Multi-solid-waste synergistic micro-expansive mine filling material as well as preparation method and application thereof

Abstract

The invention discloses a multi-solid-waste synergistic micro-expansive mine filling material and a preparation method and application thereof, and belongs to the technical field of solid waste resource utilization, the multi-solid-waste synergistic micro-expansive mine filling material comprises the following components by weight: 20-30% of a solid waste-based material, 0.2-0.4% of an excitation-rapid hardening complexing agent, 10-20% of fly ash, 4-6% of semi-dry desulfurization ash, and 45-65% of tailing sand; according to the invention, a mixture obtained by compounding the base water glass and the alcohol amine hydrogen peroxide is used as an excitation-rapid setting complexing agent, under the action of the excitation-rapid setting complexing agent, on one hand, sodium hydroxide and water glass in the base water glass can carry out alkali excitation on the steel slag tailings, the blast furnace water slag, the furnace slag and the desulfurized gypsum to form a solid waste-based cementing material, and on the other hand, the steel slag tailings, the blast furnace water slag, the furnace slag and the desulfurized gypsum are subjected to alkali activation; main hydration products comprise ettringite (AFt) and hydrated calcium silicate gel (C-S-H), and the hydration products are interspersed and lapped with one another, so that internal pores are effectively filled to promote formation of a gel system.

Description

Technical Field

[0001] This invention belongs to the technical field of solid waste resource utilization, and particularly relates to multi-solid waste synergistic micro-expansion mine filling materials, their preparation methods and applications. Background Technology

[0002] Mineral resources are a prerequisite for human societal development, and mining is a crucial means of obtaining them. However, with the advancement of mining technology, underground mining, while yielding mineral resources, also creates numerous underground goafs. The neglect of these goafs poses significant safety hazards. For example, the instability, collapse, or landslides of goafs can damage vast amounts of land and vegetation, and even cause serious safety accidents. Therefore, it is necessary to protect or treat existing mining goafs using various technological means to mitigate potential risks.

[0003] Currently, using the backfilling method to mine deposits is one of the best technical supports for protecting the surface from subsidence. Current backfill materials generally use waste rock, fly ash, or tailings as raw materials, combined with cement, mortar, etc., as binders, and obtained through blending and mixing to obtain composite fillers with good mechanical properties suitable for filling goaf areas. For example, Chinese patent CN117105624 A discloses a fly ash-based mine backfill material and its preparation method, which involves gradually modifying fly ash, breaking down the outer structure through ball milling, reducing the degree of polymerization, and promoting the formation of calcium silicate and calcium aluminate cementitious substances. However, although this type of filler also has good early strength, with prolonged use, the formed filler shrinks internally, leading to the collapse of the internal stable structure, and subsequently causing the entire filler to crack, affecting the support of the goaf area.

[0004] Steel slag tailings, blast furnace slag, furnace slag, desulfurization gypsum, fly ash, semi-dry desulfurization ash, and tailings sand are all solid wastes. Currently, their large-scale open-air storage not only occupies valuable land but also pollutes the surrounding environment and groundwater. Therefore, how to utilize steel slag tailings, blast furnace slag, furnace slag, desulfurization gypsum, fly ash, semi-dry desulfurization ash, and tailings sand as raw materials on a large scale, and through the compounding of relevant reagents, to obtain a material that can spontaneously generate a micro-expansion effect within the packing material to offset some or all of the shrinkage force and prevent large-area cracking of the packing material, has become an urgent problem to be solved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a multi-solid waste synergistic micro-expansion mine filling material and its preparation method and application to solve the problems mentioned in the background art or achieve better technical effects.

[0006] To solve the above-mentioned technical problems, the inventors, through practice and summarization, derived the technical solution of this invention. This invention discloses a multi-solid waste synergistic micro-expansion mine filling material, the composition of which, by weight percentage, is as follows: solid waste-based material 20-30%, activating-rapid setting composite agent 0.2-0.4%, fly ash 10-20%, semi-dry desulfurization ash 4-6%, and tailings sand 45-65%.

[0007] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag, and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag, and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is less than 0.5%, and the moisture content of the blast furnace slag is less than 12%.

[0008] Furthermore, by weight percentage, the composition of each component is as follows: solid waste-based material 28%, activating-accelerating composite agent 0.2%, fly ash 14%, semi-dry desulfurization ash 4%, and tailings sand 53.8%;

[0009] The total iron content of the steel slag tailings is 0.3%, and the water content of the blast furnace slag is 12%.

[0010] Furthermore, the activation-rapid coagulation composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, wherein the mass ratio of basic water glass to alcoholic hydrogen peroxide is 2:1 to 1:2.

[0011] Furthermore, the mass ratio of sodium hydroxide to water glass in the basic water glass is 1:2 to 1:4.

[0012] Furthermore, the mass ratio of diethanolamine to hydrogen peroxide in the ethanolamine-based hydrogen peroxide is 1:2 to 1:4.

[0013] Furthermore, the fly ash is secondary ash with a fineness of ≤25% residue on a 45μm sieve; the semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0014] Furthermore, the tailings sand has a moisture content of ≤1% and a median particle size of ≤0.2mm.

[0015] Furthermore, the preparation method of any of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill materials includes the following steps:

[0016] S1: Solid waste-based materials are ground using a vertical grinding mill to obtain solid waste-based micro powder materials;

[0017] S2: The activation-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based micro powder material in S1 are mixed. Sodium hydroxide and water glass in the activation-accelerating composite agent can alkali-activate the solid waste-based material and secondary ash. Through hydration reaction, ettringite and CSH are generated. The ettringite and CSH interpenetrate and overlap, filling the internal pores, promoting the formation of the gel system, improving strength and durability, and obtaining a multi-solid waste synergistic micro-expansion mine filling material.

[0018] Furthermore, in S1, the grinding fineness is 400~500 mesh.

[0019] Furthermore, the application of any of the aforementioned multi-solid waste synergistic micro-expansion mine backfill materials in backfilling goaf areas.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) The present invention uses a mixture of basic water glass and amino hydrogen peroxide as an activation-accelerating composite agent. Under the action of the activation-accelerating composite agent, the sodium hydroxide and water glass in the basic water glass can activate the steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum to form solid waste-based cementitious materials. The main hydration products include ettringite (AFt) and hydrated calcium silicate gel (CSH). These hydration products interpenetrate and overlap with each other, effectively filling the internal pores and promoting the formation of a cementitious system, which can avoid cracking caused by the shrinkage of the filler.

[0022] (2) The activating-accelerating composite agent of the present invention can also activate fly ash (secondary ash) to form a pozzolanic effect, that is, the glassy SiO2 and Al2O3 in fly ash react with Ca(OH)2 generated by Ca hydration in an alkaline environment to form cementitious products such as hydrated calcium silicate (CSH) and hydrated calcium aluminate, thereby improving strength and durability.

[0023] (3) The nitrogen atom in the diethanolamine in the hydrogen peroxide of the present invention can react with the Al released from solid waste-based cementitious materials and fly ash. 3+ Ca 2+ Metal ions form soluble complexes; hydrogen peroxide oxidizes semi-dry desulfurization ash, and during the transformation of calcium sulfite to calcium sulfate, a slight volume expansion occurs (CaSO3 + H2O2 → CaSO4 + H2O), which fills the pores and improves mechanical properties. The generated sulfate (CaSO4 gypsum) is used to regulate the setting rate. Attached Figure Description

[0024] Figure 1 These are sample images of the multi-solid waste synergistic micro-expansion mine backfill materials prepared in Examples 1-6 and Comparative Examples 1-5 of the present invention;

[0025] In the figure, (a) is Example 1; (b) is Example 2; (c) is Example 3; (d) is Example 4; (e) is Example 5; (f) is Example 6; (g) is Comparative Example 1; (h) is Comparative Example 2; (i) is Comparative Example 3; (j) is Comparative Example 4; and (k) is Comparative Example 5. Detailed Implementation

[0026] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0027] Unless otherwise specified, all raw materials or reagents used in the following examples are commercially available products or products prepared using conventional techniques.

[0028] Among them, steel slag tailings contain CaO (48.43%), Fe2O3 (22.77%), SiO2 (14.11%), MgO (6.10%), Al2O3 (2.29%), MnO (1.88%), P2O5 (1.57%) and others (2.85%).

[0029] In blast furnace slag, CaO (37.00%), SiO2 (33.38%), Al2O3 (16.34%), MgO (8.62%), SO3 (1.63%), TiO2 (0.93%), Fe2O3 (0.75%), Na2O (0.56%), and others (0.79%).

[0030] The slag contained SiO2 (45.31%), Al2O3 (26.36%), CaO (15.03%), Fe2O3 (7.49%), Na2O (1.97%), MgO (1.30%), TiO2 (0.86%), K2O (0.62%), and others (1.06%).

[0031] In desulfurized gypsum, SO3 (53.88%), CaO (38.13%), SiO2 (3.71%), MgO (1.83%), Al2O3 (1.10%) and others (1.35%).

[0032] Fly ash is a secondary ash supplied by power plants. The differences between it and primary ash are as follows:

[0033] Grade 1 ash: Fineness (45μm sieve residue) ≤12%, Loss on ignition (carbon content) ≤5%, Water requirement ratio ≤95%, Activity index (28-day strength ratio) ≥75%;

[0034] Secondary ash: Fineness (45μm sieve residue) ≤25% (some standards allow up to 30%), loss on ignition (carbon content) ≤8%, water requirement ratio ≤105%, activity index (28-day strength ratio) slightly lower than primary ash.

[0035] Calcium-based semi-dry desulfurization ash: SO3 (35.40%), CaO (54.10%), SiO2 (0.52%), FexOy (0.66%), MgO (1.54%), Al2O3 (0.35%), K2O (2.44%), Cl - (3.34%) and others (1.65%);

[0036] Sodium-based semi-dry desulfurization ash: SO3 (39.71%), Na2O (57.57%), SiO2 (0.04%), Fe2O3 (0.06%), MgO (0.23%), ZnO (0.09%), Cl - (2.21%) and others (0.09%).

[0037] Tailings sand: SiO2 (54.65%), Al2O3 (19.18%), Fe2O3 (7.49%), Na2O (7.13%), MgO (4.47%), CaO (4.15%), K2O (1.17%), S (0.91%) and others (0.85%).

[0038] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0039] Solid waste-based materials 20-30%,

[0040] Activation-rapid setting composite agent 0.2~0.4%,

[0041] fly ash 10-20%,

[0042] Semi-dry desulfurization ash 4-6%,

[0043] Tailings sand 45-65%.

[0044] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, furnace slag, and desulfurization gypsum, with a mass ratio of 2:6:1.5:0.5. The total iron content of the steel slag tailings is no more than 0.5%, and the moisture content of the blast furnace slag is no more than 12%.

[0045] The activating-rapid-coagulating composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide. The mass ratio of basic water glass to alcoholic hydrogen peroxide is 2:1 to 1:2. The mass ratio of sodium hydroxide in basic water glass to water glass is 1:2 to 1:4. The mass ratio of diethanolamine in alcoholic hydrogen peroxide to hydrogen peroxide is 1:2 to 1:4.

[0046] Fly ash is secondary ash supplied by power plants, and semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0047] The moisture content of the tailings sand is not greater than 1%, and the median particle size is not greater than 0.2 mm;

[0048] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0049] (1) Use a vertical grinding mill to grind solid waste-based materials to a fineness of 400-500 mesh to obtain solid waste-based cementitious materials;

[0050] (2) Mix the activating-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0051] Under the action of the activating-accelerating composite agent, the sodium hydroxide and water glass in the alkaline water glass can, on the one hand, alkali activate steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum to form solid waste-based cementitious materials. The main hydration products include ettringite (AFt) and hydrated calcium silicate gel (CSH). The hydration products interpenetrate and overlap, effectively filling the internal pores and promoting the formation of a cementitious system. On the other hand, the sodium hydroxide and water glass in the alkaline water glass activate fly ash (secondary ash) to form a pozzolanic effect. That is, the glassy SiO2 and Al2O3 in the fly ash undergo a secondary reaction with Ca(OH)2 generated by Ca hydration in an alkaline environment to form cementitious products such as hydrated calcium silicate (CSH) and hydrated calcium aluminate, thereby improving strength and durability.

[0052] The nitrogen atom in diethanolamine in amine-based hydrogen peroxide can react with Al atoms released from solid waste-based cementitious materials and fly ash. 3+ Ca 2+ Metal ions form soluble complexes; hydrogen peroxide oxidizes semi-dry desulfurization ash, and during the transformation of calcium sulfite to calcium sulfate, CaSO3 + H2O2 → CaSO4 + H2O undergoes slight volume expansion, filling pores and improving mechanical properties, and the generated sulfate (CaSO4 gypsum) is used to regulate the setting rate.

[0053] Example 1

[0054] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0055] Solid waste-based materials 30%,

[0056] Activation-rapid setting composite agent 0.3%,

[0057] fly ash 10%,

[0058] Semi-dry desulfurization ash 6%,

[0059] Tailings sand 53.7%.

[0060] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.3% and the water content of the blast furnace slag is 11%.

[0061] The activating-rapid-coagulating composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, with a mass ratio of basic water glass to alcoholic hydrogen peroxide of 2:1. The mass ratio of sodium hydroxide to water glass in the basic water glass is 1:3, and the mass ratio of diethanolamine to hydrogen peroxide in the alcoholic hydrogen peroxide is 1:4.

[0062] Fly ash is secondary ash supplied by power plants, and semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0063] The tailings sand has a moisture content of 1% and a median particle size of 0.16 mm.

[0064] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0065] (1) Solid waste-based materials are ground to a fineness of 400 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0066] (2) Mix the activating-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0067] Example 2

[0068] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0069] Solid waste-based materials 20%,

[0070] Activation-rapid setting composite agent 0.4%,

[0071] fly ash 20%,

[0072] Semi-dry desulfurization ash 4%,

[0073] Tailings sand 55.6%.

[0074] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.5% and the water content of the blast furnace slag is 12%.

[0075] The activating-rapid-coagulating composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, with a mass ratio of basic water glass to alcoholic hydrogen peroxide of 1:2. The mass ratio of sodium hydroxide to water glass in the basic water glass is 1:2, and the mass ratio of diethanolamine to hydrogen peroxide in the alcoholic hydrogen peroxide is 1:3.

[0076] Fly ash is secondary ash supplied by power plants, and semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0077] The tailings sand has a moisture content of 0.6% and a median particle size of 0.2 mm.

[0078] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0079] (1) Solid waste-based materials are ground to a fineness of 500 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0080] (2) Mix the activating-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0081] Example 3

[0082] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0083] Solid waste-based materials 26%,

[0084] Activation-rapid setting composite agent 0.2%,

[0085] fly ash 16%,

[0086] 5% of semi-dry desulfurization ash

[0087] Tailings sand 52.8%.

[0088] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.4% and the water content of the blast furnace slag is 10%.

[0089] The activating-rapid-coagulating composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, with a mass ratio of basic water glass to alcoholic hydrogen peroxide of 1:1. The mass ratio of sodium hydroxide to water glass in the basic water glass is 1:4, and the mass ratio of diethanolamine to hydrogen peroxide in the alcoholic hydrogen peroxide is 1:2.

[0090] Fly ash is secondary ash supplied by power plants, and semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0091] The tailings sand has a moisture content of 0.9% and a median particle size of 0.12 mm.

[0092] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0093] (1) Solid waste-based materials are ground to a fineness of 450 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0094] (2) Mix the activating-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0095] Example 4

[0096] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0097] Solid waste-based materials 22%,

[0098] Activation-rapid setting composite agent 0.4%,

[0099] fly ash 18%,

[0100] Semi-dry desulfurization ash 6%,

[0101] Tailings sand 53.6%.

[0102] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.5% and the water content of the blast furnace slag is 10%.

[0103] The activating-rapid-coagulating composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, with a mass ratio of basic water glass to alcoholic hydrogen peroxide of 2:1. The mass ratio of sodium hydroxide to water glass in the basic water glass is 1:4, and the mass ratio of diethanolamine to hydrogen peroxide in the alcoholic hydrogen peroxide is 1:3.

[0104] Fly ash is secondary ash supplied by power plants, and semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0105] The tailings sand has a moisture content of 0.8% and a median particle size of 0.14 mm.

[0106] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0107] (1) Solid waste-based materials are ground to a fineness of 500 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0108] (2) Mix the activating-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0109] Example 5

[0110] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0111] Solid waste-based materials 28%,

[0112] Activation-rapid setting composite agent 0.2%,

[0113] fly ash 14%,

[0114] Semi-dry desulfurization ash 4%,

[0115] Tailings sand 53.8%.

[0116] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.3% and the water content of the blast furnace slag is 12%.

[0117] The activating-rapid-coagulating composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, with a mass ratio of basic water glass to alcoholic hydrogen peroxide of 1:2. The mass ratio of sodium hydroxide to water glass in the basic water glass is 1:3, and the mass ratio of diethanolamine to hydrogen peroxide in the alcoholic hydrogen peroxide is 1:2.

[0118] Fly ash is secondary ash supplied by power plants, and semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0119] The tailings sand has a moisture content of 0.7% and a median particle size of 0.18 mm.

[0120] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0121] (1) Solid waste-based materials are ground to a fineness of 400 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0122] (2) Mix the activating-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0123] Example 6

[0124] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0125] Solid waste-based materials 24%,

[0126] Activation-rapid setting composite agent 0.3%,

[0127] fly ash 12%,

[0128] 5% of semi-dry desulfurization ash

[0129] Tailings sand 58.7%.

[0130] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.4% and the water content of the blast furnace slag is 11%.

[0131] The activating-rapid-coagulating composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, with a mass ratio of basic water glass to alcoholic hydrogen peroxide of 1:1. The mass ratio of sodium hydroxide to water glass in the basic water glass is 1:2, and the mass ratio of diethanolamine to hydrogen peroxide in the alcoholic hydrogen peroxide is 1:4.

[0132] Fly ash is secondary ash supplied by power plants, and semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0133] The tailings sand has a moisture content of 0.8% and a median particle size of 0.16 mm.

[0134] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0135] (1) Solid waste-based materials are ground to a fineness of 450 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0136] (2) Mix the activating-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0137] Comparative Example 1

[0138] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0139] Solid waste-based materials 24%,

[0140] Activation-rapid setting composite agent 0.3%,

[0141] fly ash 12%,

[0142] 5% of semi-dry desulfurization ash

[0143] Tailings sand 58.7%.

[0144] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.4% and the water content of the blast furnace slag is 11%.

[0145] The activating-rapid-coagulating composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, with a mass ratio of basic water glass to alcoholic hydrogen peroxide of 1:1. The mass ratio of sodium hydroxide to water glass in the basic water glass is 1:2, and the mass ratio of diethanolamine to hydrogen peroxide in the alcoholic hydrogen peroxide is 1:4.

[0146] Fly ash is the primary ash supplied by the power plant, and semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0147] The tailings sand has a moisture content of 0.8% and a median particle size of 0.16 mm.

[0148] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0149] (1) Solid waste-based materials are ground to a fineness of 450 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0150] (2) Mix the activating-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0151] Comparative Example 2

[0152] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0153] Solid waste-based materials 24%,

[0154] 0.3% quick-setting composite agent

[0155] fly ash 12%,

[0156] 5% of semi-dry desulfurization ash

[0157] Tailings sand 58.7%.

[0158] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.4% and the water content of the blast furnace slag is 11%.

[0159] The quick-setting composite agent is an alcoholic hydrogen peroxide, and the mass ratio of diethanolamine to hydrogen peroxide in the alcoholic hydrogen peroxide is 1:4.

[0160] Fly ash is secondary ash supplied by power plants, and semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0161] The tailings sand has a moisture content of 0.8% and a median particle size of 0.16 mm.

[0162] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0163] (1) Solid waste-based materials are ground to a fineness of 450 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0164] (2) Mix the quick-setting composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0165] Comparative Example 3

[0166] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0167] Solid waste-based materials 24%,

[0168] Activating compound 0.3%,

[0169] fly ash 12%,

[0170] 5% of semi-dry desulfurization ash

[0171] Tailings sand 58.7%.

[0172] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.4% and the water content of the blast furnace slag is 11%.

[0173] The activating agent is basic water glass, and the mass ratio of sodium hydroxide to water glass in the basic water glass is 1:2.

[0174] Fly ash is secondary ash supplied by power plants, and semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0175] The tailings sand has a moisture content of 0.8% and a median particle size of 0.16 mm.

[0176] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0177] (1) Solid waste-based materials are ground to a fineness of 450 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0178] (2) Mix the activating compound, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0179] Comparative Example 4

[0180] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0181] Solid waste-based materials 24%,

[0182] Activation-rapid setting composite agent 0.3%,

[0183] fly ash 12%,

[0184] 5% of semi-dry desulfurization ash

[0185] Tailings sand 58.7%.

[0186] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.4% and the water content of the blast furnace slag is 11%.

[0187] The activating-rapid-coagulating composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, with a mass ratio of basic water glass to alcoholic hydrogen peroxide of 1:1. The mass ratio of sodium hydroxide to water glass in the basic water glass is 1:2, and the mass ratio of diethanolamine to hydrogen peroxide in the alcoholic hydrogen peroxide is 1:4.

[0188] Fly ash is secondary ash supplied by the power plant, and semi-dry desulfurization ash is sodium-based semi-dry desulfurization ash.

[0189] The tailings sand has a moisture content of 0.8% and a median particle size of 0.16 mm.

[0190] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0191] (1) Solid waste-based materials are ground to a fineness of 450 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0192] (2) Mix the activating-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0193] Comparative Example 5

[0194] Multi-solid-waste synergistic micro-expansion mine backfill material, by weight percentage, has the following raw material composition:

[0195] Solid waste-based materials 24%,

[0196] Activation-rapid setting composite agent 0.3%,

[0197] fly ash 12%,

[0198] Semi-dry desulfurization ash 0%,

[0199] Tailings sand 63.7%.

[0200] The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag and desulfurization gypsum is 2:6:1.5:0.5. The total iron content of the steel slag tailings is 0.4% and the water content of the blast furnace slag is 11%.

[0201] The activating-rapid-coagulating composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, with a mass ratio of basic water glass to alcoholic hydrogen peroxide of 1:1. The mass ratio of sodium hydroxide to water glass in the basic water glass is 1:2, and the mass ratio of diethanolamine to hydrogen peroxide in the alcoholic hydrogen peroxide is 1:4.

[0202] Fly ash is a secondary ash supplied by power plants.

[0203] The tailings sand has a moisture content of 0.8% and a median particle size of 0.16 mm.

[0204] The preparation method of the above-mentioned multi-solid waste synergistic micro-expansion mine backfill material includes the following steps:

[0205] (1) Solid waste-based materials are ground to a fineness of 450 mesh using a vertical grinding mill to obtain solid waste-based cementitious materials;

[0206] (2) Mix the activating-accelerating composite agent, fly ash, tailings sand and solid waste-based cementitious material in step (1) to obtain multi-solid waste synergistic micro-expansion mine filling material.

[0207] The multi-solid-waste synergistic micro-expansion mine backfill materials prepared in Examples 1-6 and Comparative Examples 1-5 were subjected to compressive strength tests (3d, 7d, 28d) and setting time tests according to JGJ / T 70-2009 "Standard for Basic Performance Test Methods of Building Mortar" and NB / T 51070-2017 "Test Methods for Coal Mine Paste Backfill Materials". The test results are shown in Table 1 below. The samples from Examples 1-6 and Comparative Examples 1-5 are as follows... Figure 1 As shown.

[0208] Table 1 Performance of Multi-Solid Waste Synergistic Micro-Expansion Mine Backfill Material

[0209]

[0210] Analysis of Table 1 above shows that, in the various embodiments of the present invention, the compressive strength of Example 5 is significantly higher than that of the other examples, and the setting time is shorter than that of the other examples. A comparison between Example 6 and Comparative Example 1 reveals that when the fly ash in the raw materials is replaced by primary fly ash provided by the power plant instead of secondary fly ash, the compressive strength of the mine backfill material in the early stage decreases slightly; however, the compressive strength of the mine backfill material in the later stage increases. Replacing the fly ash with primary fly ash has almost no effect on the setting time of the mine backfill material.

[0211] A comparison of Example 6 and Comparative Example 2 reveals that when the activating-accelerating composite agent in the formulation is replaced with an accelerating composite agent (without the addition of basic water glass), although the setting time of the resulting mine backfill material is shortened, the compressive strength of the material decreases significantly. This is because the sodium hydroxide and water glass in the basic water glass can, on the one hand, alkali-activate steel slag tailings, blast furnace slag, furnace slag, and desulfurization gypsum to form solid waste-based cementitious materials. The main hydration products include ettringite (AFt) and hydrated calcium silicate gel (CSH). These hydration products interpenetrate and overlap, effectively filling the internal pores and promoting the formation of a cementitious system. On the other hand, the sodium hydroxide and water glass in the basic water glass activate fly ash (secondary ash) to form a pozzolanic effect. That is, the glassy SiO2 and Al2O3 in the fly ash undergo a secondary reaction with Ca(OH)2 generated by Ca hydration in an alkaline environment to form cementitious products such as hydrated calcium silicate (CSH) and hydrated calcium aluminate, thereby improving strength and durability.

[0212] A comparison of Example 6 and Comparative Example 3 reveals that when the activating-rapid-setting composite agent in the formulation was replaced with an activating composite agent (without the addition of amine-based hydrogen peroxide), although the compressive strength of the resulting mine backfill material was slightly improved, the setting time of the material was significantly increased. This is because the nitrogen atoms in the diethanolamine in the amine-based hydrogen peroxide can react with the Al atoms released from the solid waste-based cementitious materials and fly ash. 3+ Ca2+ Metal ions form soluble complexes; hydrogen peroxide oxidizes semi-dry desulfurization ash, and during the transformation of calcium sulfite to calcium sulfate, CaSO3 + H2O2 → CaSO4 + H2O undergoes slight volume expansion, and the generated sulfate (CaSO4 gypsum) is used to regulate the setting rate.

[0213] A comparison between Example 6 and Comparative Example 4 reveals that when calcium-based semi-dry desulfurization ash in the formulation is replaced with sodium-based semi-dry desulfurization ash, the compressive strength of the mine backfill material decreases, and the setting time is prolonged. This is because sodium-based semi-dry desulfurization ash lacks calcium, preventing the CaSO3 + H2O2 → CaSO4 + H2O volume micro-expansion that fills pores and improves mechanical properties; simultaneously, sodium has side effects, reducing mechanical properties.

[0214] A comparison of Example 6 and Comparative Example 5 shows that when semi-dry desulfurization ash is not added to the formulation of the mine backfill material, the compressive strength of the mine backfill material decreases, and the setting time is significantly prolonged. This is because the micro-volume expansion from CaSO3 + H2O2 to CaSO4 + H2O cannot occur, thus failing to fill the pores and improve mechanical properties.

Claims

1. A multi-solid-waste synergistic micro-expansion mine backfill material, characterized in that, By weight percentage, the composition of each component is as follows: solid waste-based material 20-30%, activating-accelerating composite agent 0.2-0.4%, fly ash 10-20%, semi-dry desulfurization ash 4-6%, and tailings sand 45-65%; The solid waste base material is a mixture of steel slag tailings, blast furnace slag, furnace slag, and desulfurization gypsum. The mass ratio of steel slag tailings, blast furnace slag, furnace slag, and desulfurization gypsum is 2:6:1.5:0.

5. The total iron content of the steel slag tailings is less than 0.5%, and the moisture content of the blast furnace slag is less than 12%.

2. The multi-solid waste synergistic micro-expansion mine backfill material according to claim 1, characterized in that, The composition of each component by weight percentage is as follows: solid waste-based material 28%, activating-accelerating composite agent 0.2%, fly ash 14%, semi-dry desulfurization ash 4%, and tailings sand 53.8%; The total iron content of the steel slag tailings is 0.3%, and the water content of the blast furnace slag is 12%.

3. The multi-solid waste synergistic micro-expansion mine backfill material according to claim 1 or 2, characterized in that, The activation-rapid coagulation composite agent is a mixture of basic water glass and alcoholic hydrogen peroxide, wherein the mass ratio of basic water glass to alcoholic hydrogen peroxide is 2:1 to 1:

2.

4. The multi-solid waste synergistic micro-expansion mine backfill material according to claim 3, characterized in that, The mass ratio of sodium hydroxide to water glass in the alkaline water glass is 1:2 to 1:

4.

5. The multi-solid waste synergistic micro-expansion mine backfill material according to claim 3, characterized in that, The mass ratio of diethanolamine to hydrogen peroxide in the amino group hydrogen peroxide is 1:2 to 1:

4.

6. The multi-solid waste synergistic micro-expansion mine backfill material according to claim 1 or 2, characterized in that, The fly ash is a secondary ash with a fineness of ≤25% residue on a 45μm sieve; the semi-dry desulfurization ash is a calcium-based semi-dry desulfurization ash.

7. The multi-solid waste synergistic micro-expansion mine backfill material according to claim 1 or 2, characterized in that, The tailings sand has a moisture content of ≤1% and a median particle size of ≤0.2mm.

8. A method for preparing a multi-solid waste synergistic micro-expansion mine backfill material as described in any one of claims 1 to 7, characterized in that, The steps are as follows: S1: Solid waste-based materials are ground using a vertical grinding mill to obtain solid waste-based micro powder materials; S2: The activation-accelerating composite agent, fly ash, semi-dry desulfurization ash, tailings sand and solid waste-based micro powder material in S1 are mixed. Sodium hydroxide and water glass in the activation-accelerating composite agent can alkali-activate the solid waste-based material and secondary ash. Through hydration reaction, ettringite and CSH are generated. The ettringite and CSH interpenetrate and overlap, filling the internal pores, promoting the formation of the gel system, improving strength and durability, and obtaining a multi-solid waste synergistic micro-expansion mine filling material.

9. The preparation method of the multi-solid waste synergistic micro-expansion mine backfill material according to claim 8, characterized in that, In S1, the grinding fineness is 400~500 mesh.

10. The application of the multi-solid waste synergistic micro-expansion mine backfill material according to any one of claims 1 to 7 in backfilling goaf areas.

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