热处理温度对低硅含量SiO_(2)微粉固废性能的影响

Effect of heat treatment temperature on performance of low-silica SiO_(2) micropowder solid waste

对回收的w(SiO_(2))<85%的低硅含量SiO_(2)微粉固废进行了不同温度(400、500、600、700、800、900和1000℃)保温5 h的热处理,并对热处理后的粉体进行了分析。结果表明:随着热处理温度升高,试样逐渐烧结。热处理温度低于800℃时,SiO_(2)微粉保持原有粒状、球状SiO_(2)颗粒团聚体结构。但热处理温度为500℃及以下时,团聚体强度较低。热处理温度800℃以上结块严重,并析出方石英相。热处理温度控制在600~800℃可制得具有一定强度,体积密度在0.73~0.95 g·cm^(-3)的球壳结构的球状粉体,该粉体可以作为轻质原料用在低温保温浇注料,也可以作为其他行业填料。

Recycled SiO_(2) micropowder solid waste(SiO_(2)<85 mass%)was heat treated at 400,500,600,700,800,900,and 1000℃for 5 h,respectively,and then the heat treated powders were analyzed.The results show that the samples are gradually sintered as the heat treatment temperature increases.Below 800℃,the original structure of granular and spherical SiO_(2) aggregates remains.However,at 500℃or below,the aggregates strength is low.Above 800℃,SiO_(2) micropowder agglomerates seriously and cristobalite is precipitated.When the heat treatment temperature is in the range of 600-800℃,the spherical SiO_(2) micropowder with a certain strength and the bulk density of 0.73-0.95 g·cm^(-3) and a core-shell structure can be prepared,which can be used as a lightweight raw material for low temperature insulation castables and as a filler for other industries.