Fine-grain tailing mold bag body capable of accelerating drainage and solidification and preparation method of fine-grain tailing mold bag body

Abstract

The invention discloses a fine-grain tailing mold bag body for accelerating drainage and solidification and a preparation method thereof, and relates to the technical field of tailing damming construction, the fine-grain tailing mold bag body comprises a mold bag, polypropylene fiber, polyacrylamide and fine-grain tailing slurry; the addition amount of the polypropylene fibers is 0.1-0.9% of the mass of the fine tailings, and the length of the polypropylene fibers is 3-12 mm; the adding amount of the polyacrylamide is 0.01%-0.1% of the mass of the fine tailings; the preparation method comprises the following steps: taking fine tailing slurry as a raw material; or the fine-grained tailings are used as raw materials, the fine-grained tailings and water are mixed and blended into fine-grained tailings slurry, and the mass concentration of the fine-grained tailings slurry is smaller than or equal to 70%; mixing the fine tailing pulp with polypropylene fibers; continuously adding polyacrylamide to form a mixture; and filling the mixture into a mold bag to obtain the product. The method has the beneficial effects that drainage consolidation and solidification of the fine grain tailing filling mold bag can be accelerated, the production cost is reduced, and the problems of pollution and the like caused by addition of inorganic compound materials are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of tailings dam construction, in particular to a fine-grained tailings mold bag body capable of accelerating drainage and solidification and a preparation method thereof. Background Art

[0002] With the development of my country's mineral resources and the continuous growth and rise of the mining and metallurgical industry, huge tailings have followed. A small part of these tailings, the coarse tailings, are comprehensively utilized, and the vast majority, especially the fine tailings, are discharged into tailings ponds for storage. The tailings recycling rate is less than 20%.

[0003] Tailings dam is a dam built to form a storage area for various ore tailings. At present, according to the direction of the axis of the dam top of the accumulation sub-dam, the construction methods of tailings dam can be divided into upstream tailings dam construction method, downstream tailings dam construction method and midline tailings dam construction method.

[0004] In my country, upstream damming is widely used due to its advantages of simple process, easy management, low initial investment and low operating cost. More than 85% of tailings ponds in my country adopt this method. However, this method often encounters difficulties in damming fine-grained tailings, such as poor drainage and stability of the dam body, and it is difficult to ensure the stability of the tailings dam. According to relevant data, the disease rate of high-mud and ultra-fine tailings dams in my country is relatively high. The upstream fine-grained tailings dam has become one of the difficulties encountered in tailings treatment technology. If it is not handled properly, it is easy to cause a dam breach. Once the dam breaches, it will have serious consequences for the safety of life and property of the people downstream and surrounding areas. Therefore, how to effectively solve the safe and efficient damming of fine-grained tailings is of great significance to ensuring the sustainable development of the national mining industry and the safe production of mining enterprises.

[0005] Tailings filling mold bag dam construction technology refers to a large area of ​​continuous bag-shaped materials made of upper and lower layers of high-strength geotextiles, and a filling body formed after tailings are pumped into the bag and consolidated. However, due to the long dehydration and consolidation time of fine-grained tailings filling mold bags, the construction cost increases. In current engineering practice, mold bag dam construction uses coarse-grained tailings with short dehydration and consolidation time for filling. Therefore, it is urgent to shorten the dehydration and consolidation time of fine-grained tailings filling mold bags, so as to improve the utilization rate of fine-grained tailings and reduce construction costs. Summary of the invention

[0006] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a fine-grained tailings mold bag body and a preparation method thereof that accelerates drainage and solidification. Specifically, a new method for accelerating the drainage and solidification of fine-grained tailings mold bags is provided, which can shorten the dehydration and consolidation time of the fine-grained tailings filling mold bags, thereby avoiding the problem of increased construction costs due to the long dehydration and consolidation time of the fine-grained tailings filling mold bags.

[0007] The technical solution of the present invention is as follows: The first aspect of the present invention provides a fine-grained tailings mold bag body for accelerating drainage and consolidation, comprising fine-grained tailings slurry, polypropylene fiber, and polyacrylamide; The fine tailings slurry is prepared from fine tailings and water, and the mass concentration of the fine tailings slurry is ≤70%; The amount of the polypropylene fiber added is 0.1% to 0.9% of the mass of the fine tailings added, and the length of the polypropylene fiber is 3 mm to 12 mm; The amount of polyacrylamide added is 0.01% to 0.1% of the mass of the fine tailings added.

[0008] As a preferred embodiment of the present invention, the amount of the polypropylene fiber added is 0.3% to 0.9% of the mass of the fine tailings added, and the length of the polypropylene fiber is 5 mm to 12 mm; The amount of polyacrylamide added is 0.015% to 0.09% of the mass of the fine tailings added.

[0009] As a preferred embodiment of the present invention, the amount of the polypropylene fiber added is 0.5% to 0.9% of the mass of the fine tailings added, and the length of the polypropylene fiber is 6 mm to 12 mm; The amount of polyacrylamide added is 0.02% to 0.08% of the mass of the fine tailings added.

[0010] As a preferred embodiment of the present invention, the amount of the polypropylene fiber added is 0.6% to 0.8% of the mass of the fine tailings added, and the length of the polypropylene fiber is 7 mm to 11 mm; The amount of polyacrylamide added is 0.025% to 0.07% of the mass of the fine tailings added.

[0011] As a preferred embodiment of the present invention, the amount of the polypropylene fiber added is 0.65% to 0.75% of the mass of the fine tailings added, and the length of the polypropylene fiber is 8 mm to 10 mm; The amount of polyacrylamide added is 0.04% to 0.06% of the mass of the fine tailings added.

[0012] As a preferred embodiment of the present invention, the added amount of the polypropylene fiber is 0.7% of the added mass of the fine tailings, and the length of the polypropylene fiber is 9 mm.

[0013] As a preferred embodiment of the present invention, the amount of polyacrylamide added is 0.05% of the mass of the fine tailings added.

[0014] As a preferred embodiment of the present invention, the molecular weight of the polyacrylamide is 7 to 9 million Daltons.

[0015] As a preferred embodiment of the present invention, the molecular weight of the polyacrylamide is 8 million Daltons.

[0016] The second aspect of the present invention provides a method for preparing the fine-grained tailings mold bag body that accelerates drainage and consolidation, and the preparation method comprises the following steps: Using fine tailings slurry as raw material; or using fine tailings as raw material, mixing fine tailings with water to prepare fine tailings slurry; the mass concentration of the fine tailings slurry is ≤70%; mixing the fine tailings slurry with polypropylene fibers; mixing the fine tailings slurry with polypropylene fibers; Continue to add polyacrylamide to form a mixture; The mixture is filled into a mold bag to obtain a fine-grained tailings mold bag body with accelerated drainage and consolidation.

[0017] The present invention has at least one of the following beneficial effects: The present invention prepares a tailings mold bag body by adding a certain content of polyacrylamide and a certain content and length of polypropylene fiber to the fine-grained tailings. Through the joint action of polyacrylamide and polypropylene fiber, on the one hand, the drainage, consolidation and solidification of the fine-grained tailings filling mold bag can be accelerated, thereby solving the problem of increased construction costs due to the long dehydration and consolidation time of the fine-grained tailings filling mold bag, and improving the utilization rate of the fine-grained tailings; on the other hand, it avoids the addition of inorganic chemical materials such as cement and lime to produce a large amount of harmful gases such as carbon dioxide and sulfur dioxide, and also consumes a large amount of non-renewable resources such as coal. The waste residue after calcination will also cause secondary pollution, effectively avoiding environmental safety risks. At the same time, if cement is used as a curing agent for filling the mold bag with fine-grained tailings, the dosage is too large, the price of the curing agent is high, which is not conducive to reducing costs; even if low-dosage cement is used, due to the large amount of mold bag dam engineering, the cement consumption, and the cost are high. Therefore, the new flocculation-fiber curing method developed by the present invention can greatly reduce production costs and reduce environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram of an experimental instrument for testing drainage performance in Examples 1 and 2 of the present invention; Figure 2 This is a diagram of the polypropylene fiber used in Example 2 of the present invention; Figure 3 This is a comparison chart of drainage performance under different amounts of polyacrylamide added in Example 1 of the present invention; Figure 4This is a comparison chart of the drainage performance of 3 mm polypropylene fiber at different addition amounts in Example 2 of the present invention; Figure 5 This is a comparison chart of the drainage performance of 6 mm polypropylene fiber at different addition amounts in Example 2 of the present invention; Figure 6 This is a comparison chart of the drainage performance of 9 mm polypropylene fiber at different addition amounts in Example 2 of the present invention; Figure 7 This is a comparison chart of the drainage performance of 12 mm polypropylene fiber at different addition amounts in Example 2 of the present invention; Figure 8 This is a comparison chart of the drainage performance of polypropylene fibers of different lengths at an addition amount of 0.7% in Example 2 of the present invention. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] One embodiment of the present invention provides a fine-grained tailings mold bag body for accelerating drainage and consolidation, comprising a mold bag, fine-grained tailings slurry, polypropylene fiber, and polyacrylamide; The fine tailings slurry is prepared from fine tailings and water, and the mass concentration of the fine tailings slurry is ≤70%; The amount of the polypropylene fiber added is 0.1% to 0.9% of the mass of the fine tailings added, and the length of the polypropylene fiber is 3 mm to 12 mm; The amount of polyacrylamide added is 0.01% to 0.1% of the mass of the fine tailings added.

[0021] Another embodiment of the present invention provides a method for preparing a fine-grained tailings mold bag body that accelerates drainage and consolidation, the preparation method comprising the following steps: Using fine tailings slurry as raw material; or using fine tailings as raw material, mixing fine tailings with water to prepare fine tailings slurry; the mass concentration of the fine tailings slurry is ≤70%; mixing the fine tailings slurry with polypropylene fibers; Continue to add polyacrylamide to form a mixture; The mixture is filled into a mold bag to obtain a fine-grained tailings mold bag body with accelerated drainage and consolidation.

[0022] Due to the lack of large-scale stirring tools when testing in the laboratory, Examples 1-2 first mix the fine-grained tailings with polypropylene fibers; continue to add polyacrylamide to form a mixture, and finally add water to adjust the fine-grained tailings slurry to a mass concentration of ≤70%; fill the mixture into the mold bag to obtain a fine-grained tailings mold bag body that accelerates drainage and consolidation. In actual production, the fine-grained tailings can be first added with water to be adjusted to a fine-grained tailings slurry with a mass concentration of ≤70% (specifically, it can be 60%, 50%, 40%, 30%, 20%, etc.), and then mixed with polypropylene fibers; continue to add polyacrylamide to form a mixture; fill the mixture into the mold bag to obtain a fine-grained tailings mold bag body that accelerates drainage and consolidation. Those skilled in the art can select the above method to prepare a fine-grained tailings mold bag body according to actual conditions.

[0023] The new method of the invention can accelerate the consolidation and solidification of the mold bag filled with fine tailings and reduce the engineering cost.

[0024] In one embodiment, polyacrylamide with a molecular weight of 8 million Daltons was added in amounts of 0%, 0.025%, 0.05%, 0.075%, 0.1%, 0.125% and 0.15%. It was found that the flocculation system formed by adding 0.05% polyacrylamide exhibited the best performance, and the total drainage volume increased by 11.8% compared with the control group of 0% polyacrylamide. Too high an addition will increase the viscosity of the slurry, thereby hindering the drainage process; while too low an addition will make it difficult to construct an effective flocculation system, resulting in poor drainage performance.

[0025] In one embodiment, polypropylene fibers are added in amounts of 0.1%, 0.3%, 0.5%, 0.7%, and 0.9%. Studies have shown that, among fibers of different fiber lengths, polypropylene fibers added in an amount of 0.7% exhibit the best drainage effect.

[0026] When the fiber addition amount is too low, the fiber distribution in the slurry is uneven, making it difficult to fully form the required flocculation structure, making it difficult to achieve effective connection between particles, restricting the formation of drainage channels, and ultimately causing a decrease in drainage performance. On the contrary, when the fiber addition amount is at a higher level, the viscosity of the slurry will increase accordingly, causing the fibers to entangle with each other to form dense agglomerates. These agglomerates constitute high resistance areas, hindering the water flow from smoothly penetrating the filter cake layer, thereby reducing the overall drainage efficiency. In addition, when the fiber addition amount is too high, a tightly stacked structure is easily formed, which will further compress the effective drainage path, resulting in a slower rate of water release.

[0027] It was further discovered that, in one embodiment, after clarifying that 0.7% addition amount of polypropylene fiber was the optimal addition amount, the role of fiber length in optimizing the flocculation structure and improving the drainage efficiency was further revealed. By comparing the drainage effects of fibers of different lengths at an addition amount of 0.7%, experiments were conducted using fibers of four grades, namely, 3 mm, 6 mm, 9 mm, and 12 mm in length.

[0028] The test showed that in all the experimental links, 0.7% of the 9 mm long polypropylene fiber showed the best drainage performance, and its drainage was significantly higher than that of other length fibers. Compared with the fine tailings slurry without fiber addition, the fiber increased the total drainage by 36.2%. This result shows that the 9 mm long fiber performed best in optimizing the flocculation structure and strengthening the aggregation force between particles, thereby promoting the acceleration of water discharge.

[0029] In contrast, 3mm and 12mm fibers performed poorly. 3mm fibers were too short to fully capture and bind fine particles, resulting in a weak flocculation effect. The filter cake lacked diverse drainage channels, making it difficult for water to be quickly discharged. 12mm fibers were too long and easily tangled in the slurry, obstructing water flow and resulting in poor drainage. Too long fibers may also cause the internal structure of the filter cake to be too dense, further increasing water flow resistance and slowing down drainage.

[0030] The drainage performance of 6mm fiber is between 3mm and 9mm, which means that the fiber length of 6mm has a certain drainage effect, but has not yet reached the optimal state.

[0031] The present invention is further described in detail below with specific examples, but the present invention is not limited to the following specific examples.

[0032] Example 1 In order to determine the amount of polyacrylamide to be added, the following method was performed: A certain amount of fine tailings was weighed, and polyacrylamide with a molecular weight of 8 million Daltons was added to the fine tailings in amounts of 0%, 0.025%, 0.05%, 0.075%, 0.1%, 0.125% and 0.15% of the mass of the fine tailings, respectively, and water was added to adjust the tailings slurry to a mass concentration of 60% to obtain a mixture.

[0033] The mixture was then transferred to a cylindrical consolidation container ( Figure 1 In the experiment, the drainage and consolidation of the slurry was achieved through the geotextile. The dewatering amount at different times was recorded. Since most of the free water had been discharged in the first 5 hours, only the drainage in the first 5 hours was recorded.

[0034] Figure 3The results of Example 1 are shown. When the amount of polyacrylamide added is 0.025%~0.1%, the total drainage of the original tailings slurry is increased compared with that without polyacrylamide. Among them, when the amount of polyacrylamide added is 0.025%, 0.05%, and 0.075%, respectively, the total drainage of the original tailings slurry is significantly increased compared with that without polyacrylamide. In particular, when the amount of polyacrylamide added is 0.05%, the total drainage of the original tailings slurry is increased by 11.8% compared with that without polyacrylamide.

[0035] Example 2 On the basis of adding 0.05% of the optimal polyacrylamide content of fine tailings in Example 1, polypropylene fibers of 3 mm, 6 mm, 9 mm, and 12 mm in length were further added in amounts of 0.1%, 0.3%, 0.5%, 0.7%, and 0.9% of the mass of the fine tailings, respectively. Figure 2 The actual picture of the added polypropylene fiber is shown. Continue to add water to adjust the tailings slurry to 60% mass concentration. After mixing evenly, immediately transfer the slurry to Figure 1 The drainage device shown was used to carry out a 5-hour drainage experiment and record the drainage volume at each time point.

[0036] Figure 4-7 The drainage effects of various amounts of polypropylene fibers added when the fiber lengths in Example 2 are 3 mm, 6 mm, 9 mm, and 12 mm are shown respectively. By comparison, it is found that the polypropylene fibers added at an amount of 0.7% exhibit the best drainage effect. When the addition amount is 0.7%, the combined effect of fiber length and flocculant has a significant effect on drainage performance.

[0037] Figure 8 The results show that in Example 2, after continuing to use 0.7% as the optimal addition amount, in order to further evaluate the effect of fiber length on drainage performance, the drainage effects of fibers of different lengths at 0.7% addition amount were compared to further reveal the role of fiber length in optimizing flocculation structure and improving drainage efficiency. Figure 8 It can be seen that the 9 mm long polypropylene fiber with an addition amount of 0.7% showed the best drainage effect during the entire experiment. Compared with the fine tailings slurry without added fibers, its total drainage volume increased by 36.2%.

[0038] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A fine-grained tailings mold bag body for accelerating drainage and consolidation, characterized in that: Including mold bags, fine tailings slurry, polypropylene fiber, polyacrylamide; The fine tailings slurry is prepared from fine tailings and water, and the mass concentration of the fine tailings slurry is ≤70%; The amount of the polypropylene fiber added is 0.1% to 0.9% of the mass of the fine tailings added, and the length of the polypropylene fiber is 3 mm to 12 mm; The amount of polyacrylamide added is 0.01% to 0.1% of the mass of the fine tailings added.

2. The fine-grained tailings mold bag body for accelerating drainage and consolidation according to claim 1 is characterized in that: The amount of the polypropylene fiber added is 0.3% to 0.9% of the mass of the fine tailings added, and the length of the polypropylene fiber is 5 mm to 12 mm; The amount of polyacrylamide added is 0.015% to 0.09% of the mass of the fine tailings added.

3. The fine-grained tailings mold bag body for accelerating drainage and consolidation according to claim 1 is characterized in that: The amount of the polypropylene fiber added is 0.5% to 0.9% of the mass of the fine tailings added, and the length of the polypropylene fiber is 6 mm to 12 mm; The amount of polyacrylamide added is 0.02% to 0.08% of the mass of the fine tailings added.

4. The fine-grained tailings mold bag body for accelerating drainage and consolidation according to claim 1 is characterized in that: The amount of the polypropylene fiber added is 0.6% to 0.8% of the mass of the fine tailings added, and the length of the polypropylene fiber is 7 mm to 11 mm; The amount of polyacrylamide added is 0.025% to 0.07% of the mass of the fine tailings added.

5. The fine-grained tailings mold bag body for accelerating drainage and consolidation according to claim 1 is characterized in that: The amount of the polypropylene fiber added is 0.65% to 0.75% of the mass of the fine tailings added, and the length of the polypropylene fiber is 8 mm to 10 mm; The amount of polyacrylamide added is 0.04% to 0.06% of the mass of the fine tailings added.

6. The fine-grained tailings mold bag body for accelerating drainage and consolidation according to claim 1 is characterized in that: The amount of the polypropylene fiber added is 0.7% of the mass of the fine tailings added, and the length of the polypropylene fiber is 9 mm.

7. The fine-grained tailings mold bag body for accelerating drainage and consolidation according to claim 1 is characterized in that: The amount of polyacrylamide added is 0.05% of the mass of the fine tailings added.

8. The fine-grained tailings mold bag body for accelerating drainage and consolidation according to claim 1 is characterized in that: The molecular weight of the polyacrylamide is 7 to 9 million Daltons.

9. The fine-grained tailings mold bag body for accelerating drainage and consolidation according to claim 1 is characterized in that: The molecular weight of the polyacrylamide is 8 million Daltons.

10. A method for preparing a fine-grained tailings mold bag body for accelerating drainage and consolidation as claimed in any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: Using fine tailings slurry as raw material; or using fine tailings as raw material, mixing fine tailings with water to prepare fine tailings slurry; the mass concentration of the fine tailings slurry is ≤70%; mixing the fine tailings slurry with polypropylene fibers; Continue to add polyacrylamide and mix to form a mixture; The mixture is filled into a mold bag to obtain a fine-grained tailings mold bag body with accelerated drainage and consolidation.

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