高纯镁橄榄石质轻质微孔原料的制备

Preparation of high-purity forsterite light-weight micropore starting materials

以菱镁矿细粉和天然硅石粉为原料,按m(MgO)m(SiO 2)=32配料,分别采用三种不同方案(干磨并半干法成型、湿磨并湿法挤泥成型、湿磨并半干法成型)制备生坯,分别经1300、1400、1500和1600℃保温3 h煅烧制备出高纯镁橄榄石质轻质微孔合成原料,并对试样进行了显气孔率、体积密度和常温耐压强度检测和显微结构分析。结果表明:1、对物料湿磨有助于降低镁橄榄石的完全生成温度,且试样的微气孔分布更均匀;使用湿磨并半干法成型制得试样的显气孔率较低,体积密度较大,强度较高,而另两者差别不大。2、随着煅烧温度的提高,试样的显气孔率下降,体积密度增大,常温耐压强度增加;但煅烧温度高于1500℃时,试样的显气孔率迅速下降,体积密度迅速增大,强度迅速增加,尤以使用湿磨物料成型的试样变化最快,因此制备镁橄榄石质轻质微孔料的煅烧温度不宜超过1500℃。

The high-purity forsterite light-weight micropore starting materials were prepared using magnesite fine powder and natural silica powder with the mass ratio of MgO SiO 2=32 as the raw materials,milling and molding by different methods(dry milling+semi-dry molding,wet milling+mud extrusion molding,wet milling+semi-dry molding),and calcining at different temperatures(1300,1400,1500 and 1600℃,respectively)for 3 h.Then the apparent porosity,the bulk density and the crushing strength were tested and the microstructure was analyzed.The results show that:wet milling helps to reduce the complete formation temperature of forsterite and makes the micropore distribution more uniform;the specimens prepared by wet milling and semi-dry molding have lower apparent porosity,higher bulk density and higher strength,the others make little difference;with the increasing calcination temperature,the apparent porosity decreases,the bulk density and the cold crushing strength increase;however,when exceeding 1500℃,the apparent porosity decreases sharply,the bulk density and the strength increase rapidly,especially for the wet milled specimens,thus the calcination temperature shall not exceed 1500℃.