高岭石
化学
无机化学
核化学
化学工程
材料科学
矿物学
工程类
作者
Carolina Belver,and Miguel Angel Bañares Muñoz,Miguel Vicente
摘要
Four metakaolins were prepared by calcination of a natural Spanish kaolin (Navalacruz deposit, Zamora province) at 600, 700, 800, and 900 °C. These four metakaolins, more reactive than the parent kaolin, were submitted to acid and alkaline activations. Acid activation was carried out with 6 M HCl at room temperature and at 90 °C under reflux conditions, with times of treatment of 6 and 24 h. Treatment at room temperature did not produce any alteration in the structure or in the properties of the metakaolins. Treatment under reflux conditions for 6 h led to the removal of most of the octahedral Al3+ cations, and the formation of an amorphous silica phase, with surface area up to 219 m2/g, because of a high development of both the internal and the external surface of the solids. Acid treatment under stronger conditions (reflux, 24 h) also removed the octahedral cations, but provoked an amorphization of the silica obtained (S ≈ 23 m2/g). The metakaolin prepared by calcination at 900 °C showed a lower reactiv...
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