METHOD OF PRODUCING GRANULAR MACROPOROUS ALUMINIUM OXIDE Russian patent published in 2024 - IPC C01F7/25 C01F7/441 C01F7/34 B01J21/04 B01J32/00 

FIELD: chemistry.

SUBSTANCE: invention can be used in producing aluminium oxide catalysts. Method for synthesis of macroporous aluminium oxide involves bringing into contact aqueous solutions of aluminium nitrate and ammonia, which are drained into the initial volume of desalinated water or pulp from the previous precipitation at 68-72 °C. Molar ratio of ammonia and aluminium when merging streams of solutions is 3.0-3.2. Ammonia solution with concentration of not less than 14 mol/dm³ is additionally poured into the reactor, wherein the ammonia concentration increases from 0.25 to 0.70 mol/dm^3. Precipitate is stabilized for at least 5 hours. Further, filtration is carried out to obtain a mother solution and a precipitate, which is mixed with desalinated water of the same volume as the filtrate, and ammonia solution with concentration of not less than 14 mol/dm³ is added, after which it is filtered and the washing and filtration operation is repeated once more. Filtrate and a wet precipitate are obtained, which is dried at a temperature of not less than 100 °C to residual moisture content of not more than 15 wt.%. Precipitate is crushed; the obtained powder is mixed with demineralised water. Then, cylindrical granules are formed in the extruder through a spinneret with a hole size of 1.5 to 6 mm, after which they are dried at temperature of 100 to 120 °C for at least 6 hours. Temperature is increased from 190 to 210 °C for 1 hour and held for 1 hour. Dry granules are placed in a muffle furnace and calcined in two stages with temperature rise from 290 to 310 °C for 1 h and holding for at least 1 h, then with temperature rise from 500 to 1000 °C at speed of not more than 5 °C/min and holding for at least 3 hours.

EFFECT: invention increases volume fraction of macropores of granulated aluminium oxide.

1 cl, 2 tbl, 16 ex