Ceramic coating for mine conveying pipeline and preparation method of ceramic coating

Abstract

The invention discloses a ceramic coating for a mine conveying pipeline and a preparation method of the ceramic coating, and belongs to the technical field of mine conveying pipelines. Based on the performance balance of the lining and the composite pipe, various powder combinations are selected as additives, and the ceramic coating with excellent comprehensive performance is prepared on the inner surface of the seamless steel pipe by adjusting and balancing the effects and mutual influences of various additives, so that the substrate steel pipe can be sufficiently protected; the matching of the thermal expansion coefficient and the hardness of a steel pipe-transition layer-ceramic coating composite system is realized, the interface stress is reduced, and the prepared ceramic composite steel pipe has the characteristics of high wear resistance, corrosion resistance, good impact resistance, long service life, high temperature resistance and the like, and can be applied to high-temperature and high-pressure scenes such as deep wells, mines and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of mine transportation pipelines, and in particular relates to a ceramic coating for mine transportation pipelines and a preparation method thereof. Background Art

[0002] Mine pipelines, as core infrastructure in the mining industry, are primarily used for the long-distance transportation of solid-liquid mixtures such as slurry, tailings, and fine concentrate. By replacing traditional rail and road transport, they reduce transportation costs by 30%-50%, significantly reducing dust pollution, eliminating material spillage, and lowering the incidence of traffic accidents. In backfill mining, pipeline systems are a key vehicle for resource recycling, transporting backfill materials such as gangue and fly ash to goafs, thereby increasing mineral recovery and controlling surface subsidence.

[0003] While metal pipes, such as steel pipes, offer initial strength advantages, they also face challenges such as corrosion, rapid wear, and high maintenance costs. At the end of the 20th century, ultra-high molecular weight polyethylene (UHMWPE) pipes gradually became mainstream due to their wear resistance (4-7 times that of steel pipes), lightweight (density only 1 / 8 that of steel), and resistance to acid and alkali corrosion. However, due to limitations in glass transition temperature, thermal deformation temperature, and pressure bearing capacity, they are difficult to meet the high-temperature and high-pressure requirements of deep mines and other high-pressure environments.

[0004] Alumina ceramics have a Mohs hardness of 9 and a wear resistance over 20 times that of ordinary steel pipes. In applications such as pulverizing systems and mining transportation, their service life can reach over 15 times that of ordinary steel pipes. Al2O3 ceramics offer stable chemical properties, excellent resistance to acid, alkali, and salt corrosion, a roughness of Ra ≤ 0.2μm, and can withstand temperatures of 800-1200°C, making them suitable for conveying high-temperature slag, slurry, or molten metal. However, the inherent brittleness of ceramics results in insufficient impact strength, limiting their application.

[0005] In view of this, ceramic-metal composite pipes lined with ceramic layers have become the current research focus. Summary of the Invention

[0006] In response to the issues raised in the background art, the present invention aims to provide a ceramic coating for mining pipelines and its preparation method. This invention balances the performance of the lining and composite pipe by selecting a combination of powders as additives. By adjusting and balancing the effects of the various additives and their mutual influence, a ceramic coating with excellent overall performance is provided. This coating is prepared by reacting a thermite and additives on the inner surface of a steel pipe, eliminating the need for complex preparation processes. The resulting product exhibits excellent wear resistance, corrosion resistance, and impact resistance, making it suitable for industrial production.

[0007] To achieve the above object, the present invention specifically adopts the following technical solutions: The present invention provides a ceramic coating for a mine conveying pipeline, which is prepared by applying the following weight parts of additive powder and thermite on the inner surface of a steel pipe: 15-22 parts of zirconium oxide, 2.5-5 parts of yttrium oxide, 7.5-12 parts of silicon dioxide, 1.4-2.6 parts of titanium dioxide, 0.5-2.5 parts of cerium dioxide, 2-4 parts of sodium tetraborate, 2-3.5 parts of chromium carbide, 4-8 parts of silicon carbide whiskers, 1.5-2.5 parts of nickel oxide, and 3.5-6 parts of ZrO2-carbon nanotubes.

[0008] Preferably, the steel pipe is selected from any one of 42CrMo, 15CrMo, Q345B, 20#, and 45# seamless steel pipes.

[0009] Preferably, the mass ratio of the additive powder to the thermite is (16-20):(80-84), and the thermite is composed of aluminum powder and iron oxide in a mass ratio of 1:(4.2-4.6).

[0010] Preferably, the length of the silicon carbide whisker is 50-200 nm, and the aspect ratio is 20-50.

[0011] Preferably, the ZrO2-carbon nanotube preparation method is: disperse carbon nanotubes and ZrOCl2 in ethanol respectively, mix the two, add glycerol, adjust the pH and increase the temperature to carry out alcohol thermal reaction, and then dry and calcine to obtain the product.

[0012] Preferably, the particle size of zirconium oxide, yttrium oxide, silicon dioxide, titanium dioxide, cerium dioxide, sodium tetraborate, chromium oxide, chromium trioxide, and nickel oxide is 0.1-10 μm; the particle size of thermite is 20-50 μm.

[0013] The present invention also provides a method for preparing the ceramic coating for the mine transportation pipeline, comprising the following steps: Step 1: Prepare the base seamless steel pipe, clean its inner surface and set aside; Step 2: Weigh the additive powder and thermite according to the formula, add them into the mixer and mix thoroughly; Step 3: The obtained mixture is loaded into a seamless steel pipe, the thermite is ignited, and self-propagating high-temperature synthesis is performed by high-speed centrifugation to form a ceramic coating on the inner surface of the seamless steel pipe.

[0014] As a preference, the mixture in step 3 is prepared according to the surface area of the steel pipe of 0.4-0.6 g / cm 2 The seamless steel pipe is loaded; the rotation speed of the high-speed centrifuge is 1050-1450 rpm.

[0015] Preferably, after the centrifugal forming in step 3, the step further includes annealing at 850-950° C. for 1.5-2 h.

[0016] Preferably, the thickness of the obtained lining ceramic coating is 2.0-3.0 mm.

[0017] The present invention generates an alumina ceramic matrix through a thermite reaction and also uses a series of additives to strengthen it: zirconia has a phase transformation toughening effect, which can improve the thermal shock resistance and fracture toughness of the ceramic layer and reduce crack propagation; yttrium oxide prevents volume expansion caused by high-temperature phase transformation, enhances high-temperature stability, and refines the grain size, improving the uniformity of the ceramic layer; silicon dioxide can reduce pores and cracks in the ceramic layer and improve corrosion resistance; cerium dioxide, as a rare earth oxide, has redox properties that promote oxygen transport during the reaction, reduce porosity, and can also fill cracks by migration during the annealing process after centrifugal forming, thereby improving the density and flexural strength of the ceramic layer. Sodium tetraborate can lower the melting point of the reaction system, promote the formation of a liquid phase, improve reactant mass transfer and interface wettability. Silicon carbide whiskers enhance the strength of the ceramic layer through a fiber toughening mechanism, inhibit crack propagation, and improve the bonding between the coating and the transition layer. Nickel oxide can promote the formation of a liquid metal phase, accelerate the dissolution and redistribution of carbides, and help further optimize the gradient structure in the transition layer.

[0018] On this basis, titanium dioxide can form a small amount of titanium-rich carbide distributed at the alumina grain boundaries, improving the physical property matching between the ceramic layer and the metal transition layer and achieving a hardness gradient transition; chromium carbide can promote interface bonding, and its dual-phase reinforcement with titanium-rich carbide further balances the performance adaptation of the transition layer; ZrO2-carbon nanotubes can relieve thermal stress and reduce cracks, and its coating structure can significantly enhance the interface bonding between the particles and the matrix, improve overall toughness and adjust the gradient structure. By regulating the types and proportions of the above-mentioned additives, the present invention forms a carbide gradient distribution in the transition layer, constructs a multi-scale reinforcement system, achieves thermal expansion coefficient and hardness matching between the ceramic layer-transition layer-metal matrix, reduces interface stress, and effectively improves the impact strength, density and interface bonding performance of the ceramic coating.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention places a formulated thermite and additive powder inside a steel pipe, spins it at high speed in a centrifuge, and ignites the powder. Using the high temperature generated by the thermite reaction, a self-propagating high-temperature synthesis (SHT) is performed. The powder is heated to a molten state, while the inner wall of the steel pipe also partially melts and fuses with it. Under the action of centrifugal force, the denser particles form a transition layer near the inner wall of the steel pipe, while the less dense particles form a uniform ceramic coating on the surface. The resulting composite steel pipe-transition layer-ceramic coating system effectively improves the wear and corrosion resistance of pipeline transportation through the ceramic coating, while the transition layer effectively strengthens the bond between the steel pipe and the ceramic coating, while balancing their thermal expansion coefficients and acting as a gradient buffer.

[0020] This invention overcomes the limitations of traditional ceramics and ultra-high molecular weight polyethylene. By combining a special ceramic coating with a corresponding transition layer, it achieves multiple performance advantages, meeting the requirements of high-temperature and high-pressure applications such as deep-well mines. During the preparation of the ceramic coating, the invention precisely controls the types and proportions of various additives during the thermite reaction, aiming to ensure that the various additive components complement each other and are used in appropriate amounts to achieve optimal performance enhancement. Ultimately, it can significantly improve the composite pipe's impact resistance, high temperature resistance, and wear resistance. The resulting ceramic composite steel pipe has the characteristics of high wear resistance, corrosion resistance, good impact resistance, long service life, and high temperature resistance. DETAILED DESCRIPTION

[0021] To make the objects, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be described clearly and completely below in conjunction with the examples. Where specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, all are commercially available conventional products.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] Example 1 A method for preparing a ceramic-lined mine transportation composite pipeline comprises the following steps: 1. Separately, ultrasonically disperse the acid-purified carbon nanotubes and ZrOCl2 (1:1 mass ratio) in anhydrous ethanol. After mixing, add an appropriate amount of glycerol, adjust the pH to 12 with sodium hydroxide, heat to 200°C and maintain constant temperature for 12 hours, then dry and calcine at 500°C for 2 hours. Weigh, by weight, 20 parts zirconium oxide, 4 parts yttrium oxide, 10 parts silicon dioxide, 2 parts titanium dioxide, 1.8 parts cerium dioxide, 3 parts sodium tetraborate, 2.6 parts chromium carbide, 6 parts silicon carbide whiskers, 2 parts nickel oxide, and 4.8 parts ZrO2-carbon nanotubes. Aluminum powder and iron oxide (1:4.4 mass ratio) are combined to form a thermite. This is then mixed with the additive powder (18:82 mass ratio) in a mixer and thoroughly mixed to obtain a mixture for later use.

[0024] 2. Take 42CrMo seamless steel pipe, clean its inner surface, and then press the mixture and the inner surface area of the steel pipe to 0.5 g / cm 2The seamless steel pipe was loaded, the thermite was ignited with a magnesium rod, and self-propagating high-temperature synthesis was performed by high-speed centrifugation at 1300 rpm. After 40 minutes, the centrifuge was stopped, the steel pipe was transferred to a furnace, heated to 900°C and annealed for 2 hours to obtain a steel pipe lined with a ceramic coating (average thickness 2.2 mm).

[0025] Example 2 A method for preparing a ceramic-lined mine transportation composite pipeline comprises the following steps: 1. Separately, ultrasonically disperse the acid-purified carbon nanotubes and ZrOCl2 (1:1 mass ratio) in anhydrous ethanol. After mixing, add an appropriate amount of glycerol, adjust the pH to 12 with sodium hydroxide, heat to 200°C and maintain constant temperature for 12 hours, then dry and calcine at 500°C for 2 hours. Weigh, by weight, 15 parts zirconium oxide, 5 parts yttrium oxide, 12 parts silicon dioxide, 1.4 parts titanium dioxide, 0.8 parts cerium dioxide, 4 parts sodium tetraborate, 3.5 parts chromium carbide, 4 parts silicon carbide whiskers, 2.5 parts nickel oxide, and 6 parts ZrO2-carbon nanotubes. Aluminum powder and iron oxide (1:4.4 mass ratio) are combined to form a thermite. This is then mixed with the additive powder (20:80 mass ratio) in a mixer and thoroughly mixed to obtain a mixture for later use.

[0026] 2. Take 42CrMo seamless steel pipe, clean its inner surface, and then press the mixture and the inner surface area of the steel pipe to 0.5 g / cm 2 The seamless steel pipe was loaded, the thermite was ignited with a magnesium rod, and self-propagating high-temperature synthesis was performed by high-speed centrifugation at 1300 rpm. After 40 minutes, the centrifuge was stopped, the steel pipe was transferred to a furnace, heated to 900°C and annealed for 2 hours to obtain a steel pipe lined with a ceramic coating (average thickness 2.0 mm).

[0027] Example 3 A method for preparing a ceramic-lined mine transportation composite pipeline comprises the following steps: 1. Separately, ultrasonically disperse the acid-leached purified carbon nanotubes and ZrOCl2 (1:1 mass ratio) in anhydrous ethanol. After mixing, add an appropriate amount of glycerol, adjust the pH to 12 with sodium hydroxide, heat to 200°C and maintain constant temperature for 12 hours, then dry and calcine at 500°C for 2 hours. Weigh, by weight, 22 parts zirconium oxide, 2.5 parts yttrium oxide, 7.5 parts silicon dioxide, 2.6 parts titanium dioxide, 2.5 parts cerium dioxide, 2 parts sodium tetraborate, 2 parts chromium carbide, 8 parts silicon carbide whiskers, 1.5 parts nickel oxide, and 3.5 parts ZrO2-carbon nanotubes. Aluminum powder and iron oxide (1:4.4 mass ratio) are combined to form a thermite. This is then mixed with the additive powder (16:84 mass ratio) in a mixer and thoroughly mixed to obtain a mixture for later use.

[0028] 2. Take 42CrMo seamless steel pipe, clean its inner surface, and then press the mixture and the inner surface area of the steel pipe to 0.5 g / cm 2 The seamless steel pipe was loaded, the thermite was ignited with a magnesium rod, and self-propagating high-temperature synthesis was performed by high-speed centrifugation at 1300 rpm. After 40 minutes, the centrifuge was stopped, the steel pipe was transferred to a furnace, heated to 900°C and annealed for 2 hours to obtain a steel pipe lined with a ceramic coating (average thickness 2.3 mm).

[0029] Comparative Example 1 The step parameters are the same as those in Example 1, except that titanium dioxide is not added to the additive powder.

[0030] Comparative Example 2 Refer to the step parameters of Example 1, except that no cerium dioxide is added to the additive powder.

[0031] Comparative Example 3 Refer to the step parameters of Example 1, except that silicon carbide whiskers are not added to the additive powder.

[0032] Comparative Example 4 Refer to the step parameters of Example 1, except that no chromium carbide is added to the additive powder.

[0033] Comparative Example 5 Refer to the step parameters of Example 1, except that ordinary carbon nanotubes are used instead of ZrO2-carbon nanotubes in the additive powder.

[0034] The performance of the ceramic-lined steel pipe samples prepared in Examples 1-3 and Comparative Examples 1-5 was tested (YB / T176-2017, SY / T 6662.8-2016), and the results are shown in Table 1.

[0035] Table 1 Performance test results of ceramic-lined steel pipe samples

[0036] As can be seen from Table 1, the ceramic coating prepared by the process of the present invention has high density and hardness, excellent corrosion resistance, and can provide sufficient protection for the base steel pipe; in addition, the present invention achieves matching of thermal expansion coefficient and hardness between the steel pipe-transition layer-ceramic coating composite system, reduces interfacial stress, and the prepared ceramic composite steel pipe has the characteristics of high wear resistance, corrosion resistance, good impact resistance, long service life, and high temperature resistance, and can be used in high temperature and high pressure scenarios such as deep mines.

[0037] The embodiments described above merely represent several preferred embodiments of the present invention. While the descriptions are relatively specific and detailed, they are not intended to limit the present invention. It should be noted that those skilled in the art will readily appreciate that the present invention is susceptible to various variations and modifications. Any modifications, equivalent substitutions, or improvements within the scope of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A ceramic coating for mine transportation pipeline, characterized in that: Made of the following weight parts of additive powder and thermite on the inner surface of the steel pipe: 15-22 parts of zirconium oxide, 2.5-5 parts of yttrium oxide, 7.5-12 parts of silicon dioxide, 1.4-2.6 parts of titanium dioxide, 0.5-2.5 parts of cerium dioxide, 2-4 parts of sodium tetraborate, 2-3.5 parts of chromium carbide, 4-8 parts of silicon carbide whiskers, 1.5-2.5 parts of nickel oxide, and 3.5-6 parts of ZrO2-carbon nanotubes.

2. The ceramic coating for mine transportation pipeline according to claim 1, characterized in that: The steel pipe is selected from any one of 42CrMo, 15CrMo, Q345B, 20#, and 45# seamless steel pipes.

3. The ceramic coating for mine transportation pipeline according to claim 1, characterized in that: The mass ratio of the additive powder to the thermite is (16-20):(80-84), and the thermite is composed of aluminum powder and iron oxide in a mass ratio of 1:(4.2-4.6).

4. The ceramic coating for mine transportation pipeline according to claim 1, characterized in that: The length of silicon carbide whiskers is 50-200 nm, and the aspect ratio is 20-50.

5. The ceramic coating for mine transportation pipeline according to claim 1, characterized in that: The preparation method of the ZrO2-carbon nanotubes is as follows: carbon nanotubes and ZrOCl2 are dispersed in ethanol respectively, the two are mixed, glycerol is added, the pH is adjusted, the temperature is increased to carry out alcohol thermal reaction, and then drying and calcining are carried out to obtain the ZrO2-carbon nanotubes.

6. The ceramic coating for mine transportation pipeline according to claim 1, characterized in that: The particle sizes of zirconium oxide, yttrium oxide, silicon dioxide, titanium dioxide, cerium dioxide, sodium tetraborate, chromium oxide, chromium trioxide and nickel oxide are 0.1-10 μm; the particle size of thermite is 20-50 μm.

7. The method for preparing a ceramic coating for a mine transportation pipeline according to any one of claims 1 to 6, characterized in that: The steps include: Step 1: Prepare the base seamless steel pipe, clean its inner surface and set aside; Step 2: Weigh the additive powder and thermite according to the formula, add them into the mixer and mix thoroughly; Step 3: The obtained mixture is loaded into a seamless steel pipe, the thermite is ignited, and self-propagating high-temperature synthesis is performed by high-speed centrifugation to form a ceramic coating on the inner surface of the seamless steel pipe.

8. The method for preparing a ceramic coating for a mine transportation pipeline according to claim 7, characterized in that: In step 3, the mixture is adjusted to the inner surface area of the steel pipe at 0.4-0.6 g / cm 2 The seamless steel pipe is loaded; the rotation speed of the high-speed centrifuge is 1050-1450rpm.

9. The method for preparing a ceramic coating for a mine transportation pipeline according to claim 7, characterized in that: After centrifugal forming, step three further includes annealing at 850-950° C. for 1.5-2 h.

10. The method for preparing a ceramic coating for a mine transportation pipeline according to claim 7, characterized in that: The thickness of the obtained lining ceramic coating is 2.0-3.0 mm.

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