| Effect of different calcination conditions on physical and chemical properties of calcined coal kaolin has been investigated in this dissertation. Firstly, test on affection of particle size of raw material shows that the finer the size is, the better the integrated indexes of product are. Secondly, study on calcination temperature indicates that the best results achieved at 9500C Thirdly, experiment on different heating-up time in which temperature raised to 9500C improved that the product which temperature raised in 4.5 hours had the best properties. Fourthly, we found the best constant temperature time is 4 hours. Fifthly, when calcined additives or reduction atmosphere were applied in constant temperature period, the products had decreased Fe3 content and greatly improved brightness. Finally, when the best calcination indexes achieved above were applied together, we got ideal product, which brightness is 95.63, density is 0.28 g/ml , oil absorption is 1.04 mug, activity is 18.10A1203%, and index of covering is 19.86cm2/g. In this dissertation the text results is synthesized and tried to give theoretical explanation on the effects of particle size, calcination temperature, heating-up time and constant temperature time on brightness, density, oil absorption, activity and index of covering of product respectively. The DTA/TG, XRD, SEM and TEM were applied in the study to explore how the structure and the crystal form of product change. With TEM photos we can see lots of even distribution, fine pores on the surface of calcined sample. It is shown that calcined kaolin product with better indexes could be achieved with optimized calcination parameters.
|
PDF Full Text Request