中国産カオリナイト質粘土を選択溶解処理して調整したメソポア材料の水蒸気吸着特性(その3) : 仮焼温度の影響

概要

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To develop an effective alkali extraction of amorphous SiO_2 from calcined kaolinite for preparation ofmesoporous material, the effect of calcining conditions was examined. A Chinese kaolinitic clay samplewas calcined at various temperature (850-1100 ℃ ) for 24hours. Each 3g of the calcined sample wassuspended in 1N KOH solution (15ml) at 90 ℃ for 24hours, followed by washing and drying. When thesamples calcined at 950 ℃ or more were selectively leached, mesoporous materials were obtained. Thesample calcined at 1050 ℃ and selectively leached, showed narrow pore size distribution, and the specificsurface area and total pore volume were 75.5m^2/g and 0.126ml/g, respectively. The water vapor adsorptionisotherm also showed steep increase at the relative vapor pressure P/P_0=0.6, therefore this mesoporoussample was thought to be the candidate as humidity self-control material. Moreover, it was able to beconfirmed from ^29Si MAS NMR measurement that for the 950 ℃ calcined sample the leaching of amorphoussilica ended almost and remained Si existed in the mullite phase. Therefore, the calcining condition isimportant in making mesoporous material from kaolinitic clay by the selectively leaching processing.
日本粘土学会の論文
1999-06-30