用SiO2微粉制备碳化硅粉体的研究

为回收利用SiO2微粉,探究了以SiO2微粉为原料通过碳热还原法制备碳化硅粉体的最佳工艺条件;研究了分别以石油焦、活性炭和石墨粉为还原剂对冶炼效果的影响。在最佳碳质还原剂的基础上,研究了不同配碳比(还原剂与SiO2微粉的质量比为1∶3.5、1∶3、1∶2.5、1∶2、1∶1.5)和不同冶炼时间(15、30、45、60 min)对冶炼效果的影响。结果表明:石油焦、活性炭、石墨粉3种碳质还原剂中,石油焦的冶炼效果最佳;将石油焦与原料SiO2微粉以质量比1∶2进行混合,在中频感应炉中以1650℃冶炼45 min为最佳冶炼工艺条件;以此能够得到晶粒生长较好、品质较高的碳化硅粉体,碳化硅含量高达93.50%(w)。

Preparation of silicon carbide powder from silica fume

In order to recycle silica fume,the optimum process conditions for preparing silicon carbide powder by carbothermal reduction using silica fume as the raw material were studied.The effects of petroleum coke,activated carbon and graphite powder as reducing agents on the smelting effect were studied.The influences of the carbon ratio(mass ratio of reducing agent to silica fume,1∶3.5,1∶3,1∶2.5,1∶2,and 1∶1.5)and the smelting time(15,30,45,and 60 min)were studied on the basis of the best carbon reducing agent.The results indicate that the petroleum coke has the best smelting effect among the three kinds of carbon reducing agents;the best smelting process condition is the carbon ratio of 1∶2 and the smelting time of 45 min at 1650℃in medium frequency induction furnaces;the high quality silicon carbide powder obtained at the optimum condition has good grain growth and the content of silicon carbide can reach 93.50 mass%.