly ash slurry included the following steps.

[0031] Step 1: The water, solid strong alkali, and fly ash were separately weighed and poured successively into a reactor, and the resulting mixture was stirred at a rotational speed of 1,000 rpm for 5 min to obtain a carbonated fly ash slurry.

[0032] Step 2: The solubilizing agent was added to the reactor, the reactor was sealed, the temperature in the reactor was maintained at room temperature, then carbon dioxide was introduced to maintain a carbon dioxide pressure in the reactor at 3 bar, and the resulting slurry was stirred at a rotational speed of 1,000 rpm for 5 min.

[0033] Step 3: Carbon dioxide was further introduced into the reactor to allow the carbon dioxide pressure in the reactor to reach 10 bar, and then the slurry was stirred at a rotational speed of 80 rpm for 15 min to obtain a fly ash slurry with carbon dioxide stored.

Example 2

[0034] A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored was provided, which was prepared from the following raw materials in parts by mass: water: 120 parts, fly ash: 40 parts, solubilizing agent: 20 parts, and solid strong alkali: 3 parts.

[0035] A mass of an ash with a particle size less than or equal to 100 ?m in the fly ash accounted for 80% or more of a total mass of the fly ash; in the fly ash, a silica content was 33.1% and a calcium oxide content was 18.0%; the solubilizing agent was polyoxyethylene sorbitan monolaurate, and a concentration of the solubilizing agent was 3 wt %; and the solid strong alkali was sodium hydroxide.

[0036] A preparation method of the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored in this example was the same as that in Example 1.

Example 3

[0037] A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored was provided, which was prepared from the following raw materials in parts by mass: water: 120 parts, fly ash: 40 parts, solubilizing agent: 20 parts, and solid strong alkali: 3 parts.

[0038] A mass of an ash with a particle size less than or equal to 100 ?m in the fly ash accounted for 80% or more of a total mass of the fly ash; in the fly ash, a silica content was 37.5% and a calcium oxide content was 11.6%; the solubilizing agent was polyoxyethylene sorbitan monolaurate, and a concentration of the solubilizing agent was 3 wt %; and the solid strong alkali was sodium hydroxide.

[0039] A preparation method of the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored in this example was the same as that in Example 1.

Example 4

[0040] A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored was provided, which was prepared from the following raw materials in parts by mass: water: 120 parts, fly ash: 40 parts, solubilizing agent: 20 parts, and solid strong alkali: 2 parts.

[0041] A mass of an ash with a particle size less than or equal to 100 ?m in the fly ash accounted for 80% or more of a total mass of the fly ash; in the fly ash, a silica content was 35.5% and a calcium oxide content was 24.5%; the solubilizing agent was polyoxyethylene sorbitan monolaurate, and a concentration of the solubilizing agent was 3 wt %; and the solid strong alkali was sodium hydroxide.

[0042] A preparation method of the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored in this example was the same as that in Example 1.

Example 5

[0043] A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored was provided, which was prepared from the following raw materials in parts by mass: water: 120 parts, fly ash: 40 parts, solubilizing agent: 20 parts, and solid strong alkali: 1 part.

[0044] A mass of an ash with a particle size less than or equal to 100 ?m in the fly ash accounted for 80% or more of a total mass of the fly ash; in the fly ash, a silica content was 35.5% and a calcium oxide content was 24.5%; the solubilizing agent was polyoxyethylene sorbitan monolaurate, and a concentration of the solubilizing agent was 3 wt %; and the solid strong alkali was sodium hydroxide.

[0045] A preparation method of the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored in this example was the same as that in Example 1.

Example 6

[0046] A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored was provided, which was prepared from the following raw materials in parts by mass: water: 120 parts, fly ash: 40 parts, solubilizing agent: 10 parts, and solid strong alkali: 3 parts.

[0047] A mass of an ash with a particle size less than or equal to 100 ?m in the fly ash accounted for 80% or more of a total mass of the fly ash; in the fly ash, a silica content was 35.5% and a calcium oxide content was 24.5%; the solubilizing agent was polyoxyethylene sorbitan monolaurate, and a concentration of the solubilizing agent was 3 wt %; and the solid strong alkali was sodium hydroxide.

[0048] A preparation method of the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored in this example was the same as that in Example 1.

Example 7

[0049] A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored was provided, which was prepared from the following raw materials in parts by mass: water: 120 parts, fly ash: 30 parts, solubilizing agent: 20 parts, and solid strong alkali: 3 parts.

[0050] A mass of an ash with a particle size less than or equal to 100 ?m in the fly ash accounted for 80% or more of a total mass of the fly ash; in the fly ash, a silica content was 35.5% and a calcium oxide content was 24.5%; the solubilizing agent was polyoxyethylene sorbitan monolaurate, and a concentration of the solubilizing agent was 3 wt %; and the solid strong alkali was sodium hydroxide.

[0051] A preparation method of the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored in this example was the same as that in Example 1.

Example 8

[0052] A fly ash-based fire-prevention and extinguishing material with carbon dioxide mineralized and stored was provided, which was prepared from the following raw materials in parts by mass: water: 120 parts, fly ash: 20 parts, solubilizing agent: 20 parts, and solid strong alkali: 3 parts.

[0053] A mass of an ash with a particle size less than or equal to 100 ?m in the fly ash accounted for 80% or more of a total mass of the fly ash; in the fly ash, a silica content was 35.5% and a calcium oxide content was 24.5%; the solubilizing agent was polyoxyethylene sorbitan monolaurate, and a concentration of the solubilizing agent was 3 wt %; and the solid strong alkali was sodium hydroxide.

[0054] A preparation method of the fly ash-based fire-prevention and extinguishing material with the carbon dioxide mineralized and stored in this example was the same as that in Example 1.

[0055] The fly ash slurries prepared in Examples 1 to 8 each were subjected to vacuum suction filtration, vacuum drying, grinding, and the like, and then the storage capacity of carbon dioxide in each of the fly ash slurries was determined by thermogravimetric analysis-mass spectrometry (TGA-MS) to evaluate the ability of each of the fly ash slurries to mineralize and store carbon dioxide.

[0056] Specific data is shown in Table 1.

[0057] It can be seen from Table 1 and Examples 1 to 3 that the use of a fly ash with a high calcium oxide content can significantly increase a storage capacity of carbon dioxide to 166.78 g/kg, and this is because a fly ash slurry allows storage of carbon dioxide mainly through a reaction of calcium ions with dissolved carbon dioxide to produce a calcium carbonate precipitate.

[0058] It can be seen from Examples 1, 4, and 5 that the larger the amount of the strong alkali added during preparation, the larger the storage capacity of carbon dioxide, and this is because the higher the concentration of the strong alkali in the fly ash slurry, the more the activated free silica and the more the generated CSH gel, such that increased calcium can be dissolved from a mineral phase and a solid solution to increase the storage capacity of carbon dioxide.

[0059] It can be seen from Examples 1 and 6 that, after a content of the solubilizing agent in the fly ash slurry is increased, the storage capacity of carbon dioxide will also be increased significantly, and this is because the solubilizing agent increases the solubility of metasilicic acid, such that increased metasilicic acid participates in the subsequent reaction to produce an increased amount of the CSH gel.

[0060] It can be seen from Examples 1, 7, and 8 that an increase of a water-solid ratio can also promote the storage of carbon dioxide in the fly ash slurry to some degree.

Example 9

[0061] The fly ash slurry prepared in Example 1 was used for preventing and controlling the spontaneous combustion of coal in a closed coal mine goaf. The fly ash slurry with carbon dioxide stored was delivered to the goaf through a pipeline, and on the day before and after the application of the fly ash slurry, a gas in the goaf was collected and subjected to composition analysis. Composition analysis results are shown in Table 2.

TABLE-US-00001 TABLE 1 Storage capacities of carbon dioxide in the fly ash slurries prepared in Examples 1 to 8 Parts Parts Parts Storage of the of the of the Calcium capacity fly solubilizing strong oxide of carbon Example ash agent alkali content dioxide 1 40 20 3 24.5% 166.78 g/Kg 2 40 20 3 18.0% 124.52 g/Kg 3 40 20 3 11.6% 72.26 g/Kg 4 40 20 2 24.5% 152.56 g/Kg 5 40 20 1 24.5% 143.64 g/Kg 6 40 10 3 24.5% 156.25 g/Kg 7 30 20 3 24.5% 169.31 g/Kg 8 20 20 3 24.5% 179.04/Kg

TABLE-US-00002 TABLE 2 Composition analysis results of the gas in the goaf before and after the application of the fly ash slurry Oxygen Carbon dioxide Gas collection time concentration concentration Before the application of the 6.2454% 2.7237% fly ash slurry After the application of the 4.7376% 3.6841% fly ash slurry

[0062] It can be seen from Table 2 that, after the application of the fly ash slurry with carbon dioxide stored, the oxygen concentration in the closed goaf is decreased from 6.2454% to 4.7376%, which meets the requirement that an oxygen concentration in a closed area should be no more than 5.0% stipulated in the Detailed Rules for Fire Prevention and Extinguishing of Coal Mine. This is because the slurry absorbs heat released by oxidation of remaining coal in goaf when the remaining coal is oxidized and heated, and an increase of a temperature of the slurry itself reduces the solubility of carbon dioxide to release a large amount of carbon dioxide, thereby reducing an oxygen concentration in the goaf. Therefore, it can be known that the fly ash-based fire-prevention and extinguishing material with the carbon dioxide stored can significantly prevent and control the spontaneous combustion of coal in goaf.

Example 10

[0063] A filtrate of the fly ash slurry prepared in Example 1 was mixed with long-flame coal, the resulting mixture was allowed to stand for 5 d and then dried, and then an SSA and pore volume of the coal were measured by SSA and pore size analyzers, respectively. Test data is shown in Table 3.

[0064] It can be seen from Table 3 that, after the coal sample is treated with the filtrate, the SSA and pore volume of the coal sample both are reduced. This is because pores of the treated coal sample are filled with the filtrate, a calcium carbonate crystal is precipitated from the filtrate after drying, and dissolved calcium and magnesium in the coal can react with carbonate ions in the filtrate to produce calcium carbonate and magnesium carbonate precipitates. Because the pores are blocked due to adsorption or precipitation, the reduction of the SSA and pore volume can effectively slow down an oxidation reaction of the coal sample.

TABLE-US-00003 TABLE 3 Changes of the SSA and pore volume before and after treatment with the filtrate of the fly ash slurry Sample SSA (m.sup.2/g) Pore volume (cc/g) Raw coal sample 2.28 0.00402 Treated coal sample 1.49 0.00268

[0065] In addition to sodium hydroxide used in the above examples, potassium hydroxide or a mixture of sodium hydroxide and potassium hydroxide may be used as the solid strong alkali.

[0066] In addition to polyoxyethylene sorbitan monolaurate used in the above examples, another nonionic surfactant may be used as the solubilizing agent, such as polyoxyethylene sorbitan monolaurate sorbate, polyoxyethylene laurate, polyglyceryl fatty acid ester, fatty alcohol polyoxyethylene ether, and polyoxyethylene-polyoxypropylene block copolymer.

[0067] The above examples are merely preferred technical solutions of the present disclosure, and may not be construed as a limitation to the present disclosure. The examples in the present disclosure and features in the examples may be combined with each other in a non-conflicting situation. The protection scope of the present disclosure should be subject to the technical solutions described in the claims, including the equivalent replacements of the technical features in the technical solutions, that is, equivalent replacements or improvements made without departing from the scope should fall within the protection scope of the present disclosure.