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US 5,571,419 AGranted
Method of producing pure water
AssigneeKurita Water Insustries Ltd.
InventorsYoshinobu Obata, Nobuhiro Orita, Hiroshi Kurobe
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Abstract
Raw water is made acidic so that the pH is not more than 4.5 and heated in the presence of an oxidizing agent to decompose TOC components in the raw water, and then deionized, thereby producing ultrapure water having a greatly low concentration of organic matters.
Claims6
A method of producing pure water, comprising:
- contacting raw water containing hydrofluoric acid and TOC components with a weak basic anion exchange resin to remove fluoride ions from the raw water,
- making the raw water acidic so that pH is not more than 4.5, and heating the raw water in a presence of an oxidizing agent to decompose the TOC components, and
- deionizing the raw water.
Dependencies are inferred from the claim text.