Coal-based solid waste filling material conveying performance improver, preparation method and application

Abstract

The invention provides a coal-based solid waste filling material conveying performance improver, a preparation method and application, the preparation method comprises the following steps: preparing a long-side-chain and short-main-chain type polycarboxylic acid water reducing agent with the solid content of 20-40%, and mixing the long-side-chain and short-main-chain type polycarboxylic acid water reducing agent with a sacrificial agent to obtain a high-mud-resistance type polycarboxylic acid water reducing agent; on the basis of the high-mud-resistance polycarboxylic acid water reducing agent, the mass percentage of the sacrificial agent is 0.1-0.5%; on the basis of the modifier, 50%-75% by mass of a high-mud-resistance polycarboxylic acid water reducer, 20%-40% by mass of a thickening suspending agent and 5%-10% by mass of an air entraining agent are mixed and stirred uniformly to obtain the modifier. The modifier is added into the coal-based solid waste filling material, so that the fluidity and the stability of the coal-based solid waste filling material, such as solid waste slurry of coal gangue, fly ash, gasification slag and the like, can be adjusted and improved.

Description

Technical Field

[0001] The present application relates to the technical field of goaf filling disposal and coal mine filling and mining engineering, and in particular to a coal-based solid waste filling material transportation performance improver, a preparation method and an application. Background Art

[0002] At present, an important disposal direction for bulk coal-based solid wastes such as gangue, fly ash, and gasification slag is to prepare them into fluidized slurry materials and pump them into goafs. This can not only achieve the disposal of solid wastes such as gangue, but also prevent hazards such as spontaneous combustion of coal residues in goafs and further compaction and settlement of goafs.

[0003] There are two key problems in the transportation and filling process of solid waste slurry such as coal gangue: First, it is difficult to transport and pump the slurry through pipes. Low-concentration slurry is prone to segregation, sedimentation and siltation in the pipe, and high-concentration slurry has large pumping resistance and short pumping distance. Second, when the slurry is pumped to the goaf, the diffusion radius is short and the absorption capacity is limited if the concentration is too high. If the concentration is too low, solid-liquid separation is easy to occur, and the exuded water has an adverse effect on the tunnel and mining working face. At present, in the fluidized filling project of coal-based solid waste, the water reducer used in the field of concrete preparation is used to solve this problem. However, compared with the concrete components, the solid waste slurry has a high mud content (montmorillonite, kaolin, etc.) and a more complex composition, resulting in serious ineffective adsorption of conventional water reducers (water reducer molecules are adsorbed inside the interlayers of layered silicate minerals such as montmorillonite and cannot play a dispersing role), and the use effect is poor. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems in the related art to a certain extent. The present application proposes a coal-based solid waste filling material transportation performance improver, a preparation method and an application. By adding the improver to the coal-based solid waste filling material, the fluidity and stability of the solid waste slurry of the coal-based solid waste filling material such as coal gangue, fly ash, etc. can be adjusted and improved, and the solid waste slurry of the coal-based solid waste filling material can be solved. The solid waste slurry of the coal-based solid waste filling material is subjected to the phase change of components, siltation and pipe blockage, or poor fluidity over time, large transportation resistance and other problems during the pipeline transportation process.

[0005] According to an embodiment of the first aspect of the present application, a method for preparing a coal-based solid waste filling material transport performance improver is proposed, comprising the following steps: A long side chain short main chain polycarboxylate water reducer with a solid content of 20%-40% is prepared, and the long side chain short main chain polycarboxylate water reducer is mixed with a sacrificial agent and then dried to obtain a high mud resistance polycarboxylate water reducer; wherein the mass percentage of the sacrificial agent is 0.1%-0.5% based on the high mud resistance polycarboxylate water reducer; Taking the improver as a basis, 50%-75% of the highly anti-mud polycarboxylic acid water-reducing agent, 20%-40% of the thickening suspending agent and 5%-10% of the air entraining agent are mixed and stirred in accordance with the mass percentage to obtain the improver.

[0006] In some embodiments, the thickening suspending agent includes hydroxypropyl methylcellulose and xanthan gum; wherein, based on the improver, the hydroxypropyl methylcellulose is 15%-25% by weight; the xanthan gum is 5%-15% by weight; And / or, the air entraining agent comprises sodium lauryl sulfate.

[0007] In some embodiments, the preparation process of the long side chain short main chain polycarboxylate water reducer comprises: Pre-emulsifying the side chain monomer to form a mixed solution A; Premixing the main chain monomer and the functional monomer to form a mixed solution B; After adding the mixed solution A and part of the initiator into the reactor, the oxygen in the reactor is removed and the temperature is raised to 70-80° C.; then the mixed solution B and the remaining initiator are added dropwise to the reactor, and after the addition is complete, the temperature in the reactor is raised to 80-85° C. and kept for reaction for 1-2 hours; The reactor is cooled to below 40° C. and the pH value of the reaction liquid therein is adjusted to 6.5-7.5; the reaction liquid is purified and impurities removed to obtain the long side chain and short main chain polycarboxylate water reducer.

[0008] In some embodiments, the side chain monomer includes polyethylene glycol monomethyl ether with a molecular weight of 2000-2400; the side chain monomer is dissolved in a solvent and mixed with a chain transfer agent for pre-emulsification; wherein the mass ratio of the side chain monomer to the solvent is 1:2; And / or, the chain transfer agent comprises mercaptoacetic acid or mercaptopropionic acid, wherein the chain transfer agent is 0.5%-1% of the mass of the side chain monomer.

[0009] In some embodiments, the backbone monomer comprises acrylic acid or methacrylic acid; And / or, the functional monomer includes methacrylic acid phosphate; the mass of the functional monomer is 1%-3% of the mass of the main chain monomer; And / or, the concentration of the mixed solution B is 30%-40%.

[0010] In some embodiments, the molar ratio of the main chain monomer to the side chain monomer is 1:0.8-1.2; And / or, the initiator includes ammonium persulfate or azobisisobutyronitrile; the mass of the initiator is 0.5%-1.5% of the total mass of the side chain monomer, the main chain monomer and the functional monomer.

[0011] In some embodiments, the sacrificial agent includes a quaternary ammonium salt surfactant; And / or, the quaternary ammonium salt surfactant includes hexadecyltrimethylammonium chloride or octadecyltrimethylammonium chloride; And / or, the mass of the quaternary ammonium salt surfactant is 0.1%-0.5% of the mass of the long side chain short main chain polycarboxylate water reducer; The long side chain short main chain polycarboxylate water reducer is mixed with the sacrificial agent, heated to 40° C.-50° C., stirred and mixed for 2-3 hours, and then cooled to room temperature to obtain the high mud resistance polycarboxylate water reducer.

[0012] According to an embodiment of the second aspect of the present application, a coal-based solid waste filling material transport performance improver is proposed, which is obtained using the preparation method described in any of the above embodiments.

[0013] According to an embodiment of the third aspect of the present application, it is proposed that the improver described in any of the above embodiments be used in the fluidization disposal of goaf gangue as coal-based solid waste filling material.

[0014] In some embodiments, the modifier is added to water at a temperature of at least 40°C to prepare a modifier slurry with a mass concentration of 2%-8%; the modifier slurry is mixed with coal-based solid waste filling materials during the goaf filling process, wherein the mass of the modifier slurry is 0.3%-1% of the mass of the coal-based solid waste filling materials.

[0015] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 It is a flow chart of a method for preparing a coal-based solid waste filling material transport performance improver provided in one embodiment of the present application; Figure 2 is a graph showing changes in flow properties of coal-based solid waste filling material slurry before and after the use of a modifier provided in one embodiment of the present application; Figure 3 This is a first scenario of fluidized disposal of goaf waste provided in one embodiment of the present application; Figure 4 This is the second scenario of fluidization disposal of goaf waste rock provided in one embodiment of the present application. DETAILED DESCRIPTION

[0017] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be construed as limiting the present application. On the contrary, the present application includes all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0018] The present application is an improvement based on the defects of the following related technologies. At present, an important disposal direction for bulk coal-based solid wastes such as gangue and fly ash is to prepare them into fluidized slurry materials and pump them into the goaf, which can not only achieve the disposal of solid wastes such as gangue, but also prevent the spontaneous combustion of coal residues in the goaf, further compaction and settlement of the goaf and other hazards.

[0019] There are two key problems in the transportation and filling process of solid waste slurry such as coal gangue: First, it is difficult to transport and pump the slurry through pipes. Low-concentration slurry is prone to segregation, sedimentation and siltation in the pipe, and high-concentration slurry has large pumping resistance and short pumping distance. Second, when the slurry is pumped to the goaf, the diffusion radius is short and the absorption capacity is limited if the concentration is too high. If the concentration is too low, solid-liquid separation is easy to occur, and the exuded water has an adverse effect on the tunnel and mining working face. At present, in the fluidized filling project of coal-based solid waste, the water reducer used in the field of concrete preparation is used to solve this problem. However, compared with the concrete components, the solid waste slurry has a high mud content (montmorillonite, kaolin, etc.) and a more complex composition, resulting in serious ineffective adsorption of conventional water reducers (water reducer molecules are adsorbed inside the interlayers of layered silicate minerals such as montmorillonite and cannot play a dispersing role), and the use effect is poor.

[0020] The related art mentions a preparation method of a coal gangue-based filling paste coagulant and water-retaining agent, in which sodium hydroxide is used as an activator. In actual application, the cost is difficult to control, and the workers' operation is dangerous. In addition, some related technologies propose a rheological additive for red mud fly ash grouting filling material and a red mud fly ash grouting filling material. This is a rheological additive for the problem of high viscosity after red mud and fly ash are mixed with water, and solves the problem of large loss of fluidity over time. This product is mainly proposed for red mud (there is an alkali-induced gelation reaction when it coexists with fly ash), and the improvement effect on coal gangue slurry is not obvious. Finally, some related technologies have proposed fly ash alkali metal chelation hardening blocking slurry materials and methods for preventing and controlling coal spontaneous combustion. The alkali metals in the fly ash are activated, and then quickly chelated to inhibit the sedimentation and cementation hardening of the fly ash, thereby preventing the fly ash slurry from clogging the pipe. However, the fly ash suspension preparation method proposed in this study for fly ash pure slurry has no obvious improvement effect on coal gangue slurry (which does not have the conditions for alkaline metal activation and chelation).

[0021] Based on this, the technical solution of the embodiment of the present application provides a coal-based solid waste filling material transportation performance improver, a preparation method and an application. By adding the improver to the coal-based solid waste filling material, the addition of the improver ensures the high fluidity of the coal-based solid waste filling material slurry, by reducing the unit water content, improving its liquid phase viscosity and other methods, so as to achieve the goals of reducing its pipeline transportation resistance, improving its anti-segregation ability, and increasing the diffusion radius during the filling of the goaf, etc., and solves the problems of component phase change, siltation and pipe blockage, or poor fluidity over time and large transportation resistance of the solid waste slurry of the coal-based solid waste filling material during pipeline transportation.

[0022] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0023] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0024] To achieve the above-mentioned purpose, according to the embodiment of the first aspect of the present application, a method for preparing a coal-based solid waste filling material transport performance improver is proposed. Figure 1 , including the following steps: S1: preparing a long side chain short main chain polycarboxylate water reducer with a solid content of 20%-40%, and mixing the long side chain short main chain polycarboxylate water reducer with a sacrificial agent and drying the mixture to obtain a high mud resistance polycarboxylate water reducer; wherein the mass percentage of the sacrificial agent is 0.1%-0.5% based on the high mud resistance polycarboxylate water reducer; S2: Taking the improver as a base, 50%-75% of high anti-mud polycarboxylic acid water-reducing agent, 20%-40% of thickening suspending agent and 5%-10% of air entraining agent are mixed and stirred evenly according to the mass percentage to obtain the improver.

[0025] The preparation of a long side chain short main chain polycarboxylate water reducer with a solid content of 20%-40% in S1 includes the following steps: (1) pre-emulsifying side chain monomers to form a mixed solution A; (2) pre-mixing the main chain monomers and the functional monomers to form a mixed solution B; (3) adding the mixed solution A and part of the initiator to a reactor, removing oxygen from the reactor and heating the reactor to 70-80° C.; then dripping the mixed solution B and the remaining initiator into the reactor, and after the dripping is completed, heating the reactor to 80-85° C. and keeping the temperature for reaction for 1-2 hours; (4) cooling the reactor to below 40° C. and adjusting the pH value of the reaction solution therein to 6.5-7.5; and then purifying and removing impurities from the reaction solution to obtain a long side chain short main chain polycarboxylate water reducer.

[0026] In the process of preparing a long side chain short main chain polycarboxylate water reducer, the generation of the mixed solution A in step (1) comprises: dissolving the side chain monomer in a solvent and mixing it with a chain transfer agent for pre-emulsification, wherein the side chain monomer comprises polyethylene glycol monomethyl ether (MPEG) having a molecular weight of 2000-2400; the solvent may be deionized water, wherein the mass ratio of the side chain monomer to the solvent is 1:2; and the chain transfer agent comprises mercaptoacetic acid or mercaptopropionic acid, wherein the chain transfer agent is 0.5%-1% of the mass of the side chain monomer.

[0027] For example, MPEG and deionized water are mixed in a mass ratio of 1:2 and then heated to 50-60°C and stirred until completely dissolved. Then a small amount of chain transfer agent (such as mercaptopropionic acid, the amount of which is 0.5%-1% of the mass of MPEG) is added and pre-emulsified for 30 minutes to obtain a mixed solution A.

[0028] In the process of preparing the long side chain short main chain polycarboxylate water reducer, in step (2), the main chain monomer and the functional monomer are premixed to form a mixed solution B, wherein the main chain monomer includes acrylic acid or methacrylic acid; the functional monomer is a functional monomer for improving mud resistance and includes methacrylic acid phosphate; the mass of the functional monomer is 1%-3% of the mass of the main chain monomer; and the concentration of the mixed solution B is 30%-40%.

[0029] For example, a main chain monomer (acrylic acid (AA)) and methyl methacrylate phosphate (PME) are mixed to obtain a mixed solution, wherein the mass of methyl methacrylate phosphate is 1%-3% of the mass of the main chain monomer; the mixed solution is then diluted with deionized water and stirred to obtain a mixed solution B, wherein the concentration of the mixed solution B is 30%-40%.

[0030] In the process of preparing a long side chain short main chain polycarboxylate water reducer, in step (3), the mixed solution A and part of the initiator are first added to the reactor, wherein the initiator includes ammonium persulfate or azobisisobutyronitrile; wherein the part of the initiator added to the reactor together with the mixed solution A is 20%-30% of the total initiator mass. Nitrogen is introduced into the reactor to remove oxygen therein, and the reactor is heated to 70-80°C. Then the mixed solution B and the remaining initiator are slowly added dropwise to the reactor. The process takes 2-3 hours and the temperature in the reactor is maintained at 75±2°C. After the addition is completed, the temperature in the reactor is raised to 80-85°C and the reaction is kept warm for 1-2 hours to ensure complete conversion of the monomers. In addition, in this process, the molar ratio of the main chain monomer to the side chain monomer is 1:0.8-1.2; the mass of the initiator is 0.5%-1.5% of the total mass of the side chain monomer, the main chain monomer and the functional monomer.

[0031] For example, pre-emulsified MPEG solution and 20%-30% ammonium persulfate (APS, dissolved in water) are added to a four-necked flask, nitrogen is passed into the four-necked flask to exclude oxygen and the temperature of the four-necked flask is raised to 70-80°C; mixed solution B and the remaining initiator solution are slowly added dropwise through a dropping funnel for 2-3 hours, the temperature is maintained at 75±2°C, and after the addition is completed, the temperature is raised to 80-85°C, and the reaction is kept warm for 1-2 hours to ensure complete conversion of the monomers.

[0032] In the process of preparing the long side chain short main chain polycarboxylate water reducer, in step (4), the reactor is cooled to below 40° C. and a neutralizing agent such as a 30% NaOH solution is used to adjust the pH value of the reaction liquid in the reactor to 6.5-7.5, wherein the neutralization process is exothermic and the dripping speed needs to be controlled; the reaction liquid is then purified and impurities are removed, for example, by a method of purification and impurity removal by vacuum distillation or dialysis to remove unreacted monomers and small molecular impurities, to obtain a long side chain short main chain polycarboxylate water reducer, which is a light yellow transparent liquid (solid content 20%-40%).

[0033] In S1, a long side chain short main chain polycarboxylate water reducer is mixed with a sacrificial agent and then dried to obtain a high mud resistance polycarboxylate water reducer; wherein the sacrificial agent includes a quaternary ammonium salt surfactant; the quaternary ammonium salt surfactant includes hexadecyl trimethyl ammonium chloride or octadecyl trimethyl ammonium chloride; the mass of the quaternary ammonium salt surfactant is 0.1%-0.5% of the mass of the long side chain short main chain polycarboxylate water reducer. In this process, the long side chain short main chain polycarboxylate water reducer is mixed with the sacrificial agent, heated to 40℃-50℃, stirred and mixed for 2-3h, and then cooled to room temperature, and the solution is further dried in a vacuum drying oven at 60℃, -0.1MPa for 24 hours to obtain a white powder, i.e., a high mud resistance polycarboxylate water reducer.

[0034] Among them, the presence of minerals such as montmorillonite and illite in solid waste slurries such as coal gangue can easily cause the failure of ordinary water reducers. This is mainly due to the interaction between the RCOO-functional group in the water reducer and the Mg adsorbed by clay minerals. 2+ , Ca 2+ Cationic reaction, loss; or part of the water reducer molecules are adsorbed into the interlayer structure of clay minerals and cannot function. This application prepares a high-anti-mud water reducer with a long side chain and a short main chain containing a sacrificial agent. It is better suitable for the characteristics of high mud content in solid waste-based slurry.

[0035] Polycarboxylate water reducer ensures that the water requirement per unit volume is reduced under the same fluidity conditions of solid waste slurry materials such as coal gangue. Various solid waste powder particles such as coal gangue will be weakly ionized in water. Due to the electrostatic attraction of positive and negative charges and the van der Waals attraction between particles, they attract each other and form floccules, which will contain a large amount of water, resulting in an increase in ineffective water consumption. However, increasing the amount of water will cause serious water seepage in the slurry. Polycarboxylate water reducer reduces the agglomeration effect of powder particles by adjusting the zeta potential (negative potential deviation) on the surface of the particles, releasing more free water and improving the flow effect.

[0036] Therefore, the water reducer in this application has a particularity. It is a long side chain short main chain polycarboxylate water reducer. Its long side chain can prevent the ineffective adsorption of clay minerals on the interlayer of water reducer macromolecules; at the same time, the long side chain short main chain polycarboxylate water reducer in the application is compounded with a sacrificial agent, which can preferentially react with the Mg adsorbed by clay minerals. 2+ , Ca 2+ Cationic reaction prevents further reaction of effective components to adapt to the problem of high content of slurry clay powder (montmorillonite, kaolin) and poor adaptability of ordinary water reducers in the fluidized disposal process of large-scale coal gangue and other coal-based solid wastes.

[0037] In S2, taking the improver as a benchmark, 50%-75% of a high anti-mud polycarboxylic acid water-reducing agent, 20%-40% of a thickening suspending agent and 5%-10% of an air-entraining agent are mixed and stirred in accordance with the mass percentage to obtain the improver, wherein the thickening suspending agent comprises hydroxypropyl methylcellulose and xanthan gum; wherein the hydroxypropyl methylcellulose is 15%-25%; the xanthan gum is 5%-15%; and the air-entraining agent comprises sodium lauryl sulfate.

[0038] For example, the mass percentage of hydroxypropyl methylcellulose in the modifier can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 23%, 25%, etc., wherein when the content of hydroxypropyl methylcellulose in the modifier is too high, such as higher than 25%, the viscosity of the solid waste filling slurry formed by mixing the modifier with the coal-based solid waste filling material is too high when the modifier is used, affecting the fluidity of the solid waste filling slurry; conversely, when the content of hydroxypropyl methylcellulose in the modifier is too low, such as lower than 15%, the suspension capacity of the solid waste filling slurry formed by mixing the modifier with the coal-based solid waste filling material is insufficient when the modifier is used, resulting in solid-liquid separation of the solid waste filling slurry and a high water seepage rate. At the same time, the mass percentage of xanthan gum in the modifier can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 15%, etc. When the xanthan gum content in the modifier is too high, such as higher than 15%, when the modifier is used, the viscosity of the solid waste filling slurry formed by mixing the modifier with the coal-based solid waste filling material is too high, affecting the fluidity of the solid waste filling slurry; conversely, when the xanthan gum content in the modifier is too low, such as lower than 5%, when the modifier is used, the suspension capacity of the solid waste filling slurry formed by mixing the modifier with the coal-based solid waste filling material is insufficient, resulting in solid-liquid separation of the solid waste filling slurry and a high water seepage rate.

[0039] The thickening suspending agent in the present application is prepared by mixing two polymers, hydroxypropyl methylcellulose and xanthan gum, in a certain proportion. Both xanthan gum and hydroxypropyl methylcellulose have the function of improving the cohesion of the slurry, but the "composite" use of the two can play a synergistic role and reduce the usage amount. Xanthan gum and hydroxypropyl methylcellulose are dissolved in water to form a compound colloid and present a three-dimensional spatial network structure, which increases the ability of the liquid phase component to fix the solid particles, so that the coal-based solid waste filling material such as gangue and other solid waste slurries have strong cohesion (sand carrying capacity) and anti-water separation ability when transported in pipelines.

[0040] Sodium dodecyl sulfate is used as an air entraining agent. The mass percentage of sodium dodecyl sulfate in the modifier can be 5%, 6%, 7%, 8%, 9% or 10%, etc. When the content of sodium dodecyl sulfate in the modifier is too high, such as higher than 10%, when the modifier is used, the solid waste filling slurry formed after the modifier and the coal-based solid waste filling material are mixed will generate excessive bubbles, affecting the later strength of the solid waste filling slurry; on the contrary, when the content of sodium dodecyl sulfate in the modifier is too low, such as lower than 5%, the solid waste filling slurry will not generate enough bubbles, and the effect of improving fluidity is insufficient. A certain amount of tiny independent bubbles can be generated and evenly distributed in the slurry. These tiny independent bubbles play the role of ball bearings in the grouting material, which can greatly improve the fluidity of the slurry. In addition, it needs to be explained that the amount of sodium dodecyl sulfate used has been scientifically and reasonably tested. Although it can generate a certain amount of tiny independent bubbles, it has no effect on the strength of grouting and filling.

[0041] According to an embodiment of the second aspect of the present application, a coal-based solid waste filling material transport performance improver is proposed, which is obtained using the preparation method in any of the above embodiments.

[0042] According to an embodiment of the third aspect of the present application, it is proposed that the improver in any of the above embodiments be used in the fluidization disposal of goaf gangue as coal-based solid waste filling material.

[0043] Among them, in some embodiments, the modifier is added to water with a temperature of at least 40°C to prepare a modifier slurry with a mass concentration of 2%-8%; the modifier slurry is mixed with coal-based solid waste filling materials during the goaf filling process, wherein the mass of the modifier slurry is 0.3%-1% of the mass of the coal-based solid waste filling materials, wherein the coal-based solid waste filling materials include cement, fly ash, coal gangue powder, etc.

[0044] To facilitate further understanding of the present application, the scheme of the present application is further described below in conjunction with the embodiments. Those skilled in the art will understand that the description in the present application is only part of the examples, and any other suitable specific examples are within the scope of the present application.

[0045] Example 1 The present embodiment provides a coal-based solid waste filling material transport performance improver, and its preparation method and specific operating parameters are as follows: polyethylene glycol monomethyl ether (MPEG) (molecular weight 2000) and deionized water are mixed in a mass ratio of 1:2 and then heated to 60°C, stirred until completely dissolved, and then mercaptopropionic acid is added in an amount of 0.5% of the mass of MPEG, and pre-emulsified for 30 minutes to obtain a mixed solution A.

[0046] Acrylic acid and methyl methacrylate phosphate (PME) are mixed to obtain a mixed solution, wherein the mass of methyl methacrylate phosphate is 1% of the mass of the main chain monomer; the mixed solution is then diluted with deionized water and stirred to obtain a mixed solution B, wherein the concentration of the mixed solution B is 30%.

[0047] Add mixed solution A and 20% ammonium persulfate (APS) to a four-necked flask, pass nitrogen into the four-necked flask to remove oxygen and raise the temperature of the four-necked flask to 80°C; slowly drip mixed solution B and the remaining ammonium persulfate solution through a dropping funnel for 2 hours, wherein the total mass of the initiator ammonium persulfate is 0.5% of the total mass of polyethylene glycol monomethyl ether, acrylic acid and methacrylic acid phosphate, keep the temperature in the four-necked flask at 75±2°C, and after the dripping is completed, heat it to 85°C and keep it for 2 hours to ensure that polyethylene glycol monomethyl ether, acrylic acid and methacrylic acid phosphate are completely converted, and the molar ratio of acrylic acid to MPEG is 1:1. Then cool the reactor to below 40°C and use a neutralizer such as a 30% NaOH solution to adjust the pH value of the reaction solution in the reactor to 7, and then purify and remove impurities from the reaction solution to obtain a long side chain short main chain polycarboxylic acid water reducer, which is a light yellow transparent liquid. The long side chain short main chain polycarboxylate water reducer and octadecyl trimethyl ammonium chloride were mixed and heated to 50°C and stirred for 2 hours, then cooled to room temperature and dried in a vacuum drying oven at 60°C and -0.1 MPa for 24 hours to obtain a white powder, i.e., a high anti-mud polycarboxylate water reducer. The amount of octadecyl trimethyl ammonium chloride was 0.1% of the mass of the long side chain short main chain polycarboxylate water reducer.

[0048] Taking the improver as a basis, 65% of high anti-mud polycarboxylic acid water-reducing agent, 20% of hydroxypropyl methylcellulose, 10% of xanthan gum and 5% of sodium lauryl sulfate are mixed and stirred according to the mass percentage to obtain the improver.

[0049] Example 2 This embodiment is different from Embodiment 1 in the following aspects: the molecular weight of polyethylene glycol monomethyl ether (MPEG) is 2400.

[0050] Example 3 This embodiment is different from Embodiment 1 in that acrylic acid and methyl methacrylate phosphate (PME) are mixed to obtain a mixed solution, wherein the mass of methyl methacrylate phosphate is 3% of the mass of the main chain monomer.

[0051] Example 4 This embodiment is different from Embodiment 1 in the following aspects: the molar ratio of acrylic acid to MPEG is 1:0.8.

[0052] Example 5 This embodiment is different from Embodiment 1 in that the long side chain short main chain polycarboxylate water reducer and octadecyl trimethyl ammonium chloride are mixed, heated to 50°C, stirred and mixed for 3 hours, and then cooled to room temperature and dried to obtain a high mud resistance polycarboxylate water reducer, and the amount of octadecyl trimethyl ammonium chloride used is 0.5% of the mass of the long side chain short main chain polycarboxylate water reducer.

[0053] Example 6 This embodiment is different from Embodiment 1 in that, based on the improver, 55% of high anti-mud polycarboxylic acid water-reducing agent, 24% of hydroxypropyl methylcellulose, 12% of xanthan gum and 9% of air-entraining agent are mixed and stirred evenly according to the mass percentage to obtain the improver.

[0054] Example 7 This embodiment is different from Embodiment 1 in that, based on the improver, 75% of high anti-mud polycarboxylic acid water-reducing agent, 15% of hydroxypropyl methylcellulose, 5% of xanthan gum and 5% of sodium lauryl sulfate are mixed and stirred evenly according to the mass percentage to obtain the improver.

[0055] Comparative Example 1 This comparative example has the following differences compared to Example 1: the molecular weight of polyethylene glycol monomethyl ether (MPEG) is 400.

[0056] Comparative Example 2 This comparative example is different from Example 1 in that methyl methacrylate phosphate (PME) is not added, acrylic acid is directly diluted with ionized water and stirred evenly to obtain solution B, wherein the concentration of solution B is 30%.

[0057] Comparative Example 3 This comparative example is different from Example 1 in that no octadecyltrimethylammonium chloride is added.

[0058] Comparative Example 4 This comparative example is different from Example 1 in that, based on the improver, 30% of high anti-mud polycarboxylic acid water-reducing agent, 40% of hydroxypropyl methylcellulose, 20% of xanthan gum and 10% of sodium lauryl sulfate are mixed and stirred in percentage by mass to obtain the improver.

[0059] Comparative Example 5 This comparative example is different from Example 1 in that, based on the improver, 90% of high anti-mud polycarboxylic acid water-reducing agent, 6% of hydroxypropyl methylcellulose, 3% of xanthan gum and 1% of sodium lauryl sulfate are mixed and stirred evenly according to the mass percentage to obtain the improver.

[0060] Comparative Example 6 This comparative example is different from Example 1 in that, based on the improver, 65% of high-anti-mud polycarboxylate water-reducing agent, 30% of hydroxypropyl methylcellulose and 5% of sodium lauryl sulfate are mixed and stirred evenly according to the mass percentage to obtain the improver.

[0061] Comparative Example 7 This comparative example is different from Example 1 in that, based on the improver, 65% of high-mud-resistant polycarboxylate water-reducing agent, 30% of xanthan gum and 5% of sodium lauryl sulfate are mixed and stirred evenly according to the mass percentage to obtain the improver.

[0062] Comparative Example 8 This comparative example is different from Example 1 in that, based on the improver, 65% of high-anti-mud polycarboxylic acid water-reducing agent, 25% of hydroxypropyl methylcellulose, and 10% of xanthan gum are mixed and stirred in percentage by mass to obtain the improver.

[0063] Comparative Example 9 This comparative example is different from Example 1 in that, taking the improver as a reference, 65% of a common water reducing agent, 20% of hydroxypropyl methylcellulose, 10% of xanthan gum and 5% of sodium lauryl sulfate are mixed and stirred in percentage by mass to obtain the improver.

[0064] Test Case The modifiers in the above embodiments and comparative examples are added into stirring warm water at a temperature above 40°C to prepare a modifier slurry with a mass concentration of 4%, which is combined with a coal-based solid waste filling material such as coal gangue powder to form a filling slurry 1-21, and is used in the fluidized disposal of gangue in goaf areas, wherein Table 1 and Table 2 are Figure 2 The properties of different filling slurries are listed in.

[0065] Table 1 Performance of filling slurry under the same dosage of modifier

[0066] As shown in Table 1, filling slurries 1-3 are directly formed by coal-based solid waste filling materials (particle size < 3 mm). If there is no interaction between the solid and the liquid, the two phases will move relative to each other, resulting in solid phase deposition and siltation. Figure 2 Figure a and Figure b in the figure, so the adhesion between the slurry and the aggregate is improved, and the liquid phase carrying capacity is improved. At the same time, if the viscosity of the slurry is too large, although segregation does not occur, the excessive adhesion limits the fluidity of the filling slurry. Figure 2 Figure c in .

[0067] This improver releases more free water through the high-anti-mud water-reducing component, and at the same time, hydroxypropyl methylcellulose and xanthan gum are used in combination to control the liquid phase cohesion, and the introduced trace bubbles enhance its fluidity. The combined effect of different functional components makes the solid waste slurry have sufficient plastic viscosity, and the aggregate is suspended in the cement slurry without segregation and exudation, while having high fluidity, such as Figure 2 As shown in Figures d-f in the figure and the filling slurries 4-6 in Table 1, the filling slurries 4-6 can be filled in the voids of the goaf under their own weight to form a uniform and dense structure.

[0068] This application achieves the "flowing without segregation" state of gangue or coal-based solid waste slurry through the application of a transport performance improver with high fluidity, strong resistance to segregation and gap passing goals. This type of transport performance improver has the following two usage scenarios.

[0069] For example Figure 3 This is the first application scenario of fluidized disposal of gangue in goaf provided by this embodiment: add the modifier in Example 1 to stirring warm water above 40°C to prepare a modifier slurry with a mass concentration of 4%; prepare gangue powder (particle size <3mm) into gangue slurry with a concentration of 76%, and fill the modifier slurry and gangue slurry into the back of the goaf of the coal mine through pipelines through two routes: the ground and the adjacent one, to achieve filling treatment (i.e., the application of the filling slurry in Scheme 4 in Table 1). The use of the modifier can significantly reduce the slurry transportation resistance, increase the diffusion distance of the slurry in the goaf, reduce the proportion of condensed water, improve the gangue disposal capacity and efficiency, and at the same time avoid a large amount of exudate water affecting the normal coal mining face.

[0070] For example Figure 4 This is the second application scenario of fluidized disposal of gangue in coal mine goafs provided by this embodiment: the application is carried out in the form of "gangue aggregate to build a skeleton + clean (sand) slurry to reinforce and cement": large-sized block gangue (gangue particle size ≥ 10cm) is thrown into the tunnel by a gangue thrower to form a structural skeleton, and the filling slurry in Scheme 4 in Table 1 is used to fill and reinforce through the pipes reserved inside, and the gaps between the blocks are filled and compacted by relying on its self-flowing and self-compacting ability to form a complete large-volume coal gangue compact cluster. The application of modifiers can prepare a filling slurry with excellent fluidity and gap permeability, thereby realizing the construction of a complete large-volume coal gangue filling body.

[0071] This modifier can increase the concentration of solid waste slurry such as coal gangue to more than 78% while maintaining high fluidity, thereby improving the treatment efficiency of solid waste such as gangue. At the same time, it can keep the slurry at a high resistance to segregation and fluidity over time, avoid the risks of siltation and pipe blockage during pipeline transportation, improve the efficiency of gangue slurry passing through cracks (voids) in goaf areas, and expand its diffusion radius.

[0072] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0073] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for preparing a coal-based solid waste filling material transport performance improver, characterized in that: The following steps are involved: A long side chain short main chain polycarboxylate water reducer with a solid content of 20%-40% is prepared, and the long side chain short main chain polycarboxylate water reducer is mixed with a sacrificial agent and then dried to obtain a high mud resistance polycarboxylate water reducer; wherein the mass percentage of the sacrificial agent is 0.1%-0.5% based on the high mud resistance polycarboxylate water reducer; Taking the improver as a basis, 50%-75% of the highly anti-mud polycarboxylic acid water-reducing agent, 20%-40% of the thickening suspending agent and 5%-10% of the air entraining agent are mixed and stirred in accordance with the mass percentage to obtain the improver.

2. The preparation method according to claim 1, characterized in that: The thickening suspending agent includes hydroxypropyl methylcellulose and xanthan gum; wherein, based on the improver, the hydroxypropyl methylcellulose is 15%-25% by weight; and the xanthan gum is 5%-15% by weight; And / or, the air entraining agent comprises sodium dodecyl sulfate.

3. The preparation method according to claim 1 or 2, characterized in that: The preparation process of the long side chain short main chain polycarboxylate water reducer comprises: Pre-emulsifying the side chain monomer to form a mixed solution A; Premixing the main chain monomer and the functional monomer to form a mixed solution B; After adding the mixed solution A and part of the initiator into the reactor, the oxygen in the reactor is removed and the temperature is raised to 70-80° C.; then the mixed solution B and the remaining initiator are added dropwise to the reactor, and after the addition is complete, the temperature in the reactor is raised to 80-85° C. and kept for reaction for 1-2 hours; The reactor is cooled to below 40° C. and the pH value of the reaction liquid therein is adjusted to 6.5-7.5; the reaction liquid is purified and impurities removed to obtain the long side chain and short main chain polycarboxylate water reducer.

4. The preparation method according to claim 3, characterized in that: The side chain monomer includes polyethylene glycol monomethyl ether with a molecular weight of 2000-2400; the side chain monomer is dissolved in a solvent and mixed with a chain transfer agent for pre-emulsification; wherein the mass ratio of the side chain monomer to the solvent is 1:2; And / or, the chain transfer agent comprises mercaptoacetic acid or mercaptopropionic acid, wherein the chain transfer agent is 0.5%-1% of the mass of the side chain monomer.

5. The preparation method according to claim 3, characterized in that: The main chain monomer includes acrylic acid or methacrylic acid; And / or, the functional monomer includes methacrylic acid phosphate; the mass of the functional monomer is 1%-3% of the mass of the main chain monomer; And / or, the concentration of the mixed solution B is 30%-40%.

6. The preparation method according to claim 3, characterized in that: The molar ratio of the main chain monomer to the side chain monomer is 1:0.8-1.2; And / or, the initiator includes ammonium persulfate or azobisisobutyronitrile; the mass of the initiator is 0.5%-1.5% of the total mass of the side chain monomer, the main chain monomer and the functional monomer.

7. The preparation method according to claim 1, characterized in that: The sacrificial agent includes a quaternary ammonium salt surfactant; And / or, the quaternary ammonium salt surfactant includes hexadecyltrimethylammonium chloride or octadecyltrimethylammonium chloride; And / or, the mass of the quaternary ammonium salt surfactant is 0.1%-0.5% of the mass of the long side chain short main chain polycarboxylate water reducer; The long side chain short main chain polycarboxylate water reducer is mixed with the sacrificial agent, heated to 40° C.-50° C., stirred and mixed for 2-3 hours, and then cooled to room temperature to obtain the high mud resistance polycarboxylate water reducer.

8. A coal-based solid waste filling material transport performance improver, characterized in that: The compound is obtained by the preparation method described in any one of claims 1 to 7.

9. The modifier described in claim 8 is used in the fluidization disposal of goaf gangue using coal-based solid waste filling materials.

10. The use according to claim 9, characterized in that The modifier is added into water with a temperature of at least 40°C to prepare a modifier slurry with a mass concentration of 2%-8%; the modifier slurry is mixed with coal-based solid waste filling materials during the filling process of the goaf, wherein the mass of the modifier slurry is 0.3%-1% of the mass of the coal-based solid waste filling materials.

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