1982年起我们用火电厂废弃物粉煤灰代稻草灰作铁水保温覆盖剂进行了应用试验,从直观感觉,粉煤灰具有良好的保温、聚渣作用,使用后铁水包容易清理,完全可以用作灰铸铁、球墨铸铁铁水的保温覆盖剂。其主要化学成份(％)为:SiO_250～60,Al_2O_25～30,Ca+MgO<10,其它10,灼减量<5。在粉煤灰中含有30～70%左右的空心微珠,此系一种超轻质的高级耐火材料,粉煤次之所以能起稻草灰的作用,即在於空心微珠的存在。它具有如下物理特性:粒径1～300微米;容重为250～400公斤/米~3;视比重为0.5～0.75克/厘米~3;熔点>1400～1500℃;导热系数在室温时一般为0.071～0.095千卡/米·时·度;导温系数在室温时一般为 Since 1982, we used coal ash waste from thermal power plant on behalf of the straw ash as a hot metal thermal insulation covering agent for the application of test, from the intuitive feeling, fly ash has a good insulation, residue role, the use of hot metal easy to clean, it is entirely possible For gray cast iron, ductile iron hot water covering agent. Its main chemical composition (%) is: SiO_250 ~ 60, Al_2O_25 ~ 30, Ca + MgO <10, the other 10, burning reduction <5. In the fly ash contains about 30 to 70% of hollow beads, which is an ultra-light high-grade refractories, the second reason that the coal ash can play the role of straw, that is, the presence of hollow beads. It has the following physical properties: particle size of 1 to 300 microns; bulk density of 250 to 400 kg / m ~ 3; apparent specific gravity of 0.5 to 0.75 g / cm3; melting point> 1400 ~ 1500 ℃; thermal conductivity at room temperature is generally 0.071 ~ 0.095 kcal / m · degree · degrees; temperature coefficient at room temperature is generally