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US 6,720,437 B2Granted
Fluorinated carboxylic acid recovery and reuse
AssigneeE. I. Du Pont de Nemours and Company
InventorsClay Woodward Jones, Ta-Wei Fu
Life of this patent
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Abstract
Fluorinated carboxylic acid, used as a surfactant in fluoropolymerization in aqueous media, can be recovered by scrubbing from the exhaust gas of the dryer during polymer drying and, after concentration and treatment with alumina, directly reused in fluoropolymerization in aqueous media.
Claims9
A process for the recovery and recycle of fluorinated carboxylic acid contained in the exhaust gas produced from the drying of fluoropolymer that has been polymerized in aqueous media containing fluorinated carboxylic acid comprising:
- a) scrubbing the exhaust gas to produce a scrubber solution containing fluorinated carboxylic acid,
- b) concentrating said scrubber solution to produce a concentrated scrubber solution,
- c) contacting the concentrated scrubber solution with alumina to produce a recovered fluorinated carboxylic acid solution, and
- d) directly reusing said recovered fluorinated carboxylic acid solution in a fluoropolymerization in aqueous dispersion.
1 more element
Dependencies are inferred from the claim text.