| 摘要 |
1,259,381. Iron oxide catalysts. H. F. A. TOPSOE. 28 Jan., 1970 [6 March, 1969], No. 11930/69. Heading B1E. [Also in Division C1] A high temperature shift catalyst comprising iron oxide characterised by the presence of less than 50 ppm sulphur (claimed per se) is prepared by precipitating iron as a salt of an organic acid from solutions of iron salts in the form of coarse crystals, washing the precipitate to remove soluble impurities, then treating the precipitate with an alkali solution to obtain a flocculent iron oxide of high specific surface area and regenerate the organic acid reagent. The alkali solution may be NH 4 OH, NaOH, KOH. The organic acid may be oxalic acid and is preferably added in the form of its ammonium or alkali metal salt. The catalyst may contain Cr 2 O 3 and/or PbO as promotors. The precipitation of ferrous oxalate may be carried out at room temperature and the hydrolysis by means of the alkali solution at a temperature between 50‹C and 100‹C. The promotors, e.g. Cr 2 O 3 , PbO, may be added by treating the resulting Fe(OH) 2 suspension, after washing, with their soluble nitrates. Mixed oxide catalysts may also be prepared by the process of the invention by treating solutions containing soluble salts in addtion to the iron with the ammonium or alkali metal salt of an organic acid, e.g. oxalic acid. |
