Cable trench backfill material prepared from muck and preparation method of cable trench backfill material

Abstract

The invention discloses a cable trench backfill material prepared from muck, which is prepared from the following components in parts by weight: 1000 to 1500 parts of cement, 700 to 800 parts of calcined muck, 350 to 400 parts of limestone, 90 to 100 parts of gypsum, 7200 to 7800 parts of in-situ muck, 100 to 200 parts of polyacrylamide solution, 20 to 30 parts of macromolecular water-absorbent resin and 2200 to 2500 parts of water. The invention further discloses a preparation method of the cable trench backfill material prepared from the muck, the muck is used as a raw material of the backfill material, use of a cementing material is reduced, carbon emission is reduced, and the utilization rate of the muck is increased; the polyacrylamide and the high-molecular water-absorbent resin are combined to promote the high-molecular water-absorbent resin to absorb more moisture in a short time, so that the water retention performance of the backfill material is effectively improved.

Description

Technical Field

[0001] The invention belongs to the field of resource utilization of slag solid waste, and particularly relates to a cable trench backfill material prepared from slag and a preparation method thereof. Background Art

[0002] With the development of the electric power industry, power cable transmission has become the main way of urban power supply. The reliable operation of these cables is an important link to ensure the safe operation of the entire power grid, and the reliable operation of cross-linked cables is closely related to the operating temperature of their insulation. The cable is laid in the medium (backfill material), so the heat dissipation of the medium affects the temperature field of the cable, thereby affecting the current carrying capacity of the cable. In order to ensure that the cable has sufficient transmission capacity, the thermal resistance of the backfill material in the cable trench is usually controlled.

[0003] In the prior art, river sand is generally used as the backfill material for cable trenches. The conduction modes of heat radiation in the backfill material are: through the contact points between solid phases, air in the gaps, and water conduction. Among them, the thermal conductivity of the solid phase in the soil is the largest, and the thermal conductivity of the air is the smallest. When the particles are piled up, there are always a large number of pores and a dense structure cannot be formed. Therefore, the thermal conductivity of backfill materials such as river sand is affected by the water content. The water in the river sand is very easy to evaporate, which reduces the water content in the river sand, seriously affecting the heat dissipation performance of the river sand. In addition, with the strengthening of the concept of ecological protection in society, river sand is a non-renewable resource and its mining is gradually restricted.

[0004] Secondly, with the continuous development of my country's urbanization process, a large amount of construction waste has been generated due to projects such as surface improvement and underground space development, which needs to be treated. In the existing technology, the waste is usually treated as solid waste landfill, which not only causes waste of resources, but also occupies a large amount of land resources. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a cable trench backfill material prepared using slag, which solves the problem of poor thermal conductivity of existing backfill materials, and uses engineering slag instead of river sand as the raw material of cable trench backfill material, so that the slag can be utilized as a resource.

[0006] Another object of the present invention is to provide a method for preparing cable trench backfill material using slag.

[0007] The purpose of the present invention is achieved through the following technical solutions: A cable trench backfill material prepared from slag, comprising the following components by weight: 1000~1500 parts of cement; 700~800 parts of calcined slag; 350~400 parts of limestone; 90~100 parts of gypsum; 7200~7800 parts of in-situ slag; 100-200 parts of polyacrylamide solution; 20-30 parts of polymer water-absorbing resin; 2200~2500 parts of water.

[0008] A method for preparing a cable trench backfill material using slag, comprising the following steps: (1) Mix cement, calcined slag, limestone and gypsum to obtain a mixture A; (2) Mixing the mixture A and the dry in-situ debris in a ratio of 2 to 7:1 to obtain a mixture B; (3) pouring the mixture B into a disc granulator, spraying it with the polyacrylamide solution, and forming spherical particles in the disc granulator; (4) The spherical particles are mixed with a polymer water-absorbing resin and water to obtain a composite backfill material.

[0009] Preferably, the preparation steps of the calcined slag are as follows: (1) Dissolve the in-situ slag in water and filter the mud and sand and gravel with a 10-200 mesh sieve. Then dry the mud at 80-120°C and ball grind it into powder. (2) Calcine the powder obtained in step (1) in a muffle furnace for 1 to 3 hours to obtain activated calcined slag.

[0010] Preferably, during the calcination process, the heating rate of the muffle furnace is 5°C / min to 10°C / min, and the calcination temperature is 600°C to 800°C.

[0011] Preferably, the preparation steps of the polyacrylamide solution are as follows: 0 to 200 parts of polyacrylamide are dissolved in 2500 parts of water to obtain an aqueous polyacrylamide solution.

[0012] Preferably, the concentration of the polyacrylamide solution is 0.05-0.1 g / mL.

[0013] Preferably, the mass ratio of the spherical particles to the polymer water-absorbing resin and water is 100-200:2-2.5:60-80.

[0014] Preferably, the diameter of the spherical particles is less than 5 mm.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The present invention separates the useful components (such as sand and gravel) from the slag, activates the slag at high temperature, makes it have volcanic ash activity and certain gelling properties, and then passes it through a disc granulator with the remaining slag to prepare a backfill material that meets the requirements. While realizing the utilization of solid waste, it also reduces the use of gelling materials, reduces carbon emissions, and improves the utilization rate of slag; (2) The cable trench backfill material prepared from slag disclosed in the present invention is coated with a layer of water-absorbing and water-retaining material on the surface. Since the polymer water-absorbing resin will swell when it comes into contact with water, the expanded polymer water-absorbing resin can be filled in the pores of the spherical particles to form a deposit with fewer pores, thereby avoiding the problem of a large number of gaps that cannot form a dense structure during accumulation and leading to water evaporation. The combination of polyacrylamide and the polymer water-absorbing resin can not only promote the polymer water-absorbing resin to absorb more water in a short time and improve the water-retaining performance of the backfill material; it can also adjust the elasticity and toughness of the polymer water-absorbing resin, effectively improve the cracking characteristics of the polymer water-absorbing resin, and improve the temperature stability and chemical stability of the polymer water-absorbing resin, thereby improving the water-retaining performance of the backfill material in the cable trench. Therefore, under the action of the two, a high moisture content can be maintained for a long time, the thermal conductivity is increased, the heat dissipation of the cable is facilitated, and the current carrying capacity of the cable is increased.

[0016] (3) The cable trench backfill material prepared using slag disclosed in the present invention has excellent water absorption performance, can absorb and store moisture when it rains, and can maintain a certain moisture content under drought conditions; it has a certain thermal conductivity and will not become hardened. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of granulation of backfill material of the present invention.

[0018] The markings of the components in the accompanying drawings: 1-disc granulator, 2-materials required for granulation, 3-water. DETAILED DESCRIPTION

[0019] The purpose of the present invention is further described in detail below with reference to the accompanying drawings and specific examples. The examples cannot be described one by one here, but the implementation methods of the present invention are not therefore limited to the following examples.

[0020] Example 1 Calcination activated slag: (1) Dissolve the in-situ slag in water and filter the mud and sand and gravel with a 200-mesh screen. Then dry the mud at 105°C and ball-mill it into powder. (2) The powder was calcined in a muffle furnace at 800°C for 1 hour at a heating rate of 5°C / min to obtain activated calcined slag.

[0021] Backfill material preparation: (1) 1282 parts of cement, 750 parts of calcined slag, 375 parts of limestone and 93 parts of gypsum were mixed uniformly to obtain a mixture A with a total mass of 2500 parts.

[0022] (2) Mix 2500 parts of mixture A and 7500 parts of dry in-situ debris to obtain mixture B, i.e., the ratio of in-situ debris to mixture A is 3:1.

[0023] (3) Pour 10,000 parts of the mixture B prepared above into a disc granulator, and then spray 2,500 parts of water into the disc granulator containing the mixture B to form spherical particles to obtain a backfill material.

[0024] Example 2 Except for the following technical features, the other technical features of this embodiment are the same as those of Embodiment 1: The prepared spherical particles, high molecular water-absorbing resin and water are uniformly mixed in a mass ratio of 100:2:60 to obtain a composite backfill material.

[0025] Example 3 Except for the following technical features, the other technical features of this embodiment are the same as those of Embodiment 1: 10,000 parts of the mixture B prepared above were poured into a disc granulator, and then 100 parts of polyacrylamide were dissolved in 2,500 parts by weight of water to obtain a polyacrylamide solution, and finally the polyacrylamide solution was sprayed on the disc granulator containing the mixture B to prepare spherical particles.

[0026] The prepared spherical particles, high molecular water-absorbing resin and water are uniformly mixed in a mass ratio of 100:2:60 to obtain a composite backfill material.

[0027] Example 4 This embodiment provides a method for preparing a backfill material with improved efficiency.

[0028] A method for preparing cable trench backfill material using slag can also extract gelling material from the slag and mix it with the slag to directly prefabricate materials in an artificial aggregate factory, and use it on demand at the working site according to actual needs, thereby improving the preparation efficiency of the backfill material.

[0029] Comparative Example 1 The river sand disclosed in the prior art is used as the backfill material of the cable trench.

[0030] Table 1 is the performance test of the backfill materials disclosed in each embodiment. It can be seen from Table 1 that the backfill material prepared by Example 1 (backfill material without polyacrylamide and high molecular water-absorbing resin) has a higher cylinder pressure strength, but a lower thermal conductivity, and its standard cylinder pressure strength is 2.8MPa. The backfill material prepared by Example 2 (backfill material only mixed with high molecular water-absorbing resin) has better water retention performance. Although the strength is lower than that of Example 1, the thermal conductivity is better, and its standard cylinder pressure strength is 1.7MPa, which meets the requirements of the cable trench for backfill materials. The backfill material prepared by Example 3 (both polyacrylamide and high molecular water-absorbing resin are mixed) has the best water retention performance but the lowest strength, and its standard cylinder pressure strength is 1.27MPa, but the strength required by the backfill material required by the cable does not need to be very high, which also meets the requirements of the cable trench backfill material.

[0031] The molecular chain of polyacrylamide contains a large number of amide groups, which can be adsorbed on the surface of suspended particles in the backfill material, so that the fine particles in the backfill material can be quickly settled, which helps to improve the stability of the material. Secondly, after polyacrylamide is dissolved in water, it will increase the viscosity of the solution. In the slurry backfill material, the appropriate addition of polyacrylamide can make the material have good fluidity, which is convenient for transportation and filling. In addition, polyacrylamide can also play a certain role in enhancing adhesion and water retention. The polymer water-absorbing resin will swell when it meets water. The expanded polymer water-absorbing resin can be filled in the pores of the spherical particles to form a pile with fewer pores, avoiding the problem of a large number of gaps during accumulation that cannot form a dense structure and cause water evaporation. The combination of polyacrylamide and polymer water-absorbing resin can not only promote the polymer water-absorbing resin to absorb more water in a short time and improve the water retention performance of the backfill material; it can also adjust the elasticity and toughness of the polymer water-absorbing resin and effectively improve the characteristics of the rupture of the polymer water-absorbing resin; furthermore, polyacrylamide can improve the temperature stability and chemical stability of the polymer water-absorbing resin.

[0032] The above specific implementation modes are preferred embodiments of the present invention and cannot be used to limit the present invention. Any other changes or other equivalent replacement methods that do not deviate from the technical solution of the present invention are included in the protection scope of the present invention.

Claims

1. A cable trench backfill material prepared using slag, characterized in that: In parts, it includes the following components: 1000~1500 parts of cement; 700~800 parts of calcined slag; 350~400 parts of limestone; 90~100 parts of gypsum; 7200~7800 parts of in-situ slag; 100-200 parts of polyacrylamide solution; 20-30 parts of polymer water-absorbing resin; 2200~2500 parts of water.

2. The method for preparing the cable trench backfill material according to claim 1, characterized in that: The following steps are involved: (1) Mix cement, calcined slag, limestone and gypsum to obtain a mixture A; (2) Mixing the mixture A and the dry in-situ debris in a ratio of 2 to 7:1 to obtain a mixture B; (3) pouring the mixture B into a disc granulator, spraying it with the polyacrylamide solution, and forming spherical particles in the disc granulator; (4) The spherical particles are mixed with a polymer water-absorbing resin and water to obtain a composite backfill material.

3. The method for preparing the cable trench backfill material according to claim 2, characterized in that: The preparation steps of the calcined slag are as follows: (1) Dissolve the in-situ slag in water and filter the mud and sand and gravel with a 10-200 mesh sieve. Then dry the mud at 80-120°C and ball grind it into powder. (2) Calcine the powder obtained in step (1) in a muffle furnace for 1 to 3 hours to obtain activated calcined slag.

4. The method for preparing the cable trench backfill material according to claim 3, characterized in that: During the calcination process, the heating rate of the muffle furnace is 5°C / min to 10°C / min, and the calcination temperature is 600°C to 800°C.

5. The method for preparing the cable trench backfill material according to claim 2, characterized in that: The preparation steps of the polyacrylamide solution are as follows: 0 to 200 parts of polyacrylamide are dissolved in 2500 parts of water to obtain an aqueous polyacrylamide solution.

6. The method for preparing the cable trench backfill material according to claim 2, characterized in that: The mass ratio of the spherical particles to the polymer water-absorbing resin and water is 100-200:2-2.5:60-80.

7. The method for preparing cable trench backfill material using slag according to claim 2, characterized in that: The diameters of the spherical particles are all less than 5 mm.

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