Investigation On The Intercalation And Delamination Of Kaolin From Coal Measures

Kaolin is broadly used in ceramics, paper industry, rubber, plastic, petrochemical, binder and other fields, due to it's special physical and chemical properties. Most of the export products of kaolin in our country are of low values, however, most of the import product of kaolin are with high values. Therefore, how to develop new processing technology for the kaolin product with high values becomes one of the hot topics in the field of kaolin processing.Using kaolin form coal measures as the raw materials, the kaolinite intercalation composite and its delamination were investigate in this paper. The kaolin/urea intercalation composite with high intercalation ratio was fabricated by using the replacement intercalation method. The delamination of kaolin from coal measure was realized by using the intercalation method and then the heat treatment in low temperatures. The main results are shown as follows:1. Kaolin/Dimethylsulfoxide intercalation composite was prepared by using Dimethylsulfoxide (DMSO) as the intercalation agent. X-ray Diffraction analysis, Fourier Transform Infrared Spectra analysis, the thermogravimetric and Differential Scanning Calorimeter and other measurements were used to investigate the effects of the reaction time, temperature and the concentration of DMSO on the intercalation ratio of Kaolin/DMSO intercalation composite. The optimal technical process to prepare the Kaolin/DMSO intercalation composite was determined and the highest intercalation ratio reached 94.68%.2. Kaolin/urea intercalation composite were prepared by two different ways. One is to intercalate the urea into kaolinite directly. The other is to intercalate the urea into kaolinite indirectly, in other words, by using the replacement method. The effects of the concentration of urea, reaction temperature and time on the intercalation ratio were investigated. The results show that the highest intercalation ratio of 96.68% for the kaolin/urea intercalation composite can be prepared by using kaolin/DMSO intercalation composite as the precursor, and the urea saturation solution as the replacement intercalation agents. The kaolin/urea intercalation composite was investigated by using XRD, FT-IR and TG-DSC.3. The specific surface area of kaolin can be increased from 16.06 m2/g to 47.72 m2/g by the processing of kaolin/urea intercalation composite with mechanical method and then heat treated at low temperatures. It is revealed by XRD, SEM and specific surface analysis that the thickness of the kaolinite sheet becomes thinner and its particle size becomes smaller with the delamination of kaolin from coal measures. The effects of intercalation ratio, washing under ultrasonic method, immersing in acid solution and heat treatment were discussed in this paper. It is demonstrated that the delamination of kaolin from coal measures becomes more and more effect with the increasing of intercalation ratio of kaolin/urea intercalation composite. The effect of the heat treatment at the low temperature is superior to the ultrasonic washing with water and the immersing in acid, et al. The delamination of kaolin from coal measures becomes more and more eminent and the specific surface area becomes larger and larger with the increasing of the heat treatment temperature for the kaolin/urea intercalation composite.