Title:
PURIFICATION CATALYST FOR WASTE GAS AND ITS PRODUCTION
Document Type and Number:
Japanese Patent JP3239156
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To decrease the use amt. of an alkali compd. used to obtain a catalyst precursor when a catalyst is produced, by preparing a catalyst containing rhodium, aluminum, zirconium and zinc and allowing rhodium to be present in a form of a hardly reducible oxide in the catalyst.
SOLUTION: In the production of this purification catalyst for waste gas to selectively remove nitrogen oxides even under condition of excess oxygen, first, rhodium nitrate, zinc nitrate, zirconium nitrate and aluminum nitrate are mixed to prepare an aq. soln. in such a manner that the ratio of atoms of rhodium, zinc, zirconium and aluminum is, for example, 1:10:70:80. Then while stirring the aq. soln., an ammonia soln. is dropped. Further, the aq. soln. is heated during stirring for mild heat treatment, and the obtd. soln. is filtered by sucking to obtain a gel coprecipitate. The gel is washed with pure water, dried and pulverized in a mortar to obtain a fine powder. The powder is calcined to obtain an oxide catalyst.
Inventors:
Masaharu Hadano
Application Number:
JP31049897A
Publication Date:
December 17, 2001
Filing Date:
November 12, 1997
Export Citation:
Assignee:
Next Generation Exhaust Gas Catalyst Research Co., Ltd.
International Classes:
B01D53/94; B01J23/60; B01J23/62; B01J37/03; B01J37/08; F01N3/10; (IPC1-7): B01J23/60; B01D53/94; B01J37/03; F01N3/10
Domestic Patent References:
| JP10165818A | ||||
| JP2111441A | ||||
| JP9122492A | ||||
| JP2102735A | ||||
| JP1080633A |
Attorney, Agent or Firm:
Hiroyuki Niwa (1 outside)