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:
Oct. 31, 1995
Filed:
Sep. 08, 1994
Applicant:
Inventors:
Stephen T Arrington, Duncan, OK (US);
Gary W Bradley, Duncan, OK (US);
Assignee:
HydroChem Industrial Services, Inc., Houston, TX (US);
Primary Examiner:
Int. Cl.
CPC ...
C02F / ;
U.S. Cl.
CPC ...
210717 ; 210724 ; 210726 ; 210912 ;
Abstract
Disclosed is a method to remove heavy metals from amino-carboxylic acid chelate solutions comprising adding nitrous acid to lower the pH of the aqueous solution sufficient to destroy the chelate bonds and release the metal ions and thereafter adding an appropriate strong base and optionally a sulfide salt to precipitate the liberated heavy metals.