Chrome removal and recovery
AssigneeJohn Cunningham
InventorsEdward J. Feltz, Ross Cunningham
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AssigneeJohn Cunningham
InventorsEdward J. Feltz, Ross Cunningham
Estimating the term…
The present invention is directed to a process for removing and optionally recovering hexavalent chromium from chromium waste water. The invention involves the use of a treatment mixture comprising the combination of barium carbonate and/or barium hydrate, plus one or more certain specified acetates. The process involves contacting the chrome waster water to be treated with the treatment mixture at an acetic pH not exceeding 6.0, and usually from 4.0 to 6.0, followed by filtration through an acid-resistant filter. The chromium removed by this filter in the form of barium chromate can be regenerated into chromic acid by backwashing the filter into an agitated tank and treating to produce chromic acid and barium sulfate. The thus-generated chromic acid can then be returned to the chrome plating tank for reuse after passing through a filter to remove the barium sulfate.
A process for removing chromium from chromium-containing water comprising contacting said chromium-containing water with barium carbonate and/or barium hydrate and a water-soluble acetate salt at a pH of 4-6 utilizing a weight concentration of barium carbonate and/or barium hydrate to chromimum present ranging from about 1 to 6 and a weight ratio of barium carbonate and/or barium hydrate to water-soluble acetate salt ranging from about 3 to 15:1, thereafter filtering the resultant insoluble chromium material with a first acid-resistant filter media, recovering the filtered chromium and removing the barium present by contacting said chromium with sulfuric acid thereby converting said chromium to chromic acid and precipitating said barium as insoluble barium sulfate, passing said effluent from said sulfuric acid contact through a second acid-resistant filter material to remove insoluble barium sulfate therefrom, collecting the effluent from said second filter, and reusing its chromium content in a chromium plating process.
Dependencies are inferred from the claim text.