Method and apparatus for the continuous on-site chemical reprocessing of ultrapure liquids
US4828660A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 6, 1986 |
| Grant date | May 9, 1989 |
| Priority date | — |
| Expiry date | Oct 6, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S134/902
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A continuous process and apparatus for the repurification of ultrapure liquids. An oxidant solution comprising ultrapure sulfuric acid, peroxydisulfuric acid, and ultrapure water is continuously withdrawn from a process after use. The withdrawn oxidant is reprocessed continuously by contacting with alumina to remove fluoride ions. Water is continuously separated or stripped from the oxidant solution by heating the solution and bubbling an inert gas therethrough causing the water to vaporize from the solution. The separated oxidant is continuously distilled and condensed to form a purified stream of sulfuric acid. The major portion of this stream is continuously returned to the process. The remaining minor portion is continuously cooled, subjected to analysis for purity, and diluted with ultrapure water. The diluted sulfuric acid is further cooled prior to electrochemical treatment in the anode compartment of an electrochemical cell. This converts at least a portion of the dilute sulfuric acid to peroxydisulfuric acid. The resulting solution is continuously returned to the process to be mixed with the major portion of the purified sulfuric acid. A system of apparatus to conduct the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.