Study On Surface Modification Of Coal-based Kaolin

Coal-based kaolin mineral source of China has an abundant reserves, but its utilization ratio is very low, which causes resources waste. This is because the coal-based kaolin mineral contains organic carbon, which results in lacking of plasticity and dispersibility and is very harmful to its applications. It has realistic meanings to improve its application performance by coating modification of coal-based kaolin mineral.In this paper, kaolin particle, Al2(SO4)3 and urea were dispersed in deionized water by dispersants and ultrasound. The suspension was vigorously stirred and heated in 70℃for some time followed by rapid cooling. The powder was washed with deionized water and ethanol several times. and then dried at 100℃. The properties of coated kaolin is characterized and contrasted to uncoated kaolin by means of XRD,FT-IR,TEM,SEM,BET,IEP.The analytical results showed that ideal coating result can be obtained under strictly-controlled reaction conditions. The more urea concentration or less Al3+concentration lead formation independent Al(OH)3, the more Al3+concentration or less urea concentration can't lead integrated coating, and the reaction time should be limited to a certain amount time.The results of our experiments showed that the surface of kaolin was coated a smooth amorphous Al(OH)3 film, the surface physical of the particles is similar to Al(OH)3, the dispersibility of suspension was improved.