High-strength filling material for mine and preparation method thereof

Abstract

The application relates to the technical field of mine filling materials, and discloses a high-strength filling material for mines and a preparation method. The high-strength filling material for mines 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-activated cementitious slurry and 2.5-6 parts by weight of polyurethane binder emulsion. The prepared polyhydroxy sulfonic acid grinding aid contains multiple hydroxyl groups and sulfonic acid groups, has stronger surface interaction with slag, has greater infiltration, can be strongly adsorbed in microcracks on the surface of slag after ball milling, reduces the surface energy of slag particles, improves the dispersibility of the slag particles, increases the specific surface area, and makes the activity of the slag powder be excited to a greater extent, so that the compressive strength of the filling material can be improved.

Description

TECHNICAL FIELD

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

[0002] Mine filling material is a material used for filling cavities in mining, which can control the deformation of surrounding rock and prevent surface subsidence. Mine filling material is mainly composed of tailings, cementing materials, and additives. Blast furnace slag powder is cheap, easy to obtain, and has high activity, which can be used as a cementing material and widely used in filling materials, grouting materials, and concrete. Increasing the specific surface area and dispersity of slag powder can improve its activity and enhance the mechanical strength of filling materials.

[0003] Common modifiers for slag powder include organic grinding aids, oleic acid, stearic acid, and titanate coupling agents. A Chinese patent with the publication number CN115057636B discloses a slag grinding aid, its preparation method, and cement using the slag grinding aid. The grinding aid uses polyols such as trimethylol aminomethyl methane and modified glucosan as grinding aids for grinding slag, thereby improving the strength of cement. However, the grinding aid does not significantly increase the specific surface area of slag, which is not conducive to improving the activity of slag and the strength of filling materials. SUMMARY

[0004] To address the shortcomings of the prior art, the present application provides a high-strength filling material for mines and a preparation method, including a multi-hydroxy sulfonic acid grinding aid and a grinding aid-activated slag powder, which solves the problems of low specific surface area and activity of slag powder and low strength of mine filling materials.

[0005] The high-strength filling material for mines includes 23.5-30 parts by weight of water, 50-64 parts by weight of chlorine-containing tailings, 5-16 parts by weight of pre-activated cementitious slurry, and 2.5-6 parts by weight of polyurethane binder emulsion.

[0006] The pre-activated cementitious slurry is composed of 24-32% water, 58-68% grinding aid-activated slag powder, and 10-16% calcium salt activator.

[0007] The preparation method of the high-strength filling material for mines includes the following steps: adding the grinding aid-activated slag powder and calcium salt activator to water, stirring and mixing to obtain a pre-activated cementitious slurry, and then adding water, chlorine-containing tailings, and polyurethane binder emulsion, stirring and mixing to obtain the high-strength filling material for mines.

[0008] Preferably, the proportion of particles with a particle size of ≦20μm in the chlorine-containing tailings is 30-65%.

[0009] Preferably, the specific surface area of the calcium salt activator is 400-500m2 / kg, the calcium salt stimulating agent is a solid powder mixture of calcium chloride and calcium sulfate with a mass ratio of 1: (1.6-2).

[0010] The method for preparing the grinding aid activated slag powder is as follows:

[0011] Step (1) 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 into ethanol, heating to 75-85℃, and refluxing for 36-48h, then filtering, heating and evaporating the filtrate, and cooling and crystallizing to obtain the polyhydroxy sulfonic acid grinding aid. The reaction formula is as follows:

[0012] .

[0013] Step (2) adding the polyhydroxy sulfonic acid grinding aid into water, stirring, and then adding the solution and water quenched blast furnace slag powder into a ball mill for ball milling, drying after ball milling, and obtaining the grinding aid activated slag powder.

[0014] Preferably, the ball milling time in step (2) is 60-120min.

[0015] Preferably, the amount of the water quenched blast furnace slag powder in step (2) is 100 parts by weight, and the amount of the polyhydroxy sulfonic acid grinding aid is 0.05-0.15 parts by weight.

[0016] Preferably, the method for preparing the polyurethane adhesive emulsion is as follows: stirring and mixing 100 parts by weight of vacuum dewatered polyether polyol with 21-30 parts by weight of isocyanate monomer and 11-14 parts by weight of 2,2-dimethylol propionic acid, reacting for 2.5-3h at 70-80℃ in a nitrogen atmosphere, adding 3.8-5.2 parts by weight of 1,4-butanediol, stirring and reacting for 30-40min at 40-50℃, adding triethylamine for neutralization, adding water, stirring and dispersing, and obtaining the polyurethane adhesive emulsion.

[0017] Preferably, the polyether polyol is polytetrahydrofuran ether diol or polyethylene glycol, and the isocyanate monomer is toluene diisocyanate or diphenylmethane diisocyanate.

[0018] Beneficial technical effect: The prepared multi-hydroxyl sulfonic acid grinding aid contains multiple hydroxyl groups and sulfonic acid groups, has stronger interaction with the surface of the slag, has greater infiltration effect, and the grinding aid can be strongly adsorbed in the micro-cracks on the surface of the slag after ball milling, thereby reducing the surface energy of the slag particles and improving the dispersibility of the slag particles. Moreover, the grinding aid contains multiple nitrogen atoms with lone pair electrons, which are electronegative, so that the slag particles have electrostatic repulsion effect, further improving the dispersibility of the slag particles, thereby improving the specific surface area, and the activity of the slag powder can be excited to a greater extent, which is beneficial to improving the compressive strength of the filling material.

[0019] The present application utilizes the multi-hydroxyl sulfonic acid grinding aid to modify the slag particles by ball milling, introduces sulfonic acid, multi-hydroxyl and other active groups into the slag particles, forms hydrogen bond interaction force with the urethane, carboxyl and other groups of the polyurethane binder, improves the interfacial bonding force between the slag powder and the polyurethane binder, and makes the polyurethane binder have better cementing performance, thereby further improving the compressive strength of the filling material. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The figure is the nuclear magnetic resonance hydrogen spectrum of the multi-hydroxyl sulfonic acid grinding aid. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be further described through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0022] The following chlorine-containing tailings contain 44.3% of particles with a particle size of 20 μm or less, which are produced from Sanshandao Gold Mine located on the Jiaodong Peninsula bordering Laizhou Bay. The water-quenched blast furnace slag powder has an average specific surface area of about 382.3 m 2 / kg, which is produced by Gongyi Longze Water Purification Material Co., Ltd. The average specific surface area of the calcium salt activator is about 469.5 m 2 / kg, which is a solid powder mixture composed of calcium chloride and calcium sulfate with a mass ratio of about 1:1.87.

[0023] Example 1: A method for preparing high-strength filling material for mine, comprising the following steps:

[0024] (1) 200g vacuum-dried polyethylene glycol is mixed with 42g toluene diisocyanate and 28g 2,2-dimethylol propionic acid, and stirred and reacted in a nitrogen atmosphere at 70°C for 2.5h, 40mL of acetone and 7.6g of 1,4-butanediol are added, and stirred and reacted at 40°C for 40min, triethylamine is added to neutralize the pH to 7, 200mL of water is added, and stirred and dispersed to obtain a polyurethane binder emulsion;

[0025] (2) adding 150 mL of water, 5 g of N,N'-bis(2-hydroxyethyl)ethylenediamine, 26.5 g of 3-chloro-2-hydroxypropanesulfonic acid sodium salt, and 7 g of sodium carbonate into 80 mL of ethanol, heating to 85°C, condensing refluxing for 48 h, filtering, heating and evaporating the filtrate, and cooling and crystallizing to obtain a polyhydroxy sulfonic acid grinding aid; the structural formula is:

[0026] ,

[0027] Figure 1 Nuclear magnetic resonance hydrogen spectrum shows that the chemical shift value of the polyhydroxy sulfonic acid grinding aid is 1 H NMR (400 MHz, CDCl3) δ 3.78-3.69 (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);

[0028] (3) adding 5 g of the polyhydroxy sulfonic acid grinding aid into 10 mL of water, stirring, and then adding the solution and 10 kg of water quenched blast furnace slag powder into a ball mill, ball milling for 60 min, drying after ball milling, and obtaining a grinding aid activated slag powder;

[0029] (4) adding 6.2 kg of the grinding aid activated slag powder and 1.4 kg of a calcium salt activator into 2.4 kg of water, stirring and mixing, and obtaining a pre-activated cementitious slurry;

[0030] (5) adding 9 kg of the pre-activated cementitious slurry, 62 kg of chlorine-containing tailings, and 4 kg of a polyurethane binder emulsion into 25 kg of water, stirring and mixing, and obtaining a high-strength filling material for mines.

[0031] Preparation method of a filling material for mines in Comparative Example 1, including the following steps:

[0032] (1) adding 10 kg of water quenched blast furnace slag powder into a ball mill, ball milling for 60 min, drying after ball milling, and obtaining a ball milled slag powder;

[0033] (2) adding 6.2 kg of the ball milled slag powder and 1.4 kg of a calcium salt activator into 2.4 kg of water, stirring and mixing, and obtaining a pre-activated cementitious slurry;

[0034] (3) adding 9 kg of the pre-activated cementitious slurry, 62 kg of chlorine-containing tailings, and 4 kg of a polyurethane binder emulsion (same as the preparation method in Example 1) into 25 kg of water, stirring and mixing, and obtaining a filling material for mines.

[0035] Preparation method of a filling material for mines in Comparative Example 2, including the following steps:

[0036] (1) 5 g of glycerol was added to 10 mL of water, and after stirring, the solution was added to 10 kg of water-quenched blast furnace slag powder in a ball mill, and ball milling was performed for 60 min. After ball milling, drying was performed, and an activator-activated slag powder was obtained;

[0037] (2) 6.2 kg of the activator-activated slag powder, 1.4 kg of a calcium salt activator, and 2.4 kg of water were stirred and mixed, and a pre-activated cementitious slurry was obtained;

[0038] (3) 9 kg of the pre-activated cementitious slurry, 62 kg of chlorine-containing tailings, and 4 kg of a polyurethane binder emulsion (prepared in the same manner as in Example 1) were added to 25 kg of water, and stirring and mixing were performed, and a mine filling material was obtained.

[0039] Comparative Example 3: A mine filling material was prepared by the following method, which included the following steps:

[0040] (1) 5 g of triethanolamine was added to 10 mL of water, and after stirring, the solution was added to 10 kg of water-quenched blast furnace slag powder in a ball mill, and ball milling was performed for 60 min. After ball milling, drying was performed, and an activator-activated slag powder was obtained;

[0041] (2) 6.2 kg of the activator-activated slag powder, 1.4 kg of a calcium salt activator, and 2.4 kg of water were stirred and mixed, and a pre-activated cementitious slurry was obtained;

[0042] (3) 9 kg of the pre-activated cementitious slurry, 62 kg of chlorine-containing tailings, and 4 kg of a polyurethane binder emulsion (prepared in the same manner as in Example 1) were added to 25 kg of water, and stirring and mixing were performed, and a mine filling material was obtained.

[0043] Comparative Example 4: A mine filling material was prepared by the following method, which included the following steps:

[0044] (1) 5 g of sodium dodecyl benzene sulfonate was added to 10 mL of water, and after stirring, the solution was added to 10 kg of water-quenched blast furnace slag powder in a ball mill, and ball milling was performed for 60 min. After ball milling, drying was performed, and an activator-activated slag powder was obtained;

[0045] (2) 6.2 kg of the activator-activated slag powder, 1.4 kg of a calcium salt activator, and 2.4 kg of water were stirred and mixed, and a pre-activated cementitious slurry was obtained;

[0046] (3) 9 kg of the pre-activated cementitious slurry, 62 kg of chlorine-containing tailings, and 4 kg of a polyurethane binder emulsion (prepared in the same manner as in Example 1) were added to 25 kg of water, and stirring and mixing were performed, and a mine filling material was obtained.

[0047] Example 2: A mine filling material was prepared by the following method, which included the following steps:

[0048] (1) 200 g of vacuum-dried polytetramethylene ether glycol is stirred and mixed with 60 g of diphenylmethane diisocyanate, 22 g of 2,2-dimethylol propionic acid, and then reacted at 80°C for 3 h under a nitrogen atmosphere. 50 mL of acetone and 10.4 g of 1,4-butanediol are added, and the mixture is stirred and reacted at 50°C for 30 min. Triethylamine is added to neutralize the pH to 7, 250 mL of water is added, and the mixture is stirred and dispersed to obtain a polyurethane binder emulsion;

[0049] (2) 120 mL of water, 5 g of N,N'-bis(2-hydroxyethyl)ethylenediamine, 21 g of 3-chloro-2-hydroxypropanesulfonic acid sodium, and 9 g of sodium carbonate are added to 100 mL of ethanol, heated to 75°C, and refluxed and reacted for 36 h. After filtration, the filtrate is heated and evaporated, and then cooled and crystallized to obtain a polyhydroxysulfonic acid grinding aid;

[0050] (3) 12 g of the polyhydroxysulfonic acid grinding aid is added to 20 mL of water, and then the solution is added to 10 kg of water-quenched blast furnace slag powder in a ball mill and ball-milled for 120 min. After ball-milling, the mixture is dried to obtain a grinding aid-activated slag powder;

[0051] (4) 5.8 kg of the grinding aid-activated slag powder and 1 kg of a calcium salt activator are added to 3.2 kg of water, and then stirred and mixed to obtain a pre-activated cementitious slurry;

[0052] (5) 14 kg of the pre-activated cementitious slurry, 50 kg of chlorides-containing tailings, and 6 kg of the polyurethane binder emulsion are added to 30 kg of water, and then stirred and mixed to obtain a high-strength filling material for mines.

[0053] Example 3: A preparation method of a high-strength filling material for mines, comprising the following steps:

[0054] (1) 15 g of a polyhydroxysulfonic acid grinding aid (prepared by the same method as in Example 1) is added to 20 mL of water, and then the solution is added to 10 kg of water-quenched blast furnace slag powder in a ball mill and ball-milled for 120 min. After ball-milling, the mixture is dried to obtain a grinding aid-activated slag powder;

[0055] (2) 6.8 kg of the grinding aid-activated slag powder and 1.6 kg of a calcium salt activator are added to 2.6 kg of water, and then stirred and mixed to obtain a pre-activated cementitious slurry;

[0056] (3) 5 kg of the pre-activated cementitious slurry, 64 kg of chlorides-containing tailings, and 4.5 kg of the polyurethane binder emulsion (prepared by the same method as in Example 1) are added to 26.5 kg of water, and then stirred and mixed to obtain a high-strength filling material for mines.

[0057] Example 4: A preparation method of a high-strength filling material for mines, comprising the following steps:

[0058] (1) 8.5 g of polyhydroxy sulfonic acid grinding aid (same preparation method as in Example 1) was added to 15 mL of water, and after stirring, the solution was added to 10 kg of water quenched blast furnace slag powder in a ball mill, and ball milling was performed for 90 min. After ball milling, drying was performed to obtain a grinding aid activated slag powder;

[0059] (2) 6 kg of the grinding aid activated slag powder, 1.3 kg of calcium salt activator were added to 2.7 kg of water, and after stirring and mixing, a pre-activated cementitious slurry was obtained;

[0060] (3) 16 kg of the pre-activated cementitious slurry, 58 kg of chlor-alkali tailings, and 2.5 kg of polyurethane binder emulsion (same preparation method as in Example 1) were added to 23.5 kg of water, and after stirring and mixing, a high-strength filling material for mine was obtained.

[0061] The specific surface area of the grinding aid activated slag powder (ball milled slag powder for Comparative Example 1) was tested using a pneumatic Blaine specific surface area tester.

[0062] The filling material was poured into a mold, vibrated to remove bubbles, and cured at room temperature for 28 days to obtain a test sample. The compressive strength was tested according to the method of GB / T17671-2021.

[0063] Table 1: Specific surface area and compressive strength test results of each example and comparative example

[0064]

[0065] Examples 1-4 used polyhydroxy sulfonic acid grinding aid to modify the water quenched blast furnace slag powder, and the specific surface area reached 421.2-449.7 m 2 / kg, which was significantly higher than that of Comparative Examples 1-4. The main reason was that compared with the conventional glycerol, triethanolamine, and sodium dodecyl benzene sulfonate grinding aids of Comparative Examples 2-4, the grinding aid of each example contained multiple hydroxyl and sulfonic acid groups, and had stronger interaction with the surface of the slag and greater wetting effect, which could strongly adsorb in the micro-cracks on the surface of the slag, reduce the surface energy of the slag particles, improve the dispersibility of the slag particles, and further improve the dispersibility of the slag particles due to the presence of multiple nitrogen atoms in the grinding aid with lone pair electrons and electronegativity, thereby increasing the specific surface area and enabling the activity of the slag powder to be more fully activated, which was beneficial to improving the compressive strength of the filling material. In addition, after the modification of the grinding aid on the slag particles, active groups such as sulfonic acid and polyhydroxy groups were introduced, which formed hydrogen bond interaction with the urethane, carboxyl, and other groups of the polyurethane binder, thereby improving the interfacial bonding between the slag powder and the polyurethane binder, and the polyurethane binder had better cementing performance, which further improved the compressive strength of the filling material.

[0066] The above merely provides the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high-strength filling material for mines, characterized in that, It includes 23.5-30 parts by weight of water, 50-64 parts by weight of chlorine-containing tailings, 5-16 parts by weight of pre-activated gelling slurry, and 2.5-6 parts by weight of polyurethane binder emulsion; The pre-activated gelling slurry is composed of 24-32% water, 58-68% grinding aid activated slag powder, and 10-16% calcium salt activator by mass. The preparation method of the grinding aid activated slag powder is as follows: adding the following to water: The polyhydroxysulfonic acid grinding aid was stirred, and the solution was added to a ball mill along with water-quenched blast furnace slag powder for ball milling. After ball milling, the powder was dried to obtain 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 minutes.

3. The high-strength filling material for mines according to claim 1, characterized in that, The amount of water-quenched blast furnace slag powder is 100 parts by weight, and the amount of 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 polyhydroxysulfonic acid grinding aid is as follows: add 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, heat to 75-85℃, reflux for 36-48 hours, filter, heat and evaporate the filtrate, cool and crystallize to obtain the polyhydroxysulfonic acid grinding aid.

5. The high-strength filling material for mines according to claim 1, characterized in that, The proportion of particles with a diameter of ≤20μm in the chlorine-containing tailings 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 400-500 m². 2 / kg, the calcium salt activator is a solid powder mixture 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 is as follows: 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 are stirred and mixed, and reacted at 70-80°C for 2.5-3 hours under a nitrogen atmosphere. Acetone and 3.8-5.2 parts by weight of 1,4-butanediol are added, and the mixture is stirred and reacted at 40-50°C for 30-40 minutes. Triethylamine is added for neutralization, water is added, and the mixture is stirred and dispersed 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 polytetrahydrofuran ether diol or polyethylene glycol, and the isocyanate monomer is toluene diisocyanate or diphenylmethane diisocyanate.

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

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