| 摘要 |
1513291 Nickel chromite E I DU PONT DE NEMOURS & CO 19 June 1975 [24 June 1974] 26150/75 Heading C1A [Also in Divisions B1 and C5] A "nickel chromite" catalyst is prepared by (a) forming an aqueous solution of nickel and chromium compounds having a mole ratio of Ni to Cr of 0À5:1 to 5À0 to 1, (b) adjusting the pH to coprecipitate metal solids in finely-divided form, (c) calcining and particulating the solids to form an incipient crystalline compound containing a minor amount of Cr<SP>6+</SP> and (d) reducing the Cr<SP>6+</SP> to Cr<SP>3+</SP> while maintaining the nickel in an unreducedoxide form. The reduction may be performed using hydrogen at 100-300‹C., and the particulation may be by deposition on a granular solid carriermaterial or by pelletization into granular form. The catalyst is suitable for methanating carbon oxides. The aqueous solution of step (a) is preferably dilute and may contain nickel salts such as the nitrate with hexavalent or trivalent chromium compounds. The coprecipitation is preferably achieved by addition of ammonium hydroxide at a pH range of 6-8, and the calcination is preferably at 275-600‹C |
