| 摘要 |
PROBLEM TO BE SOLVED: To suppress deterioration of catalytic activity even in the case a catalyst is used as high temperature by employing an alumina for a catalyst support which consists of alumina produced by firing an alumina precursor and activated alumina in specified amounts, respectively. SOLUTION: This alumina for catalyst supports consists of alumina obtained by firing an alumina precursor and activated alumina and is so made as not to transform toα-crystal phase even by treatment at 900-1300 deg.C and as to have sufficient specific surface area and high heat resistance. The alumina precursor to be used is a substance to be converted into alumina by firing and inorganic salts such as aluminum chloride, aluminum sulfate, etc., and collide-state alumina such as polyaluminum chloride are exemplified. The mixing ratio of the activated alumina and the alumina precursor is set to be 5-30% of the alumina precursor and 95-70% of activated alumina, respectively. The activated alumina and the alumina precursor are mixed by a stirring rotator, a stirring apparatus equipped with impellers, a ball mill, etc.
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