Grouting material for sealing CO2 in coal-based solid waste composite grouting and preparation method

Abstract

The invention discloses a grouting material for sealing CO2 in coal-based solid waste composite grouting and a preparation method, and belongs to the field of filling mining. The grouting material comprises the following components in parts by weight: 20-40 parts of coal gasification slag powder, 10-20 parts of coal gangue powder, 1-5 parts of an alkali activator, 0.1-1.0 part of a CO2 reinforced introduction agent and 15-50 parts of water. The preparation method comprises the following steps: firstly, mixing the coal gasification slag powder and the coal gangue powder in a mixer for 2-10 minutes to obtain mixed powder; secondly, sequentially adding water, an alkali activator and a CO2 reinforced introduction agent, and mixing and stirring for 3-5 minutes to obtain a mixed solution; and then, pouring the mixed solution into the mixed powder, and mixing and stirring for 5-10 minutes to obtain the grouting material. The method for sealing and storing CO2 comprises the following steps: pouring the grouting material into a mineralization reaction kettle, and stirring for 10-60 minutes in a CO2 atmosphere with the temperature of 35-60 DEG C and the pressure of 0.1-0.5 MPa to form the grouting and sealing and storing CO2 material. The prepared grouting material has the advantages of being low in cost, large in CO2 storage amount and the like.

Description

Technical Field

[0001] The present invention belongs to the field of backfill mining, and in particular relates to a coal-based solid waste composite grouting CO2 sealing material and a preparation method thereof. Background Art

[0002] As industrial solid waste, coal gasification slag and coal gangue not only occupy a large amount of land, but also cause serious pollution to the environment. However, coal gasification slag is currently often used in construction materials, ecological governance and other fields, but due to its high carbon content, low activity, and heavy metal pollution hazards, it is difficult to separate and utilize it on a large scale; coal gangue treatment methods commonly use hot pouring, drum method, and hot stuffing method, but there are problems such as poor stability and stability of coal gangue, which is not conducive to the comprehensive utilization of tailings, low utilization efficiency, and low safety factor. At the same time, large-scale CO2 emissions from the outside world during industrial production processes have brought about adverse effects such as environmental pollution, global warming, and rising sea levels. Therefore, how to dispose of solid wastes such as coal gasification slag and coal gangue on a large scale and reduce carbon dioxide emissions has become one of the problems that need to be solved urgently under the background of dual carbon.

[0003] Grouting filling is one of the core technologies of green mining. It has significant advantages such as no interference between filling and coal mining in time and space, large amount of gangue solid waste disposal, and good effect of controlling surface deformation. It has been rapidly developed in recent years. At the same time, it can make good use of solid waste such as coal gasification slag and coal gangue to prepare grouting materials, realize their large-scale disposal and resource utilization, and seal CO2 in the goaf with the help of filling materials.

[0004] At present, regarding the CO2 storage technology using filling materials, CN202210739976.5 is a full-solid waste mine filling carbon storage paste and its preparation method, which uses solid wastes such as fly ash and steel slag to prepare a full-solid waste mine filling carbon storage paste with excellent CO2 storage capacity and mechanical strength. CN202011284458.6 is a carbon dioxide storage measurement system and measurement method based on filling paste, but this technology does not further explain the carbon fixation and performance. CN202211274086.8 is a method for fluidized filling and disposal of mine solid waste to coordinate carbon dioxide storage, which forms a ground carbon fixation-ground well filling-underground carbon fixation system, but does not explain the mechanical properties and carbon fixation effect of the filling material. In addition, since most conventional filling materials do not contain additives to increase the CO2 storage effect, their CO2 storage capacity is poor.

[0005] Based on this, the present invention proposes a grouting material and a preparation method for coal-based solid waste composite grouting to seal CO2. The use of coal-based solid waste to prepare grouting materials can effectively solve the problem of high cost of traditional filling materials. By adding CO2 enhanced introduction agents, large-scale storage of CO2 can also be achieved. It is a new grouting material with multiple functions of solid waste resource utilization and CO2 storage. Summary of the invention

[0006] Purpose of the invention: In view of the shortcomings of the prior art, the present invention provides a grouting material and a preparation method for composite grouting of coal-based solid waste to store CO2, which reduces the use of cement, reduces the filling cost, improves the resource utilization rate of coal gasification slag and coal gangue solid waste and the CO2 storage efficiency, and achieves the dual purposes of large-scale disposal of bulk solid waste and CO2 storage.

[0007] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0008] The first object of the present invention is to provide a grouting material for coal-based solid waste composite grouting to seal CO2. The composition of the coal-based solid waste composite grouting to seal CO2 material includes, by weight: 20-40 parts of coal gasification slag powder, 10-20 parts of coal gangue powder, 1-5 parts of alkali activator, 0.1-1.0 parts of CO2 enhanced introduction agent, and 15-50 parts of water. The CO2 enhanced introduction agent includes at least one of sodium dodecyl sulfate, sodium rosin acid, and sodium lignin sulfonate.

[0009] Optionally, in one embodiment of the present invention, the alkaline activator includes at least one of sodium hydroxide, sodium silicate, and potassium silicate. Commonly used alkaline activators are mainly caustic soda, silicates containing alkaline elements, etc. The selected sodium hydroxide, sodium silicate, and potassium silicate are relatively common alkaline activators, which are cheap and easy to obtain. Alkaline activators can accelerate the chemical reaction rate and promote the reaction. At the same time, they can also maintain the alkaline conditions in the system and promote the occurrence of solid waste volcanic ash reaction.

[0010] Further optionally, in one embodiment of the present invention, the alkaline activator comprises, by weight: 30-70 parts of sodium hydroxide, 5-20 parts of sodium silicate, and 5-10 parts of potassium silicate.

[0011] Preferably, the alkaline activator comprises, by weight: 40-60 parts of sodium hydroxide, 10-20 parts of sodium silicate, and 5-8 parts of potassium silicate.

[0012] Optionally, in one embodiment of the present invention, the particle sizes of the coal gasification slag powder and coal gangue powder are independently 10-75 μm. In this case, the coal gasification slag powder and coal gangue powder have a larger specific surface area, which can increase their hydration activity.

[0013] Optionally, in one embodiment of the present invention, the added amount of the CO2 enhancement introduction agent is 0.4-1 part.

[0014] Optionally, in one embodiment of the present invention, the CO2 enhanced introduction agent includes at least one of sodium dodecyl sulfate, sodium rosin acid, and sodium lignin sulfonate. The CO2 enhanced introduction agent can introduce a large number of tiny, stable bubbles into the grouting material, and the alkali activator can promote the generation of reaction products in the system to produce a large amount of gel, which is adsorbed on the surface of the bubbles and has the effect of stabilizing the bubbles, thereby increasing the CO2 storage capacity in the bubbles.

[0015] Further optionally, in one embodiment of the present invention, the components of the CO2 enhanced introduction agent include, by weight: 20-60 parts of sodium dodecyl sulfate, 5-20 parts of sodium rosin acid, and 20-85 parts of sodium lignin sulfonate.

[0016] Preferably, the CO2 enhanced introduction agent comprises, by weight: 40-60 parts of sodium dodecyl sulfate, 10-20 parts of sodium rosin acid, and 40-50 parts of sodium lignin sulfonate.

[0017] The second object of the present invention is to provide a method for preparing a grouting material for storing CO2 using a coal-based solid waste composite grouting material, comprising the following steps:

[0018] S1. Put coal gasification slag powder and coal gangue powder into a mixer, mix and stir them to obtain mixed powder;

[0019] S2, mixing water, alkali activator and CO2 strengthening introduction agent for a second time to obtain a mixed solution;

[0020] S3, pouring the mixed powder into the mixed solution, and mixing and stirring for the third time to obtain the grouting material.

[0021] Optionally, in one embodiment of the present invention, in step S1, the first mixing and stirring time is 2-10 minutes.

[0022] Optionally, in one embodiment of the present invention, in step S2, the second mixing and stirring time is 3-5 minutes.

[0023] Optionally, in one embodiment of the present invention, in step S3, the third mixing and stirring time is 5-10 minutes.

[0024] Optionally, in one embodiment of the present invention, the method for preparing the grouting material for storing CO2 using the coal-based solid waste composite grouting material comprises the following steps, the components are measured by weight:

[0025] S1. Put 20-40 parts of coal gasification slag powder and 10-20 parts of coal gangue powder into a mixer and mix them evenly for 2-10 minutes to obtain a mixed powder;

[0026] S2, sequentially add 15-50 parts of water, 1-5 parts of alkali activator and 0.1-1.0 parts of CO2 enhanced introduction agent, mix and stir evenly for 3-5 minutes to obtain a mixed solution;

[0027] S3. Pour the mixed solution into the mixed powder, mix and stir for 5-10 minutes to obtain a grouting material.

[0028] The third object of the present invention is to provide an application of any of the above-mentioned grouting materials for coal-based solid waste composite grouting to store CO2 in the field of solid waste resource utilization or carbon storage.

[0029] The fourth object of the present invention is to provide a method for coal-based solid waste composite grouting to seal CO2, characterized in that it includes the following steps: pouring any of the above grouting materials into a mineralization reactor, uniformly stirring for 10-60 minutes in a CO2 atmosphere of 35-60°C and 0.1-0.5MPa to form a grouting material for sealing CO2.

[0030] Optionally, in one embodiment of the present invention, the storage amount of CO2 is higher than 1.0%.

[0031] Further optionally, in one embodiment of the present invention, the storage amount of CO2 is higher than 1.2%.

[0032] Beneficial effects: The grouting material and preparation method for coal-based solid waste composite grouting to store CO2 provided by the present invention have the following advantages compared with the prior art:

[0033] (1) Using alkaline activators to activate the activity of coal gasification slag powder and coal gangue powder, thereby replacing cement, reducing filling costs and having good economic benefits;

[0034] (2) The use of coal gasification slag and coal gangue to prepare grouting filling materials realizes the large-scale disposal and utilization of industrial solid waste, which is economical, green and environmentally friendly;

[0035] (3) Adding CO2 enhanced introduction agent into the grouting material effectively increases the CO2 storage capacity and has good promotion prospects. DETAILED DESCRIPTION

[0036] The purpose of the present invention is to provide a grouting material and a preparation method for coal-based solid waste composite grouting to seal CO2, aiming to reduce the use of cement, improve the utilization of industrial solid waste, and increase the amount of CO2 sealed, thereby achieving the dual goals of solid waste disposal and coordinated CO2 storage.

[0037] The present invention relates to a grouting material and a preparation method for coal-based solid waste composite grouting to seal CO2, and belongs to the field of solid waste resource utilization and carbon sequestration. The grouting material for coal-based solid waste composite grouting to seal CO2 in the present invention comprises, by weight: 20-40 parts of coal gasification slag powder, 10-20 parts of coal gangue powder, 1-5 parts of alkali activator, 0.1-1.0 parts of CO2 enhanced introduction agent, and 15-50 parts of water.

[0038] In the embodiment of the present invention, the method for preparing the grouting material for coal-based solid waste composite grouting to seal CO2 comprises the following steps, measured by weight:

[0039] S1. Put 20-40 parts of coal gasification slag powder and 10-20 parts of coal gangue powder into a mixer and mix them evenly for 2-10 minutes to obtain a mixed powder;

[0040] S2, sequentially add 15-50 parts of water, 1-5 parts of alkali activator and 0.1-1.0 parts of CO2 enhanced introduction agent, mix and stir evenly for 3-5 minutes to obtain a mixed solution;

[0041] S3. Pour the mixed solution into the mixed powder, mix and stir for 5-10 minutes to obtain a grouting material.

[0042] Furthermore, the present invention also uses the obtained grouting material for grouting and sealing CO2. The specific method includes: pouring the obtained grouting material into a mineralization reactor, uniformly stirring it in a CO2 atmosphere of 35-60°C and 0.1-0.5MPa for 10-60 minutes to form a grouting and sealing CO2 material.

[0043] The present invention will be further described below in conjunction with examples. According to the following examples, the present invention can be better understood. However, it is easy for those skilled in the art to understand that the specific material ratios, process conditions and results described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0044] Example 1

[0045] The specific steps of preparing the coal-based solid waste composite grouting material in this embodiment are as follows:

[0046] a. Weigh 20 parts of coal gasification slag powder (particle size distribution of 10-75μm) and 10 parts of coal gangue powder (particle size distribution of 10-75μm) and put them into a mixer and mix them evenly for 2 minutes to obtain a mixed powder;

[0047] b. Weigh 1 part of an alkali activator (50 parts of sodium hydroxide, 15 parts of sodium silicate, 7 parts of potassium silicate), 0.1 parts of a CO2 enhanced introduction agent (50 parts of sodium dodecyl sulfate, 15 parts of sodium rosin acid, 45 parts of sodium lignin sulfonate) and 15 parts of water, mix and stir evenly for 3 minutes to obtain a mixed solution;

[0048] c. Pour the mixed powder into the mixed solution, mix and stir for 5 minutes to obtain a grouting material;

[0049] d. Pour the grouting material into the mineralization reactor and stir evenly for 10 minutes in a CO2 atmosphere at 35°C and 0.1MPa to obtain the grouting CO2 sealing material.

[0050] Example 2

[0051] The specific steps of preparing the coal-based solid waste composite grouting material in this embodiment are as follows:

[0052] a. Weigh 25 parts of coal gasification slag powder (particle size distribution of 10-75μm) and 15 parts of coal gangue powder (particle size distribution of 10-75μm) and put them into a mixer and mix them evenly for 6 minutes to obtain a mixed powder;

[0053] b. Weigh 3 parts of an alkali activator (40 parts of sodium hydroxide, 10 parts of sodium silicate, 5 parts of potassium silicate), 0.4 parts of a CO2 enhanced introduction agent (40 parts of sodium dodecyl sulfate, 10 parts of sodium rosin acid, 60 parts of sodium lignin sulfonate) and 30 parts of water, mix and stir evenly for 4 minutes to obtain a mixed solution;

[0054] c. Pour the mixed powder into the mixed solution, mix and stir for 8 minutes to obtain a grouting material;

[0055] d. Pour the grouting material into the mineralization reactor and stir evenly in a CO2 atmosphere at 50°C and 0.3MPa for 30 minutes to obtain the grouting CO2 sealing material.

[0056] Example 3

[0057] The specific steps of preparing the coal-based solid waste composite grouting material in this embodiment are as follows:

[0058] a. Weigh 40 parts of coal gasification slag powder (particle size distribution of 10-75μm) and 20 parts of coal gangue powder (particle size distribution of 10-75μm) and put them into a mixer and mix them evenly for 10 minutes to obtain a mixed powder;

[0059] b. Weigh 5 parts of an alkali activator (30 parts of sodium hydroxide, 20 parts of sodium silicate, 10 parts of potassium silicate), 1 part of a CO2 enhanced introduction agent (40 parts of sodium dodecyl sulfate, 20 parts of sodium rosin acid, 50 parts of sodium lignin sulfonate) and 50 parts of water, mix and stir evenly for 5 minutes to obtain a mixed solution;

[0060] c. Pour the mixed powder into the mixed solution, mix and stir for 10 minutes to obtain a grouting material;

[0061] d. Pour the grouting material into the mineralization reactor and stir it evenly in a CO2 atmosphere at 60°C and 0.5MPa for 60 minutes to obtain the grouting CO2 sealing material.

[0062] Example 4

[0063] Same as Example 2, except that the amount of CO2 enhanced introducing agent used is different.

[0064] The specific steps of preparing the coal-based solid waste composite grouting material in this embodiment are as follows:

[0065] a. Weigh 25 parts of coal gasification slag powder (particle size distribution of 10-75μm) and 15 parts of coal gangue powder (particle size distribution of 10-75μm) and put them into a mixer and mix them evenly for 6 minutes to obtain a mixed powder;

[0066] b. Weigh 3 parts of an alkali activator (40 parts of sodium hydroxide, 10 parts of sodium silicate, 5 parts of potassium silicate), 0.1 parts of a CO2 enhanced introduction agent (40 parts of sodium dodecyl sulfate, 10 parts of sodium rosin acid, 60 parts of sodium lignin sulfonate) and 30 parts of water, mix and stir evenly for 4 minutes to obtain a mixed solution;

[0067] c. Pour the mixed powder into the mixed solution, mix and stir for 8 minutes to obtain a grouting material;

[0068] d. Pour the grouting material into the mineralization reactor and stir evenly in a CO2 atmosphere at 50°C and 0.3MPa for 30 minutes to obtain the grouting CO2 sealing material.

[0069] Example 5

[0070] Same as Example 2, except that the amount of CO2 enhanced introducing agent used is different.

[0071] The specific steps of preparing the coal-based solid waste composite grouting material in this embodiment are as follows:

[0072] a. Weigh 25 parts of coal gasification slag powder (particle size distribution of 10-75μm) and 15 parts of coal gangue powder (particle size distribution of 10-75μm) and put them into a mixer and mix them evenly for 6 minutes to obtain a mixed powder;

[0073] b. Weigh 3 parts of an alkali activator (40 parts of sodium hydroxide, 10 parts of sodium silicate, 5 parts of potassium silicate), 1 part of a CO2 enhanced introduction agent (40 parts of sodium dodecyl sulfate, 10 parts of sodium rosin acid, 60 parts of sodium lignin sulfonate) and 30 parts of water, mix and stir evenly for 4 minutes to obtain a mixed solution;

[0074] c. Pour the mixed powder into the mixed solution, mix and stir for 8 minutes to obtain a grouting material;

[0075] d. Pour the grouting material into the mineralization reactor and stir evenly in a CO2 atmosphere at 50°C and 0.3MPa for 30 minutes to obtain the grouting CO2 sealing material.

[0076] Comparative Example 1

[0077] The same as Example 2, except that no CO2 enhancing introduction agent was added in this comparative example, and the purpose was to study the effect of the CO2 enhancing introduction agent on the grouting and sealing CO2 material.

[0078] The specific steps of preparing the coal-based solid waste composite grouting material in this comparative example are as follows:

[0079] a. Weigh 25 parts of coal gasification slag powder (particle size distribution of 10-75μm) and 15 parts of coal gangue powder (particle size distribution of 10-75μm) and put them into a mixer and mix them evenly for 6 minutes to obtain a mixed powder;

[0080] b. 3 parts of an alkali activator (40 parts of sodium hydroxide, 10 parts of sodium silicate, 5 parts of potassium silicate) and 30 parts of water were uniformly mixed and stirred for 4 minutes to obtain a mixed solution;

[0081] c. Pour the mixed powder into the mixed solution, mix and stir for 8 minutes to obtain a grouting material;

[0082] d. Pour the grouting material into the mineralization reactor and stir evenly in a CO2 atmosphere at 50°C and 0.3MPa for 30 minutes to obtain the grouting CO2 sealing material.

[0083] Test Case

[0084] In order to detect the CO2 storage capacity of the grouting material, the weight of the grouting material obtained in step c and the weight of the grouting CO2 storage material obtained in step d were weighed using an analytical balance, which were recorded as m0 and m1 respectively. The weighing accuracy was 0.0001g. The average value was taken after three tests. The CO2 storage capacity was calculated using formula (1):

[0085]

[0086] In order to detect the mechanical properties of the grouting CO2 sealing material, the grouting CO2 sealing material obtained in step d was poured into a triple mold with a size of 70.7*70.7*70.7mm, placed on a vibrator and vibrated for 30 seconds, demolded after 24 hours, and placed in a curing box with a temperature of 20°C and a humidity of 95%, cured for 14 days, and then its uniaxial compressive strength was tested.

[0087] The CO2 storage capacity and mechanical property test results obtained in each comparative example and embodiment are shown in Table 1.

[0088] Table 1 Experimental results

[0089] Group <![CDATA[CO2 Sequestration Amount / %]]> Uniaxial compressive strength / MPa Example 1 6.28 1.18 Example 2 8.78 1.59 Example 3 9.86 1.72 Example 4 6.32 1.57 Example 5 9.76 1.60 Comparative Example 1 1.04 1.42

[0090] From the above results, it can be found that compared with Example 1 in which no CO2 enhancement introduction agent was added, the CO2 storage capacity of the grouting material in Examples 1-5 was significantly higher than that in Example 1 after the CO2 enhancement introduction agent was used, and the mechanical properties were slightly different, indicating that the CO2 enhancement introduction agent can effectively increase the CO2 storage capacity without weakening the mechanical properties of the grouting CO2 storage material.

[0091] The above results indicate that the grouting material and preparation method for coal-based solid waste composite grouting to seal CO2 of the present invention effectively increase the CO2 storage capacity, achieving the dual goals of solid waste disposal and CO2 storage, and providing a new material for the utilization of industrial solid waste and CO2 storage.

[0092] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A grouting material for coal-based solid waste composite grouting to store CO2, characterized in that: Its components include, by weight: 20-40 parts of coal gasification slag powder, 10-20 parts of coal gangue powder, 1-5 parts of alkali activator, 0.1-1.0 parts of CO2 enhancement introduction agent, and 15-50 parts of water. The CO2 enhancement introduction agent refers to a chemical additive that can enhance the dissolution and mineralization of CO2, including at least one of sodium dodecyl sulfate, sodium rosin acid, and sodium lignin sulfonate.

2. The grouting material for coal-based solid waste composite grouting to store CO2 according to claim 1, characterized in that: The alkaline activator includes at least one of sodium hydroxide, sodium silicate and potassium silicate; preferably, the alkaline activator includes, by weight: 30-70 parts of sodium hydroxide, 5-20 parts of sodium silicate and 5-10 parts of potassium silicate.

3. The grouting material for coal-based solid waste composite grouting to store CO2 according to claim 1, characterized in that: The added amount of the CO2 enhanced introduction agent is 0.4-1 part.

4. The grouting material for coal-based solid waste composite grouting to store CO2 according to claim 1, characterized in that: The CO2 enhanced introduction agent comprises, by weight: 20-60 parts of sodium dodecyl sulfate, 5-20 parts of sodium rosin acid, and 20-85 parts of sodium lignin sulfonate; Preferably, the CO2 enhanced introduction agent comprises, by weight: 40-60 parts of sodium dodecyl sulfate, 10-20 parts of sodium rosin acid, and 40-50 parts of sodium lignin sulfonate.

5. The grouting material for coal-based solid waste composite grouting to store CO2 according to claim 1, characterized in that: The particle sizes of the coal gasification slag powder and the coal gangue powder are independently 10-75 μm.

6. A method for preparing a grouting material for coal-based solid waste composite grouting to store CO2 as described in any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Put coal gasification slag powder and coal gangue powder into a mixer, mix and stir them to obtain mixed powder; S2, mixing water, alkali activator and CO2 strengthening introduction agent for a second time to obtain a mixed solution; S3, pouring the mixed powder into the mixed solution, and mixing and stirring for the third time to obtain the grouting material.

7. The method according to claim 6, characterized in that In step S1, the first mixing and stirring time is 2-10 minutes; In step S2, the second mixing and stirring time is 3-5 minutes; in step S3, the third mixing and stirring time is 5-10 minutes.

8. Application of the grouting material for coal-based solid waste composite grouting to store CO2 as described in any one of claims 1 to 5 in the field of solid waste resource utilization or carbon storage.

9. A method for storing CO2 by composite grouting of coal-based solid waste, characterized in that: The following steps are involved: Pour the grouting material into the mineralization reactor, stir evenly for 10-60 minutes in a CO2 atmosphere at 35-60°C and 0.1-0.5MPa to form a grouting material for sealing CO2. The grouting material is the grouting material for composite grouting sealing of CO2 by coal-based solid waste as described in any one of claims 1-5.

10. The method according to claim 9, characterized in that The storage amount of CO2 is higher than 1.0%; preferably, the storage amount of CO2 is higher than 1.2%.

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