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:
Jul. 09, 1991
Filed:
May. 03, 1989
J Francis Steadman, Orangeburg, SC (US);
Dennis J Malfer, Crestwood, MO (US);
George A Daniels, Baton Rouge, LA (US);
J Keitt Hane, Orangeburg, SC (US);
R Woodrow Wilson, Jr, Baton Rouge, LA (US);
Ethyl Corporation, Richmond, VA (US);
Abstract
Contaminants in spent nitric-sulfuric nitration acid can be removed by mixing the spent acid with urea and heating to 75.degree.-150.degree. C. Off-gas from the spent acid/urea reaction is passed through a Group IB, VB, VIB or VIII metal containing catalyst to decompose nitrous oxides and the so-treated off-gas is contacted with spent acid, denitrated spent acid, or fresh sulfuric acid, and optionally air (i.e. oxygen), to absorb oxides of nitrogen. The spent acid scrubbing fluid is then subjected to the same process for removing contaminants.