Solid waste-based self-healing mine filling material as well as preparation method and application thereof

Abstract

The invention discloses a solid waste-based self-healing mine filling material and a preparation method and application thereof, and belongs to the technical field of solid waste resource utilization, the solid waste-based self-healing mine filling material comprises the following components by weight: 35-40% of a solid waste-based material, 2-3% of a self-healing master batch A, 3-5% of a self-healing master batch B, 8-13% of semi-dry desulfurization ash, and 40-50% of tailing sand; when crack water seepage occurs after hydration of the solid-waste-based self-healing mine filling material is completed, a silanol group of sodium methyl silicate in the self-healing master batch B and dicalcium silicate and tricalcium silicate in the solid-waste-based cementing material are subjected to a dehydration cross-linking reaction, and anti-permeability silicate with an anti-capillary effect is formed; the excessive anti-permeability silicate is further dissolved and reacted by the polyether silicone oil to form a charge reduction-anti-permeability composite material, so that capillary channels are sealed while internal gaps are filled, and the compactness of the mine filling material hydrate is further improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solid waste resource utilization, and particularly relates to a solid waste-based self-healing type mine filling material and a preparation method and application thereof. BACKGROUND

[0002] After the ore body is mined, the original stress state of the stope is destroyed, thereby causing stress redistribution, which often leads to instability and damage of the ore pillar. When the stress borne by the ore body exceeds its strength after the ore body is mined, discontinuous divergence mutation occurs, that is, the phenomenon of instability and damage of the ore pillar. The main forms of disasters are: rib spalling, roof falling, water inrush, earthquake, rock burst, rock pressure bumping, ground subsidence, ground settlement, ground fissure, and various forms such as landslides, debris flows, and surface vegetation damage caused by them. Underground empty area has become an important problem restricting the development of mines. With the deepening of mining and the increase of ground pressure, underground empty area is prone to collapse accidents under the strong ground pressure, especially for underground to open-pit mining mines. A large number of stope, chamber and roadway left after underground mining are not timely treated, which brings serious hidden dangers to open-pit mining and serious threats to mine workers and equipment.

[0003] Goaf treatment refers to the technical measures such as filling or roof closure for preventing ground subsidence and eliminating safety hazards. Due to the characteristics of strong concealment, poor regularity of spatial distribution, and difficulty in predicting roof collapse and subsidence, the treatment needs to solve the technical problems of distribution range definition and quantitative judgment. Common treatment methods include full caving method, filling method and coal pillar support method, which are divided into four categories according to technical characteristics: closure, collapse, reinforcement and filling. The filling method attracts the attention and research of many technical personnel because of the use of waste rock or tailings and other materials with the characteristics of quick effect. This filling method not only realizes perfect filling of the goaf, but also utilizes waste materials to avoid environmental pollution. For example, Chinese patent CN 113060961 A discloses a kind of activator for mine filling material and its preparation method, which uses steel slag as raw material, adds high molecular water absorbing resin and microcrystalline cellulose, and alkali activates the steel slag material. The fluidity is improved, and a better filling material is finally obtained. However, although this filling material can maintain stability in the early stage, the surface of the filling material will be damaged by various external factors over time, resulting in cracks on the surface. If not repaired in time, the cracks will gradually grow along the texture, causing the filling material to break or be damaged, and there is a limitation of high maintenance cost in the later stage.

[0004] Therefore, how to optimize the design of the components inside the material to self-repair the cracks or damaged parts of the filling material, so that the filling material can realize self-healing without manual repair after the cracks occur, has become an urgent problem to be solved. SUMMARY

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

[0006] In order to solve the above technical problems, the inventors have summarized and obtained the technical scheme of the present application through practice. The present application discloses a solid waste-based self-healing mine filling material, and the components are as follows in terms of weight percentage: solid waste-based material 35-40%, self-healing masterbatch A 2-3%, self-healing masterbatch B 3-5%, semi-dry desulfurization ash 8-13%, and tailing sand 40-50%.

[0007] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, and the mass ratio of the steel slag tailings, blast furnace slag, and desulfurization gypsum is 2-3:6.5-7.5:0.5.

[0008] The self-healing masterbatch A is a mixture of malic acid and carbonic acid, and the mass ratio of the malic acid and carbonic acid is 2:1-1:2.

[0009] The self-healing masterbatch B is a mixture of polyether silicone oil and sodium methyl silicate, and the mass ratio of the polyether silicone oil and sodium methyl silicate is 2:1-1:2.

[0010] Further, the components are as follows in terms of weight percentage: solid waste-based material 39%, self-healing masterbatch A 2.5%, self-healing masterbatch B 3%, semi-dry desulfurization ash 9%, and tailing sand 46.5%.

[0011] The mass ratio of the steel slag tailings, blast furnace slag, and desulfurization gypsum is 2.5:7:0.5.

[0012] The mass ratio of the malic acid and carbonic acid is 1:1.

[0013] The mass ratio of the polyether silicone oil and sodium methyl silicate is 1:2.

[0014] Further, the total iron content of the steel slag tailings is less than or equal to 0.5%, and the moisture content of the blast furnace slag is less than or equal to 12%.

[0015] Further, the semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

[0016] Further, the water content of the tailing sand is less than or equal to 1%, and the median particle size is less than or equal to 0.2 mm.

[0017] Further, the preparation method of the solid waste-based self-healing mine filling material described above, the steps are as follows:

[0018] S1: Grind the solid waste-based material using a vertical grinding mill to obtain a solid waste-based cementitious material;

[0019] S2: Stir the solid waste-based cementitious material with self-healing masterbatch A at room temperature to obtain masterbatch A-solid waste-based cementitious material; malic acid and carbonic acid in self-healing masterbatch A can generate malate and carbonate under alkaline conditions formed by steel slag tailings and blast furnace slag. Malate and carbonate ions can form weakly interacting shielding polar groups, reducing the charge in the cementing system and reducing the chance of electrostatic attraction. Carbonate accelerates the hydration reaction of tricalcium silicate in solid waste-based material, shortens the induction period, improves early strength, optimizes pore structure distribution, reduces porosity, and makes the structure denser;

[0020] S3: The self-healing masterbatch B and semi-dry desulfurization ash are loaded into the reactor and stirred under controlled temperature to obtain masterbatch B-semi-dry desulfurization ash;

[0021] S4: After mixing masterbatch A (solid waste-based cementitious material), masterbatch B (semi-dry desulfurization ash), and tailings sand, a solid waste-based self-healing mine backfill material is obtained. When cracks and water seepage occur after the solid waste-based self-healing mine backfill material has been hydrated, the silanol groups of sodium methylsilicate in self-healing masterbatch B undergo a dehydration and cross-linking reaction with dicalcium silicate and tricalcium silicate in the solid waste-based cementitious material to form impermeable silicates, thereby increasing the density of the system.

[0022] Furthermore, in S1, the grinding fineness is 400~500 mesh.

[0023] Furthermore, in step S2, the stirring time is 20-30 minutes; in step S3, the stirring temperature is 40-50°C, and the stirring time is 10-15 minutes.

[0024] Furthermore, in step S4, the stirring time is 45-60 minutes.

[0025] Furthermore, the application of any of the aforementioned solid waste-based self-healing mine backfill materials in filling goaf areas.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] (1) In this invention, self-healing masterbatch A is added to the raw materials. When cracks and water seepage occur after the solid waste-based self-healing mine backfill material is hydrated, the malic acid and carbonic acid in the self-healing masterbatch A are both soluble in water. Under the alkaline conditions formed by steel slag tailings and blast furnace slag, malate and carbonate can be generated. The malate and carbonate ions form weak interaction through "ion association" to shield polar groups, reduce the charge in the cementing system, reduce the chance of electrostatic attraction, and the carbonate accelerates the hydration reaction of tricalcium silicate (C3S) in the solid waste-based material, shortens the induction period, thereby improving the early strength and improving the compactness of the mine backfill material during the hydration process. That is, the carbonate can change the pore structure distribution of the hydration products, reduce the total porosity, and make the structure more compact.

[0028] (2) In the self-healing masterbatch B of the present invention, the polyether silicone oil and sodium methylsilicate adhere to the surface of the semi-dry desulfurization ash to form a flocculent structure. When the solid waste-based self-healing mine filling material has cracks and water seepage after hydration, it increases the specific surface area of ​​the reaction between the polyether silicone oil and sodium methylsilicate on the one hand, and fills the internal voids of the hydrated mine filling material on the other hand, which can further improve the compactness.

[0029] (3) When cracks and water seepage occur after the solid waste-based self-healing mine backfill material is hydrated, the silanol group of sodium methyl silicate in the self-healing masterbatch B undergoes a dehydration and cross-linking reaction with dicalcium silicate and tricalcium silicate in the solid waste-based cementitious material to form impermeable silicate with an "anti-capillary" effect; the excess impermeable silicate is further dissolved and reacted by polyether silicone oil to form a charge-reducing impermeable composite material, which fills the internal voids and seals the capillary channels, further increasing the density of the hydrated mine backfill material. Attached Figure Description

[0030] Figure 1 These are sample images of solid waste-based self-healing mine backfill materials prepared in Examples 1-6 and Comparative Examples 1-3 of the present invention;

[0031] 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; and (i) is Comparative Example 3. Detailed Implementation

[0032] 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.

[0033] Unless otherwise specified, all raw materials or reagents used in the following examples are commercially available products or products prepared using conventional techniques.

[0034] 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%).

[0035] In blast furnace slag, the components are 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%).

[0036] In desulfurized gypsum, SO3 (53.88%), CaO (38.13%), SiO2 (3.71%), MgO (1.83%), Al2O3 (1.10%), and others (1.35%) are present.

[0037] Calcium-based semi-dry desulfurization ash: SO3 (35.40%), CaO (54.10%), SiO2 (0.52%), Fe x O y (0.66%), MgO (1.54%), Al2O3 (0.35%), K2O (2.44%), Cl - (3.34%) and others (1.65%);

[0038] 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%);

[0039] Tailings sand: SiO2 (57.43%), Al2O3 (19.43%), Fe2O3 (6.74%), Na2O (6.55%), MgO (4.05%), CaO (2.85%), K2O (0.84%), S (0.84%) and others (1.27%); moisture content not greater than 1%, median particle size not greater than 0.2 mm.

[0040] The solid waste-based self-healing mine backfill material, by weight percentage, has the following raw material composition:

[0041] Solid waste-based materials 35-40%,

[0042] Self-healing masterbatch A 2~3%,

[0043] Self-healing masterbatch B 3~5%,

[0044] Semi-dry desulfurization ash 8~13%,

[0045] Tailings sand 40-50%,

[0046] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, with a mass ratio of steel slag tailings, blast furnace slag, and desulfurization gypsum of 2~3:6.5~7.5:0.5. 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%.

[0047] Self-healing masterbatch A is a mixture of malic acid and carbonic acid, with a mass ratio of malic acid to carbonic acid of 2:1 to 1:2.

[0048] Self-healing masterbatch B is a mixture of polyether silicone oil and sodium methylsilicate, with a mass ratio of polyether silicone oil to sodium methylsilicate of 2:1 to 1:2.

[0049] The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0050] The moisture content of the tailings sand is no more than 1%, and the median particle size is no more than 0.2 mm.

[0051] The preparation method of the above-mentioned solid waste-based self-healing mine backfill material includes the following steps:

[0052] (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;

[0053] (2) Stir the solid waste-based cementitious material with the self-healing masterbatch A at room temperature for 20-30 minutes to obtain masterbatch A-solid waste-based cementitious material;

[0054] (3) The self-healing masterbatch B and semi-dry desulfurization ash are loaded into the reactor and stirred at 40~50℃ for 10~15 minutes to obtain masterbatch B-semi-dry desulfurization ash;

[0055] (4) Mix the masterbatch A - solid waste-based cementitious material, masterbatch B - semi-dry desulfurization ash and tailings sand for 45~60 minutes to obtain solid waste-based self-healing mine filling material.

[0056] In the raw materials of this invention, when cracks and water seepage occur after the solid waste-based self-healing mine backfill material has been hydrated, the malic acid and carbonate in the self-healing masterbatch A are both soluble in water. Under the alkaline conditions formed by steel slag tailings and blast furnace slag, malate and carbonate can be generated. The malate and carbonate ions form weak interactions through "ion association" to shield polar groups, reduce the charge in the cementing system, reduce the chance of electrostatic attraction, and the carbonate accelerates the hydration reaction of tricalcium silicate (C3S) in the solid waste-based material, shortens the induction period, thereby improving the early strength and improving the compactness of the mine backfill material during the hydration process. That is, the carbonate can change the pore structure distribution of the hydration products, reduce the total porosity, and make the structure more compact.

[0057] In the self-healing masterbatch B, polyether silicone oil and sodium methylsilicate adhere to the surface of semi-dry desulfurization ash, forming a flocculent structure. When cracks and water seepage occur after the solid waste-based self-healing mine backfill material has been hydrated, it increases the specific surface area of ​​the reaction between polyether silicone oil and sodium methylsilicate on the one hand, and fills the internal voids of the mine backfill material hydrate on the other hand, which can further improve the compaction performance.

[0058] When cracks and water seepage occur after the solid waste-based self-healing mine backfill material has been hydrated, the silanol groups of sodium methylsilicate in the self-healing masterbatch B undergo a dehydration and cross-linking reaction with dicalcium silicate and tricalcium silicate in the solid waste-based cementitious material, forming impermeable silicates with an "anti-capillary" effect; the excess impermeable silicates are further dissolved and reacted by polyether silicone oil to form a charge-reducing and impermeable composite material, which fills the internal voids while sealing the capillary channels, further increasing the density of the hydrated mine backfill material.

[0059] Example 1

[0060] The solid waste-based self-healing mine backfill material, by weight percentage, has the following raw material composition:

[0061] Solid waste-based materials 35%,

[0062] Self-healing masterbatch A 3%,

[0063] Self-healing masterbatch B 4.5%,

[0064] Semi-dry desulfurization ash 13%,

[0065] Tailings sand 44.5%,

[0066] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, with a mass ratio of 2:7.5:0.5. The total iron content of the steel slag tailings is 0.3%, and the moisture content of the blast furnace slag is 10%.

[0067] Self-healing masterbatch A is a mixture of malic acid and carbonic acid, with a mass ratio of malic acid to carbonic acid of 1:2.

[0068] Self-healing masterbatch B is a mixture of polyether silicone oil and sodium methylsilicate, with a mass ratio of polyether silicone oil to sodium methylsilicate of 2:1.

[0069] The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0070] The tailings sand has a moisture content of 0.8% and a median particle size of 0.14 mm.

[0071] The preparation method of the above-mentioned solid waste-based self-healing mine backfill material includes the following steps:

[0072] (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;

[0073] (2) Stir the solid waste-based cementitious material with the self-healing masterbatch A at room temperature for 20 minutes to obtain masterbatch A-solid waste-based cementitious material;

[0074] (3) The self-healing masterbatch B and semi-dry desulfurization ash were loaded into the reactor and stirred at 45°C for 15 minutes to obtain masterbatch B-semi-dry desulfurization ash;

[0075] (4) Mix the masterbatch A - solid waste-based cementitious material, masterbatch B - semi-dry desulfurization ash and tailings sand for 45 minutes to obtain solid waste-based self-healing mine filling material.

[0076] Example 2

[0077] The solid waste-based self-healing mine backfill material, by weight percentage, has the following raw material composition:

[0078] Solid waste-based materials 45%,

[0079] Self-healing masterbatch A 2%,

[0080] Self-healing masterbatch B 3.5%,

[0081] Semi-dry desulfurization ash 8%,

[0082] Tailings sand 41.5%,

[0083] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, with a mass ratio of 3:6.5:0.5. The total iron content of the steel slag tailings is 0.5%, and the moisture content of the blast furnace slag is 11%.

[0084] Self-healing masterbatch A is a mixture of malic acid and carbonic acid, with a mass ratio of malic acid to carbonic acid of 2:1.

[0085] Self-healing masterbatch B is a mixture of polyether silicone oil and sodium methylsilicate, with a mass ratio of polyether silicone oil to sodium methylsilicate of 1:1;

[0086] The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0087] The tailings sand has a moisture content of 0.7% and a median particle size of 0.20 mm.

[0088] The preparation method of the above-mentioned solid waste-based self-healing mine backfill material includes the following steps:

[0089] (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;

[0090] (2) Stir the solid waste-based cementitious material with the self-healing masterbatch A at room temperature for 30 minutes to obtain masterbatch A-solid waste-based cementitious material;

[0091] (3) The self-healing masterbatch B and semi-dry desulfurization ash were loaded into the reactor and stirred at 40°C for 12.5 min to obtain masterbatch B-semi-dry desulfurization ash;

[0092] (4) Mix the masterbatch A - solid waste-based cementitious material, masterbatch B - semi-dry desulfurization ash and tailings sand for 60 minutes to obtain solid waste-based self-healing mine filling material.

[0093] Example 3

[0094] The solid waste-based self-healing mine backfill material, by weight percentage, has the following raw material composition:

[0095] Solid waste-based materials 39%,

[0096] Self-healing masterbatch A 2.5%,

[0097] Self-healing masterbatch B 3%,

[0098] Semi-dry desulfurization ash 9%,

[0099] Tailings sand 46.5%,

[0100] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, with a mass ratio of 2.5:7:0.5. The total iron content of the steel slag tailings is 0.4%, and the moisture content of the blast furnace slag is 12%.

[0101] Self-healing masterbatch A is a mixture of malic acid and carbonic acid, with a mass ratio of malic acid to carbonic acid of 1:1.

[0102] Self-healing masterbatch B is a mixture of polyether silicone oil and sodium methylsilicate, with a mass ratio of polyether silicone oil to sodium methylsilicate of 1:2.

[0103] The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0104] The tailings sand has a moisture content of 1.0% and a median particle size of 0.17 mm.

[0105] The preparation method of the above-mentioned solid waste-based self-healing mine backfill material includes the following steps:

[0106] (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;

[0107] (2) Stir the solid waste-based cementitious material with the self-healing masterbatch A at room temperature for 25 minutes to obtain masterbatch A-solid waste-based cementitious material;

[0108] (3) The self-healing masterbatch B and semi-dry desulfurization ash were loaded into the reactor and stirred at 50°C for 10 min to obtain masterbatch B-semi-dry desulfurization ash;

[0109] (4) Mix the masterbatch A - solid waste-based cementitious material, masterbatch B - semi-dry desulfurization ash and tailings sand for 55 minutes to obtain solid waste-based self-healing mine filling material.

[0110] Example 4

[0111] The solid waste-based self-healing mine backfill material, by weight percentage, has the following raw material composition:

[0112] Solid waste-based materials 36%,

[0113] Self-healing masterbatch A 3%,

[0114] Self-healing masterbatch B 5%,

[0115] Semi-dry desulfurization ash 12%,

[0116] Tailings sand 44%,

[0117] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, with a mass ratio of 3:6.5:0.5. The total iron content of the steel slag tailings is 0.4%, and the moisture content of the blast furnace slag is 10%.

[0118] Self-healing masterbatch A is a mixture of malic acid and carbonic acid, with a mass ratio of malic acid to carbonic acid of 2:1.

[0119] Self-healing masterbatch B is a mixture of polyether silicone oil and sodium methylsilicate, with a mass ratio of polyether silicone oil to sodium methylsilicate of 1:2.

[0120] The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0121] The tailings sand has a moisture content of 0.9% and a median particle size of 0.18 mm.

[0122] The preparation method of the above-mentioned solid waste-based self-healing mine backfill material includes the following steps:

[0123] (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;

[0124] (2) Stir the solid waste-based cementitious material with the self-healing masterbatch A at room temperature for 20 minutes to obtain masterbatch A-solid waste-based cementitious material;

[0125] (3) The self-healing masterbatch B and semi-dry desulfurization ash were loaded into the reactor and stirred at 50°C for 10 min to obtain masterbatch B-semi-dry desulfurization ash;

[0126] (4) Mix the masterbatch A - solid waste-based cementitious material, masterbatch B - semi-dry desulfurization ash and tailings sand for 50 minutes to obtain solid waste-based self-healing mine filling material.

[0127] Example 5

[0128] The solid waste-based self-healing mine backfill material, by weight percentage, has the following raw material composition:

[0129] Solid waste-based materials 38%,

[0130] Self-healing masterbatch A 2%,

[0131] Self-healing masterbatch B 4%,

[0132] Semi-dry desulfurization ash 11%,

[0133] Tailings sand 45%,

[0134] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, with a mass ratio of 2:7.5:0.5. The total iron content of the steel slag tailings is 0.5%, and the moisture content of the blast furnace slag is 12%.

[0135] Self-healing masterbatch A is a mixture of malic acid and carbonic acid, with a mass ratio of malic acid to carbonic acid of 1:2.

[0136] Self-healing masterbatch B is a mixture of polyether silicone oil and sodium methylsilicate, with a mass ratio of polyether silicone oil to sodium methylsilicate of 2:1.

[0137] The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0138] The tailings sand has a moisture content of 1% and a median particle size of 0.16 mm.

[0139] The preparation method of the above-mentioned solid waste-based self-healing mine backfill material includes the following steps:

[0140] (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;

[0141] (2) Stir the solid waste-based cementitious material with the self-healing masterbatch A at room temperature for 20 minutes to obtain masterbatch A-solid waste-based cementitious material;

[0142] (3) The self-healing masterbatch B and semi-dry desulfurization ash were loaded into the reactor and stirred at 40°C for 15 minutes to obtain masterbatch B-semi-dry desulfurization ash;

[0143] (4) Mix the masterbatch A - solid waste-based cementitious material, masterbatch B - semi-dry desulfurization ash and tailings sand for 50 minutes to obtain solid waste-based self-healing mine filling material.

[0144] Example 6

[0145] The solid waste-based self-healing mine backfill material, by weight percentage, has the following raw material composition:

[0146] Solid waste-based materials 37%,

[0147] Self-healing masterbatch A 2.5%,

[0148] Self-healing masterbatch B 3.5%,

[0149] Semi-dry desulfurization ash 10%,

[0150] Tailings sand 47%,

[0151] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, with a mass ratio of 2.5:7:0.5. The total iron content of the steel slag tailings is 0.3%, and the moisture content of the blast furnace slag is 11%.

[0152] Self-healing masterbatch A is a mixture of malic acid and carbonic acid, with a mass ratio of malic acid to carbonic acid of 1:1.

[0153] Self-healing masterbatch B is a mixture of polyether silicone oil and sodium methylsilicate, with a mass ratio of polyether silicone oil to sodium methylsilicate of 1:1;

[0154] The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0155] The tailings sand has a moisture content of 0.7% and a median particle size of 0.20 mm.

[0156] The preparation method of the above-mentioned solid waste-based self-healing mine backfill material includes the following steps:

[0157] (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;

[0158] (2) Stir the solid waste-based cementitious material with the self-healing masterbatch A at room temperature for 25 minutes to obtain masterbatch A-solid waste-based cementitious material;

[0159] (3) The self-healing masterbatch B and semi-dry desulfurization ash were loaded into the reactor and stirred at 45°C for 12.5 min to obtain masterbatch B-semi-dry desulfurization ash;

[0160] (4) Mix the masterbatch A - solid waste-based cementitious material, masterbatch B - semi-dry desulfurization ash and tailings sand for 55 minutes to obtain solid waste-based self-healing mine filling material.

[0161] Comparative Example 1

[0162] The solid waste-based self-healing mine backfill material, by weight percentage, has the following raw material composition:

[0163] Solid waste-based materials 37%,

[0164] Self-healing masterbatch A 0%

[0165] Self-healing masterbatch B 6%,

[0166] Semi-dry desulfurization ash 10%,

[0167] Tailings sand 47%,

[0168] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, with a mass ratio of 2.5:7:0.5. The total iron content of the steel slag tailings is 0.3%, and the moisture content of the blast furnace slag is 11%.

[0169] Self-healing masterbatch B is a mixture of polyether silicone oil and sodium methylsilicate, with a mass ratio of polyether silicone oil to sodium methylsilicate of 1:1;

[0170] The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0171] The tailings sand has a moisture content of 0.7% and a median particle size of 0.20 mm.

[0172] The preparation method of the above-mentioned solid waste-based self-healing mine backfill material includes the following steps:

[0173] (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;

[0174] (2) The self-healing masterbatch B and semi-dry desulfurization ash were loaded into the reactor and stirred at 45°C for 12.5 min to obtain masterbatch B-semi-dry desulfurization ash;

[0175] (3) Stir the solid waste-based cementitious material, masterbatch B-semi-dry desulfurization ash and tailings sand for 55 minutes to obtain solid waste-based self-healing mine filling material.

[0176] Comparative Example 2

[0177] The solid waste-based self-healing mine backfill material, by weight percentage, has the following raw material composition:

[0178] Solid waste-based materials 37%,

[0179] Self-healing masterbatch A 6%,

[0180] Self-healing masterbatch B 0%,

[0181] Semi-dry desulfurization ash 10%,

[0182] Tailings sand 47%,

[0183] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, with a mass ratio of 2.5:7:0.5. The total iron content of the steel slag tailings is 0.3%, and the moisture content of the blast furnace slag is 11%.

[0184] Self-healing masterbatch A is a mixture of malic acid and carbonic acid, with a mass ratio of malic acid to carbonic acid of 1:1.

[0185] The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0186] The tailings sand has a moisture content of 0.7% and a median particle size of 0.20 mm.

[0187] The preparation method of the above-mentioned solid waste-based self-healing mine backfill material includes the following steps:

[0188] (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;

[0189] (2) Stir the solid waste-based cementitious material with the self-healing masterbatch A at room temperature for 25 minutes to obtain masterbatch A-solid waste-based cementitious material;

[0190] (3) Mix the masterbatch A-solid waste-based cementitious material, semi-dry desulfurization ash and tailings sand for 55 minutes to obtain solid waste-based self-healing mine filling material.

[0191] Comparative Example 3

[0192] The solid waste-based self-healing mine backfill material, by weight percentage, has the following raw material composition:

[0193] Solid waste-based materials 37%,

[0194] Self-healing masterbatch A 0%

[0195] Self-healing masterbatch B 0%,

[0196] Semi-dry desulfurization ash 16%,

[0197] Tailings sand 47%,

[0198] The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, with a mass ratio of 2.5:7:0.5. The total iron content of the steel slag tailings is 0.3%, and the moisture content of the blast furnace slag is 11%.

[0199] The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash;

[0200] The tailings sand has a moisture content of 0.7% and a median particle size of 0.20 mm.

[0201] The preparation method of the above-mentioned solid waste-based self-healing mine backfill material includes the following steps:

[0202] (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;

[0203] (2) Stir the solid waste-based cementitious material, semi-dry desulfurization ash and tailings sand for 55 minutes to obtain the solid waste-based self-healing mine filling material.

[0204] The solid waste-based self-healing mine filling materials prepared in Examples 1-6 and Comparative Examples 1-3 were subjected to mechanical property (compressive strength (3d, 14d, 28d)) and 28d impermeability tests respectively, according to JGJ / T 70-2009 "Standard for Basic Performance Test Methods of Building Mortar", NB / T 51070-2017 "Test Methods for Coal Mine Paste Filling Materials", and GB 18445-2012 "Cement-based Penetrating Crystalline Waterproofing Materials". The test results are shown in Tables 1 and 2 below. The samples of Examples 1-6 and Comparative Examples 1-3 are as follows. Figure 1 As shown.

[0205] Table 1 Mechanical properties of solid waste-based self-healing mine backfill materials

[0206]

[0207] Table 2. Impermeability of self-healing mine backfill materials based on solid waste (28 days)

[0208]

[0209] Analysis of Tables 1 and 2 shows that, among the embodiments of the present invention, Example 4 has the best compressive strength, while Examples 1 and 3 have the best impermeability.

[0210] A comparison of Example 6 and Comparative Example 1 reveals that when self-healing masterbatch A is not added to the formulation of the raw materials used, the compressive strength of the solid waste-based self-healing mine backfill material will decrease, and its seepage prevention ability will also decrease. This is because when cracks appear and water seeps in the solid waste-based self-healing mine backfill material after hydration, the malic acid and carbonate in the self-healing masterbatch A are both soluble in water. Under the alkaline conditions formed by steel slag tailings and blast furnace slag, malate and carbonate can be generated. The malate and carbonate ions form weak interaction shielding polar groups through "ion association", reducing the charge in the cementing system and reducing the chance of electrostatic attraction. In addition, carbonate accelerates the hydration reaction of tricalcium silicate (C3S) in the solid waste-based material, shortens the induction period, and thus improves the early strength. It can improve the compactness of the mine backfill material during the hydration process. That is, carbonate can change the pore structure distribution of hydration products, reduce the total porosity, and make the structure more compact.

[0211] A comparison between Example 6 and Comparative Example 2 reveals that when self-healing masterbatch B is not added to the formulation of the raw materials used, the compressive strength and impermeability of the solid waste-based self-healing mine backfill material also decrease. This is because the polyether silicone oil and sodium methylsilicate in the self-healing masterbatch B adhere to the surface of the semi-dry desulfurization ash, forming a flocculent structure. When cracks and water seepage occur after the solid waste-based self-healing mine backfill material has been hydrated, it increases the specific surface area of ​​the reaction between the polyether silicone oil and sodium methylsilicate, and fills the internal voids of the hydrated mine backfill material, thereby further improving the compactness. When cracks and water seepage occur after the solid waste-based self-healing mine backfill material has been hydrated, the silanol groups of sodium methylsilicate in the self-healing masterbatch B undergo a dehydration and cross-linking reaction with dicalcium silicate and tricalcium silicate in the solid waste-based cementitious material, forming impermeable silicates with an "anti-capillary" effect; the excess impermeable silicates are further dissolved and reacted by polyether silicone oil to form a charge-reducing and impermeable composite material, which fills the internal voids while sealing the capillary channels, further increasing the density of the hydrated mine backfill material.

[0212] The comparison of Example 6, Comparative Example 1, Comparative Example 2 and Comparative Example 3 shows that when self-healing masterbatch A and self-healing masterbatch B are not added to the formulation of the raw materials used, the compressive strength and seepage prevention ability of the solid waste-based self-healing mine backfill material will be greatly reduced. Compared with the simultaneous addition of self-healing masterbatch A and self-healing masterbatch B, or the addition of self-healing masterbatch A or self-healing masterbatch B alone, the compressive strength and seepage prevention ability are significantly reduced.

[0213] Therefore, by simultaneously adding self-healing masterbatch A and self-healing masterbatch B to the formulation, this invention enables a dehydration and cross-linking reaction with dicalcium silicate and tricalcium silicate in solid waste-based cementitious materials, forming impermeable silicates with an "anti-capillary" effect. Excess impermeable silicates are further dissolved and reacted by polyether silicone oil to form a charge-reducing, impermeable composite material. This composite material can fill internal voids, seal capillary channels, and increase the density of hydrates in mine backfill materials. This, in turn, improves the compressive strength and impermeability of the entire solid waste-based self-healing mine backfill material.

Claims

1. A solid waste-based self-healing mine backfill material, characterized in that, By weight percentage, the components are as follows: solid waste-based materials 35-40%, self-healing masterbatch A 2-3%, self-healing masterbatch B 3-5%, semi-dry desulfurization ash 8-13%, and tailings sand 40-50%; The solid waste-based material is a mixture of steel slag tailings, blast furnace slag, and desulfurization gypsum, wherein the mass ratio of steel slag tailings, blast furnace slag, and desulfurization gypsum is 2~3:6.5~7.5:0.5; The self-healing masterbatch A is a mixture of malic acid and carbonic acid, and the mass ratio of malic acid to carbonic acid is 2:1 to 1:

2. The self-healing masterbatch B is a mixture of polyether silicone oil and sodium methylsilicate, wherein the mass ratio of polyether silicone oil to sodium methylsilicate is 2:1 to 1:

2.

2. The solid waste-based self-healing mine backfill material according to claim 1, characterized in that, By weight percentage, the components are as follows: solid waste-based materials 39%, self-healing masterbatch A 2.5%, self-healing masterbatch B 3%, semi-dry desulfurization ash 9%, and tailings sand 46.5%; The mass ratio of steel slag tailings, blast furnace slag, and desulfurization gypsum is 2.5:7:0.5; The mass ratio of malic acid to carbonic acid is 1:1; The mass ratio of the polyether silicone oil to sodium methylsilicate is 1:

2.

3. The solid waste-based self-healing mine backfill material according to claim 1 or 2, characterized in that, The total iron content of the steel slag tailings is less than or equal to 0.5%, and the moisture content of the blast furnace slag is less than or equal to 12%.

4. The solid waste-based self-healing mine backfill material according to claim 1 or 2, characterized in that, The semi-dry desulfurization ash is calcium-based semi-dry desulfurization ash.

5. The solid waste-based self-healing mine backfill material according to claim 1 or 2, characterized in that, The tailings sand has a moisture content of less than or equal to 1% and a median particle size of less than or equal to 0.2 mm.

6. A method for preparing a solid waste-based self-healing mine backfill material according to any one of claims 1 to 5, characterized in that, The steps are as follows: S1: Grind the solid waste-based material using a vertical grinding mill to obtain a solid waste-based cementitious material; S2: Stir the solid waste-based cementitious material with self-healing masterbatch A at room temperature to obtain masterbatch A-solid waste-based cementitious material; malic acid and carbonic acid in self-healing masterbatch A can generate malate and carbonate under alkaline conditions formed by steel slag tailings and blast furnace slag. Malate and carbonate ions can form weakly interacting shielding polar groups, reducing the charge in the cementing system and reducing the chance of electrostatic attraction. Carbonate accelerates the hydration reaction of tricalcium silicate in solid waste-based material, shortens the induction period, improves early strength, optimizes pore structure distribution, reduces porosity, and makes the structure denser; S3: The self-healing masterbatch B and semi-dry desulfurization ash are loaded into the reactor and stirred under controlled temperature to obtain masterbatch B-semi-dry desulfurization ash; S4: After mixing masterbatch A (solid waste-based cementitious material), masterbatch B (semi-dry desulfurization ash), and tailings sand, a solid waste-based self-healing mine backfill material is obtained. When cracks and water seepage occur after the solid waste-based self-healing mine backfill material has been hydrated, the silanol groups of sodium methylsilicate in self-healing masterbatch B undergo a dehydration and cross-linking reaction with dicalcium silicate and tricalcium silicate in the solid waste-based cementitious material to form impermeable silicates, thereby increasing the density of the system.

7. The preparation method of the solid waste-based self-healing mine backfill material according to claim 6, characterized in that, In S1, the grinding fineness is 400~500 mesh.

8. The preparation method of the solid waste-based self-healing mine backfill material according to claim 6, characterized in that, In step S2, the stirring time is 20-30 minutes; in step S3, the stirring temperature is 40-50°C and the stirring time is 10-15 minutes.

9. The preparation method of the solid waste-based self-healing mine backfill material according to claim 6, characterized in that, In step S4, the stirring time is 45-60 minutes.

10. The application of the solid waste-based self-healing mine backfill material according to any one of claims 1 to 5 in backfilling goaf areas.

Images