Multi-solid synergistic low-permeability barrier anti-seepage material

Abstract

The invention discloses a multi-solid synergistic low-permeability barrier anti-seepage material which comprises river channel sand washing mud, fine tailing sand, bentonite, cationic guar gum and a polyacrylamide copolymer. The raw materials comprise, by mass, 50%-70% of river channel sand washing mud, 22%-35% of fine tailing sand, 6%-15% of bentonite, and 0.3%-0.5% of a cationic guar gum and polyacrylamide copolymer. The multi-solid synergistic low-permeability barrier anti-seepage material has remarkable advantages in the aspects of environmental protection, performance, application and the like, can effectively solve the problems of an existing landfill anti-seepage material, and has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste anti-seepage, and in particular to a multi-solid synergistic low-permeability barrier anti-seepage material. Background Art

[0002] In the field of landfill anti-seepage, relevant standards in my country, such as GB16889 "Pollution Control Standard for Municipal Solid Waste Landfill", GB18598 "Pollution Control Standard for Hazardous Waste Landfill", GB18599 "Pollution Control Standard for Storage and Landfill of General Industrial Solid Waste", etc., all propose to use an anti-seepage coefficient of 1×10⁻ for landfill bottom anti-seepage. 7 cm / s high-quality clay. However, there is a serious shortage of high-quality clay in my country. In the process of landfill construction, the client is often forced to use unqualified clay or bentonite blanket as a substitute because of the lack of suitable high-quality clay.

[0003] The bentonite blanket has problems such as thin thickness, easy to be punctured or lifted up, resulting in uneven distribution of bentonite and failure, and it is very easy to be affected by water flow and have anti-seepage defects. Researchers have tried to add bentonite to unqualified soil for modification to make modified clay, but there are problems such as high cost, uneven mixing, and unstable long-term performance of bentonite, which makes it difficult to use and promote on a large scale. At the same time, the bentonite in the modified clay is unevenly mixed in the clay, which is prone to weak points or characteristic permeation channels. Under the action of high head, the original fine-grained soil particle structure is unstable, and pipe bursts are prone to cause the anti-seepage structure to fail. In addition, bentonite is also easily affected by the salt in the leachate. Under high salt conditions, especially under the influence of calcium ions, its expansion performance will be severely attenuated, and it is easy to become hardened and fail. The long-term performance of the product is difficult to guarantee, posing a hidden danger to environmental safety. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a multi-solid synergistic low-permeability barrier and anti-seepage material.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A multi-solid synergistic low-permeability barrier and anti-seepage material, comprising river sand washing mud, fine-grained tailings sand, bentonite, cationic guar gum and polyacrylamide copolymer; The mass proportions of the raw materials are: 50%-70% of river sand washing mud, 22%-35% of fine-grained tailings sand, 6%-15% of bentonite, and 3-5‰ of cationic guar gum and polyacrylamide copolymer.

[0006] Furthermore, the river sand washing mud is the waste after the Yangtze River sand passes through a 0.075mm sieve. It has a large clay content, with particles below 0.063mm accounting for 60%-77%, D50 not greater than 0.03mm, and a permeability coefficient not higher than 3×10⁻ 5cm / s.

[0007] Furthermore, the electrical conductivity of the fine-grained tailings sand is not higher than 800 μS / cm, the calcium ion content in the tailings is lower than 0.02%, the pH is not lower than 5.5, and the D50 is between 0.075-0.4 mm.

[0008] Furthermore, the bentonite has a blue absorption of not less than 23 g / 100 g, a swelling index of not less than 16 ml / 2 g, a montmorillonite content of not less than 66%, a 0.075 mm sieving rate of not less than 95%, and a plastic viscosity after dispersion of more than 14 mPa·S.

[0009] Furthermore, in the cationic guar gum and polyacrylamide copolymer, the proportion of guar gum in the whole is no more than 1 / 3.

[0010] Beneficial Effects 1. Environmental protection and cost advantages: With river sand washing mud and tailings sand as the main materials, the comprehensive utilization of solid waste is realized, the storage problem of the two types of solid waste is solved, and the material cost is greatly reduced.

[0011] 2. Performance advantages: Compared with high-quality clay and modified clay, it has higher resistance to hydrostatic pressure, and the permeability coefficient is at least 10 times higher than the anti-seepage capacity of the two. The porosity of the material is minimized by grading, which reduces the amount of bentonite used. The sand substances in the tailings sand and sand washing mud ensure the stability of the overall structure, and it is not easy to form pipe surge channels under high hydrostatic pressure. Cationic guar gum and polyacrylamide copolymer effectively isolate the influence of external solution ions on the durability of bentonite. The cations enter the bentonite staggered layer to replace calcium ions, which improves the expansion capacity of the bentonite, further improves the anti-seepage capacity of the overall formula, and at the same time improves the overall viscosity and increases the stability of the system structure.

[0012] 3. Application advantages: The product is simple to produce, has a wide range of applications, and has a large market demand. It can alleviate the survival crisis of solid waste production companies to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a sample drawing of a multi-solid synergistic low-permeability barrier and anti-seepage material proposed by the present invention. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0015] A multi-solid waste synergistic low permeability barrier and anti-seepage material, the formula is 55% river sand washing mud, 35% fine tailings sand (phosphate tailings), 10% bentonite, and 3‰ cationic guar gum and polyacrylamide copolymer. The river sand washing mud is dried, crushed and passed through a 1mm sieve; the fine tailings sand should be dried and fully separated; bentonite and cationic guar gum and polyacrylamide copolymer powder are added, and after being fully stirred for 5 minutes using a cement mortar mixer, 12% pure water is added and stirred for another 5 minutes, and a sample is prepared (the sample is attached Figure 1 ), the sample compaction degree is 90%.

[0016] After the test, the permeability coefficient was 3.18×10-9cm / s, the continuous test time was 58 days, and the long-term permeability performance was stable.

[0017] Embodiment 2 A multi-solid waste synergistic low-permeability barrier and anti-seepage material, the formula is 66% river sand washing mud, 26% fine tailings sand (phosphate tailings), 8% bentonite, and 3‰ cationic guar gum and polyacrylamide copolymer. The river sand washing mud is dried, crushed and passed through a 1mm sieve; the fine tailings sand should be dried and fully separated; bentonite and cationic guar gum and polyacrylamide copolymer powder are added, and after being fully stirred for 5 minutes using a cement mortar mixer, 12% pure water is added and stirred for another 5 minutes, and a sample is prepared, and the sample compaction degree is 90%.

[0018] After the test, the permeability coefficient was 7.37×10-9cm / s, the continuous test time was 46 days, and the long-term permeability performance was stable.

[0019] 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 multi-solid synergistic low permeability barrier and anti-seepage material, characterized in that: Including river wash mud, fine-grained tailings sand, bentonite, cationic guar gum and polyacrylamide copolymer; The mass proportions of the raw materials are: 50%-70% of river sand washing mud, 22%-35% of fine-grained tailings sand, 6%-15% of bentonite, and 3-5‰ of cationic guar gum and polyacrylamide copolymer.

2. The multi-solid synergistic low permeability barrier and anti-seepage material according to claim 1, characterized in that: The river sand washing mud is the waste after the Yangtze River sand passes through a 0.075mm sieve. It has a large clay content, with particles below 0.063mm accounting for between 60% and 77%, D50 not greater than 0.03mm, and a permeability coefficient not higher than 3×10⁻ 5 cm / s.

3. The multi-solid synergistic low permeability barrier and anti-seepage material according to claim 1, characterized in that: The electrical conductivity of the fine-grained tailings sand is not higher than 800 μS / cm, the calcium ion content in the tailings is lower than 0.02%, the pH value is not lower than 5.5, and the D50 is between 0.075-0.4 mm.

4. The multi-solid synergistic low permeability barrier and anti-seepage material according to claim 1, characterized in that: The bentonite has a blue absorption of not less than 23g / 100g, a swelling index of not less than 16ml / 2g, a montmorillonite content of not less than 66%, a 0.075mm sieving rate of not less than 95%, and a plastic viscosity after dispersion of more than 14mPa·S.

5. The multi-solid synergistic low permeability barrier and anti-seepage material according to claim 1, characterized in that: In the cationic guar gum and polyacrylamide copolymer, the proportion of guar gum in the whole is no more than 1 / 3.

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