Light low-temperature foaming mining filling material, preparation method and application

Abstract

The invention discloses a lightweight low-temperature foaming mining filling material and preparation and application thereof. The lightweight low-temperature foaming mining filling material is composed of a component A and a component B according to a mass ratio of 1: 1. The component A is prepared from fly ash, desulfurized gypsum, poly (N-isopropylacrylamide) (PNIPAM), basalt fiber, expanded perlite, a foaming agent, an auxiliary agent and water; the component B comprises sodium sulfate, water glass, tetramethyl ammonium hydroxide and water. Through cooperation of compounding of double-particle-size fly ash and a'water glass-sodium sulfate-tetramethyl ammonium hydroxide 'ternary excitation system, rapid foaming and curing at low temperature are achieved, the compressive strength of one day is larger than or equal to 3.51 MPa, the compressive strength of seven days is larger than or equal to 5.66 MPa, the dry density is 0.40-0.50 g / cm < 3 >, the freeze-thaw resistance coefficient is larger than or equal to 0.94, initial setting lasts for 36-41 min, and final setting lasts for 99-106 min. The material has the advantages of light weight, early strength, low cost and environmental protection, effectively solves the problems of low-temperature failure and insufficient strength of the traditional material, and is suitable for low-temperature grouting filling of the coal mine goaf.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of mine filling materials, in particular to a light low-temperature foaming mine filling material, which is suitable for filling and grouting operation after mining, especially has good performance in low-temperature environment. BACKGROUND

[0002] Coal mine safety accidents are mainly caused by two factors: one is the explosion and suffocation risk caused by underground gas leakage; the second is the collapse of roadway or stope caused by the decrease of rock bearing capacity. In view of these problems, the use of light materials with high efficient plugging and filling performance has become a key technical approach to prevent coal mine accidents. The commonly used mine filling materials at present mainly include cement-based materials, paste materials and concrete, etc. However, the traditional filling materials still have the following significant defects: (1) the material density is high, the filling body has large unit weight, which is easy to exert high load on coal pillar and surrounding rock, thereby affecting the overall stability of the shaft and roadway structure, and even inducing secondary geological disasters such as ground subsidence; (2) under low temperature conditions, the solidification rate of the material decreases significantly, the strength develops slowly, especially in cold areas or deep mining environment, it is difficult to realize rapid and effective support of goaf, which seriously affects the construction progress and stope safety; (3) most of the current materials use cement as the main cementing component, which not only has high cost, but also needs to consume a large amount of limestone resources, which is contrary to the concept of energy saving and carbon reduction and sustainable development advocated by green mine construction; (4) the existing foaming filling materials usually need to trigger foaming under high temperature conditions, which has the problems of high energy consumption, poor controllability of reaction and insufficient uniformity of foaming. In addition, the compressive strength of many filling materials is difficult to meet the requirements of long-term stability of filling body in complex geological and high stress mining environment, which is easy to cause the crushing, deformation or damage of filling body, and threatens the overall safety of mine.

[0003] In coal mine grouting engineering, fly ash (FA) is often used as the main component or admixture of grouting material due to its wide source, low cost and certain cementitious activity. However, the pozzolanic activity of fly ash is much lower than that of cement, and with the increase of the dosage, the compressive strength of the stone body decreases significantly. When the fly ash content is >60%, the 7-day compressive strength may be less than 1 MPa, which is difficult to meet the pressure-bearing reinforcement requirements. High content of fly ash leads to loose structure of the stone body, increase of unreacted spherical particles and porosity, and reduction of density. Fly ash delays the hydration reaction, and when the content is >50%, the initial and final setting times are significantly prolonged. For example, when the content is 70%, the final setting time can be more than twice that of ordinary cement slurry, affecting the progress of grouting engineering. The particle size distribution of fly ash is uneven, resulting in poor water retention of the slurry. When the content is >60%, the water separation rate can reach more than 25%, which can easily cause segregation, delamination and pipe blockage accidents. Especially important is that the hydration reaction energy barrier of fly ash increases at low temperature (such as <10℃), and the early strength development is slow, which is difficult to meet the rapid consolidation requirements of water-rich strata. The main defects of fly ash in coal mine grouting are low strength, slow setting and low temperature failure, which are mainly due to low activity, uneven particle size and strong hydration dependence. The above defects of fly ash limit its application in grouting materials.

[0004] Fly ash is a fine particle residue produced after coal combustion, with a particle size distribution usually between 0.5-200 μm and a density of about 2.2 g / cm 3 In grouting materials, the particle size distribution of fly ash directly affects its physical properties and chemical reaction activity. Studies have shown that uneven particle size distribution of fly ash particles can increase the porosity of the material and reduce the contact area between particles, thereby affecting the strength development and stability of the grouting material. At the same time, the hydration reaction of fly ash depends on its interaction with cement hydration products, which will significantly slow down in low temperature environment, leading to further decline in material performance.

[0005] In view of the problems of fly ash in grouting materials, a series of effective measures are taken. On the one hand, fly ash of different particle sizes is used for compounding, which effectively reduces the porosity and makes the material structure more compact, thereby improving the compressive strength. On the other hand, a ternary activation system of "water glass-sodium sulfate-tetramethyl ammonium hydroxide" is constructed, which can significantly improve the activity of fly ash in low temperature environment. At the same time, a temperature-sensitive polymer poly-N-isopropyl acrylamide (PNIPAM) is used to accelerate the hydration process in low temperature environment. Through the synergistic effect of these measures, not only the early strength of the grouting material in low temperature environment is significantly improved, but also the frost resistance coefficient is greatly improved. The material can quickly foam and complete the setting process in low temperature environment, which is very suitable for grouting operation in low temperature environment, and successfully overcomes the defects of "low temperature failure" and "insufficient strength" of traditional materials in low temperature environment. SUMMARY

[0006] The present application aims to solve the technical problems of high density, low temperature failure, insufficient strength, high cost and the like of the existing mine filling material, and provides a light low-temperature foaming mine filling material, which has the characteristics of low density, appropriate strength, rapid foaming and curing in a low-temperature environment, low cost and environmental protection, and solves the defects of "low temperature failure" and "insufficient strength".

[0007] The light low-temperature foaming mine filling material disclosed by the present application comprises A component and B component in a mass ratio of 1:1, wherein the A component comprises the following raw materials in parts by weight: 100 parts of fly ash, 10-25 parts of desulfurization gypsum, 3-8 parts of poly(N-isopropyl acrylamide), 3-10 parts of basalt fiber, 5-10 parts of expanded perlite, 4-6 parts of foaming agent, 1-8 parts of additive, and 30-100 parts of water.

[0008] The B component is composed of the following raw materials in parts by weight: 3-15 parts of sodium sulfate, 10-25 parts of water glass, 0.5-3 parts of tetramethylammonium hydroxide, and 10-50 parts of water.

[0009] Preferably, the fly ash is composed of 50%-80wt% of fly ash A and 20%-50%wt of fly ash B; the average particle size of the fly ash A is 3-10μm, and the average particle size of the fly ash B is 20-50μm.

[0010] Preferably, the average particle size of the expanded perlite is 10-50μm, and the length of the basalt fiber is 1-5mm and the diameter is 5-15μm.

[0011] Preferably, the foaming agent is at least one of sodium dodecyl sulfate, sodium alpha-alkenyl sulfonate, and fatty alcohol polyoxyethylene ether.

[0012] Preferably, the modulus of the water glass is 1.0-3.0.

[0013] Preferably, the additive comprises at least one of water reducing agent, early strength agent, retarder, and thickening agent.

[0014] Preferably, the water reducing agent is at least one of polycarboxylic acid water reducing agent, naphthalene-based high-efficiency water reducing agent, and lignin sulfonate water reducing agent; the early strength agent is at least one of sodium gluconate and sodium hexametaphosphate; the retarder is at least one of triethanolamine and sodium formate; and the thickening agent is at least one of hydroxypropyl methylcellulose, xanthan gum, and polyvinylpyrrolidone.

[0015] Preferably, the present application discloses a preparation method of the light low-temperature foaming mine filling material, which specifically comprises the following steps: S1: each component of the A group is weighed according to the weight part, placed in a blender, stirred uniformly, and a uniform A group slurry is obtained; S2: each component of the B group is weighed according to the weight part, placed in a blender, stirred uniformly, and a uniform B group slurry is obtained; S3: when used, the A group and the B group are mixed by stirring at a mass ratio of 1:1, and the light low-temperature foamed mine filling material is obtained.

[0016] Preferably, the stirring speed of the step (1) is 300-600 r / min, and the stirring time is 5-10 minutes; the stirring speed of the step (2) is 200-400 r / min, and the stirring time is 1-3 minutes; the stirring speed of the step (3) is 300-500 r / min, and the stirring time is 5-15 minutes.

[0017] Preferably, the application further provides a use method of the light low-temperature foamed mine filling material, which comprises the following steps: adding the A material and the B material to a grouting system according to a mass ratio of 1:1 by using a grouting pump, and grouting by using a grouting machine.

[0018] Preferably, the application further provides an application of the light low-temperature foamed mine filling material in coal mine roadway grouting.

[0019] The application aims at the fact that the fly ash has very low pozzolanic reactivity at low temperature (<10℃), which leads to slow hydration reaction rate and insufficient early strength, and adds the temperature-sensitive polymer poly-N-isopropyl acrylamide (PNIPAM) to accelerate low-temperature hydration. On the one hand, the amide group of PNIPAM can form hydrogen bonds with the hydroxyl group on the surface of fly ash, weaken the stability of Si-O-Al bonds in the glass body, and be conducive to the contact of the activator with the active SiO2 and Al2O3 sites inside the fly ash; on the other hand, the PNIPAM chain stretches, the hydrogel swells greatly, and the volume rapidly increases to form a three-dimensional network structure, which rapidly absorbs the surrounding pore solution containing the activator (sodium sulfate, water glass, etc.) into the gel network, promotes the diffusion and penetration of the activator to the fly ash particles, accelerates the hydration of the fly ash to form C-S-H gel, reduces the hydration reaction energy barrier of the fly ash activity activation, improves the hydration reaction rate, and is beneficial to rapid hardening, and significantly improves the early strength of the grouting material at low temperature.

[0020] The early strength of the grouting material is based on the compactness of the slurry structure, and the compounding of fly ash with different particle sizes can reduce the pores through "graded filling". The particle size of the fly ash B is 20-50 mu m, which is relatively large, can form a preliminary skeleton structure in the slurry, reduce the excessive accumulation of gypsum, expanded perlite and the like, and provide basic space support for the slurry; the particle size of the fly ash A is only 1 / 5-1 / 2 of that of the fly ash B, which can effectively fill the gaps between the fly ash B particles, and can significantly reduce the total porosity of the filling body, so that the structure is more compact.

[0021] And, the fly ash A has small particle size, large specific surface area, more active sites on the particle surface, and larger contact area with water glass and sodium sulfate type activator. Therefore, at low temperature or early stage, the fly ash A with small particle size can generate secondary hydration reaction faster to generate C-S-H gel to facilitate early stage solidification. However, the fly ash with small particle size is easy to agglomerate in the slurry and has poor dispersibility. Although the fly ash B with large particle size has slow initial reaction rate, it still contains a large amount of unreacted active ingredients. At early stage, the fly ash B can act as a supporting structure; with the extension of curing time, the fly ash B will gradually participate in the reaction under the action of the activator, and the generated hydration product can further fill the pores to avoid the insufficient late stage strength growth caused by the easy agglomeration and rapid reaction of the single fine particle size fly ash.

[0022] The light low-temperature foamed mine filling material provided by the application further comprises desulfurization gypsum, basalt fiber, expanded perlite and foaming agent. The desulfurization gypsum provides SO4 2- ions react with Al 3+ , Ca 2+ in the fly ash to generate ettringite to improve early stage strength, and the desulfurization gypsum provides additional Ca 2+ ions to increase the calcium content in the system and promote the formation of C-S-H gel. The basalt fiber and the expanded perlite are light filling materials, which can not only provide the strength of the filling body, but also reduce the density; by adding the foaming agent, the porous structure is introduced to reduce the overall density of the material to meet the light filling requirement.

[0023] The application aims at the defect of low activity of fly ash at low temperature, and selects sodium sulfate (sulfate activation) and water glass (alkali activation) as inorganic activators, and combines them with tetramethyl peroxide amine to synergistically activate the fly ash, which is beneficial to improve the activity of the fly ash at low temperature. The water glass provides a high-alkali environment (OH - ) and active silicate (SiO3 2+ ) as the basis to release active SiO2 and Al2O3, and the sodium sulfate reacts with the active ingredients to generate ettringite to provide important early stage strength support for the system; the tetramethyl peroxide amine decomposes to generate free radicals (such as ·OH) at low temperature, directly attacks the Si-O-Al network on the surface of the fly ash, exposes fresh active surface, reduces the reaction activation energy, and assists the water glass and the sodium sulfate to accelerate the formation of ettringite by the fly ash to jointly improve the activity of the fly ash at low temperature.

[0024] The light low-temperature foamed mine filling material has the advantages or beneficial effects that the compressive strength of the light low-temperature foamed mine filling material of the present application is higher than 3.51 MPa at the first day, and the compressive strength is higher than 5.66 MPa at the seventh day; the dry density is between 0.40 and 0.50 g / cm3; the frost resistance coefficient is higher than 0.94; the initial setting time at 5 DEG C is between 36 and 41 min, and the final setting time is between 99 and 106 min; the light low-temperature foamed mine filling material has the performances of light weight, early strength and low-temperature rapid foaming and curing, and successfully overcomes the defects of “low-temperature failure” and “insufficient strength” of the traditional material, and is suitable for grouting in a low-temperature environment. DETAILED DESCRIPTION

[0025] In order to more clearly explain the purpose, technical scheme and advantages of the present application, the technical scheme of the present application will be described in detail below through specific examples. It should be pointed out that these examples are only used to illustrate the present application, and do not limit the protection scope of the present application, and the actual protection scope of the present application should be defined by the claims.

[0026] The materials, reagents and the like used in the following examples and comparative examples are commercially available reagents and materials unless otherwise specified. The amount of components in the following examples is 1 g per weight part or per part unless otherwise specified.

[0027] The fly ash used in the present application is obtained from a coal-fired power plant, and the chemical composition of the fly ash is as follows:

[0028] In the implementation process of the present application, the fly ash is crushed and sieved to obtain fly ash with a corresponding particle size fraction. The fly ash A1 is fly ash with an average particle size of 3 μm. The fly ash A2 is fly ash with an average particle size of 10 μm. The fly ash B1 is fly ash with an average particle size of 50 μm. The fly ash B2 is fly ash with an average particle size of 20 μm. The fly ash B3 is fly ash with an average particle size of 30 μm.

[0029] The expanded perlite has an average particle size of 20 μm; the basalt fiber has a length of 5 mm and a diameter of 10 μm.

[0030] I. Preparation of the light low-temperature foamed mine filling material

[0031] The preparation method of the light low-temperature foamed mine filling material of the examples and comparative examples of the present application specifically includes the following steps: S1: The components of the A group are weighed according to the weight parts, and are placed in a stirrer with a rotation speed of 500 r / min, and are stirred for 10 min to obtain a uniform A group slurry; S2: The components of the B group are weighed according to the weight parts, and are placed in a stirrer with a rotation speed of 300 r / min, and are stirred for 3 min to obtain a uniform B group slurry; S3: When using, mix components A and B at a mass ratio of 1:1, stir at a speed of 3400 r / min for 5 minutes to obtain the lightweight low-temperature foamed mineral filling material.

[0032] Table 1: The mass fractions (g) of each component in Examples 1-6 are as follows.

[0033]

[0034] Table 2: The mass fractions (g) of each component in Comparative Examples 1-8 are as follows.

[0035]

[0036] Comparative Example 9 The difference from Example 1 is that an equal amount of polyacrylamide (PAM) was used instead of poly(N-isopropylacrylamide) (PNIPAM), while the other conditions were the same as in Example 1.

[0037] II. Performance Evaluation: The application of the lightweight low-temperature foamed mining filling material of the examples and comparative examples in the goaf of coal mines includes the following steps: adding material A and material B to the grouting system at a mass ratio of 1:1 using a grouting pump, and grouting using a grouting machine.

[0038] 1. Gel time test At 5℃, the initial setting time and final setting time of the grouting material were tested in accordance with the national standard GB8076-2008 "Concrete Admixtures".

[0039] 2. Dry density test The grout was poured into standard specimens measuring 40mm × 40mm × 160mm, and the volume V of the specimen was calculated. The specimens were then dried in a vacuum drying oven at 45℃ until their weight became constant, cooled to room temperature, and their mass was recorded as M. The dry density was calculated using the formula ρ = M / V. The above experiment was repeated three times, and the average dry density of the three measurements was taken.

[0040] 3. Material mechanical strength testing In accordance with the requirements of AQ / T 1089-2020 standard, the prepared material slurry was first poured into a 40mm×40mm×160mm mold. After 24 hours, the sample was demolded and placed in an environment of 5±1℃ and 50% relative humidity for continued curing. The compressive strength of the material was tested on the 1st and 7th days. The average value of 5 test samples was selected for each experimental test.

[0041] 4. Freeze-thaw resistance coefficient The prepared slurry is placed in a standard curing environment to cast the mold and shape, demolded after 7 days of curing, and placed in a concrete rapid freeze-thaw tester for freeze-thaw cycle test, wherein the alternating cycle conditions are first frozen at -15°C for 30 min, then transferred to room temperature environment for thawing for 30 min, and so on for 100 times of repeated cycles, to detect the change of the compressive strength of the material, and the retention rate of the compressive strength of the sample is taken as the freeze-thaw resistance coefficient. The freeze-thaw resistance coefficient = the compressive strength used after the cycle / the compressive strength before the cycle, and the test temperature of the compressive strength is 5±1°C.

[0042] Table 3 Properties of grouting materials of different examples and comparative examples

[0043] According to the test results in Table 3, the lightweight low-temperature foamed mine filling material of the present application has a compressive strength of more than 3.51 MPa at 1 day, a compressive strength of between 5.66-5.88 MPa at 7 days, and overall shows excellent early strength; the dry density is between 0.40-0.50 g / cm³, has the characteristics of lightweight, and is beneficial to reducing the self-weight for application in coal mine goaf and other scenes; the freeze-thaw resistance coefficient is higher than 0.94, the compressive strength can be maintained at a certain proportion after 100 freeze-thaw cycles, and shows good durability under repeated freeze-thaw in low-temperature environment; the initial setting time is between 36-41 min and the final setting time is between 99-106 min at 5°C, the foaming and setting processes can be completed quickly in low-temperature environment, and it is suitable for low-temperature grouting, successfully overcoming the defects of "low-temperature failure" and "insufficient strength" of traditional materials.

[0044] By comparing the results of Example 1 and Comparative Examples 1-2, the compressive strength and freeze-thaw resistance coefficient of Comparative Examples 1-2 using only small-particle-size fly ash or large-particle-size fly ash are lower than those of Example 1, highlighting the necessity of the dual-particle-size complex system. Although the use of large-particle-size particles alone can form a skeleton, it will lead to large structural voids and low density, resulting in slow strength development. The use of small-particle-size particles alone is prone to agglomeration and has a large water demand, although the early activity is high, the overall structural property is poor, limiting the growth of the late strength. In contrast, Example 1 uses fly ash A with a particle size of 3-10 μm and fly ash B with a particle size of 20-50 μm to achieve optimal grading filling: large particles build a supporting skeleton, small particles effectively fill the voids and provide abundant early reaction sites, and finally form a more dense and high-strength microstructure, thereby significantly improving the mechanical properties and setting speed of the material, and significantly improving the compressive strength and freeze-thaw resistance coefficient of the grouting material in low-temperature environment.

[0045] By comparing the results of Example 1 and Comparative Example 3, Comparative Example 3 omits the polymer PNIPAM, and the performance at low temperature rapidly decreases, the 1-day compressive strength drops to 1.04 MPa, the freeze-thaw coefficient decreases to 0.62, and the initial setting time extends to 86 minutes. The present application accelerates low-temperature hydration by adding the temperature-sensitive polymer poly-N-isopropyl acrylamide (PNIPAM). The amide group of PNIPAM can form hydrogen bonds with the hydroxyl group on the surface of fly ash, weakening the stability of Si-O-Al bonds in the glass body, which is conducive to the contact between the activator and the active SiO2 and Al2O3 sites inside the fly ash. At the same time, the PNIPAM chain stretches, the hydrogel swells, and the volume rapidly increases to form a three-dimensional network structure, promoting the diffusion and penetration of the activator into the fly ash particles, accelerating the hydration of the fly ash to form C-S-H gel, reducing the hydration reaction energy barrier of fly ash activity activation, and improving the hydration reaction rate to facilitate rapid hardening, significantly improving the early strength and freeze-thaw coefficient of the grouting material at low temperature. Comparative Example 9 adds polyacrylamide, which does not have temperature sensitivity, and only slightly improves the compressive strength at low temperature through physical effects such as thickening.

[0046] By comparing the results of Example 1 and Comparative Example 4, Comparative Example 4 omits basalt fibers and expanded perlite, and the dry density of the material significantly increases to 0.87 g / cm³, and the compressive strength also decreases significantly. The reason is that basalt fibers effectively bear the load through their distribution in the matrix, preventing micro-crack propagation, thereby playing a core role in strengthening. Expanded perlite, as a super-light aggregate, is the main factor for achieving low density of the material. The simultaneous absence of both results in a dense structure of the material, and the loss of the strengthening effect of the fibers, ultimately leading to a significant deterioration of the overall mechanical properties of the material.

[0047] By comparing the results of Example 1 and Comparative Examples 5-7, any one of water glass, sodium sulfate, and tetramethylammonium hydroxide is omitted in Comparative Examples 5-7, which shows slow setting, significantly reduced low-temperature strength and freeze-thaw coefficient, and confirms the indispensable synergistic effect of the ternary activation system of "water glass-sodium sulfate-tetramethylammonium hydroxide". In this system, the free radicals ·OH generated by the decomposition of tetramethylammonium hydroxide can directly attack the surface of the fly ash glass body, greatly reducing the reaction activation energy; water glass provides a high-alkali environment and active silicate, releasing active SiO2 and Al2O3 to build the basis for the activation reaction; sodium sulfate provides a key source of early strength for the system by generating ettringite, and achieves rapid and high-strength solidification at low temperature through this synergistic mechanism.

[0048] By comparing the results of Example 1 and Comparative Example 8, desulfurized gypsum in the grouting system provides Ca 2+ and SO4 2- two key ions: SO4 2-participate in hydration reaction to form ettringite, which provides important early strength support for the material; meanwhile, Ca 2+ The increase of calcium content in the system effectively promotes the formation of more C-S-H gel. The lack of desulphogypsum in Comparative Example 8 leads to insufficient total amount of hydration products and weak early strength framework, which finally results in the decrease of early strength of the material.

[0049] The above examples are only provided to illustrate the present application, and are not intended to limit the possible embodiments of the present application. Based on the disclosure of the present application, those skilled in the art can make various modifications and adjustments. It is not necessary or possible to list all possible embodiments. Any modification, equivalent replacement or improvement made within the basic principles and scope of the present application shall be considered as falling within the protection scope of the present application.

Claims

1. A lightweight, low temperature foamed mine filling material, characterized in that, The A component and the B component with a mass ratio of 1:1 are included, wherein the A component includes the following raw materials in parts by weight: 100 parts of fly ash, 10-25 parts of desulfurization gypsum, 3-8 parts of poly(N-isopropyl acrylamide), 3-10 parts of basalt fiber, 5-10 parts of expanded perlite, 4-6 parts of foaming agent, 1-8 parts of additive, and 30-100 parts of water; The B component is composed of the following raw materials in parts by weight: 3-15 parts of sodium sulfate, 10-25 parts of water glass, 0.5-3 parts of tetramethylammonium hydroxide, and 10-50 parts of water; The fly ash is composed of 50%-80wt% of fly ash A and 20%-50%wt of fly ash B; the average particle size of the fly ash A is 3-10μm, and the average particle size of the fly ash B is 20-50μm.

2. A lightweight, low-temperature foamed mine filling material as claimed in claim 1, characterized in that, The average particle size of the expanded perlite is 10-50μm, and the length of the basalt fiber is 1-5mm and the diameter is 5-15μm.

3. A lightweight, low-temperature foamed mine filling material as claimed in claim 1, characterized in that, The foaming agent is at least one of sodium dodecyl sulfate, sodium α-alkenyl sulfonate, and fatty alcohol polyoxyethylene ether.

4. A lightweight, low-temperature foamed mine filling material according to any one of claims 1 to 3, characterised in that, The modulus of the water glass is 1.0-3.

0.

5. A lightweight, low-temperature foamed mine filling material according to any one of claims 1 to 3, characterised in that, The additive includes at least one of water reducing agent, early strength agent, retarder, and thickening agent.

6. A lightweight, low-temperature foamed mine filling material as claimed in claim 5, characterised in that, The water reducing agent is at least one of polycarboxylic acid water reducing agent, naphthalene-based high-efficiency water reducing agent, and lignosulfonate water reducing agent; the early strength agent is at least one of sodium gluconate and sodium hexametaphosphate; the retarder is at least one of triethanolamine and sodium formate; and the thickening agent is at least one of hydroxypropyl methyl cellulose, xanthan gum, and polyvinylpyrrolidone.

7. A process for the production of a lightweight, low-temperature foamed mine filling material as claimed in any one of claims 1 to 6, characterized in that, Specifically includes the following steps: S1: each component of the A component is weighed in parts by weight, placed in a blender, and stirred uniformly to obtain a uniform A component slurry; S2: each component of the B component is weighed in parts by weight, placed in a blender, and stirred uniformly to obtain a uniform B component slurry; S3: when used, the A component and the B component are stirred and mixed at a mass ratio of 1:1 to obtain the lightweight low-temperature foamed mine filling material.

8. A process for the production of a lightweight, low-temperature foamed mine filling material as claimed in claim 7, characterized in that The stirring speed of step (1) is 300-600r / min, and the stirring time is 5-10 minutes; the stirring speed of step (2) is 200-400r / min, and the stirring time is 1-3 minutes; and the stirring speed of step (3) is 300-500r / min, and the stirring time is 5-15 minutes.

9. A method of using a lightweight, low-temperature foamed mine filling material as claimed in any one of claims 1 to 6, characterized in that, The following steps are included: The A material and the B material are added to the grouting system at a mass ratio of 1:1 using a grouting pump, and grouting is performed using a grouting machine.

10. The lightweight low-temperature foamed mine filling material according to any one of claims 1-6 for use in grouting in a coal mine tunnel.

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