铁合金厂回收的硅微粉在不同温度下晶相结构的研究

铁合金厂冶炼过程产生的大量硅微粉烟尘, 可以作为耐火材料和窑具材料的结合剂, 活性剂和矿化剂, 可促进耐火材料固相反应和烧结, 有利于晶型的转变, 提高耐火材料的高温性能。硅微粉在高于或等于1100 ℃不析晶。1200和1300 ℃析晶规律是:首先α-石英转变为α-方石英, 然后转变为α-鳞石英。在1400～1450 ℃首先析出卡片号为290085的石英变体, 然后转变为α-方石英。 而常规转化过程是α-方石英很难形成α-鳞石英, 而且不形成290085的变体, 因此其转化规律与常规不同。在液相存在情况下, 少量α-方石英转变为α-鳞石英, 不同温度下析晶结构探讨为实际生产提供适宜的升温曲线。

Researches on Crystal Structure of Fine Silicon Powder Recollected from Silicon-iron Production at Different Temperature

Fine silicon powder mainly containing SiO2 is the dust produced during silicon-iron production。The superfine powder has amorphous structure and is metastable. It crystallizes at high temperature so that can be used as bonder, activator or mineralizer of refractory and kiln furniture. It is beneficial to the reaction and sintering of refractory, the crystal conversion and high temperature properties. The process of crystallization at a temperature range of 1200～1300 ℃ is a-quartz firstly converting into a-cristobalite and then to a- tridymite. The quartz variant (ASTM No.290085) converts to a-cristobalite at the temperature range of 1400～1450 ℃. The suitable curve of temperature rise is determined on the basis of crystal structure inves- tigation at different temperature.