Targeted dusting hole spacer for sulfur-containing ore and preparation and use method thereof

Abstract

The present application belongs to the technical field of mine blasting engineering, and particularly relates to a targeted dust reduction blast hole spacer for sulfur-containing ores and a preparation and use method thereof. The spacer comprises a shell, a bottom layer, a middle layer and an upper layer are arranged in the shell from bottom to top, a partition plate is arranged between each layer, and a protective component is arranged on the surface layer of the shell; the bottom layer is formed by molding the pretreated sulfur-containing solid waste and an expanding agent; the middle layer comprises a trigger sublayer, a buffer sublayer and a functional sublayer from bottom to top, a reaction trigger water bag is arranged in the trigger sublayer, and dust reduction functional water bags and poison suppression functional water bags are arranged in the functional sublayer; and the upper layer is formed by molding drilling slag, clean gravel and an expanding agent and has interconnected pores in the interior. The present application uses harmless pretreated slag and drilling slag as double aggregates, reaction trigger water bags, dust reduction functional water bags and poison suppression functional water bags are arranged in the shell, and a micro-expanding controllable expanding agent is added, so that targeted treatment of sulfur-containing ore blasting dust, toxic gas and heavy metal pollution is realized.

Description

Technical Field

[0001] This invention belongs to the field of mining blasting engineering technology, and particularly relates to a targeted dust suppression borehole spacer for sulfur-containing ores and its preparation and use methods. Background Technology

[0002] Sulfur-bearing ores are important sources of non-ferrous metals such as copper, lead, zinc, and iron, as well as sulfur, and play a vital role in the national economy. Sulfur-bearing mines are widely distributed in my country, and their mining scale is enormous. Medium-deep hole blasting is currently the core operation method for large-scale mining in both metal and non-metal mines. The borehole spacer, as a key component for achieving precise separation of explosive layers and optimizing the distribution of blasting energy, directly affects the blasting effect and operational safety. Existing spacers are mainly divided into three categories: air spacers, water spacers, and solid material spacers. Among them, solid material spacers are widely used in mining blasting due to their excellent energy barrier performance and ease of construction.

[0003] However, existing solid spacers have significant drawbacks in blasting scenarios involving sulfur-containing ores. Some existing spacers use a water-soluble filling system similar to CN116675468A, which, due to its single powder structure, is prone to moisture absorption and clumping, exhibits strength degradation upon contact with water, and exhibits slow solidification at low temperatures. Furthermore, its dissolution produces slurry that pollutes the environment. Spacers made from materials similar to CN104048570A that are quick-setting also suffer from limited adjustable solidification time due to their single component composition, poor adaptability to extreme conditions, insufficient toughness after molding, weak impact resistance, susceptibility to flyrock generation, and poor water resistance, making them prone to failure under conditions of water accumulation in the blast hole.

[0004] When the aforementioned spacers are used in blasting operations for sulfur-containing ores, there are two key problems: First, during the blasting process, sulfides are oxidized, releasing toxic gases such as sulfur dioxide and hydrogen sulfide, which endanger the working environment and the health of workers; Second, the material density and resistance to blasting are insufficient, which can easily lead to dust, blasting accidents, and other accidents, resulting in wasted blasting energy and aggravated environmental pollution.

[0005] In addition, existing spacers for sulfur-containing mines have the following common defects: pollution treatment methods are singular, unable to simultaneously control sulfides, heavy metals and harmful gases, and the source pollution problem remains unresolved; the expanding agent has poor compatibility with sulfur-containing environments, the expansion effect is unstable, and it is easy to cause the blast hole to crack or not to be properly sealed; the sealing structure is simple, the resistance to blasting is weak, and dust and harmful gases are easy to leak from the gaps; the utilization rate of solid waste is low, and a large amount of sulfur-containing slag cannot be used on-site, and random dumping causes secondary pollution. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a targeted dust suppression borehole spacer for sulfur-containing ores and its preparation and application methods. This invention employs a factory-prefabricated three-layer integrated shell, using harmlessly pretreated slag and on-site drilling slag as dual aggregates. The shell contains a three-water-bag system consisting of a reaction-triggered water bag, a dust-suppressing water bag, and a toxic-suppressing water bag, with the addition of a micro-expansion controllable expansion agent. Through the synergistic function of the three layers, targeted treatment of blasting dust, toxic gases, and heavy metal pollution from sulfur-containing ores is achieved.

[0007] The specific technical solution is as follows: Targeted dust suppression borehole spacers for sulfur-containing ores include: The shell is columnar, and the shell has a bottom layer, a middle layer and an upper layer arranged in sequence from bottom to top along the axial direction, with partitions between each layer; A protective component, disposed on the surface of the housing itself, is used to provide protection during the insertion of the housing into the borehole; The bottom layer is formed by compression molding a mixture of pretreated sulfur-containing solid waste and an expanding agent; The middle layer, from bottom to top, includes a trigger sublayer, a buffer sublayer, and a functional sublayer; The triggering sublayer consists of an expanding agent and at least one reaction triggering water bag. The reaction triggering water bag is made of pure deionized water encapsulated in a brittle film and is embedded in the expanding agent. The buffer sublayer is composed of a swelling agent and does not contain a water bag; The functional sublayer consists of an expanding agent, a dust-suppressing water bag, and a toxic-inhibiting water bag. The dust-suppressing water bag and the toxic-inhibiting water bag are arranged alternately and embedded in the expanding agent. The dust-suppressing water bag uses a tough film to encapsulate the mixture of deionized water and dust-suppressing agent. The toxic-inhibiting water bag uses a tough film to encapsulate the mixture of deionized water and toxic-inhibiting agent. The upper layer is formed by molding a mixture of drill slag, clean crushed stone and expansion agent, and has interconnected pores inside.

[0008] The pretreated sulfur-containing solid waste is sulfur-containing slag with a particle size of 8-20 mm, a moisture content of ≤4%, and a sulfide content of ≤1.0%.

[0009] The expanding agent is a calcium aluminate-gypsum composite expanding agent, the main components of which are anhydrous calcium sulfoaluminate and anhydrous gypsum, and 10%-15% of Grade II fly ash is added as an inert filler, and 1.5%-2.0% of citric acid is added as a retarder; the expanding agent generates ettringite after hydration reaction.

[0010] The reaction-triggered water bag accounts for 5%-10% of the total raw material mass. It is made of a brittle film, and the capacity of each bag is matched according to the amount of expanding agent used. It is filled with pure deionized water and contains no other additives. This water bag is located at the bottom of the middle layer and is preferentially ruptured under the pressure of construction compaction, providing a reaction water source for the hydration of the expanding agent.

[0011] The dust suppressant is lignin sulfonate, and the dust suppressant water bag accounts for 3%-8% of the total raw material mass. It is made of a tough film, with a single capacity of 10-15mL, and is filled with a mixture of deionized water and 0.3% lignin sulfonate.

[0012] The borehole slag accounts for 20%-30% of the total mass of the raw materials, with a particle size of 10-25mm and a moisture content of ≤6%. Clean crushed stone accounts for 5%-10% of the total mass of the raw materials and is mixed with the borehole slag, with a particle size of 10-25mm and a moisture content of ≤3%.

[0013] The shell length and outer diameter are adapted to the target borehole size, and it is made of biodegradable material.

[0014] The biodegradable material is a rigid pulp molding material; the partition is a paper partition; and the protective component is the surface layer of the shell itself.

[0015] A method for preparing a targeted dust suppression borehole spacer for sulfur-containing ores includes the following steps: (3) Shell forming: The cylindrical shell is formed by pulp molding process, and longitudinal weakening lines are preset on the inner or outer wall of the shell, and then dried and shaped. (4) Bottom layer molding: Mix the harmless pretreated sulfur-containing slag with an expansion agent, fill it into the bottom of the shell and press it to the designed thickness, and lay paper partitions; (3) Middle layer filling: Lay a layer of drying expansion agent as a pad on the bottom partition, put in the reaction trigger water bag, and then cover with expansion agent to the designed thickness, and lightly compact to form the trigger sub-layer; continue to spread drying expansion agent to form a buffer sub-layer, and scrape it flat; place dust suppression water bags and toxicity suppression water bags alternately on the buffer sub-layer, cover with expansion agent to the designed thickness, and lightly press flat to form a functional sub-layer; lay paper partition to seal the middle layer.

[0016] (4) Upper layer molding: Mix the on-site drilled slag, clean crushed stone and micro-expansion type expansion agent, fill it into the upper layer of the shell and mold it to the designed thickness; (5) Sealing: Apply a peelable moisture-proof sealing film to both ends of the shell and the seams, or vacuum seal the whole shell with a desiccant inside.

[0017] The method for using a targeted dust suppression borehole spacer for sulfur-containing ores includes the following steps: (1) Unsealing: Open the sealed packaging on site, take out the spacer, and check the integrity of the shell and water bag; (2) Hole cleaning: Before blasting, high-pressure air pipes are used to clean the water, rock powder and debris in the blast holes to ensure that the holes are dry and clean and that there are no obvious protrusions or loose rock blocks on the hole walls; the diameter and depth of the blast holes are measured to confirm that they match the outer diameter and length of the spacers. (3) Placement of spacers: After determining the position of the explosive layer according to the blasting design, prefabricated spacers are vertically placed at the end of the explosive layer, ensuring that the axis of the spacer coincides with the axis of the borehole, with the bottom layer facing the explosive layer and the top layer facing the borehole opening, and tightly fitted to the end face of the explosive layer. Then, the upper explosive layer is added above the spacer to form a charging structure of "detonator-explosive-spacer-explosive". If multi-stage separation charging is required, subsequent spacers are placed in sequence according to the design spacing; (4) Reaction triggering and sealing: Fill the borehole with drill slag and compact it in layers; the compaction pressure is transmitted to the middle triggering sublayer through the upper skeleton, causing the reaction triggering water bag at the bottom to rupture under pressure and release pure deionized water; the buffer sublayer absorbs and disperses the pressure, protecting the dust suppression and detoxification water bags in the functional sublayer; the water gradually penetrates from the triggering sublayer to trigger the micro-expansion hydration reaction of the expansion agent; continue to fill with crushed stone until it is flush with the borehole opening, and complete the sealing construction.

[0018] The beneficial effects of this invention are: (1) Excellent performance of the sealing and anti-impact gun: The upper skeleton and the expansion agent are combined to form a dense and impact-resistant sealing body. With the help of the control of components and water volume, a micro-expansion with an expansion rate of 8%-15% and an expansion force of 0.20-0.35MPa is generated, so that the spacer and the hole wall are evenly attached, thereby effectively preventing the leakage of blasting, flying stones and harmful gases, while avoiding hole wall cracking and structural damage.

[0019] (2) Improve blasting quality: Through the charging structure of “detonator-explosive-spacer-explosive-filling”, the explosive is distributed more evenly in the borehole, thereby effectively reducing the rate of large pieces at the top of the blast zone and improving blasting quality.

[0020] (3) Enhanced effective stress in rock mass: The spacer fits tightly against the borehole wall to form a high-strength seal, preventing the explosive gas from escaping, increasing the effective stress, and making the rock more fully broken.

[0021] (4) Improved construction safety and efficiency: The reaction water bag can be controlled to rupture under compaction pressure. The water source is built-in and does not require external water injection, which simplifies the operation process and effectively improves construction efficiency. The functional water bag is protected by a buffer layer and will not rupture throughout the process, with no risk of leakage.

[0022] (5) The dual slag system realizes on-site disposal of solid waste: the bottom layer uses harmless pre-treated slag to eliminate pollution, and the upper layer directly utilizes on-site drilled slag and crushed stone, thus making resource utilization of sulfur-containing solid waste. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the external structure of the targeted dust suppression borehole spacer for sulfur-containing ores according to the present invention. Figure 2 This is a schematic diagram of the internal structure of the targeted dust suppression borehole spacer for sulfur-containing ores according to the present invention. Figure 3 This is a schematic diagram of the bottom structure of the targeted dust suppression borehole spacer for sulfur-containing ores according to the present invention; Figure 4 This is a schematic diagram of the top structure of the targeted dust suppression borehole spacer for sulfur-containing ores according to the present invention; Figure 5 This is a schematic diagram showing the installation position of the spacer of the present invention inside the borehole; The components are as follows: 1. Shell; 2. Baseboard; 3. Bottom layer; 4. Partition; 5. Middle layer; 51. Reaction trigger water bag; 53. Dust suppression water bag; 54. Detoxification water bag; 6. Expanding agent; 7. Top layer; 71. Drill slag; 72. Clean gravel; 8. Blast hole; 9. Explosive layer; 10. Sealing material; 11. Detonator. Detailed Implementation

[0024] The technical solution and beneficial effects of the present invention will be further explained below with reference to the accompanying drawings and two specific embodiments.

[0025] Implementation Case 1: This embodiment takes the blasting of borehole 8 in a sulfur-bearing copper mine as an example. Borehole 8 has a diameter of 90mm and a depth of 10m. A schematic diagram of the targeted dust suppression borehole spacer structure used for this borehole is shown below. Figures 1 to 5 As shown, it consists of a shell 1, a bottom layer 3, a middle layer 5, an upper layer 7, and paper partitions 4. The shell 1 is columnar, molded from rigid pulp material, with a length of 400mm and an outer diameter of 84mm. The surface of the shell 1 itself provides protection during insertion into the borehole, and the inner wall has pre-set longitudinal weakening lines to guide the shell 1 to preferentially disintegrate in a predetermined direction at the moment of blasting. The bottom layer 3, the middle layer 5, and the upper layer 7 are arranged sequentially from bottom to top along the axial direction, with paper partitions 4 between each layer.

[0026] The bottom layer 3 is formed by molding a mixture of pretreated sulfur-containing slag and calcium aluminate-gypsum composite expanding agent 6. The sulfur-containing slag has a particle size of 16 mm, a moisture content of 2%, a sulfide content of 0.5%, and a dosage of 2.6 kg. The expanding agent 6 mainly consists of anhydrous calcium sulfoaluminate and anhydrous gypsum, with 12% of Grade II fly ash added as an inert filler and 1.8% citric acid added as a retarder. After hydration, it produces ettringite with an expansion rate of 12%, an expansion force of 0.25 MPa, and a dosage of 2.08 kg. The reaction formula for the hydration reaction to produce ettringite is: 3CaO·3Al2O3·CaSO4 + 8CaSO4 + 96H2O → 3(3CaO·Al2O3·3CaSO4·32H2O).

[0027] The middle layer 5, from bottom to top, includes a triggering sublayer, a buffer sublayer, and a functional sublayer. The triggering sublayer consists of an expanding agent 6 and reaction-triggered water bags 51. The reaction-triggered water bags 51 are made of brittle PVC film encapsulating pure deionized water. The film thickness is 40 μm, and each bag has a capacity of 150 mL and a weight of 0.83 kg. They are embedded in the expanding agent 6, with the bottom of the water bag in direct contact with the bottom partition 4. Under the pressure of construction compaction, they are preferentially subjected to pressure and rupture, providing a reaction water source for the hydration of the expanding agent. The buffer sublayer consists of the expanding agent 6 and does not contain water bags. The functional sublayer consists of the expanding agent 6, dust-suppressing functional water bags 53, and toxicity-inhibiting functional water bags 54. The dust-suppressing functional water bags 53 are made of tough PE film encapsulating a mixture of deionized water and dust suppressant. The film thickness is 60 μm, and there are 44 bags in total, each with a capacity of 12 mL. The dust suppressant in the mixture is lignin sulfonate, with a concentration of 0.3% and a weight of 0.52 kg. The water bag 54 with the toxicity-inhibiting function uses a tough film to encapsulate a mixture of deionized water and a toxicity inhibitor. The dust-reducing water bag 53 and the toxicity-inhibiting water bag 54 are arranged alternately, with a net distance of ≥10mm between the water bags, and are embedded in the expanding agent 6.

[0028] The upper layer 7 is formed by molding a mixture of drilled slag 71, clean granite crushed stone 72, and expanding agent 6, and has interconnected pores (a network of interconnected pores naturally formed between the particles). The drilled slag 71 has a particle size of 20mm, a moisture content of 5%, and a dosage of 2.6kg; the clean granite crushed stone 72 has a particle size of 20mm, a moisture content of 2%, and a dosage of 0.83kg. The total mass of all materials in the spacer is 10.0kg.

[0029] The spacer is prepared as follows: First, the shell 1 is formed using a pulp molding process to create a cylindrical shell with pre-set longitudinal weakening lines on the inner wall, followed by drying and shaping. Then, sulfur-containing slag and expanding agent 6 are added to a forced mixer and dry-mixed at 30 rpm for 3 minutes until the color is uniform. This mixture is then filled into the bottom of the shell 1 and molded to the designed thickness. Paper spacers 4 are then laid on top. When filling the middle layer 5, a reaction trigger water bag 51 is placed above the bottom spacer 4. The drying expanding agent 6 is then filled around the water bag and compacted to a thickness of 60 mm with a compaction density ≥ 1.2 g / cm³. The drying expanding agent 6 is then spread and leveled before being compacted at 0.1 MPa to form a 50 mm thick buffer sublayer. Dust-reducing water bags 53 and toxicity-inhibiting water bags 54 are then placed alternately above the buffer sublayer, covered with the drying expanding agent 6, and compacted flat at 0.1 MPa to form a 60 mm thick functional sublayer. Finally, paper spacers 4 are laid on top to seal the middle layer 5. Finally, the drilled slag 71, clean crushed stone 72, and expanding agent 6 are added to a forced mixer and dry-mixed at 30 rpm for 5 minutes until uniform. This mixture is then filled into the upper layer of shell 1 and molded under a pressure of 5 MPa. After holding the pressure for 30 seconds, the mixture is demolded to form the upper layer 7. A peelable moisture-proof sealing film or an overall vacuum-sealed package is applied to both ends and seams of shell 1, with a desiccant inside, completing the preparation of the spacer. The rupture pressure of the reaction-triggered water bag 51 is 0.05-0.15 MPa. It should be ensured that under a construction compaction pressure of 0.3-0.5 MPa, the reaction-triggered water bag 51 will rupture preferentially, prioritizing the dust suppression function water bag 53 and the toxicity suppression function water bag 54.

[0030] The method of using the targeted dust suppression borehole spacer for sulfur-containing ores is as follows: Figure 5 As shown, it includes the following steps: On-site, the sealed packaging was opened, the spacer was removed, and the integrity of the shell and water bag was checked. Before blasting, high-pressure air ducts were used to clean the water, rock powder, and debris inside the blast hole to ensure that the hole was dry and clean, and that there were no obvious protrusions or loose rock blocks on the hole wall. The diameter and depth of the blast hole were measured to confirm that they matched the outer diameter and length of the spacer. Spacer placement: The position of the explosive layer 9 was determined according to the blasting design. Then, detonators 11 and lead wires 2 were placed on the explosive layer, and the lead wires 2 were pulled out to the blast hole opening. The prefabricated spacer was vertically placed at the end of the explosive layer 9, ensuring that the axis of the spacer coincided with the axis of the blast hole, with the bottom layer facing the explosive layer and the top layer facing the blast hole opening, and tightly fitting the end face of the explosive layer 9. Then, the upper explosive layer 9 was continued to be installed above the spacer to form a "detonator-explosive-spacer-explosive" charging structure. For multi-stage compartmentalized charges, subsequent spacers are installed sequentially according to the designed spacing. Reaction triggering and sealing: Drill slag is used as sealing material 10, filled into the borehole opening, and compacted in layers. The compaction pressure is transmitted through the upper framework to the middle triggering sublayer, causing the bottom reaction triggering water bag 51 to rupture under pressure, releasing pure deionized water. The buffer sublayer absorbs and disperses the pressure, protecting the dust-suppressing water bag 53 and the toxic gas suppressing water bag 54 within the functional sublayer. Moisture gradually permeates from the triggering sublayer, triggering a micro-expansion hydration reaction of the expanding agent. The filling continues with crushed stone until it is flush with the borehole opening, completing the sealing process. After detonation, the blast impact causes the dust-suppressing water bag 53 and the toxic gas suppressing water bag 54 to rupture, releasing the dust suppressant and toxic gas suppressant in a targeted manner.

[0031] The concentration of respirable dust at the working face after blasting was 1.2 mg / m³; sulfur dioxide concentration was not detected; this invention is free of blasting debris and flyrock, improves the energy distribution utilization rate of explosives by 25%, has uniform block size, and a large block rate of less than 3%. Effective stress is increased by 21%.

[0032] Implementation Case 2: This embodiment uses the blasting of borehole 8 in a high-sulfur lead-zinc mine as an example. The borehole diameter is 110mm and the depth is 12m. A schematic diagram of the targeted dust suppression borehole spacer used for borehole 8 is shown below. Figures 1 to 4 As shown, it consists of a shell 1, a bottom layer 3, a middle layer 5, and an upper layer 7, with paper partitions 4 between each layer. The shell 1 is columnar, made of rigid pulp molding material, with a length of 500mm and an outer diameter of 104mm. The inner wall has a pre-set longitudinal weakening line to guide the shell to preferentially disintegrate in a predetermined direction at the moment of explosion.

[0033] The bottom layer 3, located at the bottom of the shell 1, is 75 mm thick and is formed by molding a mixture of pretreated sulfur-containing slag and calcium aluminate-gypsum composite expanding agent 6. The sulfur-containing slag has a particle size of 16 mm, a moisture content of 2%, a sulfide content of 0.5%, and a dosage of 3.90 kg. The composite expanding agent 6 mainly consists of anhydrous calcium sulfoaluminate and anhydrous gypsum, with 13% of Grade II fly ash added as an inert filler and 1.7% citric acid added as a retarder. After hydration, it produces ettringite, with a dosage of 3.12 kg, an expansion rate of 12%, and an expansion force of 0.25 MPa. The reaction formula for the hydration reaction to produce ettringite is: 3CaO·3Al2O3·CaSO4 + 8CaSO4 + 96H2O → 3(3CaO·Al2O3·3CaSO4·32H2O).

[0034] The middle layer 5, from bottom to top, includes a trigger sublayer, a buffer sublayer, and a functional sublayer, with the loading structure as follows: Figure 2 As shown. The triggering sublayer is 45mm thick and consists of an expanding agent 6 and a reaction-triggered water bag 51. The reaction-triggered water bag 51 uses a brittle film to encapsulate pure deionized water, with a single capacity of 150mL and a dosage of 1.25kg. It is embedded in the expanding agent 6, and the bottom of the water bag is in direct contact with the partition 4 of the bottom layer 3. Under the pressure of construction compaction, it is preferentially subjected to pressure and ruptures, providing a reaction water source for the hydration of the expanding agent. The buffer sublayer is 45mm thick and consists of the expanding agent 6, without a water bag. The functional sublayer is 60mm thick and consists of the expanding agent 6, a dust-suppressing functional water bag 53, and a toxic-suppressing functional water bag 54. The dust-suppressing functional water bag 53 uses a tough film to encapsulate a mixture of deionized water and a dust-suppressing agent, wherein the dust-suppressing agent is lignin sulfonate, the concentration of the mixture is 0.3%, the single capacity is 15mL, and the dosage is 0.78kg. The toxic-suppressing functional water bag 54 uses a tough film to encapsulate a mixture of deionized water and a toxic-suppressing agent, with a dosage of 0.78kg. Dust-reducing water bags 53 and toxic-inhibiting water bags 54 are arranged alternately, with a net distance of ≥10mm between the water bags, and are embedded in the expanding agent 6.

[0035] The upper layer 7, 110mm thick, is formed by molding a mixture of drilled slag 71, clean limestone crushed stone 72, and expanding agent 6. It has interconnected pores (a network of pores naturally formed between the particles). The drilled slag 71 has a particle size of 20mm, a moisture content of 5%, and a dosage of 3.90kg; the clean limestone crushed stone 72 has a particle size of 20mm, a moisture content of 2%, and a dosage of 1.25kg. The total mass of the spacer material is 15.0kg.

[0036] The spacer is prepared as follows: First, the shell 1 is formed using a pulp molding process to create a cylindrical shell with pre-set longitudinal weakening lines on the inner wall, followed by drying and shaping. Then, pre-treated sulfur-containing slag is mixed with expanding agent 6 and filled into the bottom of the shell 1, molded to the designed thickness, and then a paper partition 4 is laid. When filling the middle layer 5, a reaction trigger water bag 51 is placed above the bottom partition 4, and the drying expanding agent 6 is filled around the water bag and compacted to a thickness of 50 mm with a compaction density ≥1.2 g / cm³. The drying expanding agent 6 is then spread and leveled, and compacted with a pressure of 0.1 MPa to form a 50 mm thick buffer sublayer. Dust-reducing water bags 53 and toxicity-inhibiting water bags 54 are placed alternately above the buffer sublayer, covered with the drying expanding agent 6, and compacted flat with a pressure of 0.1 MPa to form a 60 mm thick functional sublayer. Finally, the paper partition 4 is laid to seal the middle layer 5. Finally, the drilled slag 71, clean crushed stone 72, and expanding agent 6 are added to a forced mixer and dry-mixed at 30 rpm for 5 minutes until uniform. This mixture is then filled into the upper layer of shell 1 and molded under a pressure of 5 MPa. After holding the pressure for 30 seconds, the mixture is demolded to form the upper layer 7. A peelable moisture-proof sealing film is applied to both ends and seams of shell 1, or the entire shell is vacuum-sealed with a desiccant inside, completing the spacer assembly. The rupture pressure of the reaction-triggered water bag 51 is 0.05-0.15 MPa. It should be ensured that under a construction compaction pressure of 0.3-0.5 MPa, the reaction-triggered water bag 51 will rupture preferentially, with the dust-suppressing water bag 53 and the toxic-suppressing water bag 54 rupturing first.

[0037] The method of using the targeted dust suppression borehole spacer for sulfur-containing ores is as follows: Figure 5 As shown, it includes the following steps: On-site, the sealed packaging was opened, the spacer was removed, and the integrity of the shell and water bag was checked. Before blasting, high-pressure air ducts were used to clean the water, rock powder, and debris inside the blast hole to ensure that the hole was dry and clean, and that there were no obvious protrusions or loose rock blocks on the hole wall. The diameter and depth of the blast hole were measured to confirm that they matched the outer diameter and length of the spacer. Spacer placement: The position of the explosive layer 9 was determined according to the blasting design. Then, detonators 11 and lead wires 2 were placed on the explosive layer, and the lead wires 2 were pulled out to the blast hole opening. The prefabricated spacer was vertically placed at the end of the explosive layer 9, ensuring that the axis of the spacer coincided with the axis of the blast hole, with the bottom layer facing the explosive layer and the top layer facing the blast hole opening, and tightly fitting the end face of the explosive layer 9. Then, the upper explosive layer 9 was continued to be installed above the spacer to form a "detonator-explosive-spacer-explosive" charging structure. For multi-stage compartmentalized charges, subsequent spacers are installed sequentially according to the designed spacing. Reaction triggering and sealing: Drill slag is used as sealing material 10, filled into the borehole opening, and compacted in layers. The compaction pressure is transmitted through the upper framework to the middle triggering sublayer, causing the bottom reaction triggering water bag 51 to rupture under pressure, releasing pure deionized water. The buffer sublayer absorbs and disperses the pressure, protecting the dust-suppressing water bag 53 and the toxic gas suppressing water bag 54 within the functional sublayer. Moisture gradually permeates from the triggering sublayer, triggering a micro-expansion hydration reaction of the expanding agent. The filling continues with crushed stone until it is flush with the borehole opening, completing the sealing process. After detonation, the blast impact causes the dust-suppressing water bag 53 and the toxic gas suppressing water bag 54 to rupture, releasing the dust suppressant and toxic gas suppressant in a targeted manner.

[0038] The concentration of respirable dust at the working face after blasting was 1.1 mg / m³; sulfur dioxide concentration was not detected; this invention is free of impellers and flyrock, improves the energy distribution utilization rate of explosives by 26%, has uniform block size, and the rate of large blocks is less than 4%. Effective stress is increased by 20%.

[0039] Comparative Example 1 In the same high-sulfur lead-zinc mine, the blast holes are 90mm in diameter and 10m deep. Conventional plastic air separators are used for the middle separation. The charging structure is "detonator-explosive-air separator-explosive". The blast hole filling material is drill slag.

[0040] The concentration of respirable dust at the working face after blasting was 6.8 mg / m³; the detected concentration of sulfur dioxide was 0.44 ppm; there were slight instances of impact and flyrock; the energy distribution and utilization rate of the explosive was low; the fragments were uneven in size, with a large fragment rate as high as 12%; and the effective stress was only 65% ​​of the theoretical design value.

[0041] Comparative Example 2 In the same high-sulfur lead-zinc mine, the blast hole diameter is 110mm and the hole depth is 12m. A conventional water bag-rock powder composite spacer is used, that is, conventional water bags and drill slag are alternately filled to form a composite spacer. The water bag is filled with pure water. The charge structure is "detonator-explosive-conventional water bag-rock powder composite spacer-explosive". The blast hole filling material is drill slag.

[0042] The concentration of respirable dust at the working face after blasting was 4.2 mg / m³; the detected concentration of sulfur dioxide was 0.21 ppm; there were slight instances of impact and flyrock; the energy distribution and utilization rate of the explosive was low; the fragments were uneven in size, with a large fragment rate of 9%. The effective stress was only 76% of the theoretical design value.

Claims

1. A targeted dust suppression borehole spacer for sulfur-containing ores, characterized in that, include: The shell is columnar, and the shell has a bottom layer, a middle layer and an upper layer arranged in sequence from bottom to top along the axial direction, with partitions between each layer; A protective component, disposed on the surface of the housing itself, is used to provide protection during the insertion of the housing into the borehole; The bottom layer is formed by compression molding a mixture of pretreated sulfur-containing solid waste and an expanding agent; The middle layer, from bottom to top, includes a trigger sublayer, a buffer sublayer, and a functional sublayer; The triggering sublayer consists of an expanding agent and at least one reaction triggering water bag. The reaction triggering water bag is made of pure deionized water encapsulated in a brittle film and is embedded in the expanding agent. The buffer sublayer is composed of a swelling agent and does not contain a water bag; The functional sublayer consists of an expanding agent, a dust-suppressing water bag, and a toxic-inhibiting water bag. The dust-suppressing water bag and the toxic-inhibiting water bag are arranged alternately and embedded in the expanding agent. The dust-suppressing water bag uses a tough film to encapsulate the mixture of deionized water and dust-suppressing agent. The toxic-inhibiting water bag uses a tough film to encapsulate the mixture of deionized water and toxic-inhibiting agent. The upper layer is formed by molding a mixture of drill slag, clean crushed stone and expansion agent, and has interconnected pores inside.

2. The targeted dust suppression borehole spacer for sulfur-containing ores according to claim 1, characterized in that, The pretreated sulfur-containing solid waste is sulfur-containing slag with a particle size of 8-20 mm, a moisture content of ≤4%, and a sulfide content of ≤1.0%.

3. A targeted dust suppression borehole spacer for sulfur-containing ores according to claim 1, characterized in that, The expanding agent is a calcium aluminate-gypsum composite expanding agent, the main components of which are anhydrous calcium sulfoaluminate and anhydrous gypsum, and 10%-15% of Grade II fly ash is added as an inert filler, and 1.5%-2.0% of citric acid is added as a retarder; the expanding agent generates ettringite after hydration reaction.

4. A targeted dust suppression borehole spacer for sulfur-containing ores according to claim 1, characterized in that, The reaction-triggered water bag accounts for 5%-10% of the total mass of the raw materials. It is made of a brittle film, and the capacity of each bag is matched according to the amount of expanding agent used. It is filled with pure deionized water and contains no other additives. The water bag is located at the bottom of the middle layer and is preferentially ruptured under the pressure of construction compaction to provide a reaction water source for the hydration of the expanding agent.

5. A targeted dust suppression borehole spacer for sulfur-containing ores according to claim 1, characterized in that, The dust suppressant is lignin sulfonate, and the dust suppressant water bag accounts for 3%-8% of the total raw material mass. It is made of a tough film, with a single capacity of 10-15mL, and is filled with a mixture of deionized water and 0.3% lignin sulfonate.

6. A targeted dust suppression borehole spacer for sulfur-containing ores according to claim 1, characterized in that, The borehole slag accounts for 20%-30% of the total mass of the raw materials, with a particle size of 10-25mm and a moisture content of ≤6%. Clean crushed stone accounts for 5%-10% of the total mass of the raw materials and is mixed with the borehole slag, with a particle size of 10-25mm and a moisture content of ≤3%.

7. A targeted dust suppression borehole spacer for sulfur-containing ores according to claim 1, characterized in that, The shell length and outer diameter are adapted to the target borehole size, and it is made of biodegradable material.

8. A targeted dust suppression borehole spacer for sulfur-containing ores according to claim 7, characterized in that, The biodegradable material is a rigid pulp molding material; the partition is a paper partition; and the protective component is the surface layer of the shell itself.

9. A method for preparing a targeted dust suppression borehole spacer for any of the sulfur-containing ores according to claims 1-8, characterized in that, Includes the following steps: (1) Shell forming: The cylindrical shell is formed by pulp molding process, and longitudinal weakening lines are preset on the inner or outer wall of the shell, and then dried and shaped. (2) Bottom layer molding: The harmless pretreated sulfur-containing slag is mixed with an expansion agent, filled into the bottom of the shell and molded to the designed thickness, and then a paper partition is laid. (3) Middle layer filling: A layer of drying expansion agent is laid on the bottom partition as a pad, the reaction trigger water bag is placed in, and then the expansion agent is covered to the designed thickness. It is lightly compacted to form the trigger sublayer; the drying expansion agent is continued to be spread to form the buffer sublayer and scraped flat; the dust suppression water bag and the toxicity inhibition water bag are placed alternately on the buffer sublayer, the expansion agent is covered to the designed thickness, and it is lightly pressed flat to form the functional sublayer; a paper partition is laid to seal the middle layer; (4) Upper layer molding: Mix the on-site drilled slag, clean crushed stone and micro-expansion type expansion agent, fill it into the upper layer of the shell and mold it to the designed thickness; (5) Sealing: Apply a peelable moisture-proof sealing film to both ends of the shell and the seams, or vacuum seal the whole shell with a desiccant inside.

10. A method of using a targeted dust suppression borehole spacer for any of the sulfur-containing ores according to claims 1-8, characterized in that, Includes the following steps: (1) Unsealing: Open the sealed packaging on site, take out the spacer, and check the integrity of the shell and water bag; (2) Hole cleaning: Before blasting, high-pressure air pipes are used to clean the water, rock powder and debris in the blast holes to ensure that the holes are dry and clean and that there are no obvious protrusions or loose rock blocks on the hole walls; the diameter and depth of the blast holes are measured to confirm that they match the outer diameter and length of the spacers. (3) Placement of spacers: After determining the position of the explosive layer according to the blasting design, prefabricated spacers are placed vertically at the end of the explosive layer, ensuring that the axis of the spacer coincides with the axis of the borehole, with the bottom layer facing the explosive layer and the top layer facing the borehole opening, and tightly fitting the end face of the explosive layer; then the upper explosive layer is added above the spacer to form a "detonator-explosive-spacer-explosive" charging structure; if multi-stage separation charging is required, subsequent spacers are placed in sequence according to the design spacing. (4) Reaction triggering and sealing: Fill the borehole with drill slag and compact it in layers; the compaction pressure is transmitted to the middle triggering sublayer through the upper skeleton, causing the reaction triggering water bag at the bottom to rupture under pressure and release pure deionized water; the buffer sublayer absorbs and disperses the pressure, protecting the dust suppression and detoxification water bags in the functional sublayer; the water gradually penetrates from the triggering sublayer to trigger the micro-expansion hydration reaction of the expansion agent; continue to fill with crushed stone until it is flush with the borehole opening, and complete the sealing construction.

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