Abstract: Low grade magnesite is one of the main research directions in the future as the raw material for the preparation of magnesia based insulating refractories.Periclase-forsterite (MgO-Mg₂SiO₄) lightweight insulating refractories were prepared by the molten salt method with high silicon magnesite and cut-off grade talc ore as raw materials by pretreating them to get light burnt magnesia and talc,and NaCl molten salt as the reaction medium.The effects of the NaCl addition,the sintering temperature,the holding time and the raw material ratio on the specimen preparation were studied.The results show that when the NaCl addition is 20% of the mass of light burnt magnesia and talc mixture,the sintering temperature is 1 200 ℃,the holding time is 6 h,and m(light burnt magnesia)∶m(talc)=5∶5,the specimen has the optimal comprehensive properties:the bulk density of 1.46 g·cm^-3 and the apparent porosity of 55.0%.In addition,it is found that self-decomposition of talc and the formation of forsterite can form pores inside the specimen.

Key words: sodium chloride molten salt, periclase, forsterite, lightweight insulating material

摘要： 低品位菱镁矿作为制备镁质隔热耐火材料的原料是未来的主要研究方向之一。以高硅菱镁矿和三级滑石矿为原料,经预处理后得到轻烧镁粉和滑石粉,以NaCl熔盐为反应介质,通过熔盐法制备了方镁石-镁橄榄石(MgO-Mg₂SiO₄)轻质隔热耐火材料。研究了NaCl加入量、烧结温度、保温时间以及原料配比对试样制备的影响。结果表明:当NaCl的加入量为轻烧镁粉-滑石粉混合料质量的20%、烧结温度为1 200 ℃、保温时间为6 h、m(轻烧镁粉)∶m(滑石粉)=5∶5时,试样的综合性能最优,此时其体积密度为1.46 g·cm^-3,显气孔率为55.0%。此外,发现滑石自分解和镁橄榄石的合成均可在试样内部形成气孔。

关键词: NaCl熔盐, 方镁石, 镁橄榄石, 轻质隔热材料