Abstract: In order to develop renewable carbon materials that can replace graphite in carbon-containing castables,biochar materials were prepared from straw and rice husk powder,respectively.The effects of the biochar materials and treatment processes (direct pyrolysis carbonization at 900 ℃,hydrothermal treatment at 180 ℃+carbonization at 900 ℃,and hydrothermal catalytic treatment at 180 or 200 ℃+carbonization at 900 ℃) on the phase composition and microstructure of the carbonization products as well as in-situ SiC whisker synthesis were investigated.The results show that after the hydrothermal treatment,the original structure of rice husk and straw partially collapses,hydrolyzes and polymerizes to form carbon microspheres.Amorphous silica and carbon were observed in the straw after hydrothermal catalytic treatment at 200 ℃ and carbonization at 900 ℃; besides the carbon content is the highest,and a large number of carbon microsphere nuclei form on the surface of carbon skeleton.Compared with graphite as the carbon source,a large number of staggered SiC whiskers form in the powder with straw-based biochar.

Key words: biochar, straw, rice husk, hydrothermal method, SiC whisker, microstructure

摘要： 为开发用于含碳浇注料中能替代石墨的可再生碳材料,分别以秸秆和稻壳粉为原料制备生物质炭,研究了生物质种类和处理工艺(直接热解+900 ℃碳化、180 ℃水热+900 ℃碳化、180和200 ℃水热催化+900 ℃碳化)对碳化产物的物相组成、显微结构及对原位合成SiC晶须的影响。结果表明:稻壳与秸秆的原始结构经水热处理后部分坍缩并发生水解聚合生成碳微球。秸秆经200 ℃水热催化+900 ℃碳化后产物中存在明显的非晶态二氧化硅与碳,且碳含量最高,大量碳微球晶核在碳骨架表面形成。相较于以石墨为碳源,添加秸秆基生物质炭的粉体中生成大量交错的SiC晶须。

关键词: 生物质炭, 秸秆, 稻壳, 水热法, SiC晶须, 显微结构