Method for making ultrapure sulfuric acid
US5164049A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 22, 1990 |
| Grant date | Nov 17, 1992 |
| Priority date | — |
| Expiry date | Aug 22, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S203/02
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Method for the production of ultrapure sulfuric acid including distillation of sulfuric acid material for the removal of soluble impurities and insoluble and non-volatile particles of 10 microns to 0.2 micron or less in size. Reprocessing is also provided. Distillation takes place in a distillation chamber having walls which are provided with means within the chamber to provide smooth convective upward flow of distilling liquid and vapor proximate the walls and means for smooth convective downward flow substantially centrally of the distillation chamber. Redirection means and packing together with reflux means insure the washing of rising vapor and direct the condensing vapor substantially centrally of the distillation chamber. Ultrapure sulfuric acid is also provided having 5 or less particles per cubic centimeter of a size of 0.5 micron and larger and less than 10 ppb of any specific trace impurity such as cations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.