| 摘要 |
Iron molybdate catalyst is ground, optionally after air or oven-drying, mixed with water to give a mass containing 37-39% wt. moisture then pelletized with 90 mins. of mixing. The ground molybdate may have a max. particle size of 0.6 mm. Waste molybdate from the pelletizing may be returned to the grinding step. The pellets may have a diameter and axial length of 3.5 mm. The molybdate may be made by mixing solutions of ammonium molybdate and ferric chloride, the ppt. being filtered and washed. The filter cake has a MoO3/Fe2O3 wt. ratio of 5-6, and water content of 55-3"1/2"% wt. Drying of this ppt. may be at 80-107 DEG C. The pellets can be dried at 100 DEG C. for 12 hr. to a water content of <5% wt.ALSO:A pelletised iron molybdate catalyst (see Division C1) is used for the oxidation of methanol in excess air to formaldehyde. The formaldehyde produced has a low formic acid content. |
