PROCESS FOR PRODUCING FINE FLAKY ALUMINA PARTICLES AND ALUMINA-BASED PLASTIC MATERIAL

摘要

The present invention provides a process forproducing fine flaky alumina particles which are suitableas a raw material for ceramics, a pigment for paint andetc., wherein aluminum hydroxide or alumina hydratehaving a particle size regulated to the order ofsubmicron is subjected to a hydrothermal treatment inwater or an aqueous alkali solution at a temperature of350°C or above and under a pressure of 200 kg/cm2 orbelow. The present invention further provides analumina-based plastic material which is produced bykneading the aforesaid fine flaky particles with anorganic water holding material and water.Methylcellulose, polyvinyl alcohol,carboxymethylcellulose, polyethylene glycol, etc. arepreferably used as the organic water holding agent.The alumina-based plastic material has a highplasticity, so that there is no need of using a largeamount of a binder. Thus a dense molded articlehaving stable properties can be prepared.