Granulated porous corundum
Патенты
| Язык: |
Немецкий |
| Тип: |
Заявка на патент |
| Номер (11) |
DE 2419277 A1 |
| Номер заявки (21): |
2419277.6-41 |
| Дата подачи заявки (22): |
22 апр. 1974 г. |
| Дата начала отсчета срока действия патента (24): |
|
| Дата публикации патента (44,45,46): |
|
| Дата публикации заявки (43): |
23 окт. 1975 г. |
Granular porous corundum having a total pore vol. 0.3-1.0 cm3/g and av. pore size 5000-30,000Å is prepd. by heat treatment of Al hydroxide or Al2O3 granules having total pore vol. 0.3-1.0 cm3/g and av. pore size 20-5000Å. The heat treatment is done in the presence of HF (≤2% of the solid wt.) by heating from 20 to 700° during ≥0.5 hr, and holding ≥0.5 hr at 700-1000°. After pore formation, HF is desorbed during heating for ≥0.5 hr at 1000-1400°. The porous corundum is suitable as a catalyst carrier. Thus, spherical γ-Al2O3 granules 2.5 mm diam. having a bulk d. of 0.76 g/cm3, total pore vol. 0.51 cm3/g, sp. surface 240 m2/g, av. pore size 40Å, and compressive strength 60 kg/cm2 were mixed with NH4F (2% of the Al2O3 wt.). The mixt. was heated within an hr from 20 to 700° and held 6 hr at 800°. The resulting porous product contained 90 α-Al2O3 and 10% γ-Al2O3 and had a bulk d. of 0.76 g/cm3, total pore vol. 0.54 cm3/g, sp. surface 12 m2/g, av. pore size 5000Å, and compressive strength 17 kg/cm2. To increase the strength, the granules were heated 2 hr at 1200°. The resulting corundum had a bulk d. of 0.76 g/cm3, total pore vol. 0.55 cm3/g, sp. surface 1 m2/g, av. pore size 8000Å, and compressive strength 50 kg/cm2.