Production of copper-zinc-aluminum catalyst, e.g. for methanol synthesis, involves two-stage precipitation from metal salt solution with alkali, using a different copper to zinc atom ratio in each stage

摘要

Copper/zinc/aluminum catalysts are obtained by 2-stage precipitation from solutions of aluminum, copper and/or zinc salts with alkaline solutions or alkali aluminate/aluminum hydroxide sol, using a different Cu/Zn atom ratio in each stage. A method for the production of a Cu/Zn/Al catalyst (I) containing copper oxide and zinc oxide with aluminum oxide as stabilizer comprises: (a) precipitation of a first precipitate (1) from solutions of Al, Cu and/or Zn salts with alkaline solution or an alkali aluminate/aluminum hydroxide sol; (b) aging precipitate 1 for 0-5 hours at 20-100 (preferably 40-90) deg C; (c) further precipitation (2) by adding a solution of compounds of Cu, Zn and/or Al with a different Cu/Zn atom ratio to that used for 1 and an alkaline solution of aluminate/Al hydroxide sol; (d) aging precipitate 2 for 0.5-5 hours at 20-100 (preferably 40-90) deg C; (e) separating the precipitate and washing to remove alkali ions; and (f) drying followed by calcining at 250-400 deg C. An Independent claim is also included for catalysts in the form of particles obtained by this method, with an inner core comprising 10-50% of the total catalyst wt. and an outer shell, and in which the Cu/Zn atom ratio shows a gradient between the core and the shell.