Solid waste regenerated flexible graphite coated steel grounding body and preparation method thereof

Abstract

The invention discloses a solid waste regenerated flexible graphite coated steel grounding body and a preparation method thereof, and relates to the technical field of solid waste regenerated flexible graphite coated steel grounding bodies, and the preparation method comprises the following steps: crushing a flexible graphite solid waste, and carrying out surface activation treatment to obtain a crushed material; preparing a conductive anticorrosive coating from one part of the crushed material; mixing the other part of the crushed material with a rubber raw material for banburying to obtain a rubber compound; and carrying out open milling on the rubber compound to obtain the flexible graphite conductive rubber. The steel base material is subjected to roughening treatment, so that dense micron-sized peaks are formed on the surface of the steel base material; spraying conductive anticorrosive paint on the surface of the roughened steel base material to obtain an intermediate base material; the surface of the middle base material is coated with flexible graphite conductive rubber, and a coating layer is subjected to vulcanization treatment. The obtained flexible graphite coated steel grounding body has good resistance reduction performance, corrosion resistance and reliability, and the binding force between the flexible graphite and the steel base material is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste recycled flexible graphite coated steel grounding bodies, and specifically relates to a solid waste recycled flexible graphite coated steel grounding body and a preparation method thereof. Background Art

[0002] At present, metal grounding electrodes in the power system face various problems during actual operation, such as difficulties in transportation and construction under complex terrain conditions, poor fitting degree between the grounding body and the soil resulting in poor resistance reduction effect, and the use of resistance reducing agents accelerating metal corrosion, etc., which seriously affect the reliability and safety of the grounding system. In order to address the corrosion problem of metal grounding bodies in the power system, flexible graphite is used to prepare grounding bodies without metal or containing a small amount of metal to replace traditional galvanized steel grounding bodies. Due to its advantages such as good corrosion resistance and significant effect of reducing grounding resistance, it has been widely used; when producing flexible graphite grounding materials, some solid wastes mainly formed by the shear-generated corner waste fragments of flexible graphite materials will be generated. At present, the main methods for treating solid wastes are centralized stacking and landfill treatment, which require a large amount of land and may cause additional environmental pollution. At the same time, during the long-term use of flexible graphite coated metal grounding bodies, they are affected by thermal expansion and contraction, mechanical vibration or soil stress, resulting in interface peeling between the flexible graphite and the metal matrix. Summary of the Invention

[0003] The purpose of the present invention is to provide a solid waste recycled flexible graphite coated steel grounding body and a preparation method thereof, to solve the environmental pollution problem caused by improper stacking and disposal of flexible graphite solid wastes, and the obtained flexible graphite coated steel grounding body has good resistance reduction performance, corrosion resistance and reliability, and improves the bonding force between the flexible graphite and the steel substrate.

[0004] To achieve the above purpose, the specific scheme adopted by the present invention is: a preparation method of a solid waste recycled flexible graphite coated steel grounding body, comprising the following steps:

[0005] Crush the flexible graphite solid waste and perform surface activation treatment to obtain crushed material;

[0006] Use a part of the crushed material, flaky zinc powder, flaky aluminum powder, chromic anhydride, ethylene glycol, fluorocarbon leveling agent, nano-clay, thickener and composite reducing agent as raw materials to prepare conductive anti-corrosion coating;

[0007] Mix another part of the crushed material with rubber raw materials and perform internal mixing at a rotation speed of 20 - 50 rpm, a temperature of 120 - 160 °C and a pressure of 0.5 - 1.5 MPa to obtain a mixed rubber; Open mill the mixed rubber to obtain flexible graphite conductive rubber, and the roller temperature for open milling is 40 - 50 °C, the roller gap is 5 - 6 mm, and the number of passes through the rollers is 3 - 5 times;

[0008] The steel substrate is roughened to form dense micron-scale peaks on its surface;

[0009] A conductive anti-corrosion coating is sprayed on the surface of the roughened steel substrate, so that the roots of the micron-scale peaks are covered with a coating layer to obtain an intermediate substrate;

[0010] A flexible graphite conductive rubber is coated on the surface of the intermediate substrate, so that a coating layer is formed on the surface of the intermediate substrate, and the coating layer is vulcanized to obtain a flexible graphite-coated steel grounding body.

[0011] As an optimized scheme of the above preparation method of a flexible graphite-coated steel grounding body regenerated from solid waste: the surface activation treatment is to mix the crushed flexible graphite solid waste and a surface activator in a volume ratio of 1:1, fully stir and then dry to obtain a crushed material.

[0012] As another optimized scheme of the above preparation method of a flexible graphite-coated steel grounding body regenerated from solid waste: the preparation method of the conductive anti-corrosion coating is as follows:

[0013] Take the crushed material, dispersant, fluorocarbon leveling agent, nano-clay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol, thickener and composite reducing agent in a mass ratio of 1-1.3:0.6-1.3:0.5-1:0.5-1:0.5-1:2-5:0.5-1:3-4:0.05-0.1:0.1-0.15 for standby;

[0014] Mix the fluorocarbon leveling agent, nano-clay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol and composite reducing agent to obtain a mixture;

[0015] Add the crushed material and dispersant to the mixture for ultrasonic oscillation, and then add the thickener to obtain the conductive anti-corrosion coating.

[0016] As another optimized scheme of the above preparation method of a flexible graphite-coated steel grounding body regenerated from solid waste: the mass ratio of the crushed material to the rubber raw material is 7:3.

[0017] As another optimized scheme of the above preparation method of a flexible graphite-coated steel grounding body regenerated from solid waste: the rubber raw material includes nitrile rubber and natural rubber, and the mass ratio of nitrile rubber to natural rubber is 1:1.

[0018] As another optimized scheme of the above preparation method of a flexible graphite-coated steel grounding body regenerated from solid waste: the roughening treatment of the steel substrate is sandblasting treatment.

[0019] As another optimized solution for the preparation method of the above-mentioned solid waste recycled flexible graphite-coated steel grounding body: the process parameters of the sandblasting treatment are: sandblasting pressure 0.5 - 0.7 MPa, sandblasting angle 60° - 80°, and sandblasting distance 100 - 200 mm.

[0020] As another optimized solution for the preparation method of the above-mentioned solid waste recycled flexible graphite-coated steel grounding body: spray a conductive anti-corrosion coating on the surface of the roughened steel substrate using a spray gun, and the spray gun forms an angle of 10 - 30° with the surface of the roughened steel substrate, the distance between the nozzle of the spray gun and the surface of the roughened steel substrate is 10 - 20 cm, and the spraying air pressure is 0.2 - 0.4 MPa.

[0021] As another optimized solution for the preparation method of the above-mentioned solid waste recycled flexible graphite-coated steel grounding body: polish the intermediate substrate before coating the flexible graphite conductive rubber on the surface of the intermediate substrate.

[0022] A solid waste recycled flexible graphite-coated steel grounding body is prepared by using the above method.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention provides a preparation method of a solid waste recycled flexible graphite-coated steel grounding body, which crushes the solid waste and performs surface activation treatment to obtain crushed materials. A part of the crushed materials is used to prepare a conductive anti-corrosion coating, and the other part of the crushed materials is obtained as flexible graphite conductive rubber after mixing and open milling; the steel substrate is roughened to form micron-level peaks on its surface, and a conductive anti-corrosion coating is sprayed on the surface of the roughened steel substrate so that the roots of the micron-level peaks are covered with a coating layer. The flexible graphite conductive rubber is coated on the surface of the intermediate steel to form a coating layer, and the coating layer is vulcanized. Finally, a flexible graphite-coated steel grounding body is obtained, realizing the efficient utilization of resources and reducing the production cost; at the same time, the corrosion resistance and grounding efficiency of the grounding body are improved, and the maintenance cost is reduced; at the same time, the micron-level peaks formed on the surface of the steel substrate increase the microscopic roughness of the surface of the steel substrate, significantly enhancing the mechanical bonding force between the flexible graphite conductive rubber and the surface of the steel substrate, and effectively preventing interface peeling caused by thermal expansion and contraction, mechanical vibration or soil stress during long-term use.

[0025] 2. In the present invention, if the flexible graphite conductive rubber is directly coated on the roughened steel substrate, the roots of the micron-sized peaks are not easily coated, resulting in gaps at the roots of the micron-sized peaks, increasing the resistance of the grounding body, and further affecting the resistance reduction performance of the grounding body. Therefore, a conductive anti-corrosion coating is sprayed on the roughened steel substrate, and low-angle spraying, shortened spraying distance, and low-pressure spraying are adopted to concentrate the coating at the roots of the micron-sized peaks, fill the gaps at the roots of the micron-sized peaks, further reduce the resistance of the grounding body, and improve the resistance reduction performance of the grounding body.

[0026] 3. In the present invention, after the steel substrate after roughening treatment is sprayed with conductive anti-corrosion coating, a small amount of conductive anti-corrosion coating exists at the tips of micron-sized peaks. Therefore, before the intermediate steel is coated with flexible graphite conductive rubber, the intermediate steel is lightly polished to remove the conductive anti-corrosion coating at the tips, thereby further improving the bonding strength between the flexible graphite conductive rubber and the intermediate steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the flexible graphite-coated steel grounding body in the present invention;

[0028] Figure 2 It is a cross-sectional schematic diagram of the flexible graphite-coated steel grounding body in the present invention. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further elaborated in detail below in conjunction with specific embodiments. The parts of the present invention that are not described and disclosed in detail in the following embodiments should be understood as the prior art known or should be known to those skilled in the art.

[0030] A method for preparing a solid waste regenerated flexible graphite coated steel grounding body comprises the following steps:

[0031] The flexible graphite solid waste is crushed and subjected to surface activation treatment to obtain crushed material. Specifically:

[0032] First, the collected flexible graphite solid waste is sorted to ensure that the flexible graphite solid waste does not contain metals, stones, waste packaging materials, textiles, etc.;

[0033] Use a ball mill to crush the flexible graphite solid waste into materials with a diameter not greater than 1 mm;

[0034] The crushed flexible graphite fixed waste is mixed with a surfactant in a volume ratio of 1:1, wherein the surfactant is prepared by mixing one or more of a silane coupling agent, a titanate coupling agent or a fatty acid with water in a volume ratio of 1:9, and after fully stirring, the water is drained and the crushed material is fully dried in a blast dryer to obtain a crushed material.

[0035] Divide the crushed material into two parts. Use a part of the crushed material, flaky zinc powder, flaky aluminum powder, chromic anhydride, ethylene glycol, fluorocarbon leveling agent, nano-clay, thickener, and composite reducing agent as raw materials to prepare a conductive anti-corrosion coating. The specific preparation method is as follows:

[0036] Take the crushed material, dispersant, fluorocarbon leveling agent, nano-clay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol, thickener, and composite reducing agent in a mass ratio of 1 - 1.3:0.6 - 1.3:0.5 - 1:0.5 - 1:0.5 - 1:2 - 5:0.5 - 1:3 - 4:0.05 - 0.1:0.1 - 0.15 and set aside.

[0037] Mix the fluorocarbon leveling agent, nano-clay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol, and composite reducing agent to obtain a mixture.

[0038] Add the crushed material and dispersant to the mixture and perform ultrasonic oscillation, then add the thickener to obtain the conductive anti-corrosion coating.

[0039] Mix the other part of the crushed material with rubber raw materials in a mass ratio of 7:3, and conduct internal mixing at a rotational speed of 20 - 50 rpm, a temperature of 120 - 160 °C, and a pressure of 0.5 - 1.5 MPa to obtain a mixed rubber. Among them, the rubber raw materials include nitrile rubber and natural rubber, and the mass ratio of nitrile rubber to natural rubber is 1:1. Open mill the mixed rubber to obtain flexible graphite conductive rubber. The roll temperature for open milling is 40 - 50 °C, the roll gap is 5 - 6 mm, and the number of passes through the rolls is 3 - 5 times to ensure the conductive performance and mechanical properties of the flexible graphite conductive rubber.

[0040] Use a carbon structural steel bar with a diameter of 12 mm as the steel substrate, and straighten, degrease, rust-remove, clean, and roughen the surface of the steel substrate to enhance the bonding force between the steel substrate and the flexible graphite conductive rubber and ensure the stable performance during the long-term use of the grounding body. Specifically, roughen the surface of the steel substrate to form dense micron-level peaks (Ra = 10 - 20 μm). The height of the micron-level peaks is 100 - 120 μm, and the density is 50 - 100 per cm 2; It increases the microscopic roughness of the steel substrate surface, significantly improves the mechanical bonding force between the flexible graphite conductive rubber and the steel substrate surface, and effectively prevents interface peeling caused by thermal expansion and contraction, mechanical vibration or soil stress during long-term use. Specifically, the roughening treatment is sandblasting treatment, and the abrasive for sandblasting treatment is selected as sharp abrasive. This type of abrasive has high hardness and distinct edges and corners, such as angular steel sand, silicon carbide sand or alumina sand, so that the abrasive forms uniform and dense micron-scale peaks on the steel substrate surface. The particle size of the abrasive is 0.3 - 0.8 mm, avoiding the formation of too deep pits on the steel substrate surface due to too large particle size and insufficient density of micron-scale peaks due to too small particle size. Therefore, controlling the particle size within 0.3 - 0.8 mm ensures the formation of dense and uniform micron-scale peaks on the steel substrate surface.

[0041] The process parameters of the sandblasting treatment are: sandblasting pressure 0.5 - 0.7 MPa, sandblasting angle 60° - 80°, sandblasting distance 100 - 200 mm, that is, inclined sandblasting, which enhances the cutting effect of the abrasive on the steel substrate and further ensures the formation of dense and uniform micron-scale peaks on the steel substrate surface.

[0042] A conductive anti-corrosion coating is sprayed on the surface of the steel substrate after roughening treatment, so that the root of the micron-scale peak is covered with a coating layer to obtain an intermediate substrate; specifically, a conductive anti-corrosion coating is sprayed on the surface of the steel substrate after roughening treatment using a spray gun, and low-angle spraying is used, that is, the spray gun forms an angle of 10 - 30° with the surface of the steel substrate after roughening treatment, so that the conductive anti-corrosion coating is deposited at the root of the micron-scale peak, avoiding the conductive anti-corrosion coating covering the tip of the micron-scale peak and affecting the bonding between the steel substrate and the flexible graphite conductive rubber; shortening the spraying distance, that is, the distance between the nozzle of the spray gun and the surface of the steel substrate after roughening treatment is 10 - 20 cm, increasing the impact force of the conductive anti-corrosion coating, and blocking the diffusion of the conductive anti-corrosion coating at the root of the micron-scale peak to the tip; low-pressure spraying, that is, the spraying air pressure is 0.2 - 0.4 MPa, reducing the scattering of the conductive anti-corrosion coating and restricting the spraying range of the conductive anti-corrosion coating, further ensuring that the conductive anti-corrosion coating is located at the root of the micron-scale peak. The tip of the micron-scale peak has a high curvature, and fluorocarbon leveling agent can reduce the surface tension of the conductive anti-corrosion coating, so that the conductive anti-corrosion coating is difficult to wet at the tip of the micron-scale peak, and it preferentially aggregates at the root of the micron-scale peak; at the same time, the addition of nano-clay increases the thixotropic index of the conductive anti-corrosion coating and inhibits its flow to the tip of the micron-scale peak when spraying the conductive anti-corrosion coating.

[0043] Coat the surface of the intermediate substrate with flexible graphite conductive rubber to form a coating layer on the surface of the intermediate substrate. After vulcanizing the coating layer, a grounding body is obtained. After spraying a conductive anti-corrosion coating on the roughened steel substrate, there is conductive anti-corrosion coating at the tips of a small number of micron-sized peaks. Therefore, before coating the intermediate steel with flexible graphite conductive rubber, the intermediate steel is mildly polished to remove the coating at the tips, further improving the bonding force between the flexible graphite conductive rubber and the intermediate steel. Specifically:

[0044] Mildly mechanically polish the intermediate substrate with a polishing pressure less than 0.1 MPa and a polishing time less than 10 s, only removing the conductive anti-corrosion coating at the tips of the micron-sized peaks and retaining the coating layer at the roots of the micron-sized peaks.

[0045] Extrude and coat the flexible graphite conductive rubber on the intermediate substrate through an extruder to form a coating layer with a thickness of 2.5 - 3.5 mm. The extrusion temperature is 120 - 160 °C, the extrusion pressure is 5 - 20 MPa, and the extrusion speed is 5 - 15 min.

[0046] The coating layer is vulcanized in a steam continuous vulcanizing rubber extruder or a salt bath continuous vulcanizing rubber extruder to form a three-dimensional network structure, improving the physical and mechanical properties of the coating layer.

[0047] The flexible graphite-coated steel grounding body prepared by the above method has good corrosion resistance and thermal stability. Among them, the coating layer has excellent corrosion resistance, can isolate the steel substrate and the solution in the soil, blocking the generation conditions of electrochemical corrosion, and thus can effectively extend the service life of the grounding body. Using solid waste to prepare the flexible graphite-coated steel grounding body, its surface is soft and elastic, can better adapt to the irregular shape of the soil, reduce the air gap, thereby reducing the contact resistance, having excellent resistance reduction performance, and then reducing the amount of the grounding body used and the construction cost; using solid waste of flexible graphite to prepare conductive anti-corrosion coating and flexible graphite-coated steel grounding body realizes the efficient recycling of resources and reduces the production cost.

[0048] Example 1

[0049] A preparation method for a regenerated flexible graphite-coated steel grounding body from solid waste, comprising the following steps:

[0050] Sort the collected flexible graphite solid waste to ensure that there are no metals, stones, waste packaging materials, textiles, etc. in the flexible graphite solid waste; use a ball mill to crush the flexible graphite solid waste into materials with a diameter not greater than 1 mm; mix the crushed flexible graphite solid waste with a surface activator in a volume ratio of 1:1, stir well and then drain the water, and fully dry in a blast dryer to obtain crushed materials. The surface activator is prepared from a silane coupling agent and water in a volume ratio of 1:9.

[0051] Take the crushed material, dispersant, fluorocarbon leveling agent, nanoclay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol, thickener and composite reducing agent in a mass ratio of 1:0.6:0.5:0.5:0.5:5:0.5:4:0.05:0.1 for standby;

[0052] Mix the carbon leveling agent, nanoclay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol and composite reducing agent to obtain a mixture;

[0053] Add the crushed material and dispersant to the mixture for ultrasonic oscillation, and then add the thickener to obtain the conductive anticorrosive coating.

[0054] Mix another part of the crushed material with the rubber raw materials in a mass ratio of 7:3, and carry out internal mixing at a rotational speed of 20 rpm, a temperature of 160 °C and a pressure of 1.5 MPa to obtain the mixed rubber. The rubber raw materials include nitrile rubber and natural rubber, and the mass ratio of nitrile rubber to natural rubber is 1:1; Open mill the mixed rubber to obtain flexible graphite conductive rubber. The roll temperature for open milling is 40 °C, the roll gap is 5 mm, and the number of passes through the rolls is 3 times to ensure the conductive performance and mechanical properties of the flexible graphite conductive rubber.

[0055] Use a carbon structural steel bar with a diameter of 12 mm as the steel substrate, and carry out rust removal, cleaning and sandblasting on the steel substrate. The sandblasting pressure is 0.5 MPa, the sandblasting angle is 80 °, and the sandblasting distance is 100 mm, so that micron-level peaks with a height of 100 μm and a density of 50 per cm 2 are formed on the surface of the steel substrate (Ra = 10 μm).

[0056] Under the conditions that the spray gun forms an angle of 10° with the surface of the roughened steel substrate, the distance between the nozzle of the spray gun and the surface of the roughened steel substrate is 10 cm, and the spraying air pressure is 0.2 MPa, spray the conductive anticorrosive coating on the surface of the roughened steel substrate to form a coating layer at the root of the micron-level peaks to obtain the intermediate substrate.

[0057] The intermediate substrate is mechanically polished for 8 s under a polishing pressure of 0.05 MPa.

[0058] Extrude the flexible graphite conductive rubber through an extruder and coat it on the intermediate substrate to form a coating layer with a thickness of 2.5 mm. The extrusion temperature is 120 °C, the extrusion pressure is 5 MPa, and the extrusion speed is 5 min; The coating layer is vulcanized in a steam continuous vulcanizing extruder or a salt bath continuous vulcanizing extruder to obtain a flexible graphite-coated steel grounding body (denoted as S1). After testing, the grounding resistance of the flexible graphite-coated steel grounding body obtained in this embodiment is 1.5 Ω during actual grounding application. Conduct a mechanical property test on the flexible graphite-coated steel grounding body obtained in this embodiment, and the peel strength of the flexible graphite-coated steel grounding body is 13.7 kN / m, indicating that the bonding force between the coating layer and the steel substrate is strong.

[0059] Example 2

[0060] A preparation method of a solid waste recycled flexible graphite coated steel grounding body, comprising the following steps:

[0061] Sort the collected flexible graphite solid waste to ensure that there are no metals, stones, waste packaging materials, textiles, etc. in the flexible graphite solid waste; use a ball mill to crush the flexible graphite solid waste into materials with a diameter not greater than 1 mm; mix the crushed flexible graphite fixed waste with a surface activator in a volume ratio of 1:1, stir well and drain the water, and obtain crushed materials after sufficient drying in a blast dryer. The surface activator is prepared from a silane coupling agent and water in a volume ratio of 1:9.

[0062] Take crushed materials, a dispersant, a fluorocarbon leveling agent, nano clay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol, a thickener and a composite reducing agent in a mass ratio of 1.3:1.3:1:1:1:2:1:3:0.1:0.15 for standby;

[0063] Mix the carbon leveling agent, nano clay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol and the composite reducing agent to obtain a mixture.

[0064] Add the crushed materials and the dispersant to the mixture for ultrasonic oscillation, and then add the thickener and stir evenly to obtain a conductive anti-corrosion coating.

[0065] Mix another part of the crushed materials with rubber raw materials in a mass ratio of 7:3, and carry out internal mixing at a rotation speed of 50 rpm, a temperature of 120 °C and a pressure of 0.5 MPa to obtain a mixed rubber. The rubber raw materials include nitrile rubber and natural rubber, and the mass ratio of nitrile rubber to natural rubber is 1:1; open mill the mixed rubber to obtain flexible graphite conductive rubber. The roll temperature for open milling is 50 °C, the roll gap is 6 mm, and the number of passes through the rolls is 5 times to ensure the conductive performance and mechanical properties of the flexible graphite conductive rubber.

[0066] Use a carbon structural steel bar with a diameter of 12 mm as the steel substrate, and carry out rust removal, cleaning and sandblasting treatment on the steel substrate. The sandblasting pressure is 0.7 MPa, the sandblasting angle is 60 °, and the sandblasting distance is 200 mm, so that micron-level peaks with a height of 120 μm and a density of 100 per cm 2 are formed on the surface of the steel substrate (Ra = 20 μm).

[0067] Under the conditions that the spray gun makes an angle of 30° with the surface of the roughened steel substrate, the distance between the nozzle of the spray gun and the surface of the roughened steel substrate is 20 cm, and the spraying air pressure is 0.4 MPa, spray the conductive anti-corrosion coating on the surface of the roughened steel substrate so that the roots of the micron-level peaks are covered with a coating layer to obtain an intermediate substrate.

[0068] The intermediate substrate is mechanically polished for 8 s under a polishing pressure of 0.05 MPa.

[0069] The flexible graphite conductive rubber is extruded through an extruder and coated on the intermediate substrate to form a coating layer with a thickness of 2.5 mm and then a coating layer with a thickness of 3.5 mm. The extrusion temperature is 160 °C, the extrusion pressure is 20 MPa, and the extrusion speed is 15 min; the coating layer is vulcanized in a steam continuous vulcanizing rubber extruder or a salt bath continuous vulcanizing rubber extruder to obtain a flexible graphite-coated steel grounding body. After testing, the grounding resistance of the flexible graphite-coated steel grounding body obtained in this example is 1.6 Ω during actual grounding application. It should be noted that the actual grounding application conditions of the flexible graphite-coated steel grounding body obtained in this example are the same as those in Example 1; the mechanical properties of the flexible graphite-coated steel grounding body obtained in this example are tested. It should be noted that the conditions for testing the mechanical properties in this example are the same as those in Example 1, and the peel strength of the flexible graphite-coated steel grounding body is 13.9 kN / m, indicating a strong bonding force between the coating layer and the steel substrate.

[0070] Example 3

[0071] A preparation method of a flexible graphite-coated steel grounding body from solid waste regeneration includes the following steps:

[0072] The collected flexible graphite solid waste is sorted to ensure that it does not contain metals, stones, waste packaging materials, textiles, etc.; the flexible graphite solid waste is crushed into materials with a diameter not greater than 1 mm using a ball mill; the crushed flexible graphite solid waste is mixed with a surface activator in a volume ratio of 1:1, fully stirred and then drained of water, and then fully dried in a blast dryer to obtain crushed materials. The surface activator is prepared from a silane coupling agent and water in a volume ratio of 1:9.

[0073] Take crushed materials, a dispersant, a fluorocarbon leveling agent, nano-clay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol, a thickener, and a composite reducing agent in a mass ratio of 1.2:1.0:0.8:0.8:0.8:3.5:0.8:3.5:0.08:0.7 for standby;

[0074] The carbon leveling agent, nano-clay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol, and the composite reducing agent are mixed to obtain a mixture.

[0075] The crushed materials and the dispersant are added to the mixture for ultrasonic oscillation, and then the thickener is added to obtain a conductive anticorrosive coating.

[0076] Another part of the crushed material is mixed with the rubber raw material at a mass ratio of 7:3, and is kneaded at a rotational speed of 35 rpm, a temperature of 140 °C, and a pressure of 1 MPa to obtain a kneaded rubber. The rubber raw material includes nitrile rubber and natural rubber, and the mass ratio of nitrile rubber to natural rubber is 1:1; the kneaded rubber is open-milled to obtain flexible graphite conductive rubber. The roller temperature for open-milling is 45 °C, the roller gap is 5.5 mm, and the number of passes through the rollers is 4 times to ensure the conductive performance and mechanical properties of the flexible graphite conductive rubber.

[0077] A carbon structural steel bar with a diameter of 12 mm is used as the steel substrate, and the steel substrate is rust-removed, cleaned, and sandblasted. The sandblasting pressure is 0.6 MPa, the sandblasting angle is 70 °, and the sandblasting distance is 150 mm, so that micron-level peaks with a height of 110 μm and a density of 80 per cm 2 are formed on the surface of the steel substrate (Ra = 15 μm).

[0078] Under the conditions that the spray gun is at an angle of 20 ° to the surface of the roughened steel substrate, the distance between the nozzle of the spray gun and the surface of the roughened steel substrate is 15 cm, and the spraying air pressure is 0.3 MPa, a conductive anti-corrosion coating is sprayed on the surface of the roughened steel substrate, so that the roots of the micron-level peaks are covered with a coating layer to obtain an intermediate substrate.

[0079] The intermediate substrate is mechanically polished for 8 s under a polishing pressure of 0.05 MPa.

[0080] The flexible graphite conductive rubber is extruded through an extruder and coated on the intermediate substrate to form a coating layer with a thickness of 3 mm. The extrusion temperature is 140 °C, the extrusion pressure is 15 MPa, and the extrusion speed is 10 min; the coating layer is vulcanized in a steam continuous vulcanizing rubber extruder or a salt bath continuous vulcanizing rubber extruder to obtain a flexible graphite-coated steel grounding body. After testing, the grounding resistance of the flexible graphite-coated steel grounding body obtained in this embodiment is 1.5 Ω during actual grounding application. It should be noted that the actual grounding application conditions of the flexible graphite-coated steel grounding body obtained in this embodiment are the same as those in Embodiment 1; the mechanical properties of the flexible graphite-coated steel grounding body obtained in this embodiment are tested. It should be noted that the conditions for testing the mechanical properties in this embodiment are the same as those in Embodiment 1, and the peel strength of the flexible graphite-coated steel grounding body is 13.8 kN / m, indicating that the bonding force between the coating layer and the steel substrate is strong.

[0081] Comparative Example 1

[0082] Sort the collected flexible graphite solid waste to ensure that it does not contain metals, stones, waste packaging materials, textiles, etc.; use a ball mill to crush the flexible graphite solid waste into materials with a diameter not greater than 1 mm; mix the crushed flexible graphite solid waste with a surface activator in a volume ratio of 1:1, stir well and then drain the water, and dry it thoroughly in a blast dryer to obtain crushed material. The surface activator is prepared by mixing a silane coupling agent and water in a volume ratio of 1:9.

[0083] Mix the crushed material and the rubber raw materials in a mass ratio of 7:3, and carry out internal mixing at a rotational speed of 20 rpm, a temperature of 160 °C and a pressure of 1.5 MPa to obtain a mixed rubber. The rubber raw materials include nitrile rubber and natural rubber, and the mass ratio of nitrile rubber to natural rubber is 1:1; open mill the mixed rubber to obtain flexible graphite conductive rubber. The roll temperature for open milling is 40 °C, the roll gap is 5 mm, and the number of passes through the rolls is 3 times to ensure the conductive performance and mechanical properties of the flexible graphite conductive rubber.

[0084] Use a carbon structural steel bar with a diameter of 12 mm as the steel substrate, and carry out rust removal, cleaning and sandblasting on the steel substrate. The sandblasting pressure is 0.5 MPa, the sandblasting angle is 80°, and the sandblasting distance is 100 mm, so that the surface of the steel substrate forms micron-level peaks with a height of 100 μm and a density of 50 per cm 2 (Ra = 10 μm).

[0085] Extrude the flexible graphite conductive rubber through an extruder and coat it on the steel substrate to form a coating layer with a thickness of 2.5 mm. The extrusion temperature is 120 °C, the extrusion pressure is 5 MPa, and the extrusion speed is 5 min; the coating layer is vulcanized in a steam continuous vulcanizing rubber extruder or a salt bath continuous vulcanizing rubber extruder to obtain a flexible graphite-coated steel grounding body (denoted as D1). After testing, the grounding resistance of the flexible graphite-coated steel grounding body obtained in this embodiment is 2.4 Ω during actual grounding application. It should be noted that the actual grounding application conditions of the flexible graphite-coated steel grounding body obtained in this embodiment are the same as those in Embodiment 1; conduct mechanical property tests on the flexible graphite-coated steel grounding body obtained in this embodiment. It should be noted that the conditions for the mechanical property tests in this embodiment are the same as those in Embodiment 1, and the peel strength of the flexible graphite-coated steel grounding body is 13.3 kN / m.

[0086] Comparative Example 2

[0087] A preparation method of a solid waste recycled flexible graphite-coated steel grounding body, comprising the following steps:

[0088] Sort the collected flexible graphite solid waste to ensure that it does not contain metals, stones, waste packaging materials, textiles, etc.; use a ball mill to crush the flexible graphite solid waste into materials with a diameter not greater than 1 mm; mix the crushed flexible graphite solid waste with a surface activator in a volume ratio of 1:1, stir well and then drain the water, and obtain the crushed material after sufficient drying in a blast dryer. The surface activator is prepared from a silane coupling agent and water in a volume ratio of 1:9.

[0089] Mix the crushed material with rubber raw materials in a mass ratio of 7:3, and carry out internal mixing at a rotation speed of 20 rpm, a temperature of 160 °C and a pressure of 1.5 MPa to obtain a mixed rubber. The rubber raw materials include nitrile rubber and natural rubber, and the mass ratio of nitrile rubber to natural rubber is 1:1; open mill the mixed rubber to obtain flexible graphite conductive rubber. The roll temperature for open milling is 40 °C, the roll gap is 5 mm, and the number of passes through the rolls is 3 times.

[0090] Use a carbon structural steel bar with a diameter of 12 mm as the steel substrate, rust-remove and clean the steel substrate, extrude the flexible graphite conductive rubber through an extruder and coat it on the steel substrate to form a coating layer of 2.5 mm. The extrusion temperature is 120 °C, the extrusion pressure is 5 MPa, and the extrusion speed is 5 min; the coating layer is vulcanized in a steam continuous vulcanizing rubber extruder or a salt bath continuous vulcanizing rubber extruder to obtain a flexible graphite-coated steel grounding body (denoted as D2). After testing, the grounding resistance of the flexible graphite-coated steel grounding body obtained in this example is 1.7 Ω during actual grounding application. It should be noted that the actual grounding application conditions of the flexible graphite-coated steel grounding body obtained in this example are the same as those in Example 1; conduct a mechanical property test on the flexible graphite-coated steel grounding body obtained in this example. It should be noted that the conditions for the mechanical property test in this example are the same as those in Example 1, and the peel strength of the flexible graphite-coated steel grounding body is 10.1 kN / m.

[0091] Compared with Example 1, in Comparative Example 1, the steel substrate is roughened, and the flexible graphite conductive rubber is directly coated on the surface of the roughened steel substrate. Then, there are tiny gaps at the roots of the micron-scale peaks, and these tiny gaps increase the grounding resistance of D1; in Example 1, a conductive anti-corrosion coating is sprayed on the surface of the roughened steel substrate, so that the roots of the micron-scale peaks are covered with a coating layer to fill the tiny gaps, increasing the conductivity of the grounding body, and thus reducing the grounding resistance of S1. Therefore, the grounding resistance of D1 is higher than that of S1. Both Comparative Example 1 and Example 1 roughen the steel substrate, increasing the bonding force between the flexible graphite conductive rubber and the steel substrate.

[0092] Compared with Example 2, in Comparative Example 2, the flexible graphite conductive rubber is directly coated on the surface of the steel substrate, resulting in a weak bonding force between the flexible graphite conductive rubber and the steel substrate.

[0093] In summary, in Example 1, the surface of the steel substrate was roughened to form micron-level peaks on its surface, increasing the bonding force between the flexible graphite conductive rubber and the steel substrate. At the same time, a conductive anti-corrosion coating was sprayed on the surface of the roughened steel substrate, covering the coating layer at the root of the micron-level peaks to fill the tiny gaps, reducing the resistance of the flexible graphite-coated steel grounding body, that is, improving the resistance reduction performance of the grounding body and increasing the corrosion resistance of the grounding body.

[0094] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a solid waste regenerated flexible graphite coated steel grounding body, characterized in that: The following steps are involved: The flexible graphite solid waste is crushed and surface activated to obtain crushed material; A conductive anti-corrosion coating is prepared using a portion of crushed material, flaky zinc powder, flaky aluminum powder, chromic anhydride, ethylene glycol, a fluorocarbon leveling agent, nanoclay, a thickener and a composite reducing agent as raw materials; Another part of the crushed material is mixed with the rubber raw material, and is kneaded at a speed of 20-50rpm, a temperature of 120-160°C and a pressure of 0.5-1.5MPa to obtain a rubber mix; the rubber mix is ​​open-mixed to obtain a flexible graphite conductive rubber, and the roll temperature of the open-mixed process is 40-50°C, the roll distance is 5-6mm, and the number of roll passes is 3-5 times; The steel substrate is roughened to form dense micron-sized peaks on its surface; The conductive anti-corrosion coating is sprayed on the surface of the roughened steel substrate so that the base of the micron-sized peaks is covered with the coating layer to obtain an intermediate substrate; The flexible graphite conductive rubber is coated on the surface of the intermediate substrate to form a coating layer on the surface of the intermediate substrate, and the coating layer is vulcanized to obtain a flexible graphite-coated steel grounding body.

2. The method for preparing a solid waste regenerated flexible graphite coated steel grounding body according to claim 1, characterized in that: The surface activation treatment is to mix the crushed flexible graphite solid waste with a surfactant in a volume ratio of 1:1, fully stir and then dry to obtain a crushed material.

3. The method for preparing a solid waste recycled flexible graphite coated steel grounding body according to claim 1, characterized in that: The preparation method of the conductive anti-corrosion coating is as follows: The crushed material, dispersant, fluorocarbon leveling agent, nano clay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol, thickener and composite reducing agent are prepared in a mass ratio of 1-1.3:0.6-1.3:0.5-1:0.5-1:0.5-1:2-5:0.5-1:3-4:0.05-0.1:0.1-0.15 for later use; the fluorocarbon leveling agent, nano clay, flaky aluminum powder, flaky zinc powder, chromic anhydride, ethylene glycol and composite reducing agent are mixed to obtain a mixture; Add crushed material and dispersant into the mixture for ultrasonic vibration, and then add thickener to obtain conductive anti-corrosion coating.

4. The method for preparing a solid waste regenerated flexible graphite coated steel grounding body according to claim 1, characterized in that: The mass ratio of crushed material to rubber raw material is 7:

3.

5. The method for preparing a solid waste regenerated flexible graphite coated steel grounding body according to claim 1, characterized in that: The rubber raw materials include nitrile rubber and natural rubber, and the mass ratio of the nitrile rubber to the natural rubber is 1:

1.

6. The method for preparing a solid waste recycled flexible graphite coated steel grounding body according to claim 1, characterized in that: The roughening treatment of the steel substrate is sandblasting.

7. The method for preparing a solid waste recycled flexible graphite coated steel grounding body according to claim 6, characterized in that: The process parameters of sandblasting are: sandblasting pressure 0.5-0.7MPa, sandblasting angle 60°-80°, and sandblasting distance 100-200mm.

8. The method for preparing a solid waste recycled flexible graphite coated steel grounding body according to claim 1, characterized in that: A spray gun is used to spray conductive anti-corrosion coating on the roughened steel substrate surface, and the spray gun is at an angle of 10-30° to the roughened steel substrate surface, the distance between the spray gun nozzle and the roughened steel substrate surface is 10-20 cm, and the spraying air pressure is 0.2-0.4 MPa.

9. The method for preparing a solid waste recycled flexible graphite coated steel grounding body according to claim 1, characterized in that: Before the surface of the intermediate substrate is coated with the flexible graphite conductive rubber, the intermediate substrate is polished.

10. A solid waste recycled flexible graphite coated steel grounding body, characterized in that: The method is prepared by any one of claims 1 to 9.

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