Coal mine hole sealing agent and preparation method thereof

Abstract

The invention discloses a coal mine hole sealing agent and a preparation method thereof. The hole sealing agent comprises 10-20 parts of polyvinyl alcohol, 5-15 parts of acrylic acid, 1-5 parts of a cross-linking agent and 1-5 parts of a nanometer material. Adding polyvinyl alcohol into water, heating to 80-90 DEG C, and stirring until the polyvinyl alcohol is completely dissolved; adding acrylic acid in a stirring state, and continuously stirring until the mixture is completely mixed; adding a cross-linking agent, and uniformly stirring; adding a nano material, and fully stirring and mixing to obtain a mixture; and curing the prepared mixture to obtain the coal mine hole sealing agent. The prepared hole sealing agent has the advantages of rapid curing, high hole sealing strength, good durability and excellent compression resistance. The hole sealing agent is suitable for coal mine drill hole sealing, gas leakage can be effectively prevented, and the safety production level of a coal mine is improved.

Description

Technical Field

[0001] The invention relates to the field of coal mining, in particular to a sealing agent for sealing coal mine boreholes and a preparation method thereof. Background Art

[0002] In the process of coal mining, in order to improve the efficiency of gas extraction and ensure the safety of coal mines, it is necessary to effectively seal the boreholes. Traditional sealing materials such as cement slurry have problems such as long curing time, poor sealing effect, and insufficient durability, which cannot meet the needs of safe production in coal mines. Therefore, the development of a new type of coal mine sealing agent has important practical significance. Summary of the invention

[0003] The object of the present invention is to provide a coal mine sealing agent and a preparation method thereof, wherein the sealing agent has rapid curing, high sealing strength, good durability and excellent compressive resistance.

[0004] To achieve the above object, according to one aspect of the present invention, a coal mine sealing agent is provided, comprising the following raw materials in parts by weight: 10-20 parts of polyvinyl alcohol, 5-15 parts of acrylic acid, 1-5 parts of cross-linking agent, and 1-5 parts of nanomaterial.

[0005] As a preferred embodiment, the polyvinyl alcohol has a molecular weight between 50,000 and 100,000.

[0006] As a preferred embodiment, the acrylic acid is partially neutralized acrylic acid.

[0007] As a preferred embodiment, the cross-linking agent is selected from at least one of borax, citric acid and oxalic acid. As a preferred embodiment, the nano material is selected from nano silicon dioxide or nano calcium carbonate.

[0008] According to another aspect of the present invention, a method for preparing the above-mentioned coal mine sealing agent is provided, comprising the following steps: a) Add polyvinyl alcohol into water, heat to 80-90℃, and stir until completely dissolved; b) Add acrylic acid while stirring and continue stirring until completely mixed; c) adding a cross-linking agent and stirring evenly; d) adding nanomaterials, and stirring and mixing to obtain a mixture; e) subjecting the obtained mixture to aging treatment to obtain a coal mine sealing agent.

[0009] As a preferred embodiment, in step e), the aging treatment time is 24-48 hours.

[0010] As a preferred embodiment, the method further comprises the step of pre-swelling the polyvinyl alcohol with water before step a).

[0011] According to the technical solution provided by the present invention, polyvinyl alcohol and acrylic acid are used as the main plugging materials, and a cross-linking agent and nanomaterials are added, so that the sealing agent has excellent physical and chemical properties. When the sealing agent is used in a coal mine borehole, it can quickly solidify to form a high-strength sealing layer, effectively prevent gas leakage, and improve the safety level of coal mine production. DETAILED DESCRIPTION

[0012] The technical scheme claimed in the present invention is further described below by some examples. However, the examples are used to explain the embodiments of the present invention and do not exceed the scope of the subject matter of the present invention. The protection scope of the present invention is not limited by the examples. Unless otherwise specified, the materials and reagents used in the present invention can be obtained from commercial products in the art. Example 1

[0013] A coal mine sealing agent was prepared according to the following weight percentages: 15 kg of polyvinyl alcohol, 10 kg of acrylic acid, 3 kg of borax, and 2 kg of nano-silicon dioxide.

[0014] The preparation steps are as follows: a) Add 15kg of polyvinyl alcohol to 100kg of water, heat to 85℃, and stir until completely dissolved; b) Slowly add 10 kg of acrylic acid while stirring, and continue stirring until completely mixed; c) Add 3kg borax and stir evenly; d) Add 2 kg of nano-silicon dioxide and stir thoroughly to mix; e) subjecting the obtained mixture to aging treatment for 24 hours to obtain a coal mine sealing agent.

[0015] When in use, the sealing agent is injected into the coal mine drill hole, and the sealing agent quickly solidifies in a short time to form a solid sealing layer. Example 2

[0016] A coal mine sealing agent was prepared according to the following weight percentages: 12 kg of polyvinyl alcohol, 8 kg of acrylic acid, 2 kg of citric acid, and 4 kg of nano calcium carbonate.

[0017] The preparation steps are as follows: a) Add 12kg of polyvinyl alcohol to 100kg of water, heat to 90℃, and stir until completely dissolved; b) slowly add 8 kg of acrylic acid while stirring, and continue stirring until completely mixed; c) Add 2kg citric acid and stir evenly; d) Add 4 kg of nano calcium carbonate and stir thoroughly to mix; e) subjecting the obtained mixture to aging treatment for 24 hours to obtain a coal mine sealing agent.

[0018] When in use, the sealing agent is injected into the coal mine drill hole, and the sealing agent quickly solidifies in a short time to form a solid sealing layer. Example 3

[0019] A coal mine sealing agent was prepared according to the following weight percentages: 18 kg of polyvinyl alcohol, 12 kg of acrylic acid, 4 kg of oxalic acid, and 3 kg of nano-silicon dioxide.

[0020] The preparation steps are as follows: a) Add 18kg of polyvinyl alcohol to 120kg of water, heat to 88°C, and stir until completely dissolved; b) Slowly add 12 kg of acrylic acid while stirring, and continue stirring until completely mixed; c) Add 4kg oxalic acid and stir evenly; d) Add 3 kg of nano silicon dioxide and stir thoroughly to mix; e) The obtained mixture is subjected to aging treatment for 36 hours to obtain a coal mine sealing agent.

[0021] When in use, the sealing agent is injected into the coal mine borehole. According to experimental results, the sealing agent begins to solidify in about 10-15 minutes and is completely cured within 1 hour. The sealing layer has excellent compressive strength and corrosion resistance. Example 4

[0022] A coal mine sealing agent was prepared according to the following weight percentages: 10 kg of polyvinyl alcohol, 5 kg of acrylic acid, 1 kg of borax, and 1 kg of nano-silicon dioxide.

[0023] The preparation steps are as follows: a) Add 10kg of polyvinyl alcohol to 100kg of water, heat to 80℃, and stir until completely dissolved; b) slowly add 5 kg of acrylic acid while stirring, and continue stirring until completely mixed; c) Add 1kg borax and stir evenly; d) Add 1 kg of nano-silicon dioxide and stir thoroughly; e) subjecting the obtained mixture to aging treatment for 24 hours to obtain a coal mine sealing agent.

[0024] When in use, the sealing agent is injected into the coal mine borehole. According to experimental results, the sealing agent begins to solidify in about 10-15 minutes and is completely cured within 1 hour. The sealing layer has excellent compressive strength and corrosion resistance. Example 5

[0025] A coal mine sealing agent was prepared according to the following weight percentages: 20 kg of polyvinyl alcohol, 15 kg of acrylic acid, 5 kg of oxalic acid, and 5 kg of nano calcium carbonate.

[0026] The preparation steps are as follows: a) Add 20kg of polyvinyl alcohol to 120kg of water, heat to 90℃, and stir until completely dissolved; b) Slowly add 15 kg of acrylic acid while stirring, and continue stirring until completely mixed; c) Add 5kg oxalic acid and stir evenly; d) Add 5 kg of nano calcium carbonate and stir thoroughly to mix; e) subjecting the obtained mixture to aging treatment for 48 hours to obtain a coal mine sealing agent.

[0027] When in use, the sealing agent is injected into the coal mine borehole. According to experimental results, the sealing agent begins to solidify in about 10-15 minutes and is completely cured within 1 hour. The sealing layer has excellent compressive strength and corrosion resistance.

[0028] In order to verify the performance of the sealing agent of the present invention, the following tests were performed: 1. Curing time test: At room temperature, the sealant samples were injected into the standard drilling model, and the time from injection to complete curing of the sealant was recorded. The test results show that the sealants in all embodiments can be completely cured within 1 hour, meeting the requirements of rapid sealing.

[0029] 2. Compressive strength test: According to GB / T 228.1-2010 standard, the compressive strength test of the cured sealant samples was carried out. The results showed that the compressive strength of the sealant samples of Examples 1, 2 and 3 reached 25 MPa, 28 MPa and 30 MPa respectively, which were significantly better than the traditional cement sealing materials.

[0030] 3. Sealing durability test: By simulating the underground environment of a coal mine, the sealing agent samples were subjected to long-term immersion and pressure cycle tests. The experimental results show that the sealing agent samples in the embodiment still maintain good structural integrity and sealing effect after immersion for 30 days, and no significant strength reduction occurs.

[0031] 4. Gas permeability test: The gas permeability of the sealing agent of the present invention and the traditional sealing material was tested through comparative experiments. The results showed that the gas permeability of the sealing agent of the present invention was one order of magnitude lower than that of the traditional sealing material, which effectively reduced the risk of gas leakage.

[0032] The above examples and test results fully demonstrate that the coal mine sealing agent of the present invention has significant technical advantages in rapid solidification, high sealing strength, durability and resistance to gas permeability, can meet the needs of safe production in coal mines, and improve gas extraction efficiency.

[0033] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various deformations and changes. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A coal mine sealing agent, characterized in that: Including the following raw materials by mass: 10-20 parts of polyvinyl alcohol, 5-15 parts of acrylic acid, 1-5 parts of cross-linking agent, and 1-5 parts of nanomaterial.

2. The coal mine sealing agent according to claim 1, characterized in that: The molecular weight of the polyvinyl alcohol is between 50,000 and 100,000.

3. The coal mine sealing agent according to claim 1 or 2, characterized in that: The acrylic acid is partially neutralized acrylic acid.

4. The coal mine sealing agent according to claim 3, characterized in that: The cross-linking agent is selected from at least one of borax, citric acid and oxalic acid.

5. The coal mine sealing agent according to claim 1 or 4, characterized in that: The nano material is selected from nano silicon dioxide or nano calcium carbonate.

6. The method for preparing the coal mine sealing agent according to any one of claims 1 to 5, comprising the following steps: a) Add polyvinyl alcohol into water, heat to 80-90℃, and stir until completely dissolved; b) Add acrylic acid while stirring and continue stirring until completely mixed; c) adding a cross-linking agent and stirring evenly; d) adding nanomaterials, and stirring and mixing to obtain a mixture; e) subjecting the obtained mixture to aging treatment to obtain a coal mine sealing agent.

7. The preparation method according to claim 6, characterized in that: In step e), the aging treatment time is 24-48 hours.

8. The preparation method according to claim 6 or 7, characterized in that: The method further comprises the step of pre-swelling the polyvinyl alcohol with water before step a).