High-strength filling material for mine and preparation method

Abstract

The invention relates to the technical field of mine filling materials, and discloses a high-strength filling material for a mine and a preparation method, the high-strength filling material for the mine comprises 23.5-30 parts by weight of water, 50-64 parts by weight of chlorine-containing tailings, 5-16 parts by weight of pre-excited gelling slurry, and 2.5-6 parts by weight of a polyurethane cementing agent emulsion. The polyhydroxy sulfonic acid grinding aid prepared by the invention contains a plurality of hydroxyl groups and sulfonic acid groups, has stronger acting force with the surface of the slag and greater infiltration effect, and can be strongly adsorbed in microcracks on the surface of the slag after ball milling, so that the surface energy of slag particles is reduced, the dispersity of the slag particles is improved, and the specific surface area is increased; the activity of the slag powder can be stimulated to a greater extent, and the compressive strength of the filling material can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mine filling materials, in particular to a high-strength filling material for mines and a preparation method thereof. Background Art

[0002] Mine filling materials are used to fill voids during mining operations, controlling surrounding rock deformation and preventing surface subsidence. They primarily consist of tailings, cementitious materials, and additives. Blast furnace slag powder is inexpensive, readily available, and highly active, making it a widely used cementitious material in filling materials, grouting materials, and concrete. Increasing the specific surface area and dispersibility of slag powder improves its activity, thereby enhancing the mechanical strength of materials such as fillers.

[0003] Commonly used slag powder modifiers include organic grinding aids, oleic acid, stearic acid, and titanate coupling agents. Chinese patent publication number CN115057636B discloses a slag grinding aid, its preparation method, and cement using the slag grinding aid. Polyols such as tris(hydroxymethyl)aminomethane and modified glucomannan are used as grinding aids for grinding slag, thereby improving the strength of the cement. However, the grinding aid does not significantly increase the specific surface area of ​​the slag, hindering its activity and the strength of the filler material. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a high-strength filling material for mines and a preparation method, including a polyhydroxysulfonic acid grinding aid and slag powder activated by the grinding aid, which solves the problems of low specific surface area and activity of slag powder and low strength of filling materials for mines.

[0005] The high-strength filling material for mines of the present invention comprises 23.5-30 parts by weight of water, 50-64 parts by weight of chlorine-containing tailings, 5-16 parts by weight of pre-excited gelling slurry, and 2.5-6 parts by weight of polyurethane binder emulsion; The pre-activated gelling slurry is composed of 24-32% by weight of water, 58-68% by weight of grinding aid activated slag powder, and 10-16% by weight of a calcium salt activator.

[0006] The preparation method of high-strength filling material for mines includes the following steps: adding grinding aid activated slag powder and calcium salt activator to water, stirring and mixing to obtain pre-activated gelling slurry, and then adding water, chlorine-containing tailings, and polyurethane binder emulsion, stirring and mixing to obtain high-strength filling material for mines.

[0007] Preferably, the proportion of particles with a diameter of ≦20 μm in the chlorine-containing tailings is 30-65%.

[0008] Preferably, the specific surface area of ​​the calcium salt activator is 400-500m 2 / kg, the calcium salt activator is a solid powder mixture consisting of calcium chloride and calcium sulfate in a mass ratio of 1: (1.6-2).

[0009] The preparation method of the grinding aid activated slag powder is: Step (1) adding water, 100 parts by weight of N,N'-bis(2-hydroxyethyl)ethylenediamine, 420-530 parts by weight of 3-chloro-2-hydroxypropanesulfonate sodium, and 140-180 parts by weight of sodium carbonate to ethanol, heating to 75-85°C, condensing and refluxing for 36-48 hours, filtering, heating and evaporating the filtrate, cooling and crystallizing, to obtain a polyhydroxysulfonic acid grinding aid. The reaction formula is: .

[0010] Step (2) adding polyhydroxysulfonic acid grinding aid to water, stirring, adding the solution and water-quenched blast furnace slag powder into a ball mill for ball milling, and drying after ball milling to obtain grinding aid activated slag powder.

[0011] Preferably, the ball milling time in step (2) is 60-120 min.

[0012] Preferably, in step (2), the amount of water-quenched blast furnace slag powder used is 100 parts by weight, and the amount of polyhydroxysulfonic acid grinding aid used is 0.05-0.15 parts by weight.

[0013] Preferably, the preparation method of the polyurethane binder emulsion is: 100 parts by weight of vacuum-dehydrated polyether polyol is mixed with 21-30 parts by weight of isocyanate monomer and 11-14 parts by weight of 2,2-dihydroxymethylpropionic acid, reacted at 70-80°C in a nitrogen atmosphere for 2.5-3h, acetone and 3.8-5.2 parts by weight of 1,4-butanediol are added, stirred and reacted at 40-50°C for 30-40min, triethylamine is added for neutralization, water is added, and the mixture is stirred and dispersed to obtain the polyurethane binder emulsion.

[0014] Preferably, the polyether polyol is polytetramethylene glycol or polyethylene glycol, and the isocyanate monomer is toluene diisocyanate or diphenylmethane diisocyanate.

[0015] Beneficial technical effects: The polyhydroxysulfonic acid grinding aid prepared by the present invention contains multiple hydroxyl and sulfonic acid groups, which have a stronger interaction with the slag surface and a greater wetting effect. After ball milling, the grinding aid can be strongly adsorbed into microcracks on the slag surface, reducing the surface energy of the slag particles and improving their dispersibility. Furthermore, the grinding aid contains multiple nitrogen atoms, which have lone pairs of electrons and exhibit electronegativity. This creates electrostatic repulsion between the slag particles, further improving their dispersibility and increasing their specific surface area. This allows for greater activation of the slag powder, which in turn helps to enhance the compressive strength of the filling material.

[0016] The present invention utilizes a polyhydroxy sulfonic acid grinding aid to perform ball milling modification on slag particles, and then introduces active groups such as sulfonic acid and polyhydroxy into the slag particles to form hydrogen bond interaction forces with groups such as carbamate and carboxyl of the polyurethane binder, thereby improving the interfacial bonding force between the slag powder and the polyurethane binder, making the polyurethane binder have better bonding properties, and further improving the compressive strength of the filling material. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of polyhydroxysulfonic acid grinding aid. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0019] The following chlorine-containing tailings have a particle size of ≤20μm, accounting for 44.3%, and are produced from the Sanshan Island gold mine on the Jiaodong Peninsula, bordering Laizhou Bay. The average specific surface area of ​​water-quenched blast furnace slag powder is about 382.3m 2 / kg, produced by Gongyi Longze Water Purification Material Co., Ltd. The average specific surface area of ​​the calcium salt activator is about 469.5m 2 / kg, is a solid powder mixture consisting of calcium chloride and calcium sulfate in a mass ratio of approximately 1:1.87.

[0020] Example 1: A method for preparing a high-strength filling material for a mine, comprising the following steps: (1) 200 g of vacuum-dehydrated polyethylene glycol was mixed with 42 g of toluene diisocyanate and 28 g of 2,2-dimethylol propionic acid, and reacted at 70°C for 2.5 h in a nitrogen atmosphere. 40 mL of acetone and 7.6 g of 1,4-butanediol were added, and the mixture was stirred and reacted at 40°C for 40 min. Triethylamine was added to neutralize the pH to 7, and 200 mL of water was added and the mixture was stirred and dispersed to obtain a polyurethane binder emulsion. (2) Add 150 mL of water, 5 g of N,N'-bis(2-hydroxyethyl)ethylenediamine, 26.5 g of sodium 3-chloro-2-hydroxypropanesulfonate, and 7 g of sodium carbonate to 80 mL of ethanol, heat to 85°C, condense and reflux for 48 hours, filter, heat and evaporate the filtrate, cool and crystallize to obtain a polyhydroxysulfonic acid grinding aid; the structural formula is: , Figure 1 The H NMR spectrum shows that the chemical shift value of polyhydroxysulfonic acid grinding aid is 1H NMR (400 MHz, CDCl3) δ3.78-3.69 (m, 6H), 3.39 (s, 2H), 3.30 (m, 2H), 2.78-2.57 (m, 8H), 2.55-2.45 (m, 4H), 2.42-2.23 (m, 4H); (3) Add 5 g of polyhydroxysulfonic acid grinding aid to 10 mL of water, stir, add the solution and 10 kg of water-quenched blast furnace slag powder into a ball mill, ball mill for 60 min, and dry after ball milling to obtain grinding aid activated slag powder; (4) Add 6.2 kg of grinding aid activated slag powder and 1.4 kg of calcium salt activator to 2.4 kg of water, stir and mix to obtain pre-activated gelled slurry; (5) Add 9 kg of pre-excited gelling slurry, 62 kg of chlorine-containing tailings, and 4 kg of polyurethane binder emulsion to 25 kg of water, stir and mix, and obtain a high-strength filling material for mines.

[0021] Comparative Example 1: A method for preparing a filling material for a mine, comprising the following steps: (1) Add 10 kg of water-quenched blast furnace slag powder into a ball mill, ball mill for 60 min, and dry after ball milling to obtain ball-milled slag powder; (2) Add 6.2 kg of ball-milled slag powder and 1.4 kg of calcium salt activator to 2.4 kg of water and stir to obtain a pre-activated gelling slurry; (3) Add 9 kg of pre-excited gelling slurry, 62 kg of chlorine-containing tailings, and 4 kg of polyurethane binder emulsion (prepared in the same manner as in Example 1) to 25 kg of water, stir and mix, and obtain a mine filling material.

[0022] Comparative Example 2: A method for preparing a filling material for a mine, comprising the following steps: (1) Add 5 g of propylene glycol to 10 mL of water, stir, add the solution and 10 kg of water-quenched blast furnace slag powder into a ball mill, and ball mill for 60 min. After ball milling, dry to obtain grinding aid activated slag powder; (2) Add 6.2 kg of grinding aid activated slag powder and 1.4 kg of calcium salt activator to 2.4 kg of water, stir and mix to obtain pre-activated gelled slurry; (3) Add 9 kg of pre-excited gelling slurry, 62 kg of chlorine-containing tailings, and 4 kg of polyurethane binder emulsion (prepared in the same manner as in Example 1) to 25 kg of water, stir and mix, and obtain a mine filling material.

[0023] Comparative Example 3: A method for preparing a filling material for a mine, comprising the following steps: (1) Add 5 g of triethanolamine to 10 mL of water, stir, add the solution and 10 kg of water-quenched blast furnace slag powder into a ball mill, and ball mill for 60 min. After ball milling, dry to obtain grinding aid activated slag powder; (2) Add 6.2 kg of grinding aid activated slag powder and 1.4 kg of calcium salt activator to 2.4 kg of water, stir and mix to obtain pre-activated gelled slurry; (3) Add 9 kg of pre-excited gelling slurry, 62 kg of chlorine-containing tailings, and 4 kg of polyurethane binder emulsion (prepared in the same manner as in Example 1) to 25 kg of water, stir and mix, and obtain a mine filling material.

[0024] Comparative Example 4: A method for preparing a filling material for a mine, comprising the following steps: (1) Add 5 g of sodium dodecylbenzenesulfonate to 10 mL of water, stir, add the solution and 10 kg of water-quenched blast furnace slag powder into a ball mill, and ball mill for 60 min. After ball milling, dry to obtain grinding aid activated slag powder; (2) Add 6.2 kg of grinding aid activated slag powder and 1.4 kg of calcium salt activator to 2.4 kg of water, stir and mix to obtain pre-activated gelled slurry; (3) Add 9 kg of pre-excited gelling slurry, 62 kg of chlorine-containing tailings, and 4 kg of polyurethane binder emulsion (prepared in the same manner as in Example 1) to 25 kg of water, stir and mix, and obtain a mine filling material.

[0025] Example 2: A method for preparing a high-strength filling material for a mine, comprising the following steps: (1) 200 g of vacuum-dehydrated polytetramethylene glycol was mixed with 60 g of diphenylmethane diisocyanate and 22 g of 2,2-dihydroxymethylpropionic acid, and reacted at 80°C for 3 h in a nitrogen atmosphere. 50 mL of acetone and 10.4 g of 1,4-butanediol were added, and the mixture was stirred and reacted at 50°C for 30 min. Triethylamine was added to neutralize the pH to 7, and 250 mL of water was added and the mixture was dispersed by stirring to obtain a polyurethane binder emulsion. (2) Add 120 mL of water, 5 g of N,N'-bis(2-hydroxyethyl)ethylenediamine, 21 g of sodium 3-chloro-2-hydroxypropanesulfonate, and 9 g of sodium carbonate to 100 mL of ethanol, heat to 75 °C, condense and reflux for 36 h, filter, heat and evaporate the filtrate, cool and crystallize to obtain a polyhydroxysulfonic acid grinding aid; (3) Add 12 g of polyhydroxysulfonic acid grinding aid to 20 mL of water, stir, add the solution and 10 kg of water-quenched blast furnace slag powder into a ball mill, ball mill for 120 min, and dry after ball milling to obtain grinding aid activated slag powder; (4) Add 5.8 kg of grinding aid activated slag powder and 1 kg of calcium salt activator to 3.2 kg of water, stir and mix to obtain pre-activated gelled slurry; (5) Add 14 kg of pre-excited gelling slurry, 50 kg of chlorine-containing tailings, and 6 kg of polyurethane binder emulsion to 30 kg of water, stir and mix, and obtain a high-strength filling material for mines.

[0026] Example 3: A method for preparing a high-strength filling material for a mine, comprising the following steps: (1) Add 15 g of polyhydroxysulfonic acid grinding aid (prepared in the same manner as in Example 1) to 20 mL of water, stir, add the solution and 10 kg of water-quenched blast furnace slag powder into a ball mill, and mill for 120 min. After ball milling, dry to obtain grinding aid activated slag powder; (2) Add 6.8 kg of grinding aid activated slag powder and 1.6 kg of calcium salt activator to 2.6 kg of water, stir and mix to obtain pre-activated gelled slurry; (3) Add 5 kg of pre-excited gelling slurry, 64 kg of chlorine-containing tailings, and 4.5 kg of polyurethane binder emulsion (prepared in the same manner as in Example 1) to 26.5 kg of water, stir and mix, and obtain a high-strength filling material for mines.

[0027] Example 4: A method for preparing a high-strength filling material for a mine, comprising the following steps: (1) Add 8.5 g of polyhydroxysulfonic acid grinding aid (prepared in the same manner as in Example 1) to 15 mL of water, stir, add the solution and 10 kg of water-quenched blast furnace slag powder into a ball mill, and mill for 90 min. After ball milling, dry to obtain grinding aid activated slag powder; (2) Add 6 kg of grinding aid activated slag powder and 1.3 kg of calcium salt activator to 2.7 kg of water, stir and mix to obtain pre-activated gelled slurry; (3) Add 16 kg of pre-excited gelling slurry, 58 kg of chlorine-containing tailings, and 2.5 kg of polyurethane binder emulsion (prepared in the same manner as in Example 1) to 23.5 kg of water, stir and mix, and obtain a high-strength filling material for mines.

[0028] The specific surface area of ​​the grinding aid-activated slag powder (comparative example 1 is ball-milled slag powder) was tested using a pneumatic Blaine surface area meter.

[0029] The filling material was poured into the mold, vibrated to remove air bubbles, and cured at room temperature for 28 days to prepare the specimen. The compressive strength was tested according to the method of GB / T17671-2021.

[0030] Table 1: Specific surface area and compressive strength test results of various embodiments and comparative examples

[0031] Example 1-Example 4: Water-quenched blast furnace slag powder was ball-milled using polyhydroxysulfonic acid grinding aid, and its specific surface area reached 421.2-449.7m 2 / kg, which is significantly higher than that of Comparative Examples 1 to 4. This is mainly because compared with the conventional propylene glycol, triethanolamine and sodium dodecylbenzenesulfonate grinding aids in Comparative Examples 2 to 4, the grinding aids in each embodiment contain multiple hydroxyl and sulfonic acid groups, which have stronger interaction with the slag surface and greater wetting effect. They can be strongly adsorbed in the microcracks on the slag surface, reducing the surface energy of the slag particles and improving the dispersibility of the slag particles. In addition, the grinding aids in each embodiment contain multiple nitrogen atoms, have lone pairs of electrons, and are electronegative, so that the slag particles have electrostatic repulsion, further improving the dispersibility of the slag particles, thereby increasing the specific surface area, so that the activity of the slag powder can be stimulated to a greater extent, which is beneficial to improving the compressive strength of the filling material. After the grinding aid modifies the slag particles, active groups such as sulfonic acid and polyhydroxyl are introduced, which form hydrogen bond interaction forces with the carbamate, carboxyl and other groups of the polyurethane binder, thereby improving the interfacial bonding force between the slag powder and the polyurethane binder. The polyurethane binder has better bonding performance, further improving the compressive strength of the filling material.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. High-strength filling material for mines, characterized by: The invention comprises 23.5-30 parts by weight of water, 50-64 parts by weight of chlorine-containing tailings, 5-16 parts by weight of pre-excited gelling slurry, and 2.5-6 parts by weight of polyurethane binder emulsion; The pre-activated gelling slurry is composed of 24-32% by weight of water, 58-68% by weight of activated slag powder as a grinding aid, and 10-16% by weight of a calcium salt activator; The preparation method of the grinding aid activated slag powder is as follows: adding the structural formula The polyhydroxysulfonic acid grinding aid is added into a ball mill after stirring, and the solution and water-quenched blast furnace slag powder are added into a ball mill for ball milling. After ball milling, the ball milling is dried to obtain the grinding aid activated slag powder.

2. The high-strength filling material for mines according to claim 1, characterized in that: The ball milling time is 60-120 min.

3. The high-strength filling material for mines according to claim 1, characterized in that: The amount of the water-quenched blast furnace slag powder is 100 parts by weight, and the amount of the polyhydroxysulfonic acid grinding aid is 0.05-0.15 parts by weight.

4. The high-strength filling material for mines according to claim 1, characterized in that: The preparation method of the polyhydroxy sulfonic acid grinding aid comprises the following steps: adding water, 100 parts by weight of N,N'-bis(2-hydroxyethyl)ethylenediamine, 420-530 parts by weight of sodium 3-chloro-2-hydroxypropanesulfonate, and 140-180 parts by weight of sodium carbonate to ethanol; heating the mixture to 75-85°C; carrying out condensation reflux reaction for 36-48 hours; filtering the mixture; heating the filtrate to evaporate the mixture; and cooling the mixture for crystallization to obtain the polyhydroxy sulfonic acid grinding aid.

5. The high-strength filling material for mines according to claim 1, characterized in that: The proportion of the chlorine-containing tailings with a particle size of ≦20 μm is 30-65%.

6. The high-strength filling material for mines according to claim 1, characterized in that: The specific surface area of ​​the calcium salt activator is 400-500m 2 / kg, the calcium salt activator is a solid powder mixture consisting of calcium chloride and calcium sulfate in a mass ratio of 1: (1.6-2).

7. The high-strength filling material for mines according to claim 1, characterized in that: The preparation method of the polyurethane binder emulsion comprises the following steps: mixing 100 parts by weight of vacuum-dehydrated polyether polyol, 21-30 parts by weight of isocyanate monomer, and 11-14 parts by weight of 2,2-dimethylolpropionic acid, reacting the mixture at 70-80° C. for 2.5-3 hours in a nitrogen atmosphere, adding acetone and 3.8-5.2 parts by weight of 1,4-butanediol, stirring and reacting the mixture at 40-50° C. for 30-40 minutes, adding triethylamine for neutralization, adding water, and stirring and dispersing the mixture to obtain the polyurethane binder emulsion.

8. The high-strength filling material for mines according to claim 7, characterized in that: The polyether polyol is polytetramethylene glycol or polyethylene glycol, and the isocyanate monomer is toluene diisocyanate or diphenylmethane diisocyanate.

9. The method for preparing a high-strength filling material for mines according to any one of claims 1 to 8, characterized in that: The following steps are involved: Grinding aid activated slag powder and calcium salt activator are added to water, stirred and mixed to obtain pre-activated gelling slurry, and then water, chlorine-containing tailings and polyurethane binder emulsion are added, stirred and mixed to obtain high-strength filling material for mines.

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