Ceramic composite tube and preparation method thereof

Abstract

The invention discloses a ceramic composite pipe and a preparation method thereof.The ceramic composite pipe is composed of a seamless steel pipe on the outer layer and aluminum oxide ceramic rings on the inner layer, the aluminum oxide ceramic rings are in threaded connection with the seamless steel pipe, and the multiple aluminum oxide ceramic rings continuously abut against one another in the seamless steel pipe; and the outer wall of the aluminum oxide ceramic ring is bonded with the inner wall of the seamless steel pipe through organic ceramic special glue. The multiple sections of aluminum oxide ceramic rings are continuously connected together in the seamless steel pipe in an abutting mode, the total length of the aluminum oxide ceramic rings can be adjusted according to the length of the seamless steel pipe, the application range of the ceramic composite pipe in actual production and life is widened, gaps between the aluminum oxide ceramic rings are perpendicular to the material conveying direction, and the material conveying efficiency is improved. And meanwhile, the size of the aluminum oxide ceramic ring can be adjusted according to the inner diameter size of the seamless steel pipe, and the production range is expanded.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic composite pipe manufacturing, and in particular relates to a ceramic composite pipe and a preparation method thereof. Background Art

[0002] Today's ceramic composite pipes are primarily manufactured using a high-tech process—the self-propagating combustion high-temperature clutch synthesis method—and the method of manually paving the inner surface of seamless steel pipes with alumina ceramic mosaics. The self-propagating combustion pipe is composed of three layers, from the inside out: corundum ceramic, a transition layer, and steel. The ceramic layer is formed from dense corundum (Al2O3) at temperatures exceeding 2200°C, forming a strong bond with the steel pipe through the transition layer. The seamless steel pipe with alumina ceramic mosaic composite pipe, on the other hand, is composed of three layers, from the inside out: alumina ceramic, an adhesive layer, and steel. Both composite pipes offer excellent resistance to wear, heat, corrosion, mechanical and thermal shock, and excellent weldability. They are ideal for conveying granular materials, abrasive materials, and corrosive media.

[0003] However, the above-mentioned ceramic composite tubes have the following problems: there are multiple gaps on the axial inner wall of the alumina ceramic mosaic composite tube that are consistent with the material conveying direction. The gaps are not wear-resistant and easy to perforate, thereby reducing the service life of the ceramic composite tube. At the same time, due to the limitation of the inner diameter size, only ceramic composite tubes with larger inner diameters can be produced; the surface of alumina on the inner wall of the self-propagating composite tube is rough, not smooth, and easy to clog. During the production process of the ceramic composite tube, the ceramic layer on its inner wall has a length limit, and only ceramic composite tubes with shorter lengths can be produced, which limits the application of ceramic composite tubes in actual production and life. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a ceramic composite tube and a preparation method thereof.

[0005] The present invention is achieved as follows: a ceramic composite tube, consisting of an outer seamless steel tube and an inner alumina ceramic ring, the seamless steel tube has good sealing performance and can withstand higher internal or external pressure, the alumina ceramic ring has ultra-high wear resistance and corrosion resistance, and is also resistant to high temperature, the alumina ceramic ring is threadedly connected to the seamless steel tube to ensure a reliable connection between the alumina ceramic ring and the seamless steel tube, multiple sections of the alumina ceramic ring are continuously abutted together in the seamless steel tube, and the total length of the alumina ceramic ring can be adjusted according to the length of the seamless steel tube, thereby expanding the application range of the ceramic composite tube in actual production and life, and making the gap between the alumina ceramic rings perpendicular to the material conveying direction, thereby extending the service life of the ceramic composite tube, the outer wall of the alumina ceramic ring is bonded to the inner wall of the seamless steel tube by a special organic ceramic glue, so that the connection between the alumina ceramic ring and the seamless steel tube is tighter and more reliable.

[0006] Preferably, the main raw materials for preparing the alumina ceramic ring include the following components in parts by mass: 2 to 6 parts of silicon dioxide and 85 to 95 parts of aluminum oxide.

[0007] Preferably, the auxiliary preparation raw materials of the alumina ceramic ring include the following components in parts by mass: 1 to 2 parts of calcium oxide, 0.5 to 1.5 parts of magnesium oxide, 0.1 to 1 part of sodium oxide, 0.01 to 0.1 part of ferric oxide, 0.01 to 0.1 part of titanium dioxide and 0.01 to 0.1 part of potassium oxide.

[0008] A method for preparing a ceramic composite tube comprises the following steps: (1) Prepare an alumina ceramic ring, the outer diameter of which is the same as the inner diameter of the seamless steel pipe, to ensure close contact between the alumina ceramic ring and the seamless steel pipe, and at the same time make a long pitch arc-shaped external thread on the outer wall of the alumina ceramic ring; (2) Making a long pitch arc-shaped internal thread on the inner wall of the seamless steel pipe; (3) Apply organic ceramic glue to the outer wall and external thread of the alumina ceramic ring; (4) Continuously placing multiple sections of alumina ceramic rings in a seamless steel pipe, so that the multiple sections of alumina ceramic rings are continuously and tightly threadedly connected to the seamless steel pipe; (5) Let it stand for a while to allow the organic ceramic special glue to dry, and the alumina ceramic ring and the seamless steel pipe to be tightly and reliably bonded together.

[0009] Preferably, the organic ceramic special adhesive is formed by mixing epoxy resin and modified amine curing agent in a ratio of 1:1.

[0010] Preferably, in step (5), the organic ceramic adhesive is heated to 40-60° C. for 1.5-2.5 hours to accelerate the drying speed of the organic ceramic adhesive.

[0011] Preferably, preparing the alumina ceramic ring comprises the following steps: (1) Weigh 2 to 6 parts by weight of silicon dioxide and 85 to 95 parts by weight of aluminum oxide, and ball mill them; (2) adding 1 to 2 parts by weight of calcium oxide, 0.5 to 1.5 parts by weight of magnesium oxide, 0.1 to 1 parts by weight of sodium oxide, 0.01 to 0.1 parts by weight of ferric oxide, 0.01 to 0.1 parts by weight of titanium dioxide, and 0.01 to 0.1 parts by weight of potassium oxide to the product obtained in step (1), and then ball milling the mixture; (3) spray granulating the product obtained in step (2); (4) pouring the microparticles obtained in step (3) into a mold and pressing it into a mold with external threads; (5) placing the model obtained in step (4) in a kiln and firing it to obtain an alumina ceramic ring; (6) The alumina ceramic ring obtained in step (5) is taken out of the kiln and cooled.

[0012] Preferably, the ball milling speed is 300-400 rpm, the ball milling time is 1.5-2.5 h, and the ball-to-material ratio is 20:1.

[0013] Preferably, the thickness of the alumina ceramic ring is 4 to 6 mm.

[0014] Preferably, the firing temperature is 1400-1600° C., and the firing time is 2-4 hours.

[0015] The beneficial effects of the present invention are as follows: multiple sections of alumina ceramic rings are continuously abutted together in the seamless steel pipe, which can not only adjust the total length of the alumina ceramic rings according to the length of the seamless steel pipe, thereby expanding the application range of the ceramic composite pipe in actual production life, but also make the gaps between the alumina ceramic rings perpendicular to the material conveying direction, thereby extending the service life of the ceramic composite pipe. At the same time, the size of the alumina ceramic rings can be adjusted according to the inner diameter size of the seamless steel pipe, thereby expanding the production range. DETAILED DESCRIPTION

[0016] The present invention is further described below.

[0017] A ceramic composite pipe is composed of an outer seamless steel pipe and an inner alumina ceramic ring. The seamless steel pipe has good sealing performance and can withstand higher internal or external pressure. The alumina ceramic ring has ultra-high wear resistance and corrosion resistance, and is also resistant to high temperature. The alumina ceramic ring is threadedly connected to the seamless steel pipe to ensure a reliable connection between the alumina ceramic ring and the seamless steel pipe. Multiple sections of the alumina ceramic ring are continuously abutted together in the seamless steel pipe, which can not only adjust the total length of the alumina ceramic ring according to the length of the seamless steel pipe, thereby expanding the application range of the ceramic composite pipe in actual production and life, but also make the gap between the alumina ceramic rings perpendicular to the material conveying direction, thereby extending the service life of the ceramic composite pipe. The outer wall of the alumina ceramic ring is bonded to the inner wall of the seamless steel pipe by a special organic ceramic glue, so that the connection between the alumina ceramic ring and the seamless steel pipe is tighter and more reliable.

[0018] The main raw materials for preparing the alumina ceramic ring include the following components in parts by mass: 2-6 parts silicon dioxide and 85-95 parts aluminum oxide. The auxiliary raw materials for preparing the alumina ceramic ring include the following components in parts by mass: 1-2 parts calcium oxide, 0.5-1.5 parts magnesium oxide, 0.1-1 part sodium oxide, 0.01-0.1 part ferric oxide, 0.01-0.1 part titanium dioxide, and 0.01-0.1 part potassium oxide.

[0019] A method for preparing a ceramic composite tube comprises the following steps: (1) Prepare an alumina ceramic ring, the outer diameter of which is the same as the inner diameter of the seamless steel pipe, to ensure close contact between the alumina ceramic ring and the seamless steel pipe, and at the same time make a long pitch arc-shaped external thread on the outer wall of the alumina ceramic ring; (2) Making a long pitch arc-shaped internal thread on the inner wall of the seamless steel pipe; (3) Apply organic ceramic glue to the outer wall and external thread of the alumina ceramic ring; (4) Continuously placing multiple sections of alumina ceramic rings in a seamless steel pipe, so that the multiple sections of alumina ceramic rings are continuously and tightly threadedly connected to the seamless steel pipe; (5) Let it stand for a while to allow the organic ceramic special glue to dry, and the alumina ceramic ring and the seamless steel pipe to be tightly and reliably bonded together.

[0020] The organic ceramic special adhesive is prepared by mixing epoxy resin and modified amine curing agent in a ratio of 1:1.

[0021] In step (5), the organic ceramic adhesive is heated to 40-60° C. for 1.5-2.5 hours to accelerate the drying speed of the organic ceramic adhesive.

[0022] The preparation of an alumina ceramic ring comprises the following steps: (1) Weigh 2 to 6 parts by weight of silicon dioxide and 85 to 95 parts by weight of aluminum oxide, and ball mill them; (2) adding 1 to 2 parts by weight of calcium oxide, 0.5 to 1.5 parts by weight of magnesium oxide, 0.1 to 1 parts by weight of sodium oxide, 0.01 to 0.1 parts by weight of ferric oxide, 0.01 to 0.1 parts by weight of titanium dioxide, and 0.01 to 0.1 parts by weight of potassium oxide to the product obtained in step (1), and then ball milling the mixture; (3) spray granulating the product obtained in step (2); (4) pouring the microparticles obtained in step (3) into a mold and pressing it into a mold with external threads; (5) placing the model obtained in step (4) in a kiln and firing it to obtain an alumina ceramic ring; (6) The alumina ceramic ring obtained in step (5) is taken out of the kiln and cooled.

[0023] The ball mill speed is 300-400 rpm, the ball milling time is 1.5-2.5 h, and the ball-to-material ratio is 20:1.

[0024] The thickness of the alumina ceramic ring is 4 to 6 mm.

[0025] The firing temperature is 1400-1600°C, and the firing time is 2-4 hours.

[0026] Example 1

[0027] A ceramic composite pipe is composed of an outer seamless steel pipe and an inner alumina ceramic ring. The seamless steel pipe has good sealing performance and can withstand higher internal or external pressure. The alumina ceramic ring has ultra-high wear resistance and corrosion resistance, and is also resistant to high temperature. The alumina ceramic ring is threadedly connected to the seamless steel pipe to ensure a reliable connection between the alumina ceramic ring and the seamless steel pipe. Multiple sections of the alumina ceramic ring are continuously abutted together in the seamless steel pipe, which can not only adjust the total length of the alumina ceramic ring according to the length of the seamless steel pipe, thereby expanding the application range of the ceramic composite pipe in actual production and life, but also make the gap between the alumina ceramic rings perpendicular to the material conveying direction, thereby extending the service life of the ceramic composite pipe. The outer wall of the alumina ceramic ring is bonded to the inner wall of the seamless steel pipe by a special organic ceramic glue, so that the connection between the alumina ceramic ring and the seamless steel pipe is tighter and more reliable.

[0028] The main raw materials for preparing the alumina ceramic ring include the following components in parts by mass: 2 parts silicon dioxide and 85 parts aluminum oxide. The auxiliary raw materials for preparing the alumina ceramic ring include the following components in parts by mass: 1 part calcium oxide, 0.5 part magnesium oxide, 0.1 part sodium oxide, 0.01 part iron oxide, 0.01 part titanium dioxide, and 0.01 part potassium oxide.

[0029] A method for preparing a ceramic composite tube comprises the following steps: (1) Prepare an alumina ceramic ring, the outer diameter of which is the same as the inner diameter of the seamless steel pipe, to ensure close contact between the alumina ceramic ring and the seamless steel pipe, and at the same time make a long pitch arc-shaped external thread on the outer wall of the alumina ceramic ring; (2) Making a long pitch arc-shaped internal thread on the inner wall of the seamless steel pipe; (3) applying organic ceramic adhesive to the outer wall and external thread of the alumina ceramic ring, wherein the organic ceramic adhesive is a mixture of epoxy resin and modified amine curing agent in a ratio of 1:1; (4) Continuously placing multiple sections of alumina ceramic rings in a seamless steel pipe, so that the multiple sections of alumina ceramic rings are continuously and tightly threadedly connected to the seamless steel pipe; (5) After standing for a period of time, the organic ceramic special adhesive is heated to 40° C. for 1.5 hours to accelerate the drying speed of the organic ceramic special adhesive and tightly and reliably bond the alumina ceramic ring and the seamless steel pipe together.

[0030] The preparation of an alumina ceramic ring comprises the following steps: (1) Weigh 2 parts by weight of silicon dioxide and 85 parts by weight of aluminum oxide, and ball-mill them; (2) adding 1 part by weight of calcium oxide, 0.5 part by weight of magnesium oxide, 0.1 part by weight of sodium oxide, 0.01 part by weight of ferric oxide, 0.01 part by weight of titanium dioxide and 0.01 part by weight of potassium oxide to the product obtained in step (1), and then ball-milling to refine, the ball-milling speed being 300 rpm, the ball-milling time being 1.5 h, and the ball-to-material ratio being 20:1; (3) spray granulating the product obtained in step (2); (4) pouring the granules obtained in step (3) into a mold, and pressing into a model with external threads, the thickness of the alumina ceramic ring being 4 mm; (5) placing the model obtained in step (4) into a kiln, and firing, the firing temperature being 1400°C, and the firing time being 2 h, to obtain an alumina ceramic ring; (6) taking the alumina ceramic ring obtained in step (5) out of the kiln, and cooling.

[0031] Example Two

[0032] A ceramic composite pipe is composed of a seamless steel pipe as an outer layer and an alumina ceramic ring as an inner layer. The seamless steel pipe has good sealing property and can bear higher internal or external pressure. The alumina ceramic ring has super high wear resistance and corrosion resistance, and is also high-temperature resistant. The alumina ceramic ring is threadedly connected with the seamless steel pipe, ensuring reliable connection of the alumina ceramic ring and the seamless steel pipe. The multiple alumina ceramic rings are continuously abutted together in the seamless steel pipe. The total length of the alumina ceramic ring can be adjusted according to the length of the seamless steel pipe, which expands the application range of the ceramic composite pipe in actual production and life, and makes the gap between the alumina ceramic rings perpendicular to the material conveying direction, thereby prolonging the service life of the ceramic composite pipe. The outer wall of the alumina ceramic ring is bonded with the inner wall of the seamless steel pipe by using special organic ceramic glue, so that the connection between the alumina ceramic ring and the seamless steel pipe is more compact and reliable.

[0033] The main preparation raw materials of the alumina ceramic ring include the following components in mass fraction: 6 parts of silicon dioxide and 95 parts of aluminum oxide. The auxiliary preparation raw materials of the alumina ceramic ring include the following components in mass fraction: 2 parts of calcium oxide, 1.5 parts of magnesium oxide, 1 part of sodium oxide, 0.1 part of ferric oxide, 0.1 part of titanium dioxide and 0.1 part of potassium oxide.

[0034] A preparation method of a ceramic composite pipe, comprising the following steps: (1) preparing an alumina ceramic ring, the outer diameter of the alumina ceramic ring being the same as the inner diameter of the seamless steel pipe, so as to ensure the close contact of the alumina ceramic ring and the seamless steel pipe, and a long-pitch circular-arc external thread is made on the outer wall of the alumina ceramic ring; (2) making a long-pitch circular-arc internal thread on the inner wall of the seamless steel pipe; (3) applying organic ceramic adhesive to the outer wall and external thread of the alumina ceramic ring, wherein the organic ceramic adhesive is a mixture of epoxy resin and modified amine curing agent in a ratio of 1:1; (4) Continuously placing multiple sections of alumina ceramic rings in a seamless steel pipe, so that the multiple sections of alumina ceramic rings are continuously and tightly threadedly connected to the seamless steel pipe; (5) After standing for a period of time, the organic ceramic special adhesive is heated to 60° C. for 2.5 hours to accelerate the drying speed of the organic ceramic special adhesive and tightly and reliably bond the alumina ceramic ring and the seamless steel pipe together.

[0035] The preparation of an alumina ceramic ring comprises the following steps: (1) Weigh 6 parts by weight of silicon dioxide and 95 parts by weight of aluminum oxide, and ball mill them; (2) Add 2 parts by weight of calcium oxide, 1.5 parts by weight of magnesium oxide, 1 part by weight of sodium oxide, 0.1 parts by weight of ferric oxide, 0.1 parts by weight of titanium dioxide and 0.1 parts by weight of potassium oxide to the product obtained in step (1), and then ball mill for refinement at a ball milling speed of 400 rpm, a ball milling time of 2.5 h, and a ball-to-material ratio of 20:1; (3) spray granulating the product obtained in step (2); (4) pouring the particles obtained in step (3) into a mold and pressing them into a mold with an external thread, wherein the thickness of the alumina ceramic ring is 6 mm; (5) placing the model obtained in step (4) in a kiln and firing it at a temperature of 1600°C for 4 hours to obtain an alumina ceramic ring; (6) The alumina ceramic ring obtained in step (5) is taken out of the kiln and cooled.

[0036] Example 3

[0037] A ceramic composite pipe is composed of an outer seamless steel pipe and an inner alumina ceramic ring. The seamless steel pipe has good sealing performance and can withstand higher internal or external pressure. The alumina ceramic ring has ultra-high wear resistance and corrosion resistance, and is also resistant to high temperature. The alumina ceramic ring is threadedly connected to the seamless steel pipe to ensure a reliable connection between the alumina ceramic ring and the seamless steel pipe. Multiple sections of the alumina ceramic ring are continuously abutted together in the seamless steel pipe, which can not only adjust the total length of the alumina ceramic ring according to the length of the seamless steel pipe, thereby expanding the application range of the ceramic composite pipe in actual production and life, but also make the gap between the alumina ceramic rings perpendicular to the material conveying direction, thereby extending the service life of the ceramic composite pipe. The outer wall of the alumina ceramic ring is bonded to the inner wall of the seamless steel pipe by a special organic ceramic glue, so that the connection between the alumina ceramic ring and the seamless steel pipe is tighter and more reliable.

[0038] The main raw materials for preparing the alumina ceramic ring include the following components by mass: 3.95 parts silicon dioxide and 92.75 parts aluminum oxide. The auxiliary raw materials for preparing the alumina ceramic ring include the following components by mass: 1.58 parts calcium oxide, 0.75 parts magnesium oxide, 0.5 parts sodium oxide, 0.04 parts iron oxide, 0.06 parts titanium dioxide, and 0.07 parts potassium oxide.

[0039] A method for preparing a ceramic composite tube comprises the following steps: (1) Prepare an alumina ceramic ring, the outer diameter of which is the same as the inner diameter of the seamless steel pipe, to ensure close contact between the alumina ceramic ring and the seamless steel pipe, and at the same time make a long pitch arc-shaped external thread on the outer wall of the alumina ceramic ring; (2) Making a long pitch arc-shaped internal thread on the inner wall of the seamless steel pipe; (3) applying organic ceramic adhesive to the outer wall and external thread of the alumina ceramic ring, wherein the organic ceramic adhesive is a mixture of epoxy resin and modified amine curing agent in a ratio of 1:1; (4) Continuously placing multiple sections of alumina ceramic rings in a seamless steel pipe, so that the multiple sections of alumina ceramic rings are continuously and tightly threadedly connected to the seamless steel pipe; (5) After standing for a period of time, the organic ceramic special adhesive is heated to 50° C. for 2 hours to accelerate the drying speed of the organic ceramic special adhesive and tightly and reliably bond the alumina ceramic ring and the seamless steel pipe together.

[0040] The preparation of an alumina ceramic ring comprises the following steps: (1) Weigh 3.95 parts by weight of silicon dioxide and 92.75 parts by weight of aluminum oxide, and ball mill them; (2) Add 1.58 parts by weight of calcium oxide, 0.75 parts by weight of magnesium oxide, 0.5 parts by weight of sodium oxide, 0.04 parts by weight of ferric oxide, 0.06 parts by weight of titanium dioxide and 0.07 parts by weight of potassium oxide to the product obtained in step (1), and then ball mill for refinement at a ball milling speed of 350 rpm, a ball milling time of 2 h, and a ball-to-material ratio of 20:1; (3) spray granulating the product obtained in step (2); (4) pouring the particles obtained in step (3) into a mold and pressing them into a mold with an external thread, wherein the thickness of the alumina ceramic ring is 5 mm; (5) placing the model obtained in step (4) in a kiln and firing it at a temperature of 1530°C for 3 hours to obtain an alumina ceramic ring; (6) The alumina ceramic ring obtained in step (5) is taken out of the kiln and cooled.

[0041] The above description is only a preferred embodiment of the present invention. Therefore, any equivalent changes or modifications made according to the structure, characteristics and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. A ceramic composite tube, characterized in that: It consists of an outer seamless steel pipe and an inner alumina ceramic ring. The alumina ceramic ring is threadedly connected to the seamless steel pipe. Multiple sections of the alumina ceramic ring are continuously abutted together in the seamless steel pipe. The outer wall of the alumina ceramic ring is bonded to the inner wall of the seamless steel pipe by a special organic ceramic glue.

2. The ceramic composite tube according to claim 1, characterized in that: The main raw materials for preparing the alumina ceramic ring include the following components in parts by mass: 2 to 6 parts of silicon dioxide and 85 to 95 parts of aluminum oxide.

3. The ceramic composite tube according to claim 2, characterized in that: The auxiliary raw materials for preparing the alumina ceramic ring include the following components in parts by mass: 1-2 parts of calcium oxide, 0.5-1.5 parts of magnesium oxide, 0.1-1 part of sodium oxide, 0.01-0.1 part of ferric oxide, 0.01-0.1 part of titanium dioxide and 0.01-0.1 part of potassium oxide.

4. A method for preparing a ceramic composite tube, characterized in that: The following steps are involved: (1) preparing an alumina ceramic ring, wherein the outer diameter of the alumina ceramic ring is the same as the inner diameter of the seamless steel pipe, and making a long pitch arc-shaped external thread on the outer wall of the alumina ceramic ring; (2) Making a long pitch arc-shaped internal thread on the inner wall of the seamless steel pipe; (3) Apply organic ceramic glue to the outer wall and external thread of the alumina ceramic ring; (4) Continuously placing multiple sections of alumina ceramic rings in a seamless steel pipe; (5) Let it stand for a while to allow the organic ceramic glue to dry.

5. The method for preparing a ceramic composite tube according to claim 4, characterized in that: The organic ceramic special adhesive is prepared by mixing epoxy resin and modified amine curing agent in a ratio of 1:

1.

6. The method for preparing a ceramic composite tube according to claim 5, characterized in that: In step (5), the organic ceramic adhesive is heated to 40-60° C. for 1.5-2.5 hours.

7. The method for preparing a ceramic composite tube according to claim 4, characterized in that: The preparation of an alumina ceramic ring comprises the following steps: (1) Weigh 2 to 6 parts by weight of silicon dioxide and 85 to 95 parts by weight of aluminum oxide, and ball mill them; (2) adding 1 to 2 parts by weight of calcium oxide, 0.5 to 1.5 parts by weight of magnesium oxide, 0.1 to 1 parts by weight of sodium oxide, 0.01 to 0.1 parts by weight of ferric oxide, 0.01 to 0.1 parts by weight of titanium dioxide, and 0.01 to 0.1 parts by weight of potassium oxide to the product obtained in step (1), and then ball milling the mixture; (3) spray granulating the product obtained in step (2); (4) pouring the microparticles obtained in step (3) into a mold and pressing it into a mold with external threads; (5) placing the model obtained in step (4) in a kiln and firing it to obtain an alumina ceramic ring; (6) The alumina ceramic ring obtained in step (5) is taken out of the kiln and cooled.

8. The method for preparing a ceramic composite tube according to claim 7, characterized in that: The ball mill speed is 300-400 rpm, the ball milling time is 1.5-2.5 h, and the ball-to-material ratio is 20:

1.

9. The method for preparing a ceramic composite tube according to claim 7, characterized in that: The thickness of the alumina ceramic ring is 4 to 6 mm.

10. The method for preparing a ceramic composite tube according to claim 7, characterized in that: The firing temperature is 1400-1600°C, and the firing time is 2-4 hours.