Preparation method of alkali-erosion-resistant sialon bonded silicon carbide refractory material

Abstract

The invention relates to an in-situ generated sialon high-strength alkali-erosion-resistant refractory material which is characterized in that high-activity monatomic silicon powder, aluminum nitride powder, high-activity a-alumina powder, silicon carbide fine powder, silicon carbide micro powder and a nickel-containing additive are premixed and co-ground in a machine for 25-30 minutes to form co-ground powder; different particles of silicon carbide and white corundum are graded and co-ground into powder, a binding agent is weighed in proportion, the powder and the binding agent are mixed in a wet mill for 25-30 minutes, the mixture is pressed into a green body, and the green body is subjected to nitridation firing at 1450-1500 DEG C; according to the invention, the dual requirements of the porous carbon industry on high strength and alkali corrosion resistance of the refractory material can be met; on the premise that the high-temperature strength is not reduced, the alkali corrosion resistance is improved, and the service life is prolonged by more than two times.

Description

Technical Field

[0001] The invention belongs to the technical field of refractory material preparation, and in particular relates to a method for preparing a alkali-corrosion-resistant Sialon-bonded silicon carbide refractory material. Background Art

[0002] Lithium battery negative electrode material is one of the key materials of lithium-ion batteries, accounting for about 10% of the cost of lithium batteries. Lithium battery negative electrode material plays the role of storing and releasing energy in lithium batteries, and mainly affects the initial efficiency and cycle performance of lithium batteries; silicon-carbon negative electrode material has high energy density, long cycle life, low expansion rate, and good safety performance. Silicon-carbon material is expected to replace graphite as the next generation of high-energy density lithium-ion battery negative electrode material, and its application prospects are very broad; porous carbon material has the advantages of high specific surface area, excellent conductivity and good mechanical stability, so it is an ideal supplementary material for silicon-carbon negative electrode; in the preparation process of fluidized bed CVD silicon-carbon negative electrode, "porous carbon" is indispensable in the upstream raw materials Indispensable key raw materials; porous carbon materials have the advantages of high specific surface area, excellent conductivity and good mechanical stability, and therefore are ideal supplementary materials for silicon-carbon negative electrodes; the preparation of porous carbon skeleton materials is crucial for the production of high-quality silicon-carbon negative electrodes, and the new technical route using porous carbon structure is expected to promote the growth of the industry; the preparation of porous carbon skeleton materials is crucial for the production of high-quality silicon-carbon negative electrodes, and the new technical route using porous carbon structure is expected to promote the growth of the industry; when preparing porous carbon skeletons from biomass raw materials, the chemical activators used are mainly KOH, NaOH and K2CO3. First, the carbon-containing raw materials are impregnated with KOH, NaOH or K2CO3 solution, and then activated under the protection of inert gas at a certain temperature to directly obtain porous carbon.

[0003] In the alkali activation process of porous carbon, the selection of the lining material of the roller kiln and the pad material for the nickel-based alloy sagger is equally important; the solid-liquid changes of potassium and the attachment and corrosion of the foaming in the furnace body during the heating and cooling process of the roller kiln, so the development of a continuous activation furnace with corrosion-resistant materials requires that the lining material and the pad material need to have good resistance to alkali erosion to ensure the long-term stable operation of the kiln; the traditional kiln lining material is alumina hollow ball bricks, and the pad material is oxide-bonded silicon carbide pads, which have poor resistance to alkali erosion during use, the roller kiln collapses, and the pad has a short service life. Therefore, the development of a high-strength alkali-resistant refractory material for the lining and pad of a porous carbon activated roller kiln is of great significance to the service life and operation safety of the porous carbon activated roller kiln. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a method for preparing an alkali-resistant Sialon-bonded silicon carbide refractory material suitable for porous carbon activated roller kiln linings and pads.

[0005] The present invention adopts the following technical solutions to achieve the above-mentioned purpose: A method for preparing an alkali-corrosion-resistant Sialon-bonded silicon carbide refractory material, wherein the raw material composition and weight percentage of the Sialon-bonded silicon carbide refractory material are as follows: 50-70wt% of silicon carbide particles, 3-8wt% of white corundum particles, 8-15wt% of high-activity elemental silicon powder, 4-10wt% of silicon carbide fine powder, 4-10wt% of high-activity α-alumina powder, 2-5wt% of aluminum nitride powder, 2-5wt% of silicon carbide micropowder, 0.1-1wt% of a nickel-containing additive, 2-5wt% of calcium wood sulfonate, and 1-2wt% of water; the nickel-containing additive, calcium wood sulfonate and water are added externally; wherein the silicon carbide particles are composed of three silicon carbide particles with different particle sizes of 1.5-2.5mm, 0.5-1.5 and 0-0.5mm, and the contents are 1 0-15wt%, 25-40wt%, 10-15wt%; wherein the white corundum particles are composed of two different particle sizes of 0-1mm and 1-3mm, and the contents are 2-5wt% and 1-3wt% respectively; the high-activity elemental silicon powder, aluminum nitride powder, high-activity a-alumina powder, silicon carbide fine powder, silicon carbide micropowder, and nickel-containing additives are premixed to form a mixed powder; calcium wood sulfonate and water form a mixed liquid; the silicon carbide particles and the mixed liquid are uniformly mixed to form a uniform film of the additive on the surface of the particles; the mixed powder is mixed with the mixed particles uniformly covered with a film to obtain a mixture; the mixture is placed in a vibration molding machine for molding treatment to obtain a green body; after the obtained green body is dried, it is placed in a nitriding sintering furnace for nitriding treatment to prepare a nickel-based-sialon combined with silicon carbide composite material.

[0006] The silicon carbide fine powder D 50 ≤10μm.

[0007] The D 50 ≤10μm.

[0008] The D of the highly active α-alumina powder 50 ≤10μm.

[0009] The aluminum nitride powder D 50 ≤10μm.

[0010] The silicon carbide powder D 50 ≤2.5μm.

[0011] The nickel-containing additive is one or more of nickel oxide or nickel-iron alloy powder.

[0012] The present invention proposes a method for preparing a alkali-resistant Sialon-bonded silicon carbide refractory material, which adopts the above technical solution and has the following beneficial effects: In order to better adapt to the corrosive environment of the porous carbon industry for lithium battery negative electrodes, meet the higher requirements for refractory materials' resistance to alkali corrosion while taking into account the high strength of the materials, the present invention, based on the Sialon combined with silicon carbide refractory materials, introduces nickel-containing additives into silicon powder as a diluent, which not only utilizes the reaction temperature reduction brought about by its low melting point and high activity, but also avoids the reaction channel being blocked prematurely due to large-area molten silicon, causing "silicon flow" and affecting the high-temperature performance of the material; at the same time, nickel is stable in caustic soda (NaOH and KOH) solutions at all concentrations and temperatures, and is the best material resistant to hot concentrated alkali and molten alkali corrosion; therefore, the introduction of nickel-containing additives improves the alkali corrosion resistance of the Sialon combined with silicon carbide composite material to a certain extent.

[0013] The present invention can meet the dual requirements of the porous carbon industry for high strength and alkali corrosion resistance of refractory materials; it can improve alkali corrosion resistance without reducing high-temperature strength and increase the service life by more than 2 times. DETAILED DESCRIPTION

[0014] The present invention will be further described below in conjunction with specific embodiments: Embodiment 1:

[0015] The mixed raw materials were weighed by mass percentage: the contents of silicon carbide particles with particle sizes of 1.5-2.5mm, 0.5-1.5, and 0-0.5mm were 10wt%, 35wt%, and 15wt%, respectively; the contents of white corundum particles with particle sizes of 0-1mm and 1-3mm were 5wt% and 3wt%, respectively; high-activity elemental silicon powder was 15wt%, silicon carbide fine powder was 4wt%, high-activity α-alumina powder was 8wt%, aluminum nitride powder was 2wt%, silicon carbide micropowder was 3wt%, and nickel oxide was added. 0.3wt%, calcium lignosulfonate was 3wt%, and water was 1.5wt%. The mixture was loaded into a mold and vibrated into shape. After drying, it was placed in a nitriding sintering furnace and nitrided at 1450°C. Finally, it was cooled to room temperature with the furnace to prepare a nickel-based-sialon-corundum-silicon carbide composite material. After testing, the performance indicators of the nitride-bonded corundum-silicon carbide ceramic composite material prepared in this embodiment are: volume density 2.70g / cm 3 , porosity 15%, room temperature compressive strength 202MPa, high temperature flexural strength 46MPa, quality change rate before and after 1300℃ anti-melting alkali test ≤5%. Embodiment 2:

[0016] The mixed raw materials were weighed by mass percentage: the contents of silicon carbide particles with particle sizes of 1.5-2.5mm, 0.5-1.5, and 0-0.5mm were 15wt%, 40wt%, and 15wt%, respectively; the contents of white corundum particles with particle sizes of 0-1mm and 1-3mm were 3wt% and 2wt%, respectively; high-activity elemental silicon powder was 10wt%, silicon carbide fine powder was 5wt%, high-activity α-alumina powder was 6wt%, aluminum nitride powder was 2wt%, silicon carbide micropowder was 2wt%, and nickel oxide was added. 0.3wt%, calcium lignosulfonate was 2.5wt%, and water was 1.2wt%. The mixture was loaded into a mold and vibrated into shape. After drying, it was placed in a nitriding sintering furnace and nitrided at 1450°C. Finally, it was cooled to room temperature with the furnace to prepare a nitride-bonded corundum-silicon carbide composite material. After testing, the performance indicators of the nickel-based-sialon-corundum-silicon carbide composite material prepared in this embodiment are: volume density 2.70g / cm 3 , porosity 15%, room temperature compressive strength 202MPa, high temperature flexural strength 46MPa, quality change rate before and after 1300℃ anti-melting alkali test ≤5%. Embodiment 3:

[0017] The mixed raw materials were weighed by mass percentage: the contents of silicon carbide particles with particle sizes of 1.5-2.5mm, 0.5-1.5, and 0-0.5mm were 10wt%, 35wt%, and 15wt%, respectively; the contents of white corundum particles with particle sizes of 0-1mm and 1-3mm were 5wt% and 1wt%, respectively; high-activity elemental silicon powder was 14wt%, silicon carbide fine powder was 5wt%, high-activity α-alumina powder was 8wt%, aluminum nitride powder was 2wt%, silicon carbide micropowder was 5wt%, and nickel-iron alloy powder was 0.5wt%, calcium wood sulfonate was 3wt%, and water was 1.5wt%. The mixture was loaded into a mold and vibrated into shape. After drying, it was placed in a nitriding sintering furnace and nitrided at 1450°C. Finally, it was cooled to room temperature with the furnace to prepare a nitride-bonded corundum-silicon carbide composite material. After testing, the performance indicators of the nickel-sialon-corundum-silicon carbide composite material prepared in this embodiment are: volume density 2.70g / cm 3 , porosity 15%, room temperature compressive strength 202MPa, high temperature flexural strength 46MPa, quality change rate before and after 1300℃ anti-melting alkali test ≤5%.

Claims

1. A method for preparing an alkali-resistant Sialon-bonded silicon carbide refractory material, characterized in that: The raw material composition and weight percentage of the Sialon-bonded silicon carbide refractory material are as follows: 50-70wt% of silicon carbide particles, 3-8wt% of white corundum particles, 8-15wt% of high-activity elemental silicon powder, 4-10wt% of silicon carbide fine powder, 4-10wt% of high-activity α-alumina powder, 2-5wt% of aluminum nitride powder, 2-5wt% of silicon carbide micropowder, 0.1-1wt% of nickel-containing additives, 2-5wt% of calcium wood sulfonate, and 1-2wt% of water; the nickel-containing additives, calcium wood sulfonate and water are added externally; wherein the silicon carbide particles are composed of three different particle sizes of silicon carbide particles of 1.5-2.5mm, 0.5-1.5 and 0-0.5mm, and the contents are 10-15wt%, 25-4 0wt%, 10-15wt%; wherein the white corundum particles are composed of two different particle sizes of 0-1mm and 1-3mm, and the contents are 2-5wt% and 1-3wt% respectively; the high-activity elemental silicon powder, aluminum nitride powder, high-activity α-alumina powder, silicon carbide fine powder, silicon carbide micropowder, and nickel-containing additives are premixed to form a mixed powder; calcium wood sulfonate and water form a mixed liquid; the silicon carbide particles and the mixed liquid are uniformly mixed to form a uniform film of the additive on the surface of the particles; the mixed powder is mixed with the mixed particles uniformly covered with a film to obtain a mixture; the mixture is placed in a vibration molding machine for molding treatment to obtain a green body; after the obtained green body is dried, it is placed in a nitriding sintering furnace for nitriding treatment to prepare a nickel-based-sialon combined with silicon carbide composite material.

2. The method for preparing the alkali-resistant Sialon-bonded silicon carbide refractory material according to claim 1, characterized in that: The silicon carbide fine powder D 50 ≤10μm.

3. The method for preparing the alkali-resistant Sialon-bonded silicon carbide refractory material according to claim 1, characterized in that: The D 50 ≤10μm.

4. The method for preparing the alkali-resistant Sialon-bonded silicon carbide refractory material according to claim 1, characterized in that: The D of the highly active α-alumina powder 50 ≤10μm.

5. The method for preparing the alkali-resistant Sialon-bonded silicon carbide refractory material according to claim 1, characterized in that: The aluminum nitride powder D 50 ≤10μm.

6. The method for preparing the alkali-resistant Sialon-bonded silicon carbide refractory material according to claim 1, characterized in that: The D of the silicon carbide powder 50 ≤2.5μm.

7. The method for preparing the alkali-resistant Sialon-bonded silicon carbide refractory material according to claim 1, characterized in that: The nickel-containing additive is one or more of nickel oxide or nickel-iron alloy powder.