9Ng K F, Nair N K, Liew K Y, et al. Face and pore structure of deoiled acid and heat-treated spent bleaching clays [J]. Journal of The American Oil Chemists' Society, 1997,74 ( 8 ) : 963 - 970.
10Al-Zahrani A A, Daous M A. Recycling of cent bleaching clay and oil recovery [J]. Process Safety and Environmental Protection, 2000, 78 ( 3 ) : 224- 228.