| 摘要 |
1391524 Alpha alumina SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 5 May 1972 [7 May 1971] 21032/72 Heading C1A Alpha alumina of specific surface area of at least 40 m.<SP>2</SP>/g. is made by impregnating anhydrous or hydrated alumina with a carbonizable material, heating the impregnated alumina at 400-700‹ C. to carbonize the carbonizable material, heating the carbonized alumina to at least 1300‹ C. in an inert atmosphere and removing the carbon from the product by converting to a gaseous product, e.g. by heating, below 800‹ C. in air. The carbonizable material is preferably a water-soluble carbohydrate, a natural or synthetic organic polymer used in an amount such that the alumina contains 5-25% by wt. of carbon. The initial two steps of impregnation by means of an aqueous dispersion or solution and carbonization may be repeated two or more times, and most of the solvent removed by drying prior to carbonization. |
