To develop an effective alkali extraction of amorphous Sio2 from calcined kaolinite for preparation of mesoporous material, repeated selective leaching process was examined. A Chinese kaolinitic clay sample was calcined at 1100°C for lhour. Each 100 g of the calcined samples was suspended in 1N KOH solution (100-500ml) at 90°C for 24hours. The selective leaching treatments were repeated. The mesoporous material obtained from first (solid liquid ratio; 1:1) and second treatment (solid liquid ratio; 1: 5) showed a narrow pore size distribution at around 2.0-3.0nm in pore radius. The specific surface area and total pore volume were 83.2 m2/g and 0.167ml/g, respectively. The water vapor adsorption isotherm showed a rapid increase at about 60%RH. It was found that the mesoporous sample was candidate as humidity self-control material. However, more examination of calcing conditions was required to separate amorphous silica phase and γ-alumina phase completely.
