摘要
首先将菱镁石在850℃下煅烧2h获得轻烧氧化镁,并将其水化成氢氧化镁;然后以这种氢氧化镁（烘干后）为原料,分别按细磨-轻烧、细磨-轻烧-细磨、轻烧-细磨3种细磨工艺制备轻烧氧化镁（分别在500-900℃保温1h的条件下轻烧）;再将轻烧氧化镁粉末成型、干燥后,在电炉中于1600℃煅烧3h得到烧结镁砂,考察了细磨工艺对烧结镁砂体积密度的影响。结果表明（1）将氢氧化镁按细磨-轻烧-细磨-成型-烧结的工艺可以制得高密度的烧结镁砂。这是由于两道细磨工序严重破坏了氧化镁晶体的假晶结构及其之间的团聚现象,减少了二次气孔的存在,提高了素坯体积密度,从而提高了烧结镁砂的体积密度。（2）通过对烧结镁砂的显微组织结构分析,确定该工艺的最佳轻烧温度为850℃,此时可以制得体积密度达到3.46g·cm-3,晶粒较大且均匀的烧结镁砂。
First,magnesite was burned at 850 ℃ for 2 h.Then,the production is converted into magnesium hydrate using hydration method.The process of producing high-density sintered magnesia with magnesium hydrate as raw material was explored.The experimental results showed that sintered magnesia with bulk density of 3.46 g·cm^-3 can be obtained by the technic-flow of grinding-calcined-grinding-molding-sintering.The pseudomorphological skeletons of Mg（OH）2 crystals and aggregates had partially collapsed after grinding ,and with the decrement of secondary pores ,the green bulk density was increased ,which resulted in the increase of sintered bulk density. SEM photomicrographs were taken of two high density sintered mag- nesia,and analysis of the grain size showed that the optimum calcination temperature should to be 850℃.
出处
《耐火材料》
EI
CAS
北大核心
2007年第2期122-125,129,共5页
Refractories
关键词
菱镁石
轻烧
细磨
水化
氧化镁
烧结镁砂
高密度
Magnesite
Calcination
Grinding
Hydration
Magnesia
Sintering
High-density
