Dust suppression method based on fiber composite cover system for tailings impoundment

Abstract

The present invention relates to the technical field of dust suppression, and specifically relates to a dust suppression method based on a fiber composite cover system for a tailings impoundment, which method aims to solve the problem that a check block may crack during the practical use of a liquid dust suppressant and thus affects the practical use effect of the liquid dust suppressant. The method comprises the following steps: step 1, determining the amount of dust raised by a certain area of tailings in a wind tunnel at a certain wind speed within a certain period of time. By means of the optimization and integration of fibrous medium materials that are widely used at present, an optimal dust suppression effect can be achieved by means of a 5% polyvinyl alcohol with a high polymerization degree, 25 g / L of wood fibers and a dust suppressant with a concentration of 0.5%; and by means of a mixed solution of a 2% polyvinyl alcohol with a high polymerization degree, 25 g / L of wood fibers and a binder with a concentration of 0.5%, the cost of dust suppression can be reduced while a dust suppression effect can be kept at 98%. In the present invention, by using the wood fibers as a filler, the anti-cracking effect of the dust suppressant block is enhanced, the cracking of a check block during the use of the liquid dust suppressant is avoided, most tailings are inhibited from raising dust, and good wind erosion resistance, water erosion resistance and freeze thawing resistance are provided.

Description

A dust suppression method based on tailings pond fiber composite covering system Technical Field

[0001] The present invention relates to the technical field of dust suppression, and in particular to a dust suppression method based on a tailings pond fiber composite covering system. Background Art

[0002] At present, the patents related to dust suppression in tailings ponds are mainly concentrated in dust suppression devices and dust suppression materials, and are mainly wet dust suppression devices, and dust suppression materials are mainly polymer dust suppression materials.

[0003] As in the prior art:

[0004] ① A tailings pond dust suppression liquid and dust suppression construction method (Publication No.: 109621592A). This invention relates to the field of mine tailings pond management technology, and more particularly to a tailings pond dust suppression liquid. The liquid comprises tailings liquid, sand, and biomass fiber material, with the weight ratio of the tailings liquid, sand, and biomass fiber material being 100:(3-10):(1-10).

[0005] ② A polymer material for fixing sand, soil and dust (publication number: 103772534B) The present invention discloses a polymer material for fixing sand, soil and dust. The polymer material is obtained by the following steps: adding 30 to 50 parts of polyvinyl alcohol to every 1000 parts of water by weight.

[0006] ③ A rainproof and crack-proof dust suppressant (Publication No.: 109321207A). Currently, most dust suppressants are sprayed to wet or adhere dust on the surface of the dust source to achieve dust suppression, resulting in poor overall performance. The present invention provides a rainproof and crack-proof dust suppressant, belonging to the technical field of dust suppressants. The dust suppressant is composed of the following raw materials in parts by weight: 2-10 parts of fully alcoholyzed high-polymerization polyvinyl alcohol, 0.01-1 part of a gelling agent, 10-30 parts of an inorganic filler, 1-6 parts of plant fiber, 0.1-1 part of a foaming agent, 1-5 parts of a pigment, and 40-80 parts of water.

[0007] The main components of existing polymer dust suppressants fall into three categories: film-forming agents, fillers, and surfactants. Film-forming agents are polymer materials, typically organic cross-linked polymers. Their polar groups can adsorb a variety of substances, forming hydrogen bonds. The adsorbed particles form bridges, allowing a single polymer to adsorb multiple particles. The degree of cross-linking between polymer molecules creates a network structure. Adding a landfill dust suppressant to water increases the surface area of ​​the mist, improving the chances of capturing fine dust particles and allowing them to quickly adhere to larger particles. This creates a semi-permanent, rain- and water-resistant polymer shell on the surface of landfill soil, acting like a protective film to reduce wind erosion and prevent atmospheric oxidation. Therefore, the main types of film-forming agents include highly absorbent polyacrylamide (PAM) and high-polymerization polyvinyl alcohol.

[0008] Filler: Filler is generally composed of starch-based substances, which play the role of increasing the viscosity of the film-forming agent solution and filling and consolidating in the dust suppressant.

[0009] Surfactant: Since both the film-forming agent and filler contained in the dust suppressant solution have a certain degree of viscosity, the formed solution is very viscous. At the same time, since the particle size of the tailings sample is very small, the tailings are easily rolled up by the dust suppressant droplets when the dust suppressant solution is sprayed on its surface, thereby affecting the film formation and crusting on the tailings surface. The addition of surfactants can enhance the penetration of the tailings surface, thereby reducing the surface tension of the dust suppressant solution.

[0010] Optimizing and integrating widely used fiber media materials revealed the curing time, polymer strength, and polymer dosage of different polymers combined with tailings. Liquid dust suppressants can cause test blocks to crack in actual applications, impacting their effectiveness. Therefore, this solution incorporates wood fiber as a filler to enhance the dust suppressant's crack-resistance.

[0011] Summary of the Invention

[0012] The purpose of the present invention is to provide a dust suppression method based on a tailings pond fiber composite covering system to solve the problem proposed in the above background technology that the use of liquid dust suppressants in actual applications may cause test block breakage, affecting the actual application effect.

[0013] To achieve the above object, the present invention provides the following technical solution: a dust suppression method based on a tailings pond fiber composite covering system, comprising the following steps:

[0014] Step 1: Measure the dust generation of a certain area of ​​tailings at a certain wind speed and time in a wind tunnel;

[0015] Step 2: Take a certain amount of tailings and put it into a petri dish. Spray the pre-prepared dust suppressants of different concentrations and types evenly on the surface of the tailings. Set up a group of blank controls.

[0016] Step 3: Naturally cure the tailings until the sample is completely dry;

[0017] Step 4: Conduct wind tests at different wind speeds in the wind tunnel;

[0018] Step 5: Calculate the dust suppression rate of the sample based on the relationship between the blowing wind speed and the loss amount, and select the optimal dust suppressant ratio and concentration. Carry out metering and weighing according to the ratio of the optimal solidified dust suppressant. Then stir and mix the selected materials, spray the mixed materials on the tailings, and then maintain the tailings.

[0019] Step 6: After one week, immerse the naturally cured specimens in a water tank at 20°C. After soaking for 4 hours, take out the specimens and place them in a refrigerator that has been pre-cooled to -15 to -18°C.

[0020] Step 7: When the refrigerator temperature drops to -15-18°C again, start timing, keep the temperature constant for 4 hours, take it out and put it into a 20°C water tank to thaw for 4 hours, which counts as one cycle. After 8 freeze-thaw cycles, observe whether there is any delamination, cracking, or other freeze-damage.

[0021] Step 8: One week later, soak the naturally cured test blocks in water for 5 days and observe whether the test blocks are deformed.

[0022] Preferably, the formula for the amount of dust generated in the first step is:

[0023] Where: q: dust generation per unit area per unit time; M0: initial mass of tailings; M1: final mass of tailings; T: dust generation time of wind tunnel tailings; S: surface area of ​​tailings.

[0024] Preferably, the wind speed in the first step is set to 10 wind speed levels of 2m / s, 3m / s, 4m / s, 4.5m / s, 5m / s, 5.5m / s, 6m / s, 7m / s, 8m / s, and 9m / s.

[0025] Preferably, the dust suppression rate formula of the sample in the fifth step is:

[0026] Where: w1 is the mass of the original tailings, w2 is the mass of the remaining tailings.

[0027] Preferably, the concentration of the dust suppressant in the second step is preferably a mixed solution of 5% high-polymerization degree polyvinyl alcohol + 25g / L wood fiber + 0.5% dust suppressant with the best dust suppression rate and 2% high-polymerization degree polyvinyl alcohol + 25g / L wood fiber + 0.5% adhesive with an economical concentration.

[0028] Preferably, the natural curing time in the third step is at least 7 days, and after the natural curing, the test block is immersed in water.

[0029] Preferably, the types and materials of the dust suppressant in the fifth step are high-polymerization degree polyvinyl alcohol, wood fiber and adhesive.

[0030] Preferably, the excess wastewater generated by spraying in the fifth step can be collected and used for stirring and mixing the prepared solidified dust suppression agent.

[0031] Compared with the prior art, the beneficial effects of the present invention are: the dust suppression method based on the tailings pond fiber composite covering system optimizes and integrates the currently widely used fiber medium materials, and through outdoor experiments, observes and studies the curing time, the strength of the formed polymer and the amount of polymer in the process of combining different polymers with tailings, and the best dust suppression effect can be achieved by using 5% high-polymerization degree polyvinyl alcohol + 25g / L wood fiber + 0.5% concentration of dust suppressant. The dust suppression cost can be reduced while maintaining 98% of the dust suppression effect by using a mixed solution of 2% high-polymerization degree polyvinyl alcohol + 25g / L wood fiber + 0.5% adhesive. The present invention uses wood fiber as a filler to enhance the anti-cracking effect of the dust suppressant block, thereby avoiding the breakage of the test block when the liquid dust suppressant is used. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Fig. 1 is a flow chart of the present invention;

[0033] FIG2 is a graph showing the tailings loss test under different conditions of the present invention;

[0034] FIG3 is a schematic diagram of the process flow of the solidification dust suppression process of the present invention. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] Example 1: Referring to Figures 1-3, the present invention provides a technical solution: a dust suppression method based on a tailings pond fiber composite covering system, comprising:

[0037] Step 1: Measure the dust generation of a certain area of ​​tailings at a certain wind speed and time in a wind tunnel; the dust generation calculation formula is:

[0038] Where: q: dust generation per unit area per unit time; M0: initial mass of tailings; M1: final mass of tailings; T: dust generation time of wind tunnel tailings; S: surface area of ​​tailings.

[0039] Step 2: Take a certain amount of tailings and put it into a petri dish. Spray the pre-prepared dust suppressants of different concentrations and types evenly on the surface of the tailings. Set up a group of blank controls.

[0040] Step 3: The tailings are naturally cured for at least 7 days until the sample is completely dry. After the sample is completely dry, the test piece is immersed in water.

[0041] Step 4: Conduct wind tests at different wind speeds in the wind tunnel;

[0042] Dust suppression rate of original sample:

[0043] Where: w1 is the mass of the original tailings, w2 is the mass of the remaining tailings, the wind speed of the blowing test is 2 minutes, and the optimal ratio concentration is selected based on the relationship between the blowing wind speed and the loss amount of the sample.

[0044] Step 5: Select the optimal dust suppressant ratio and concentration based on the relationship between the blowing wind speed and the loss amount of the sample, weigh the optimal solidified dust suppressant ratio, stir and mix the selected materials, spray the mixed materials on the tailings, and then maintain the tailings.

[0045] The in-situ solidifying dust suppressant is prepared with the optimal dust suppressant ratio, and the weight of the in-situ solidifying dust suppressant is measured, and then the in-situ solidifying dust suppressant is stirred. After stirring, the in-situ solidifying dust suppressant is sprayed on the tailings, and then the tailings are cured. At the same time, the wastewater generated by the spraying can be collected and used to stir the in-situ solidifying dust suppressant.

[0046] Step 6: After one week, immerse the naturally cured specimens in a water tank at 20°C. After soaking for 4 hours, take out the specimens and place them in a refrigerator that has been pre-cooled to -15 to -18°C.

[0047] Step 7: When the refrigerator temperature drops to -15-18°C again, start timing, keep the temperature constant for 4 hours, take it out and put it into a 20°C water tank to thaw for 4 hours, which counts as one cycle. After 8 freeze-thaw cycles, observe whether there is any delamination, cracking, or other freeze-damage.

[0048] Step 8: One week later, soak the naturally cured test blocks in water for 5 days and observe whether the test blocks are deformed.

[0049] Example 2: The tailings samples with a particle size of 10 to 300 μm are classified as fine-grained concentrated type, and the coarse particles with a particle size of more than 300 μm are classified as coarse-grained concentrated type;

[0050] Wind erosion resistance test: A certain amount of tailings is placed in a petri dish. Pre-prepared dust suppressants of different concentrations and types are evenly sprayed on the tailings surface, and a blank control is set up. After spraying, the samples are naturally cured at room temperature for one week until they are completely dry. After one week, the naturally cured samples are weighed and placed in a wind tunnel. Blowing tests are performed in the wind tunnel at different wind speeds. The mass of the original tailings is w1. Blowing is performed at each wind speed for 2 minutes. The mass of the remaining tailings is w2. Afterwards, it is weighed and recorded. w1 / w2 is the dust suppression efficiency. The optimal ratio concentration is selected based on the relationship between the blowing wind speed and the loss amount of the sample.

[0051] Freeze-Resistance Test—Low-Temperature Test: A certain amount of tailings is placed in a Petri dish. A pre-prepared mixture of 2% high-polymerization polyvinyl alcohol, 25g / L wood fiber, and 0.5% adhesive dust suppressant is evenly sprayed onto the tailings surface. A blank control is also provided. After spraying, the specimens are naturally cured at room temperature for one week until they are completely dry. After one week, the naturally cured specimens are immersed in a water tank at 20°C. After soaking for 4 hours, the specimens are removed and placed in a refrigerator pre-cooled to -15°C to -18°C. When the refrigerator temperature drops back to -15°C to -18°C, a timer is started. The specimens are kept at a constant temperature for 4 hours, then removed and thawed in a water tank at 20°C for 4 hours, forming one cycle. After eight freeze-thaw cycles, the specimens are observed for signs of delamination, cracking, or other signs of freeze-thaw damage.

[0052] After 8 freeze-thaw tests (the lowest temperature was -15°C), the appearance of the samples sprayed with the crusting agent had no obvious damage, but a layer of tailings about 0.9 mm thick would peel off the surface. The new surface after peeling still had a crusting effect, which could suppress the dusting of most tailings.

[0053] Water immersion test results: A certain amount of tailings was placed in a Petri dish. A pre-mixed mixture of 2% high-polymerization polyvinyl alcohol, 25g / L wood fiber, and 0.5% adhesive encrusting agent was evenly sprayed on the tailings surface. A blank control was set up. After spraying, the samples were naturally cured at room temperature for one week until they were completely dry. After one week, the naturally cured test pieces were immersed in water for 5 days and observed for deformation.

[0054] When samples sprayed with crusting agents of various proportions are placed in a water tank, small bubbles will overflow. The places where the small bubbles overflow will destroy the crust surface. The main reason is that the gaps between the dry tailings are filled with water, causing the air to move upward. After soaking in the water tank for one week, a small amount of tailings will fall off the surface, but the new surface still has a crusting effect.

[0055] In summary, the optimal dust suppression solution, 5% high-polymerization degree polyvinyl alcohol + 25g / L wood fiber + 0.5% binder, minimizes tailings loss in strong winds and exhibits significant dust suppression effectiveness. Each mix also exhibits strong frost and water resistance, preventing water from accumulating on the tailings surface. The most economical solution, a mixture of 2% high-polymerization degree polyvinyl alcohol + 25g / L wood fiber + 0.5% binder, is the most reasonable option, achieving a tailings dust suppression rate of at least 98%.

[0056] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A dust suppression method based on a fiber composite covering system for a tailings pond, characterized in that, it includes the following steps: The first step: Measure the dust generation amount of a certain area of tailings in a wind tunnel at a certain wind speed for a certain period of time; The second step: Put a certain amount of tailings into a culture dish, evenly spray the pre-prepared dust suppressants with different concentrations and types on the surface of the tailings, and set a group of blank controls; The third step: Naturally cure the experimental tailings until the sample is completely dry; The fourth step: Conduct a blowing test on the wind tunnel at different wind speeds; The fifth step: Based on the relationship between the blowing wind speed and the loss amount of the sample, calculate the dust suppression rate of the sample and select the optimal concentration ratio of the dust suppressant. Weigh the selected materials according to the ratio of the optimal solidified dust suppressant, then stir and mix the selected materials, spray the mixed materials on the tailings, and then cure the tailings; The sixth step: After one week, immerse the naturally cured test block, take out the test block after immersion, and put it into a pre-cooled refrigerator; The seventh step: When the refrigerator temperature drops to -15 - 18 °C again, start timing, keep the temperature constant for 4 hours, take out and put it into a water tank to thaw for 4 hours as a cycle. After multiple cycles of freeze-thaw, observe whether there are freezing damage phenomena such as delamination, cracking, etc.; The eighth step: After one week, soak the naturally cured test blocks in water for 5 days and observe whether the test blocks deform.

2. The dust suppression method based on a fiber composite covering system for a tailings pond according to claim 1, characterized in that, The formula for the dust generation amount in the first step is as follows: In the formula: q: Dust generation amount per unit area per unit time; M0: Initial mass of tailings; M1: Final mass of tailings; T: Dust generation time of tailings in the wind tunnel; S: Surface area of tailings.

3. The dust suppression method based on a fiber composite covering system for a tailings pond according to claim 1, characterized in that, In the first step, the wind speed is set at 10 wind speed levels: 2 m / s, 3 m / s, 4 m / s, 4.5 m / s, 5 m / s, 5.5 m / s, 6 m / s, 7 m / s, 8 m / s, 9 m / s.

4. The dust suppression method based on a fiber composite covering system for a tailings pond according to claim 1, characterized in that, In the fifth step, the formula for the sample dust suppression rate is as follows: In the formula: w1 is the mass of the original tailings, and w2 is the mass of the remaining tailings.

5. The dust suppression method based on a fiber composite covering system for a tailings pond according to claim 1, characterized in that, In the second step, the concentration of the dust suppressant is preferably a 5% high degree of polymerization polyvinyl alcohol + 25 g / L wood fiber + 0.5% concentration of the dust suppressant and an economic concentration of 2% high degree of polymerization polyvinyl alcohol + 25 g / L wood fiber + 0.5% binder mixed solution.

6. The dust suppression method based on a fiber composite covering system for a tailings pond according to claim 1, characterized in that, In the third step, the natural curing time is at least 7 days, and after natural curing, the test block is put into water for soaking.

7. The dust suppression method based on a fiber composite covering system for a tailings pond according to claim 1, characterized in that, In the fifth step, the types and materials of the dust suppressant are high degree of polymerization polyvinyl alcohol, wood fiber and binder.

8. A dust suppression method based on a fiber composite covering system for a tailings pond according to claim 1, characterized in that, the excess wastewater generated by spraying in the fifth step can be collected and used for stirring and mixing the prepared solidified dust suppression agent.

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