关键词: 生物质炭, 秸秆, 稻壳, 水热法, SiC晶须, 显微结构

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