CN-121990575-A - Method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass

Abstract

The invention relates to the technical field of inorganic nonmetallic materials, in particular to a method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass. The method comprises the steps of taking agricultural waste biomass as a carbon source, combining the agricultural waste biomass with a silicon source, carrying out sol-gel reaction to obtain raw material powder, carrying out compression molding on the raw material powder, and then carrying out microwave heating at 800-1500 ℃ in an air atmosphere for one-step synthesis to obtain SiC powder. The method does not need protective atmosphere, omits carbonization step, has simple process, low cost and environmental protection, ensures that the product morphology comprises nano fibers, particles, rod-shaped structures and the like, realizes the recycling of agricultural wastes, and has good application prospect in the field of advanced ceramics.

Inventors

• GUAN LI
• LI MINGLIANG
• GUO XIAOQIN
• CHENG KEQIANG
• ZHANG RUI
• YANG JUNZHUO
• ZHANG YUANYUAN
• ZHU YUJIE
• HAN SHIJIE
• GAO QIANCHENG
• ZHANG XINYUE

Assignees

• 郑州航空工业管理学院

Dates

Publication Date

20260508

Application Date

20260212

Claims (9)

1. 1. The method for synthesizing the SiC powder by one-step microwave heating of the agricultural waste biomass is characterized by comprising the following steps of: the agricultural waste biomass is taken as a carbon source and combined with a silicon source to carry out sol-gel reaction to obtain a gel-state product; And (3) in an air atmosphere, carrying out microwave heating on the gel product at 800-1500 ℃ for one-step synthesis to obtain SiC powder.
2. 2. The method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass, which is characterized in that the molar ratio of a carbon source to a silicon source is 3:0.8-1.5, and the silicon source is ethyl orthosilicate, silica sol, quartz sand or silicon powder.
3. 3. The method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass according to claim 1, wherein before one-step microwave heating synthesis, a gel product is subjected to compression molding, and the compression molding pressure is 1-50 MPa.
4. 4. The method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass according to claim 1, wherein in the microwave heating process, the temperature is raised from room temperature to 800-1500 ℃ for heat preservation, and the heat preservation time is 0-120 min.
5. 5. The method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass according to claim 1, wherein the microwave heating time is 30-200 min, the frequency is 2450MHz, the wavelength is 1-1 m, and the microwave input power rate is 0.05-1.00 kW/min.
6. 6. The method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass according to claim 1, wherein the temperature of the sol-gel reaction is 40-60 ℃.
7. 7. The method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass according to claim 1, wherein the specific preparation process of the sol-gel reaction comprises the steps of adding a carbon source and a dispersing aid agent into an acidic solution to obtain a mixed solution, then adding a silicon source, and adjusting the pH to hydrolyze the mixed solution into a gel state to obtain a gel state raw material.
8. 8. The method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass according to claim 7 is characterized in that the acidic solution is a citric acid aqueous solution or an oxalic acid aqueous solution, the pH of the acidic solution is 2-4, the molar ratio of a carbon source to acid is 100:8-15, the volume ratio of a silicon source to a dispersing aid is 1-3:3-20, the dispersing aid is absolute ethyl alcohol or water, and the pH is adjusted to be 8-10 by adopting ammonia water or a sodium hydroxide solution.
9. 9. The method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass according to claim 1, wherein the agricultural waste biomass is moldy crops, agricultural waste straws, crop rhizomes, crop leaves or crop shells, the particle size of the agricultural waste biomass is 40-80 meshes, and the steps of pretreatment and pretreatment are drying and grinding.

Description

Method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass Technical Field The invention relates to the technical field of inorganic nonmetallic materials, in particular to a method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass. Background With the continuous improvement of agricultural scale, the yield and year of agricultural waste are increasing. The instability of the climate every year also leads to the occurrence of extensive mildewing, budding and the like of crops, which results in the agricultural economy being hit to different extents. Agricultural waste is a precious biomass resource, and has huge application potential due to wide sources, low cost and various structures, so that the resource utilization of the agricultural waste biomass is urgent. SiC is widely used as a high-performance advanced ceramic in biomass derived products, and is an indispensable strategic material in development processes of high-tech fields due to its excellent physicochemical properties. SiC has high tensile strength, high elastic modulus, excellent high temperature resistance, wear resistance, corrosion resistance and thermal stability, excellent semiconductor characteristics and wide application fields. The conventional method for preparing biomass-derived SiC involves multiple steps, inert atmosphere protection and high-temperature slow reaction. The multi-step is to prepare the SiC material by carbonizing the biomass raw material and then combining with a silicon source, wherein the carbonization is carried out in an inert gas atmosphere within the temperature range of 600-1000 ℃, and the preparation of biomass-derived SiC is also carried out by heating and synthesizing at a temperature higher than 1300 ℃ under the protection of the inert gas atmosphere. Although the methods realize the utilization of agricultural waste resources, the preparation process is complex and the production cost is high. Disclosure of Invention In order to solve the problems, the invention provides a method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass. The invention adopts a one-step synthesis mode to prepare the SiC powder by microwave heating, wherein, the cheap agricultural waste biomass is used as a carbon source, the biomass carbon source and the silicon source are used as raw materials, and a sol-gel method is adopted to prepare the raw material powder, so that the preparation process is optimized, the preparation time is saved, the problems of complex process and high production cost in the existing biomass-derived SiC preparation are solved, and the problem of environmental pollution caused by the traditional agricultural waste treatment mode is solved, thereby realizing one-step synthesis of the biomass-derived SiC powder. In order to achieve the above purpose, the invention adopts the following technical scheme: the invention aims to provide a method for synthesizing SiC powder by one-step microwave heating of agricultural waste biomass, which comprises the following steps: S1, combining agricultural waste biomass serving as a carbon source with a silicon source, and performing sol-gel reaction to obtain a gel product. S2, carrying out microwave heating one-step synthesis on the gel product at 800-1500 ℃ in an air atmosphere to obtain SiC powder. In the preferred embodiment of the invention, the molar ratio of the carbon source to the silicon source is 3:0.8-1.5, and the silicon source is ethyl orthosilicate, silica sol, quartz sand or silicon powder. In a preferred embodiment of the invention, the gel product is subjected to compression molding before microwave heating and one-step synthesis, wherein the compression molding pressure is 1-50 MPa. In the preferred embodiment of the invention, in the microwave heating process, the temperature is raised from room temperature to 800-1500 ℃ for heat preservation, and the heat preservation time is 0 min-120 min. In the preferred embodiment of the invention, the microwave heating time is 30-200 min, the frequency is 2450MHz, the wavelength is 1 mm-1 m, and the microwave input power rate is 0.05 kW/min-1.00 kW/min. In a preferred embodiment of the invention, the sol-gel reaction temperature is 40 ℃ to 60 ℃. In a preferred embodiment of the invention, the specific preparation process of the sol-gel reaction comprises the steps of adding a carbon source and a dispersing aid to an acidic solution to obtain a mixed solution, then adding a silicon source, and adjusting the pH to hydrolyze the mixed solution into a gel state to obtain a gel state raw material. In a preferred embodiment of the invention, the acidic solution is an aqueous solution of citric acid or an aqueous solution of oxalic acid, the pH of the acidic solution is 2-4, the molar ratio of the carbon source to the acid is 100:8-15, the volume ratio of the silicon source to the auxiliary dispersing agent is