A mining backfill preparation process based on tailings sand recovery and reuse

Abstract

The invention discloses a mining backfill material preparation process based on tailings sand recovery and reuse, which is applied to the field of environmental protection technology. The process reduces the use of other materials and additives and uses tailings sand waste as the main raw material to prepare the backfill material, which can not only effectively save costs, but also effectively avoid the precipitation of harmful substances and secondary pollution. By adding a shaped internal reinforcement keel as the skeleton of the backfill material, the strength of the backfill material is effectively improved, and the backfill material can be prevented from being broken and collapsed during transportation and backfilling. The internal reinforcement net is used to adsorb heavy metal ions in the backfill material to prevent the heavy metal ions from infiltrating into the groundwater layer. The internal reinforcement column is also used to help the infiltration of rainwater, effectively preventing the occurrence of waterlogging in the reclaimed backfill pit, and the internal reinforcement column can filter the infiltrating rainwater, further effectively preventing the harmful substances from infiltrating into the groundwater layer, thereby achieving the increase and purification of the strength of the backfill material and effectively preventing secondary pollution.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to a mining backfill material preparation process based on tailings sand recovery and reuse. Background Art

[0002] Tailings sand contains some substances that may pollute the environment. If not properly treated, it may pollute groundwater, soil, etc. By recycling and reusing tailings sand, the emission of these pollutants can be reduced and the environment can be protected.

[0003] Valuable minerals can be extracted from tailings sand to increase resource recovery and utilization. Of course, the waste after tailings sand extraction can also be made into backfill to backfill the mine. At present, the preparation process of backfill uses waste as raw materials, adding steel slag, slag, fly ash, additives and water for mixing and stirring. However, due to the abuse of other materials and various additives added to the raw materials, some heavy metal ions are precipitated and infiltrated into the groundwater layer, resulting in secondary pollution of the mine by the backfill, especially for the mine reclaimed after backfilling. In addition, the backfill prepared by the existing process is not strong enough and is easy to be crushed during transportation and backfilling, resulting in collapse of the mine due to false backfilling.

[0004] To this end, we use this technical solution to solve the problem that the existing backfill material preparation process is prone to secondary pollution. Summary of the invention

[0005] The purpose of the present invention is to improve the backfill preparation process in the prior art. Compared with the prior art, a mining backfill preparation process based on the recovery and reuse of tailings sand is provided. By reducing the use of other materials and additives on the basis of the existing preparation process, the backfill is prepared with tailings sand waste as the main raw material, which can not only effectively save costs, but also effectively avoid the precipitation of harmful substances and cause secondary pollution. By adding a shaped internal reinforcement keel as the skeleton of the backfill, the strength of the backfill is effectively improved, and the backfill can be prevented from being broken and collapsed during transportation and backfilling. The internal reinforcement net is used to adsorb heavy metal ions in the backfill to prevent the heavy metal ions from infiltrating into the groundwater layer. The internal reinforcement column is also used to help the infiltration of rainwater, effectively preventing the occurrence of waterlogging in the reclaimed backfill mine pit, and the internal reinforcement column can filter the infiltrating rainwater, further effectively preventing the harmful substances from infiltrating into the groundwater layer.

[0006] The strength of the backfill material can be increased and purified, effectively preventing the backfill material from causing secondary pollution to the mine.

[0007] A mining backfill preparation process based on tailings sand recovery and reuse comprises the following steps:

[0008] S1, firstly use magnetic separation to extract the useful components in the tailings sand, and then treat the solid waste left after the extraction;

[0009] S2, then crushing the solid waste, using a screening machine to separate the fine powder produced by the crushing from the impurities and the blocky waste rock, recycling the waste rock as aggregate for building materials, treating the impurities by chemical and physical methods to convert them into harmless substances, and collecting the powdery waste;

[0010] S3, putting the collected fine powder into a mixing mixer, and adding gelling material and water into the mixer for mixing and stirring, the ratio of gelling material to fine powder is 1:3-9, wherein the formula of gelling material is as follows, by weight:

[0011] Cement clinker 10%-30%, slag powder 10%-50%, steel slag powder 10%-50%, fly ash 5%-25%, dust ash 5%-15%, gypsum 5%-45%, desulfurization ash 5-35%;

[0012] S4, the stirred mixture is placed in a mold for pressing and shaping, and after the mixture is solidified, it is taken out and backfilled into the mining pit.

[0013] Further, the mold filling in step S4 includes the following steps:

[0014] S41, taking a mold box with an opening at the upper end, first laying an anti-cracking mesh sheet on the bottom of the mold box, and then laying an anti-cracking mesh bag on the side walls around the mold box;

[0015] S42, then put the shaped inner reinforcement keel into the mold box, so that the shaped inner reinforcement keel is in the middle of the mold box, and then pour the mixed and stirred mixture into the mold box, and vibrate the mold box during the pouring process to make the mixture compact without leaving any gaps;

[0016] S43, finally, the anti-cracking mesh is laid again on the upper surface of the mixture, and then the mold cover is covered to compact the mixture into shape.

[0017] Furthermore, the anti-cracking net bag and the anti-cracking mesh in step S41 are both made of degradable plastic material, and the anti-cracking net bag is an integrated structure. The function of the anti-cracking net bag and the anti-cracking mesh is to effectively improve the surface anti-cracking performance of the backfill material when it is just formed, to prevent the backfill material from being broken due to impact during transportation and backfilling, and in order to avoid secondary pollution to the mine pit, the anti-cracking net bag and the anti-cracking mesh are both made of degradable plastic material.

[0018] Furthermore, the shaped inner reinforcement keel in step S42 includes a central inner reinforcement column and four peripheral inner reinforcement columns, and the central inner reinforcement column is located at the center of the other four peripheral inner reinforcement columns, and the central inner reinforcement column and each peripheral inner reinforcement column are fixedly connected with an inner reinforcement net, and the four peripheral inner reinforcement columns are also connected with the inner reinforcement net. Multiple inner reinforcement columns and inner reinforcement nets are combined together as the skeleton of the backfill material, which adheres the raw materials together, effectively improves the strength of the backfill material, prevents it from cracking and breaking, and can also effectively reduce the amount of binder used, avoid adding too much chemical agents, thereby reducing the secondary pollution to the backfill pit as much as possible.

[0019] Optionally, the internal reinforcement column includes a bonding column, which is a three-dimensional hollow mesh structure, and a pressure-resistant guide column is fixedly embedded in the middle of the bonding column. The bonding column serves to connect the internal reinforcement mesh, and the pressure-resistant guide column serves to increase the compression resistance of the backfill material, thereby effectively improving the strength of the backfill material.

[0020] Optionally, the pressure-resistant diversion column includes a hollow column, and water-degradable membranes are fixedly connected to the upper and lower open ends of the hollow column, and a plurality of adsorption filter pads evenly spaced above and below are fixedly connected to the inner wall of the hollow column, a plurality of drip holes are opened on the adsorption filter pad, and the adsorption filter pad is made of synthetic resin. The hollow column plays a role in improving the pressure resistance of the backfill material, and also serves as a channel for rainwater infiltration. The water-degradable membrane plays a role of blocking materials during the mold filling process to prevent the mixture from blocking the hollow column. After backfilling, the water-degradable membrane can be degraded under the action of water, so that rainwater can infiltrate along the hollow column, and the adsorption filter pad can also adsorb and filter heavy metal ions carried in the rainwater, thereby effectively preventing harmful substances from infiltrating into the groundwater layer.

[0021] Furthermore, the internal mesh includes a plurality of mesh nodes distributed at equal intervals, and a plurality of mesh wires are fixedly connected between two adjacent mesh nodes. The mesh nodes and the mesh wires are interwoven and connected with each other to bond the mixture together, playing a role similar to that of an adhesive, thereby effectively reducing the amount of adhesive used. Moreover, the interwoven connection characteristics of the mesh nodes and the mesh wires can effectively prevent cracking inside the mixture.

[0022] Furthermore, an ion adsorption collection sheet is fixedly embedded in the middle of the mesh node. The mesh node and mesh wire are both made of polyurethane, and the ion adsorption collection sheet is made of synthetic resin. The ion adsorption collection sheet is used to absorb heavy metal ions in the mixture, effectively preventing the precipitation of harmful substances and causing secondary pollution to the mine. The mesh node and mesh wire are both made of environmentally friendly polyurethane material in order not to pollute the mine.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] (1) This scheme reduces the use of other materials and additives on the basis of the existing preparation process, and uses tailings sand waste as the main raw material to prepare backfill material, which can not only effectively save costs, but also effectively avoid the precipitation of harmful substances and secondary pollution. By adding a shaped internal reinforcement keel as the skeleton of the backfill material, the strength of the backfill material is effectively improved. During the transportation and backfilling process, the backfill material can be prevented from breaking and causing collapse. The internal reinforcement net is used to adsorb heavy metal ions in the backfill material to prevent the heavy metal ions from infiltrating into the groundwater layer. The internal reinforcement column is also used to help the infiltration of rainwater, effectively preventing the occurrence of waterlogging in the reclaimed backfill pit. The internal reinforcement column can filter the infiltrating rainwater, further effectively preventing harmful substances from infiltrating into the groundwater layer, thereby increasing the strength and purification of the backfill material, and effectively preventing the backfill material from causing secondary pollution to the mine pit.

[0025] (2) The anti-cracking net bag and the anti-cracking mesh in step S41 are both made of degradable plastic material, and the anti-cracking net bag is an integrated structure. The function of the anti-cracking net bag and the anti-cracking mesh is to effectively improve the surface anti-cracking performance of the backfill material when it is just formed, to prevent the backfill material from being broken due to impact during transportation and backfilling, and in order to avoid secondary pollution to the mine pit, the anti-cracking net bag and the anti-cracking mesh are both made of degradable plastic material.

[0026] (3) The shaped inner reinforcement keel in step S42 includes a central inner reinforcement column and four peripheral inner reinforcement columns, and the central inner reinforcement column is located at the center of the other four peripheral inner reinforcement columns. The central inner reinforcement column and each peripheral inner reinforcement column are fixedly connected with an inner reinforcement net, and the four peripheral inner reinforcement columns are also connected with an inner reinforcement net. Multiple inner reinforcement columns and inner reinforcement nets are combined together as the skeleton of the backfill material, which adheres the raw materials together, effectively improves the strength of the backfill material, prevents it from cracking and breaking, and can also effectively reduce the amount of binder used, avoid adding too much chemical agents, thereby minimizing secondary pollution to the backfill pit.

[0027] (4) The internal reinforcement column includes a bonding column, which is a three-dimensional hollow mesh structure, and a pressure-resistant guide column is fixedly embedded in the middle of the bonding column. The bonding column serves to connect the internal reinforcement mesh, and the pressure-resistant guide column serves to increase the compression resistance of the backfill material, thereby effectively improving the strength of the backfill material.

[0028] (5) The pressure-resistant diversion column includes a hollow column, and water-degradable membranes are fixedly connected to the upper and lower open ends of the hollow column, and a plurality of adsorption filter pads with equal spacing are fixedly connected to the inner wall of the hollow column. The adsorption filter pad is provided with a plurality of drip holes, and the adsorption filter pad is made of synthetic resin. The hollow column plays a role in improving the pressure resistance of the backfill material, and also serves as a channel for rainwater infiltration. The water-degradable membrane plays a role in blocking the material during the molding process to prevent the mixture from blocking the hollow column. After backfilling, the water-degradable membrane can be degraded under the action of water, so that rainwater can infiltrate along the hollow column. In addition, the adsorption filter pad can adsorb and filter heavy metal ions carried in the rainwater, thereby effectively preventing harmful substances from infiltrating into the groundwater layer.

[0029] (6) The internal mesh includes a plurality of mesh nodes distributed at equal intervals, and a plurality of mesh wires are fixedly connected between two adjacent mesh nodes. The mesh nodes and mesh wires are interwoven and connected with each other to bond the mixture together, playing a role similar to that of an adhesive, thereby effectively reducing the amount of adhesive used. In addition, the interwoven connection characteristics of the mesh nodes and mesh wires can also effectively prevent cracking inside the mixture.

[0030] (7) An ion adsorption collection sheet is fixedly embedded in the middle of the mesh node. The mesh node and mesh wire are made of polyurethane. The ion adsorption collection sheet is made of synthetic resin. The ion adsorption collection sheet is used to absorb heavy metal ions in the mixture, effectively preventing the precipitation of harmful substances and causing secondary pollution to the mine. The mesh node and mesh wire are made of environmentally friendly polyurethane material in order not to pollute the mine. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a process flow chart of the present invention;

[0032] Figure 2 This is a schematic diagram of the first step of the mold installation step of the present invention;

[0033] Figure 3 This is a schematic diagram of the second step of the mold installation process of the present invention;

[0034] Figure 4 This is a schematic diagram of the third step of the mold installation process of the present invention;

[0035] Figure 5 This is a three-dimensional diagram of the shaping inner keel of the present invention;

[0036] Figure 6 It is a three-dimensional diagram of the inner-added column of the present invention;

[0037] Figure 7 It is a cross-sectional view of the inner-increased column of the present invention;

[0038] Figure 8 This is the main view of the internal network of the present invention;

[0039] Fig. 9 It is a partial structural diagram of the internal augmentation network of the present invention.

[0040] Description of the numbers in the figure:

[0041] 1 mold box, 2 anti-cracking net bag, 3 shaping internal keel, 4 anti-cracking mesh, 5 mold cover, 6 internal increase column, 601 bonding column, 602 pressure-resistant diversion column, 6021 hollow column, 6022 water-degradable membrane, 6023 adsorption filter pad, 7 internal increase net, 701 net node, 702 mesh wire, 703 ion adsorption collection sheet. DETAILED DESCRIPTION

[0042] The embodiments will be combined with the drawings in the specification to clearly and completely describe the technical solution of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without making any creative work shall fall within the scope of protection of the present invention. Example 1

[0043] A mining backfill preparation process based on tailings sand recovery and reuse, please refer to Figure 1 , including the following steps:

[0044] S1, firstly use magnetic separation to extract the useful components in the tailings sand, and then treat the solid waste left after the extraction;

[0045] S2, then crushing the solid waste, using a screening machine to separate the fine powder produced by the crushing from the impurities and the blocky waste rock, recycling the waste rock as aggregate for building materials, treating the impurities by chemical and physical methods to convert them into harmless substances, and collecting the powdery waste;

[0046] S3, putting the collected fine powder into a mixing mixer, and adding gelling material and water into the mixer for mixing and stirring, the ratio of gelling material to fine powder is 1:3-9, wherein the formula of gelling material is as follows, by weight:

[0047] Cement clinker 10%-30%, slag powder 10%-50%, steel slag powder 10%-50%, fly ash 5%-25%, dust ash 5%-15%, gypsum 5%-45%, desulfurization ash 5-35%;

[0048] S4, the stirred mixture is placed in a mold for pressing and shaping, and after the mixture is solidified, it is taken out and backfilled into the mining pit. Example 2

[0049] Based on Example 1, please refer to Figure 2 , 3 and Figure 4 The mold filling in step S4 includes the following steps:

[0050] S41, take a mold box 1 with an opening at the upper end, first lay an anti-cracking mesh 4 on the bottom of the mold box 1, and then lay an anti-cracking net bag 2 on the side walls of the mold box 1;

[0051] S42, then put the shaped inner reinforcement keel 3 into the mold box 1, so that the shaped inner reinforcement keel 3 is in the middle of the mold box 1, and then pour the mixed and stirred mixture into the mold box 1, and vibrate the mold box 1 during the pouring process to make the mixture compact without leaving any gaps;

[0052] S43, finally laying the anti-cracking mesh 4 again on the upper surface of the mixture, and then covering the mold cover 5 to compact the mixture into shape;

[0053] See also Figure 2 In step S41, the anti-cracking net bag 2 and the anti-cracking mesh sheet 4 are both made of degradable plastic material, and the anti-cracking net bag 2 is an integrated structure. The anti-cracking net bag 2 and the anti-cracking mesh sheet 4 are used to effectively improve the anti-cracking performance of the surface of the backfill material when it is just formed, and prevent the backfill material from being broken due to impact during transportation and backfilling. In order not to cause secondary pollution to the mine pit, the anti-cracking net bag 2 and the anti-cracking mesh sheet 4 are both made of degradable plastic material;

[0054] See also Figure 5 The shaping inner reinforcement keel 3 in step S42 includes a central inner reinforcement column 6 and four peripheral inner reinforcement columns 6, and the central inner reinforcement column 6 is located at the center of the other four peripheral inner reinforcement columns 6, and the central inner reinforcement column 6 and each peripheral inner reinforcement column 6 are fixedly connected with an inner reinforcement net 7, and the four peripheral inner reinforcement columns 6 are also connected with the inner reinforcement net 7. The multiple inner reinforcement columns 6 and the inner reinforcement net 7 are combined together as the skeleton of the backfill material, which adheres the raw materials together, effectively improves the strength of the backfill material, prevents it from cracking and breaking, and can also effectively reduce the amount of binder used, avoid adding too much chemical agents, thereby reducing the secondary pollution to the backfill pit as much as possible;

[0055] See also Figure 6 , 7The inner increase column 6 includes a bonding column 601, which is a three-dimensional hollow net structure, and a pressure-resistant guide column 602 is fixedly embedded in the middle of the bonding column 601. The bonding column 601 plays a role in connecting the inner increase net 7, and the pressure-resistant guide column 602 increases the pressure resistance of the backfill material, thereby effectively improving the strength of the backfill material. The pressure-resistant guide column 602 includes a hollow column 6021, and the upper and lower opening ends of the hollow column 6021 are fixedly connected with a water-degradable membrane 6022, and the inner wall of the hollow column 6021 is fixedly connected with a plurality of adsorption filter pads 6023 distributed at equal intervals above and below, and the adsorption filter pad 60 A plurality of drip holes are provided on 23, and the adsorption filter pad 6023 is made of synthetic resin. The hollow column 6021 improves the compression resistance of the backfill material and also serves as a channel for rainwater infiltration. The water-degradable membrane 6022 plays a blocking role in the process of molding to prevent the mixture from blocking the hollow column 6021. After backfilling, the water-degradable membrane 6022 can be degraded under the action of water, so that rainwater can infiltrate along the hollow column 6021. In addition, the adsorption filter pad 6023 can also adsorb and filter heavy metal ions carried in the rainwater, thereby effectively preventing harmful substances from infiltrating into the groundwater layer.

[0056] See also Figure 8 , 9 The inner increase net 7 includes a plurality of equally spaced net nodes 701, and a plurality of mesh wires 702 are fixedly connected between two adjacent net nodes 701. The net nodes 701 and the mesh wires 702 are interwoven and connected to each other to bond the mixture together, playing a role similar to that of an adhesive, thereby effectively reducing the amount of adhesive used. Moreover, the interwoven connection characteristics of the net nodes 701 and the mesh wires 702 can also effectively prevent the internal cracking of the mixture. An ion adsorption collection sheet 703 is fixedly embedded in the middle of the net node 701. The net node 701 and the mesh wire 702 are both made of polyurethane, and the ion adsorption collection sheet 703 is made of synthetic resin. The ion adsorption collection sheet 703 is used to absorb heavy metal ions in the mixture, effectively preventing the precipitation of harmful substances and causing secondary pollution to the mine. The net node 701 and the mesh wire 702 are both made of environmentally friendly polyurethane material in order not to pollute the mine.

[0057] The above description is only the best implementation mode adopted by the present invention in combination with current practical needs, but the protection scope of the present invention is not limited thereto.

Claims

1. A mining backfill preparation process based on tailings sand recovery and reuse, characterized in that: The following steps are involved: S1, firstly use magnetic separation to extract the useful components in the tailings sand, and then treat the solid waste left after the extraction; S2, then crushing the solid waste, using a screening machine to separate the fine powder produced by the crushing from the impurities and the blocky waste rock, recycling the waste rock as aggregate for building materials, treating the impurities by chemical and physical methods to convert them into harmless substances, and collecting the powdery waste; S3, putting the collected fine powder into a mixing mixer, and adding gelling material and water into the mixer for mixing and stirring, the ratio of gelling material to fine powder is 1:3-9, wherein the formula of gelling material is as follows, by weight: Cement clinker 10%-30%, slag powder 10%-50%, steel slag powder 10%-50%, fly ash 5%-25%, dust ash 5%-15%, gypsum 5%-45%, desulfurization ash 5-35%; S4, placing the stirred mixture into a mold for pressing and shaping, and after the mixture solidifies, taking it out and backfilling it into the mining pit; The mold installation in the S4 step includes the following steps: S41, taking a mold box (1) with an opening at the top, first laying an anti-cracking mesh (4) on the bottom of the mold box (1), and then laying an anti-cracking mesh bag (2) on the side walls of the mold box (1); S42, then placing the shaped internal reinforcement keel (3) into the mold box (1), so that the shaped internal reinforcement keel (3) is located in the middle of the mold box (1), and then pouring the mixed and stirred mixture into the mold box (1), and vibrating the mold box (1) during the pouring process to make the mixture compacted without leaving any gaps; S43, finally laying the anti-cracking mesh (4) again on the upper surface of the mixture, and then covering the mold cover (5) to compact the mixture into shape; The anti-cracking net bag (2) and the anti-cracking mesh sheet (4) in step S41 are both made of degradable plastic material, and the anti-cracking net bag (2) is an integrated structure; The shaping inner augmentation keel (3) in step S42 comprises a central inner augmentation column (6) and four peripheral inner augmentation columns (6), and the central inner augmentation column (6) is located at the center of the other four peripheral inner augmentation columns (6), and an inner augmentation net (7) is fixedly connected between the central inner augmentation column (6) and each peripheral inner augmentation column (6), and the four peripheral inner augmentation columns (6) are also connected with the inner augmentation net (7); The inner reinforcement column (6) comprises a bonding column (601), the bonding column (601) is a three-dimensional hollow mesh structure, and a pressure-resistant flow-guiding column (602) is fixedly embedded in the middle of the bonding column (601); The pressure-resistant guide column (602) comprises a hollow column (6021), the upper and lower opening ends of the hollow column (6021) are both fixedly connected to a water-degradable membrane (6022), and the inner wall of the hollow column (6021) is fixedly connected to a plurality of adsorption filter pads (6023) distributed at equal intervals in the upper and lower directions, the adsorption filter pad (6023) is provided with a plurality of drip holes, and the adsorption filter pad (6023) is made of synthetic resin; The inner increase net (7) comprises a plurality of net nodes (701) distributed at equal intervals, and a plurality of net wires (702) are fixedly connected between two adjacent net nodes (701); An ion adsorption collection sheet (703) is fixedly embedded in the middle of the mesh node (701); the mesh node (701) and the mesh wire (702) are both made of polyurethane, and the ion adsorption collection sheet (703) is made of synthetic resin.

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