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:
Aug. 28, 1990
Filed:
May. 26, 1988
Paul Spekman, Minneapolis, MN (US);
Fremont Industries, Inc., Shakopee, MN (US);
Abstract
A process for removal and recovery of chromium ions (chromate, dichromate, or combinations thereof) from aqueous waste water of surface treatment phosphatizing solutions and for recycling of the treated waste water following replenishment wherein the aqueous waste water is initially partially clarified in a settling tank, with the effluent then being passed through an ion exchange column for removal of substantially all of the chromium ions therefrom. Following treatment in the ion exchange resin column, the chromium-free material is recharged with a supply of fresh chromium ions until the chrome ion content is at the desired level for metal surface treatment. The spent ion exchange resin columns are removed and replaced, as necessary, with the recharge of the resin columns making additional chromium available as a resource.