Method for analyzing free fluorine in solutions containing hydrofluoric acid solution, and apparatus for practicing the method
US6537822B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 5, 2000 |
| Grant date | Mar 25, 2003 |
| Priority date | — |
| Expiry date | Jan 19, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/19
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Free fluorine is measured in a hydrofluoric acid-containing solution with a coexistent metallic ion based on a total fluorine concentration, a total acid concentration, a metallic ion concentration, the equilibrium constant of hydrofluoric acid, and equilibrium constants of metal fluoride complexes. It is possible to accurately analyze free fluorine in a hydrofluoric acid-containing solution without being affected by a coexistent metal and by the passage of time. This technique may be used to accurately control the concentration of free fluorine in a hydrofluoric acid-containing mixed acid pickling solution at the production site of a stainless steel so that improvement in descaling capability as well as reduction in the amount of chemical materials can be achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.