The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 21, 1987
Filed:
Mar. 03, 1986
Werner Biffar, Frankenthal, DE;
Otto Hofstadt, Ludwigshafen, DE;
Klaus Kartte, Beindersheim, DE;
Erwin Thomas, Freinsheim, DE;
Franz-Josef Weiss, Neuhofen, DE;
BASF Aktiengesellschaft, , DE;
Abstract
Noble metal catalyst, in particular platinum catalysts, which are applied on carriers and have become poisoned by metals as a result of being used for many years in the preparation of hydroxyl-ammonium salts by catalytic reduction of nitric oxide with hydrogen in an aqueous mineral acid are regenerated by a process in which the metallic impurities are dissolved using nitric acid or aqua regia, the solution is neutralized, the troublesome metals are precipitated from the neutralized solution by means of a selective precipitating reagent, and the purified platinum solution is reused for the preparation of the catalyst. Organic complexing agents which form insoluble or sparingly soluble complexes with the metallic impurities are preferably used as precipitating reagents.