CN114394844A - Method for preparing silicon carbide ceramic by 3D printing of waste and silicon carbide ceramic - Google Patents

Abstract

The invention discloses a method for preparing silicon carbide ceramic by waste 3D printing and the silicon carbide ceramic. The method comprises the following steps: sequentially carbonizing and crushing the wood waste to obtain wood carbon powder; mixing the wood carbon powder with a binder, and performing 3D printing and forming to obtain a wood carbon blank; dissolving carbon-containing waste in an organic solvent to obtain a carbon-containing solution, and immersing the wooden carbon blank in the carbon-containing solution for solution impregnation pyrolysis to obtain a wooden carbon preform; and evaporating silicon in the silicon-containing waste material by heating to obtain gas-phase silicon, and sintering the wood-carbon prefabricated body in the gas-phase silicon to obtain the silicon carbide ceramic. The invention comprehensively utilizes the wood waste, the carbon-containing waste and the silicon-containing waste with high efficiency, and prepares the silicon carbide by gas-phase reaction sintering of the silicon-containing waste, thereby solving the technical problems of high cost, impurity pollution, incapability of preparing silicon carbide ceramics with complex structures and the like at present.

Description

Translated fromChinese

一种废料3D打印制备碳化硅陶瓷的方法及碳化硅陶瓷Method for preparing silicon carbide ceramics by 3D printing of waste materials and silicon carbide ceramics

技术领域technical field

本发明属于碳化硅陶瓷技术领域，更具体地，涉及一种废料3D打印制备碳化硅陶瓷的方法及碳化硅陶瓷。The invention belongs to the technical field of silicon carbide ceramics, and more particularly relates to a method for preparing silicon carbide ceramics by 3D printing of waste materials and silicon carbide ceramics.

背景技术Background technique

碳化硅陶瓷具有良好的化学稳定性、高导热性、低热膨胀性和高抗热震性等综合品质，在航空航天、汽车、化学催化、热交换和电磁吸收/屏蔽等领域应用广泛。目前，SiC陶瓷主要合成途径包括化学气相沉积、先驱体浸渍裂解和反应熔渗等，这些方法所需的原料和设备昂贵，因此亟需一种可有效降低碳化硅生产的原料成本和反应温度的方法，从而提高碳化硅陶瓷的经济性和应用范围。Silicon carbide ceramics have comprehensive qualities such as good chemical stability, high thermal conductivity, low thermal expansion and high thermal shock resistance, and are widely used in aerospace, automotive, chemical catalysis, heat exchange and electromagnetic absorption/shielding. At present, the main synthesis methods of SiC ceramics include chemical vapor deposition, precursor impregnation cracking and reaction infiltration, etc. The raw materials and equipment required for these methods are expensive, so a kind of raw material cost and reaction temperature that can effectively reduce the production of silicon carbide is urgently needed. method, thereby improving the economy and application range of silicon carbide ceramics.

人类在生活和生产过程中产生大量的固体废料。如木材是世界上最丰富的可再生和可持续资源，在人们的生产和生活中占有重要地位，可用于制作器具、家具和建筑物等。然而在木材产品的加工和生产过程中，却不可避免地产生木质废料，如稻壳、秸秆、落叶、枯草、树枝和木屑等。煤炭和石油都属于化石能源，是有机质经过千万年甚至亿年的演化形成的不可再生资源，石油被称为“工业的血液”，煤炭被称为“工业的粮食”，随着开采日益加剧，人类面临着严重的资源短缺问题，然而石油和煤炭资源利用过程中产生的煤灰、石油沥青、煤焦沥青等残渣废料造成了严重的环境保护问题。随者光伏产业发展，硅片切割过程中不可避免会产生许多硅泥废料，不仅损失了昂贵的晶体硅，同时还会造成严重的环境污染。随着“碳中和、碳达峰”目标的提出，资源的回收与利用也成为了重要的减排手段。有效提高废物资源利用率和产品附加值是人们关注的重点。Humans generate a large amount of solid waste in the process of life and production. For example, wood is the most abundant renewable and sustainable resource in the world and plays an important role in people's production and life, and can be used to make utensils, furniture and buildings. However, during the processing and production of wood products, wood wastes, such as rice husks, straws, fallen leaves, dry grass, branches and wood chips, are inevitably generated. Both coal and oil belong to fossil energy sources, which are non-renewable resources formed by the evolution of organic matter over tens of millions of years or even hundreds of millions of years. Oil is called "the blood of industry", and coal is called "the food of industry". However, the residues and wastes such as coal ash, petroleum pitch, coal tar pitch and other wastes produced in the utilization of petroleum and coal resources have caused serious environmental protection problems. With the development of the photovoltaic industry, a lot of silicon mud waste will inevitably be generated in the process of silicon wafer cutting, which not only loses expensive crystalline silicon, but also causes serious environmental pollution. With the goal of "carbon neutrality and carbon peaking", the recycling and utilization of resources has also become an important means of emission reduction. Effectively improving the utilization rate of waste resources and the added value of products is the focus of people's attention.

目前，已有研究工作通过固体废料制备碳化硅陶瓷，如201711057626.6公开了一种金刚石切割废料制备高品质碳化硅的方法，该发明通过将含硅金刚石线切割废料、高纯碳粉和还原剂压制成球后再经过高温冶炼、破碎和酸洗获得碳化硅粉，极大利用了含硅废料。但是，该发明仍需要高成本的高纯碳源作为反应物，且在冶炼过程中，废料中杂质的污染无法避免，需要进一步的纯化工艺，得到的碳化硅粉体需要进一步加工得到构件。201710725687.9公开了一种用晶体硅的碳化硅切割废料制备碳化硅多孔陶瓷的方法，该发明将晶体硅切割废料与碳粉、铵盐、酚醛树脂充分混合后干压成型，经高温烧结得到碳化硅多孔陶瓷。但该方法无法避免废料中杂质污染的问题，大大降低了碳化硅陶瓷的品质，且干压成型无法制备复杂结构的碳化硅陶瓷，需要进一步机加工以满足使用需求。At present, research work has been done to prepare silicon carbide ceramics from solid waste. For example, 201711057626.6 discloses a method for preparing high-quality silicon carbide from diamond cutting waste. After being formed into balls, silicon carbide powder is obtained by high-temperature smelting, crushing and pickling, which makes great use of silicon-containing waste. However, this invention still requires a high-cost high-purity carbon source as a reactant, and in the smelting process, the pollution of impurities in the waste cannot be avoided, and further purification processes are required, and the obtained silicon carbide powder needs to be further processed to obtain components. 201710725687.9 discloses a method for preparing silicon carbide porous ceramics from silicon carbide cutting waste of crystalline silicon. The invention fully mixes the crystalline silicon cutting waste with carbon powder, ammonium salt, and phenolic resin, and then dry pressing and molding, and sintering at high temperature to obtain silicon carbide Porous ceramics. However, this method cannot avoid the problem of impurity contamination in waste materials, which greatly reduces the quality of silicon carbide ceramics, and dry pressing cannot prepare silicon carbide ceramics with complex structures, and further machining is required to meet the needs of use.

发明内容SUMMARY OF THE INVENTION

针对现有技术的以上缺陷或改进需求，本发明提供了一种废料3D打印制备碳化硅陶瓷的方法及碳化硅陶瓷，其目的在于通过对木质废料、含碳废料及含硅废料的高效综合利用，通过含硅废料气相反应烧结制备获得碳化硅，由此解决目前高成本、杂质污染、无法制备复杂结构的碳化硅陶瓷等的技术问题。In view of the above defects or improvement needs of the prior art, the present invention provides a method for preparing silicon carbide ceramics by 3D printing of waste materials and silicon carbide ceramics, the purpose of which is to efficiently and comprehensively utilize wood waste, carbon-containing waste and silicon-containing waste. , silicon carbide is prepared by gas-phase reaction sintering of silicon-containing waste, thereby solving the current technical problems of high cost, impurity pollution, and inability to prepare silicon carbide ceramics with complex structures.

为实现上述目的，按照本发明的一个方面，提供了一种废料3D打印制备碳化硅陶瓷的方法，包括下列步骤：In order to achieve the above object, according to one aspect of the present invention, a method for preparing silicon carbide ceramics by 3D printing of waste materials is provided, comprising the following steps:

S1：将木质废料依次经过碳化、粉碎后得到木质碳粉；S1: the wood waste is sequentially carbonized and pulverized to obtain wood toner;

S2：将所述木质碳粉与粘结剂混合，通过3D打印成形得到木质碳坯体；S2: mixing the wood carbon powder with a binder, and forming a wood carbon body by 3D printing;

S3：将含碳废料溶于有机溶剂中得到含碳溶液，将所述木质碳坯体浸入所述含碳溶液中进行溶液浸渍热解得到木质碳预制体；S3: dissolving carbon-containing waste in an organic solvent to obtain a carbon-containing solution, and immersing the lignocarbon body in the carbon-containing solution for solution immersion and pyrolysis to obtain a lignocarbon preform;

S4：通过加热使含硅废料中硅蒸发得到气相硅，将所述木质碳预制体在气相硅中进行烧结得到碳化硅陶瓷。S4: vaporizing silicon in the silicon-containing waste by heating to obtain fumed silicon, and sintering the wood-carbon preform in the fumed silicon to obtain silicon carbide ceramics.

优选地，在步骤S1中，所述木质废料为稻壳、秸秆、落叶、枯草、树枝、木块和木屑中的一种或几种。Preferably, in step S1, the wood waste is one or more of rice husks, straws, fallen leaves, dry grass, branches, wood blocks and wood chips.

优选地，所述的木质碳粉的粒径为0.5～100微米；所述的3D打印成形为立体光固化成形、粉末床熔融成形、材料挤出成形或粘结剂喷射成形。Preferably, the particle size of the wood carbon powder is 0.5-100 microns; and the 3D printing molding is stereo light curing molding, powder bed fusion molding, material extrusion molding or binder injection molding.

优选地，所述含碳废料为石油沥青和/或煤焦沥青，所述有机溶剂为汽油、柴油、煤油、二甲苯、甲苯、二硫化碳、四氯化碳和正己烷中的一种或多种；所述含碳废料与有机溶剂的质量比为(1～5)：5。此处，低于这一比例会导致浸渍液固含量偏低，浸渍后质量变化不大，高于这一比例会难以溶解完全。Preferably, the carbon-containing waste is petroleum pitch and/or coal tar pitch, and the organic solvent is one or more of gasoline, diesel, kerosene, xylene, toluene, carbon disulfide, carbon tetrachloride and n-hexane ; The mass ratio of the carbon-containing waste to the organic solvent is (1-5):5. Here, if the ratio is lower than this, the solid content of the impregnating liquid will be low, and the quality of the impregnation will not change much. If the ratio is higher than this ratio, it will be difficult to dissolve completely.

优选地，所述溶液浸渍热解具体包括：将所述木质碳坯体浸入含碳溶液中，在真空浸渍罐中抽真空至0～200Pa，保压15～60min后移至真空气氛碳化炉中，通入保护气体，以0.1～5℃/min的升温速率加热至800～1200℃，保温2～10h后获得木质碳预制体。Preferably, the solution immersion pyrolysis specifically includes: immersing the wood-based carbon body in a carbon-containing solution, vacuuming to 0-200 Pa in a vacuum immersion tank, maintaining the pressure for 15-60 min, and then transferring it to a carbonization furnace in a vacuum atmosphere , introducing protective gas, heating to 800-1200° C. at a heating rate of 0.1-5° C./min, and keeping the temperature for 2-10 hours to obtain a wood-based carbon preform.

优选地，所述方法还包括：通过重复步骤S3的次数来调节木质碳预制体的孔隙率，重复步骤S3的次数越多，所述木质碳预制体的孔隙率越小，所述木质碳预制体的孔隙率为35～80％。Preferably, the method further comprises: adjusting the porosity of the ligno-carbon preform by repeating the number of times of step S3, the more times the step S3 is repeated, the smaller the porosity of the ligno-carbon preform, the The porosity of the body is 35-80%.

优选地，在步骤S4中，所述含硅废料为硅泥废料和/或煤灰；所述含硅废料与木质碳预制体的质量比为(2.5～5.5)：1。其中，硅泥废料例如为在硅片切割过程中产生，本发明中硅泥废料来源于光伏硅片切割过程中的废料。Preferably, in step S4, the silicon-containing waste is silicon mud waste and/or coal ash; the mass ratio of the silicon-containing waste to the wood-carbon preform is (2.5-5.5):1. Wherein, the silicon mud waste is, for example, generated in the process of cutting silicon wafers, and the silicon mud waste in the present invention is derived from the wastes in the cutting process of photovoltaic silicon wafers.

含硅废料与木质碳预制体的质量比和含硅废料有关，当含硅废料为硅泥废料时，其中硅单质占有很大比例，按照硅碳计量比则选择较小的质量比例2.5：1，当含硅废料为煤灰时，其中二氧化硅占有很大比例，按照硅碳计量比则选择较大的质量比例5.5：1，若为二者的混合物，则选择中间的比例即可。The mass ratio of the silicon-containing waste to the wood-carbon preform is related to the silicon-containing waste. When the silicon-containing waste is silicon mud waste, the silicon element occupies a large proportion. According to the silicon-carbon metering ratio, a smaller mass ratio of 2.5:1 is selected. , when the silicon-containing waste is coal ash, in which silicon dioxide occupies a large proportion, according to the silicon-carbon metering ratio, the larger mass ratio of 5.5:1 is selected. If it is a mixture of the two, the middle ratio can be selected.

优选地，所述步骤S4具体为：将含硅废料在100～200℃的烘箱中保温10～24h烘干，经烘干后的含硅废料铺放在坩埚底部，将木质碳预制体放于坩埚中的支撑体上；将坩埚放入真空气氛烧结炉中，通入保护气或抽真空，以5～10℃/min的升温速率加热至1300～1800℃，保温2～5h获得碳化硅陶瓷。Preferably, the step S4 is specifically as follows: drying the silicon-containing waste at a temperature of 100-200° C. for 10-24 hours, placing the dried silicon-containing waste on the bottom of the crucible, and placing the wood-based carbon preform on the bottom of the crucible. On the support body in the crucible; put the crucible into the vacuum atmosphere sintering furnace, pass in protective gas or vacuumize, heat it to 1300-1800 ℃ at a heating rate of 5-10 ℃/min, and keep it for 2-5 hours to obtain silicon carbide ceramics .

按照本发明的另一个方面，提供了一种碳化硅陶瓷。According to another aspect of the present invention, a silicon carbide ceramic is provided.

优选地，所述碳化硅陶瓷的孔隙率为2～70％。Preferably, the porosity of the silicon carbide ceramic is 2-70%.

总体而言，通过本发明所构思的以上技术方案与现有技术相比，至少能够取得下列有益效果。In general, compared with the prior art, the above technical solutions conceived by the present invention can at least achieve the following beneficial effects.

(1)本发明采用木质废料、含碳废料和含硅废料为原料，木质废料经过处理后获得木质碳粉，采用3D打印技术成形木质碳坯体，木质碳坯体此时具有一定的孔隙率，将该木质碳坯体浸入溶解有含碳废料的有机溶液中，经过溶液浸渍热解可以使得碳进入木质碳坯体的孔隙中，对其进行增密，从而改变木质碳坯体的孔隙率。然后含硅废料气相反应烧结获得宏观结构可控的碳化硅零件。该方法实现了木质废弃物、含碳废料和含硅废料的高效综合合理应用，所使用的原料均为廉价易得的废料，加以回收利用后可大大减少环境污染，并降低碳化硅生产成本，有效提高了废物资源的利用率和产品附加值，促进了可持续发展。同时，采用3D打印技术可以有效解决碳化硅陶瓷复杂异形零件加工难的问题，根据需求成形所需结构的碳化硅零件，进一步拓展了碳化硅陶瓷的应用范围。(1) The present invention uses wood waste, carbon-containing waste and silicon-containing waste as raw materials, the wood waste is processed to obtain wood carbon powder, and the 3D printing technology is used to form a wood carbon body, and the wood carbon body has a certain porosity at this time. , the woody carbon body is immersed in an organic solution that dissolves carbon-containing waste, and through solution immersion and pyrolysis, carbon can enter the pores of the woody carbon body and densify it, thereby changing the porosity of the woody carbon body. . The silicon-containing waste is then sintered by gas-phase reaction sintering to obtain silicon carbide parts with controllable macrostructure. The method realizes the efficient, comprehensive and rational application of wood waste, carbon-containing waste and silicon-containing waste. It effectively improves the utilization rate of waste resources and the added value of products, and promotes sustainable development. At the same time, the use of 3D printing technology can effectively solve the problem of difficult processing of complex special-shaped parts of silicon carbide ceramics, and form silicon carbide parts with the required structure according to requirements, which further expands the application scope of silicon carbide ceramics.

(2)本发明提供的方法通过重复步骤S3的次数来调节木质碳预制体的孔隙率，重复步骤S3的次数越多，所述木质碳预制体的孔隙率越小，本发明中所述木质碳预制体的孔隙率为35～80％。实现了在含碳溶液浸渍热解阶段，可以控制该过程的次数实现木质碳坯体的孔隙率调控，从而得到孔隙率符合要求的木质碳预制体。(2) The method provided by the present invention adjusts the porosity of the wood-based carbon preform by repeating the number of times of step S3. The more times the step S3 is repeated, the smaller the porosity of the wood-carbon preform. The porosity of the carbon preform is 35-80%. It is realized that in the carbon-containing solution impregnation pyrolysis stage, the times of the process can be controlled to realize the regulation of the porosity of the wood-based carbon body, thereby obtaining a wood-based carbon preform with a porosity that meets the requirements.

(3)本发明在步骤S4含硅废料的气相反应烧结过程中，采用“架空”的烧结方案，通过加热使含硅废料中的硅蒸发获得气相硅源，即烘干后的含硅废料铺放在坩埚底部，将木质碳预制体放于坩埚中的支撑体上，使气相硅源与木质碳预制体反应，防止木质碳预制体与含硅废料直接接触，避免了含硅废料中的杂质对碳化硅造成污染。(3) In the present invention, in the gas-phase reaction sintering process of the silicon-containing waste in step S4, the "overhead" sintering scheme is adopted, and the silicon in the silicon-containing waste is evaporated by heating to obtain a gas-phase silicon source, that is, the dried silicon-containing waste is laid. Put it at the bottom of the crucible, put the wood carbon preform on the support in the crucible, make the gas phase silicon source react with the wood carbon preform, prevent the wood carbon preform from directly contacting the silicon-containing waste, and avoid impurities in the silicon-containing waste Contamination of silicon carbide.

(4)本发明所采用的木质废料3D打印-含碳废料浸渍热解-含硅废料气相反应烧结的方案不采用高纯度原料即可获得综合性能好的碳化硅陶瓷，各个步骤均有相应的科学原理为依据，可行性强。3D打印是一种基于离散-堆积原理的材料成形技术，无需复杂模具，只要根据模型的三维数据文件便可以驱动3D打印机工作成形所需的零件，利于实现高性能复杂碳化硅的高效、低碳、绿色制备与应用，3D打印是一种“增材”加工方式，相较于传统的“减材”加工，可整体成形复杂结构零件，实现原料可循环利用，进一步降低了原料成本。并且本发明所使用的3D打印技术覆盖面广，可根据实际需求选择相应的3D打印技术，以满足大、中、小尺寸复杂碳化硅构件的多样化制备与应用。(4) The scheme of wood waste 3D printing-carbon-containing waste impregnation and pyrolysis-silicon-containing waste gas-phase reaction sintering adopted in the present invention can obtain silicon carbide ceramics with good comprehensive performance without using high-purity raw materials, and each step has corresponding It is based on scientific principles and has strong feasibility. 3D printing is a material forming technology based on the principle of discrete-accumulation. It does not require complex molds. As long as the three-dimensional data files of the model are used, the 3D printer can be driven to form the required parts, which is conducive to the realization of high-efficiency, low-carbon and high-performance complex silicon carbide. , Green preparation and application, 3D printing is an "additive" processing method. Compared with traditional "subtractive" processing, it can form complex structural parts as a whole, realize the recycling of raw materials, and further reduce the cost of raw materials. In addition, the 3D printing technology used in the present invention has a wide coverage, and the corresponding 3D printing technology can be selected according to actual needs to meet the diversified preparation and application of large, medium and small-sized complex silicon carbide components.

附图说明Description of drawings

图1是本发明较佳实施例提供的废料3D打印制备碳化硅陶瓷的方法流程图。FIG. 1 is a flowchart of a method for preparing silicon carbide ceramics by 3D printing of waste materials provided by a preferred embodiment of the present invention.

具体实施方式Detailed ways

为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。此外，下面所描述的本发明各个实施方式中所涉及到的技术特征只要彼此之间未构成冲突就可以相互组合。In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

本发明提供的废料3D打印制备碳化硅陶瓷的方法，首先以木质废料碳化、机械粉碎后获得的木质碳粉作为3D打印的原料，然后通过3D打印成形所需结构的木质碳坯体，再经过含碳废料溶液浸渍热解后获得孔隙率可控的木质碳预制体，最后经过含硅废料气相反应烧结获得碳化硅陶瓷。The method for preparing silicon carbide ceramics by waste 3D printing provided by the present invention firstly uses wood carbon powder obtained by carbonizing and mechanically pulverizing wood waste as a raw material for 3D printing, and then forms a wood carbon body with a desired structure through 3D printing, and then passes through The carbon-containing waste solution is impregnated and pyrolyzed to obtain a wood-carbon preform with controllable porosity, and finally silicon carbide ceramics are obtained by gas-phase reaction sintering of the silicon-containing waste.

参见图1，具体包括以下步骤：See Figure 1, which includes the following steps:

S1：将木质废料依次经过碳化、粉碎后得到木质碳粉；S1: the wood waste is sequentially carbonized and pulverized to obtain wood toner;

所述木质废料优选为稻壳、秸秆、落叶、枯草、树枝、木块和木屑中的一种或几种。The wood waste is preferably one or more of rice husks, straws, fallen leaves, dry grass, branches, wood blocks and sawdust.

所述碳化包括以下步骤：将所述木质废料置于碳化炉中，通入氮气或氩气作为保护气体，以10℃/min的升温速率加热至800℃，保温5h获得木质碳，再通过机械粉碎筛分后获得木质碳粉。The carbonization includes the following steps: placing the wood waste in a carbonization furnace, feeding nitrogen or argon as a protective gas, heating to 800° C. at a heating rate of 10° C./min, maintaining the temperature for 5 hours to obtain wood carbon, and then passing the mechanical After crushing and sieving, wood carbon powder is obtained.

所述木质碳粉的粒径优选为0.5～100微米。The particle size of the wood carbon powder is preferably 0.5-100 microns.

S2：将所述木质碳粉与粘结剂混合，通过3D打印成形得到木质碳坯体；S2: mixing the wood carbon powder with a binder, and forming a wood carbon body by 3D printing;

所述粘结剂优选为尼龙粉末、聚醚砜粉末、环氧树脂粉末、液体环氧树脂AB胶、液态酚醛树脂和光敏树脂的一种或多种。The binder is preferably one or more of nylon powder, polyethersulfone powder, epoxy resin powder, liquid epoxy resin AB glue, liquid phenolic resin and photosensitive resin.

将所述粘结剂与木质碳粉进行混合后，采用3D打印技术成形木质碳坯体；所述3D打印技术优选为立体光固化、粉末床熔融、材料挤出、粘结剂喷射。After mixing the binder with the wood carbon powder, a 3D printing technology is used to form a wood carbon body; the 3D printing technology is preferably stereo light curing, powder bed melting, material extrusion, and binder injection.

S3：将含碳废料溶于有机溶剂中得到含碳溶液，将所述木质碳坯体浸入所述含碳溶液中进行溶液浸渍热解得到木质碳预制体；S3: dissolving carbon-containing waste in an organic solvent to obtain a carbon-containing solution, and immersing the lignocarbon body in the carbon-containing solution for solution immersion and pyrolysis to obtain a lignocarbon preform;

所述含碳废料优选为含碳废料为石油沥青和/或煤焦沥青，所述有机溶剂优选为汽油、柴油、煤油、二甲苯、甲苯、二硫化碳、四氯化碳和正己烷中的一种或多种；所述含碳废料和有机溶剂的质量比优选为(1～5)：5；将含碳废料和有机溶剂充分混合后置于超声装置中获得含碳溶液。The carbon-containing waste is preferably petroleum pitch and/or coal tar pitch, and the organic solvent is preferably one of gasoline, diesel oil, kerosene, xylene, toluene, carbon disulfide, carbon tetrachloride and n-hexane or more; the mass ratio of the carbon-containing waste and the organic solvent is preferably (1-5):5; the carbon-containing waste and the organic solvent are fully mixed and placed in an ultrasonic device to obtain a carbon-containing solution.

所述溶液浸渍热解包括以下步骤：将所述木质碳坯体置于含碳溶液中，在真空浸渍罐中抽真空至0～200Pa，保压15～60min后移至真空气氛碳化炉中，通保护气氛，以0.1～5℃/min的升温速率加热至800～1200℃，保温2～10h后获得木质碳预制体，通过重复步骤S3的次数来调节木质碳预制体的孔隙率，重复步骤S3的次数越多，所述木质碳预制体的孔隙率越小，所述木质碳预制体的孔隙率为35～80％。The solution impregnation pyrolysis includes the following steps: placing the wood-based carbon body in a carbon-containing solution, vacuuming to 0-200 Pa in a vacuum impregnation tank, maintaining the pressure for 15-60 min, and then transferring it to a carbonization furnace in a vacuum atmosphere, Passing through a protective atmosphere, heating to 800-1200°C at a heating rate of 0.1-5°C/min, and keeping the temperature for 2-10 hours to obtain a wood-carbon preform, and adjusting the porosity of the wood-carbon preform by repeating the number of times of step S3, repeating the steps The more times of S3, the smaller the porosity of the wood-carbon preform, and the porosity of the wood-carbon preform is 35-80%.

S4：通过加热使含硅废料中硅蒸发得到气相硅，将所述木质碳预制体在气相硅中进行烧结得到碳化硅陶瓷。S4: vaporizing silicon in the silicon-containing waste by heating to obtain fumed silicon, and sintering the wood-carbon preform in the fumed silicon to obtain silicon carbide ceramics.

所述含硅废料优选为硅泥废料和/或煤灰；所述含硅废料与木质碳预制体的质量比为(2.5～5.5)：1。The silicon-containing waste is preferably silicon mud waste and/or coal ash; the mass ratio of the silicon-containing waste to the wood-based carbon preform is (2.5-5.5):1.

所述气相反应烧结包括以下步骤：将含硅废料放在100～200℃的烘箱中保温10～24h烘干；之后取一定量的含硅废料铺放在坩埚底部，将木质碳预制体放在支撑体上放在坩埚中并用盖子盖上；将坩埚放入真空气氛烧结炉中，通入保护气或抽真空，以5～10℃/min的升温速率加热至1300～1800℃，保温2～5h获得碳化硅。The gas-phase reaction sintering includes the following steps: placing the silicon-containing waste in an oven at 100-200° C. for 10-24 hours and drying; then taking a certain amount of the silicon-containing waste and laying it on the bottom of the crucible, and placing the wood carbon preform on the bottom of the crucible. The support is placed in a crucible and covered with a lid; the crucible is placed in a vacuum atmosphere sintering furnace, a protective gas or vacuum is introduced, and heated to 1300-1800 ℃ at a heating rate of 5-10 ℃/min, and the temperature is kept for 2- 5h to obtain silicon carbide.

所述碳化硅的孔隙率优选为2～70％。The porosity of the silicon carbide is preferably 2 to 70%.

下面通过具体实施例对本发明的技术方案进行详细说明：The technical scheme of the present invention is described in detail below by specific embodiments:

实施例1Example 1

S1：将秸秆置于碳化炉中，通入氮气作为保护气体，以10℃/min的升温速率加热至800℃，保温5h获得木质碳，机械粉碎过筛后获得粒径为50微米的木质碳粉。S1: Put the straw in a carbonization furnace, introduce nitrogen as a protective gas, heat it to 800 °C at a heating rate of 10 °C/min, keep it for 5 hours to obtain wood carbon, mechanically pulverize and sieve to obtain wood carbon with a particle size of 50 microns pink.

S2：选择尼龙粉末为粘结剂，与木质碳粉进行混合，设计所需的模型，通过粉末床熔融成形得到木质碳坯体；打印后的木质碳坯体孔隙为60％～70％。S2: Select nylon powder as a binder, mix with wood carbon powder, design the required model, and obtain a wood carbon body through powder bed fusion molding; the porosity of the printed wood carbon body is 60% to 70%.

S3：将石油沥青溶于汽油中获得含碳溶液，二者质量比为1：5，充分混合后置于超声装置中获得含碳废料溶液。将所述木质碳坯体置于含碳废料溶液中，在真空浸渍罐中抽真空至200Pa，保压15min后移至真空气氛碳化炉中，通保护气氛，以5℃/min的升温速率加热至800℃，保温2h后获得孔隙率为80％木质碳预制体。S3: dissolving petroleum pitch in gasoline to obtain a carbon-containing solution, the mass ratio of the two is 1:5, fully mixed and placed in an ultrasonic device to obtain a carbon-containing waste solution. The woody carbon body was placed in a carbon-containing waste solution, evacuated to 200Pa in a vacuum impregnation tank, moved to a vacuum atmosphere carbonization furnace after maintaining the pressure for 15min, passed through a protective atmosphere, and heated at a heating rate of 5°C/min To 800 ℃, after 2 hours of heat preservation, a wood-carbon preform with a porosity of 80% was obtained.

S4：选择硅泥废料，与木质碳预制体的质量比为2.5：1，将硅泥废料放在100℃的烘箱中保温24h烘干；铺放在坩埚底部，将木质碳预制体放在支撑体上放在坩埚中并用盖子盖上；将坩埚放入真空气氛烧结炉中，通入保护气，以5℃/min的升温速率加热至1300℃，保温2h获得孔隙率为70％的碳化硅。S4: Select the silicon mud waste, the mass ratio to the wood carbon preform is 2.5:1, put the silicon mud waste in an oven at 100°C for 24 hours and dry it; lay it at the bottom of the crucible, and place the wood carbon preform on the support Put the crucible in a crucible and cover it with a lid; put the crucible into a vacuum atmosphere sintering furnace, pass in protective gas, heat it to 1300 °C at a heating rate of 5 °C/min, and keep it for 2 hours to obtain silicon carbide with a porosity of 70%. .

实施例2Example 2

S1：将稻壳置于碳化炉中，通入氩气作为保护气体，以10℃/min的升温速率加热至800℃，保温5h获得木质碳，机械粉碎过筛后获得粒径为0.5微米的木质碳粉。S1: Put the rice husks in a carbonization furnace, pass argon gas as a protective gas, heat to 800 °C at a heating rate of 10 °C/min, keep for 5 hours to obtain wood carbon, and mechanically pulverize and sieve to obtain a particle size of 0.5 μm. Wood toner.

S2：选择光敏树脂为粘结剂，与木质碳粉进行混合，设计所需的模型，通过立体光固化成形得到木质碳坯体；S2: Select the photosensitive resin as the binder, mix it with the wood carbon powder, design the required model, and obtain the wood carbon body by stereo light curing;

S3：将煤焦沥青溶于柴油中获得含碳溶液，二者质量比为5：5，充分混合后置于超声装置中获得含碳废料溶液。将所述木质碳坯体置于含碳废料溶液中，在真空浸渍罐中抽真空至0Pa，保压60min后移至真空气氛碳化炉中，通保护气氛，以0.1℃/min的升温速率加热至800℃，保温10h后获得孔隙率为35％的木质碳预制体。S3: dissolving coal tar pitch in diesel oil to obtain a carbon-containing solution, the mass ratio of the two is 5:5, fully mixed and placed in an ultrasonic device to obtain a carbon-containing waste solution. The woody carbon body was placed in a carbon-containing waste solution, evacuated to 0 Pa in a vacuum impregnation tank, moved to a vacuum atmosphere carbonization furnace after maintaining the pressure for 60 min, passed through a protective atmosphere, and heated at a heating rate of 0.1 °C/min. At 800°C, the wood-carbon preform with a porosity of 35% was obtained after being kept for 10 hours.

S4：选择煤灰，与木质碳预制体的质量比为5.5：1，将硅泥废料放在200℃的烘箱中保温12h烘干；铺放在坩埚底部，将木质碳预制体放在支撑体上放在坩埚中并用盖子盖上；将坩埚放入真空气氛烧结炉中，通入保护气，以10℃/min的升温速率加热至1800℃，保温5h获得孔隙率为2％的碳化硅。S4: Select coal ash, the mass ratio of the wood-carbon preform is 5.5:1, put the silicon mud waste in an oven at 200°C for 12 hours and dry it; lay it at the bottom of the crucible, and place the wood-carbon preform on the support Put it in a crucible and cover it with a lid; put the crucible into a vacuum atmosphere sintering furnace, pass in a protective gas, heat it to 1800°C at a heating rate of 10°C/min, and keep it for 5h to obtain silicon carbide with a porosity of 2%.

实施例3Example 3

S1：将木块置于碳化炉中，通入氩气作为保护气体，以10℃/min的升温速率加热至800℃，保温5h获得木质碳，机械粉碎过筛后获得粒径为100微米的木质碳粉。S1: Put the wood block in a carbonization furnace, pass argon gas as a protective gas, heat it to 800 °C at a heating rate of 10 °C/min, keep it for 5 hours to obtain wood carbon, and mechanically pulverize and sieve to obtain a particle size of 100 microns. Wood toner.

S2：选择液态酚醛树脂为粘结剂，设计所需的模型，通过粘结剂喷射与木质碳粉进行混合成形得到木质碳坯体；S2: Select the liquid phenolic resin as the binder, design the required model, and form the wood carbon body by mixing the binder jet with the wood carbon powder;

S3：将石油沥青溶于二甲苯中获得含碳溶液，二者质量比为2：5，充分混合后置于超声装置中获得含碳废料溶液。将所述木质碳坯体置于含碳废料溶液中，在真空浸渍罐中抽真空至100Pa，保压30min后移至真空气氛碳化炉中，通保护气氛，以5℃/min的升温速率加热至1200℃，保温5h后获得孔隙率为50％的木质碳预制体。S3: Dissolving petroleum pitch in xylene to obtain a carbon-containing solution, the mass ratio of the two is 2:5, fully mixed and placed in an ultrasonic device to obtain a carbon-containing waste solution. The woody carbon body was placed in a carbon-containing waste solution, evacuated to 100Pa in a vacuum impregnation tank, moved to a vacuum atmosphere carbonization furnace after maintaining the pressure for 30min, passed through a protective atmosphere, and heated at a heating rate of 5°C/min At 1200°C, the wood-carbon preform with a porosity of 50% was obtained after being kept for 5 hours.

S4：选择硅泥废料和煤灰，二者以质量比1：1的比例充分混合，含硅废料与木质碳预制体的以质量比为4：1，将含硅废料放在150℃的烘箱中保温16h烘干；铺放在坩埚底部，将木质碳预制体放在支撑体上放在坩埚中并用盖子盖上；将坩埚放入真空气氛烧结炉中，通入保护气，以5℃/min的升温速率加热至1600℃，保温3h获得孔隙率为21％的碳化硅。S4: Select silicon mud waste and coal ash, and mix them fully in a mass ratio of 1:1. The mass ratio of silicon-containing waste and wood-carbon preform is 4:1. Place the silicon-containing waste in an oven at 150 °C Incubate for 16h and dry in medium; lay it on the bottom of the crucible, place the wood-carbon preform on the support, put it in the crucible and cover it with a lid; put the crucible into the vacuum atmosphere sintering furnace, pass in the protective gas, and heat it at 5℃/ The heating rate of min was heated to 1600 °C, and the temperature was maintained for 3 h to obtain silicon carbide with a porosity of 21%.

实施例4Example 4

S1：将木屑置于碳化炉中，通入氮气作为保护气体，以5℃/min的升温速率加热至800℃，保温3h获得木质碳，机械粉碎过筛后获得粒径为1微米的木质碳粉。S1: Put the wood chips in a carbonization furnace, introduce nitrogen as a protective gas, heat to 800°C at a heating rate of 5°C/min, keep the temperature for 3 hours to obtain wood carbon, and obtain wood carbon with a particle size of 1 micron after mechanical pulverization and sieving. pink.

S2：选择液态酚醛树脂为粘结剂，与木质碳粉进行混合，设计所需的模型，通过材料挤出成形得到木质碳坯体；S2: Select liquid phenolic resin as binder, mix with wood carbon powder, design the required model, and obtain wood carbon body by material extrusion;

S3：将煤焦沥青溶于甲苯中获得含碳溶液，二者质量比为3：5，充分混合后置于超声装置中获得含碳废料溶液。将所述木质碳坯体置于含碳废料溶液中，在真空浸渍罐中抽真空至200Pa，保压60min后移至真空气氛碳化炉中，通保护气氛，以1℃/min的升温速率加热至1000℃，保温2h后获得孔隙率为60％的木质碳预制体。S3: Dissolving coal tar pitch in toluene to obtain a carbon-containing solution, the mass ratio of the two is 3:5, fully mixed and placed in an ultrasonic device to obtain a carbon-containing waste solution. The woody carbon body was placed in a carbon-containing waste solution, evacuated to 200 Pa in a vacuum impregnation tank, moved to a vacuum atmosphere carbonization furnace after maintaining the pressure for 60 min, and heated at a heating rate of 1°C/min through a protective atmosphere. At 1000°C, the wood-based carbon preform with a porosity of 60% was obtained after being kept for 2 hours.

S4：选择硅泥废料和煤灰，二者以质量比2：1的比例充分混合，含硅废料与木质碳预制体的以质量比为3.5：1，将含硅废料放在200℃的烘箱中保温12h烘干；铺放在坩埚底部，将木质碳预制体放在支撑体上放在坩埚中并用盖子盖上；将坩埚放入真空气氛烧结炉中，通入保护气，以10℃/min的升温速率加热至1500℃，保温5h获得孔隙率为36％的碳化硅。S4: Select silicon mud waste and coal ash, and mix them fully in a mass ratio of 2:1. The mass ratio of silicon-containing waste and wood-carbon preform is 3.5:1. Place the silicon-containing waste in an oven at 200°C. Incubate for 12h and dry in medium; lay it on the bottom of the crucible, put the wood-carbon preform on the support, put it in the crucible and cover it with a lid; put the crucible into the vacuum atmosphere sintering furnace, pass in the protective gas, and heat it at 10℃/ The heating rate of min was heated to 1500 °C, and the temperature was kept for 5 h to obtain silicon carbide with a porosity of 36%.

实施例5Example 5

S1：将木屑置于碳化炉中，通入氮气作为保护气体，以5℃/min的升温速率加热至800℃，保温3h获得木质碳，机械粉碎过筛后获得粒径为30微米的木质碳粉。S1: Put the wood chips in a carbonization furnace, introduce nitrogen as a protective gas, heat to 800°C at a heating rate of 5°C/min, keep the temperature for 3 hours to obtain wood carbon, mechanically pulverize and sieve to obtain wood carbon with a particle size of 30 microns pink.

S2：选择聚醚砜粉末为粘结剂，与木质碳粉进行混合，设计所需的模型，通过粉末床熔融成形得到木质碳坯体；S2: Select polyethersulfone powder as binder, mix with wood carbon powder, design the required model, and obtain wood carbon body by powder bed fusion molding;

S3：将煤焦沥青溶于正己烷中获得含碳溶液，二者质量比为5：5，充分混合后置于超声装置中获得含碳废料溶液。将所述木质碳坯体置于含碳废料溶液中，在真空浸渍罐中抽真空至100Pa，保压30min后移至真空气氛碳化炉中，通保护气氛，以1℃/min的升温速率加热至1000℃，保温2h后获得孔隙率为80％的木质碳预制体。S3: dissolving coal tar pitch in n-hexane to obtain a carbon-containing solution, the mass ratio of the two is 5:5, fully mixed and placed in an ultrasonic device to obtain a carbon-containing waste solution. The woody carbon body was placed in a carbon-containing waste solution, evacuated to 100 Pa in a vacuum impregnation tank, moved to a vacuum atmosphere carbonization furnace after maintaining the pressure for 30 min, passed through a protective atmosphere, and heated at a heating rate of 1 °C/min. At 1000°C, the wood-carbon preform with porosity of 80% was obtained after holding for 2 hours.

S4：选择硅泥废料和煤灰，二者以质量比1：1的比例充分混合，含硅废料与木质碳预制体的以质量比为3.5：1，将含硅废料放在200℃的烘箱中保温12h烘干；铺放在坩埚底部，将木质碳预制体放在支撑体上放在坩埚中并用盖子盖上；将坩埚放入真空气氛烧结炉中，通入保护气，以10℃/min的升温速率加热至1500℃，保温3h获得孔隙率为70％的碳化硅。S4: Select silicon mud waste and coal ash, and mix them fully in a mass ratio of 1:1. The mass ratio of silicon-containing waste and wood-carbon preform is 3.5:1. Place the silicon-containing waste in an oven at 200°C Incubate for 12h and dry in medium; lay it on the bottom of the crucible, put the wood-carbon preform on the support, put it in the crucible and cover it with a lid; put the crucible into the vacuum atmosphere sintering furnace, pass in the protective gas, and heat it at 10℃/ The heating rate of min was heated to 1500 °C, and the temperature was maintained for 3 h to obtain silicon carbide with a porosity of 70%.

实施例6Example 6

S1：将木屑置于碳化炉中，通入氮气作为保护气体，以5℃/min的升温速率加热至800℃，保温3h获得木质碳，机械粉碎过筛后获得粒径为60微米的木质碳粉。S1: Put the wood chips in a carbonization furnace, introduce nitrogen as a protective gas, heat to 800°C at a heating rate of 5°C/min, keep the temperature for 3 hours to obtain wood carbon, and obtain wood carbon with a particle size of 60 microns after mechanical pulverization and screening pink.

S2：选择环氧树脂粉末为粘结剂，与木质碳粉进行混合，设计所需的模型，通过粉末床熔融成形得到木质碳坯体；S2: Select epoxy resin powder as binder, mix with wood carbon powder, design the required model, and obtain wood carbon body by powder bed fusion molding;

S3：将煤焦沥青溶于正己烷中获得含碳溶液，二者质量比为5：5，充分混合后置于超声装置中获得含碳废料溶液。将所述木质碳坯体置于含碳废料溶液中，在真空浸渍罐中抽真空至100Pa，保压60min后移至真空气氛碳化炉中，通保护气氛，以1℃/min的升温速率加热至1000℃，保温2h后获得孔隙率为50％的木质碳预制体。S3: dissolving coal tar pitch in n-hexane to obtain a carbon-containing solution, the mass ratio of the two is 5:5, fully mixed and placed in an ultrasonic device to obtain a carbon-containing waste solution. The woody carbon body was placed in a carbon-containing waste solution, evacuated to 100Pa in a vacuum impregnation tank, moved to a vacuum atmosphere carbonization furnace after maintaining the pressure for 60min, passed through a protective atmosphere, and heated at a heating rate of 1°C/min At 1000°C, the wood-carbon preform with porosity of 50% was obtained after holding for 2 hours.

S4：选择硅泥废料和煤灰，二者以质量比0.5：1的比例充分混合，含硅废料与木质碳预制体的以质量比为3.5：1，将含硅废料放在200℃的烘箱中保温12h烘干；铺放在坩埚底部，将木质碳预制体放在支撑体上放在坩埚中并用盖子盖上；将坩埚放入真空气氛烧结炉中，通入保护气，以10℃/min的升温速率加热至1500℃，保温3h获得孔隙率为21％的碳化硅。S4: Select silicon mud waste and coal ash, and mix them fully in a mass ratio of 0.5:1. The mass ratio of silicon-containing waste and wood-carbon preform is 3.5:1. Place the silicon-containing waste in an oven at 200°C Incubate for 12h and dry in medium; lay it on the bottom of the crucible, put the wood-carbon preform on the support, put it in the crucible and cover it with a lid; put the crucible into the vacuum atmosphere sintering furnace, pass in the protective gas, and heat it at 10℃/ The heating rate of min was heated to 1500 °C, and the temperature was maintained for 3 h to obtain silicon carbide with a porosity of 21%.

实施例7Example 7

S1：将木屑置于碳化炉中，通入氮气作为保护气体，以5℃/min的升温速率加热至800℃，保温3h获得木质碳，机械粉碎过筛后获得粒径为60微米的木质碳粉。S1: Put the wood chips in a carbonization furnace, introduce nitrogen as a protective gas, heat to 800°C at a heating rate of 5°C/min, keep the temperature for 3 hours to obtain wood carbon, and obtain wood carbon with a particle size of 60 microns after mechanical pulverization and screening pink.

S2：选择环氧树脂AB胶为粘结剂，与木质碳粉进行混合，设计所需的模型，通过粉末床熔融成形得到木质碳坯体；S2: Select epoxy resin AB glue as binder, mix with wood carbon powder, design the required model, and obtain wood carbon body by powder bed fusion molding;

S3：将石油沥青溶于四氯化碳获得含碳溶液，二者质量比为2：5，充分混合后置于超声装置中获得含碳废料溶液。将所述木质碳坯体置于含碳废料溶液中，在真空浸渍罐中抽真空至0Pa，保压60min后移至真空气氛碳化炉中，通保护气氛，以1℃/min的升温速率加热至1000℃，保温2h后获得孔隙率为60％的木质碳预制体。S3: dissolving petroleum pitch in carbon tetrachloride to obtain a carbon-containing solution, the mass ratio of the two is 2:5, fully mixed and placed in an ultrasonic device to obtain a carbon-containing waste solution. The woody carbon body was placed in a carbon-containing waste solution, evacuated to 0 Pa in a vacuum impregnation tank, moved to a vacuum atmosphere carbonization furnace after maintaining the pressure for 60 min, passed through a protective atmosphere, and heated at a heating rate of 1 °C/min. At 1000°C, the wood-based carbon preform with a porosity of 60% was obtained after being kept for 2 hours.

S4：选择硅泥废料和煤灰，二者以质量比2：1的比例充分混合，含硅废料与木质碳预制体的以质量比为3.5：1，将含硅废料放在200℃的烘箱中保温12h烘干；铺放在坩埚底部，将木质碳预制体放在支撑体上放在坩埚中并用盖子盖上；将坩埚放入真空气氛烧结炉中，通入保护气，以10℃/min的升温速率加热至1500℃，保温3h获得孔隙率为36％的碳化硅。S4: Select silicon mud waste and coal ash, and mix them fully in a mass ratio of 2:1. The mass ratio of silicon-containing waste and wood-carbon preform is 3.5:1. Place the silicon-containing waste in an oven at 200°C. Incubate for 12h and dry in medium; lay it on the bottom of the crucible, put the wood-carbon preform on the support, put it in the crucible and cover it with a lid; put the crucible into the vacuum atmosphere sintering furnace, pass in the protective gas, and heat it at 10℃/ The heating rate of min was heated to 1500 °C, and the temperature was kept for 3 h to obtain silicon carbide with a porosity of 36%.

实施例8Example 8

S1：将木屑置于碳化炉中，通入氮气作为保护气体，以5℃/min的升温速率加热至800℃，保温3h获得木质碳，机械粉碎过筛后获得粒径为0.5微米的木质碳粉。S1: Put the wood chips in a carbonization furnace, introduce nitrogen as a protective gas, heat to 800 °C at a heating rate of 5 °C/min, keep the temperature for 3 hours to obtain wood carbon, mechanically pulverize and sieve to obtain wood carbon with a particle size of 0.5 μm pink.

S2：选择液态环氧树脂为粘结剂，与木质碳粉进行混合，设计所需的模型，通过材料挤出成形得到木质碳坯体；S2: Select the liquid epoxy resin as the binder, mix it with the wood carbon powder, design the required model, and obtain the wood carbon body through material extrusion;

S3：将石油沥青溶于二甲苯获得含碳溶液，二者质量比为5：5，充分混合后置于超声装置中获得含碳废料溶液。将所述木质碳坯体置于含碳废料溶液中，在真空浸渍罐中抽真空至0Pa，保压60min后移至真空气氛碳化炉中，通保护气氛，以1℃/min的升温速率加热至1000℃，保温2h后获得孔隙率为35％的木质碳预制体。S3: Dissolving petroleum pitch in xylene to obtain a carbon-containing solution, the mass ratio of the two is 5:5, fully mixed and placed in an ultrasonic device to obtain a carbon-containing waste solution. The woody carbon body was placed in a carbon-containing waste solution, evacuated to 0 Pa in a vacuum impregnation tank, moved to a vacuum atmosphere carbonization furnace after maintaining the pressure for 60 min, passed through a protective atmosphere, and heated at a heating rate of 1 °C/min. At 1000°C, the wood-carbon preform with a porosity of 35% was obtained after being kept for 2 hours.

S4：选择硅泥废料和煤灰，二者以质量比2：1的比例充分混合，含硅废料与木质碳预制体的以质量比为3.5：1，将含硅废料放在200℃的烘箱中保温12h烘干；铺放在坩埚底部，将木质碳预制体放在支撑体上放在坩埚中并用盖子盖上；将坩埚放入真空气氛烧结炉中，通入保护气，以10℃/min的升温速率加热至1500℃，保温3h获得孔隙率为2％的碳化硅。S4: Select silicon mud waste and coal ash, and mix them fully in a mass ratio of 2:1. The mass ratio of silicon-containing waste and wood-carbon preform is 3.5:1. Place the silicon-containing waste in an oven at 200°C Incubate for 12h and dry in medium; lay it on the bottom of the crucible, put the wood-carbon preform on the support, put it in the crucible and cover it with a lid; put the crucible into the vacuum atmosphere sintering furnace, pass in the protective gas, and heat it at 10℃/ The heating rate of min was heated to 1500 °C, and the temperature was kept for 3 h to obtain silicon carbide with a porosity of 2%.

本领域的技术人员容易理解，以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (10)

1. A method for preparing silicon carbide ceramic by 3D printing of waste materials is characterized by comprising the following steps:

s1: sequentially carbonizing and crushing the wood waste to obtain wood carbon powder;

s2: mixing the wood carbon powder with a binder, and performing 3D printing and forming to obtain a wood carbon blank;

s3: dissolving carbon-containing waste in an organic solvent to obtain a carbon-containing solution, and immersing the wooden carbon blank in the carbon-containing solution for solution impregnation pyrolysis to obtain a wooden carbon preform;

s4: and evaporating silicon in the silicon-containing waste material by heating to obtain gas-phase silicon, and sintering the wood-carbon prefabricated body in the gas-phase silicon to obtain the silicon carbide ceramic.

2. The method of claim 1, wherein in step S1, the wood waste is one or more of rice hulls, straw, fallen leaves, hay, branches, wood pieces, and wood chips.

3. The method according to claim 1 or 2, wherein the particle size of the wood carbon powder is 0.5 to 100 μm; the 3D printing and forming is three-dimensional photocuring forming, powder bed melting forming, material extrusion forming or binder spraying forming.

4. The method of claim 1, wherein the carbon-containing waste material is petroleum pitch and/or coal tar pitch, and the organic solvent is one or more of gasoline, diesel, kerosene, xylene, toluene, carbon disulfide, carbon tetrachloride, and n-hexane; the mass ratio of the carbon-containing waste to the organic solvent is (1-5): 5.

5. the method of claim 1, wherein the solution dip pyrolysis specifically comprises: and immersing the wood carbon blank into a carbon-containing solution, vacuumizing the carbon-containing solution to 0-200 Pa in a vacuum impregnation tank, maintaining the pressure for 15-60 min, moving the carbon-containing solution to a vacuum atmosphere carbonization furnace, introducing protective gas, heating the carbon-containing solution to 800-1200 ℃ at the heating rate of 0.1-5 ℃/min, and preserving the heat for 2-10 h to obtain the wood carbon preform.

6. The method of claim 5, wherein the method further comprises: adjusting the porosity of the woody carbon preform by repeating the step S3 for a greater number of times, the less the porosity of the woody carbon preform is, the more the step S3 is repeated, the porosity of the woody carbon preform is 35 to 80%.

7. The method of claim 1, wherein in step S4, the silicon-containing waste is silicon sludge waste and/or coal ash; the mass ratio of the silicon-containing waste to the wood-carbon prefabricated body is (2.5-5.5): 1.

8. the method according to claim 1, wherein the step S4 is specifically: the method comprises the following steps of (1) keeping the temperature of silicon-containing waste materials in an oven at 100-200 ℃ for 10-24 h, drying, laying the dried silicon-containing waste materials at the bottom of a crucible, and placing a wood-carbon prefabricated body on a supporting body in the crucible; and (3) putting the crucible into a vacuum atmosphere sintering furnace, introducing protective gas or vacuumizing, heating to 1300-1800 ℃ at a heating rate of 5-10 ℃/min, and preserving heat for 2-5 h to obtain the silicon carbide ceramic.

9. A silicon carbide ceramic prepared according to the method of any one of claims 1-8.

10. The silicon carbide ceramic according to claim 9, wherein the silicon carbide ceramic has a porosity of 2 to 70%.

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