微波热法煅烧高岭土的机理研究

Study of Mechanism of Kaolin Sintered by Microwave Heating

对微波法煅烧高岭土进行了初步研究。实验结果表明,微波场作用下高岭土的相变过程和常规加热法相同:即从晶相(高岭土)变成非晶相(偏高岭土)最后转变成晶相(莫来石)。但微波法与常规煅烧法相比,其相变速度加快了4～12倍,相转变温度也相应降低了200℃左右,产物的平均粒径也更小。SEM结果表明微波和常规法煅烧所得产物的晶形均以片状为主,但微波煅烧所得产物的晶形更为圆滑。此外,微波煅烧高岭土所得产物的白度和常规法相近。

Mechanism of kaolin sintered by microwave heating was investigated. The results showed that phase transformation of kaolin sintered by microwave heating is the same with that by conventional heating. It transformed from crystalline kaolin to amorphous metakaolin, and became crystalline mullite in the last. However, the phase transformation rate was higher by 4～12 times than that of the conventional heating and the phase transformation temperature decreased by about 200 ℃. Moreover, the average particle size of the product was smaller. SEM results showed that both the crystal shape of the products obtained by microwave heating and conventional heating were mainly sheet, but the product of microwave heating was much more smooth.The whiteness of the products obtained by microwave heating is similar with that of conventional heating.