Solution preparation
AssigneeImperial Chemical Industries PLC
InventorJames R. Jennings
Life of this patent
Estimating the term…
Abstract
A solution containing nitrates of iron and chromium is produced by reacting metallic iron or an iron alloy with nitric acid in the presence of a hexavalent chromium compound. The solution is the starting material for making an iron-chrome oxide catalyst for the shift reaction of carbon monoxide with steam.
Claims8
A method for producing a solution containing nitrates of iron and chromium which comprises reacting metallic iron or an alloy thereof with nitric acid in the presence of one or more hexavalent chromium compounds.
A method of making an oxide composition reducible to a catalyst, which comprises
- (a) forming a solution containing nitrates of iron and chromium by reacting metallic iron or an alloy thereof with nitric acid in the presence of one or more hexavalent chromium compounds;
- and
- (b) converting the nitrates to an intimate mixture of the oxides.
A method of making an iron-chromium oxide composition convertible by reduction to a catalyst for the high temperature shift process, said oxide composition having the following properties:
- Fe.sub.2 O.sub.3 /Cr.sub.2 O.sub.3 weight ratio:
- 20:1 to 6:1
- surface area:
- 100-250 m.sup.2 /g
- mean pore radius:
- 10-100 Angstrom units
- loss of ignition:
- over 10% .sup.w /w
- sulphur content:
- less than 0.2% .sup.w /w expressed as SO.sub.3.
- said method comprising the steps of:
- (a) producing a solution containing the nitrates of iron and chromium by reacting metallic iron or an alloy thereof with nitric acid in the presence of one or more hexavalent chromium compounds;
- (b) reacting the resulting solution with an alkali metal carbonate whereby to co-precipitate the hydroxides of iron and chromium;
- (c) washing the precipitate to decrease its alkali content to under 0.4% calculated as equivalent Na.sub.2 O;
- and
- (d) forming the precipitate into pieces having all their dimensions in range 2-20 mm, with no dimension of a single piece more than 5 times another.
Dependencies are inferred from the claim text.