Process for the production of titanium dioxide
US5409679A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 5, 1990 |
| Grant date | Apr 25, 1995 |
| Priority date | — |
| Expiry date | Jul 5, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S423/02
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The production of titanium dioxide by the sulphate process generates waste substances such as the wash filtrates, which are formed in the washing of titanium dioxide hydrate, and waste gases which contain sulphur dioxide. In this improved process the wash filtrate is used to remove the sulphur dioxide from the waste gas while the sulphuric acid content of the wash filtrate is raised and the sulphuric acid-containing process solution thus obtained is used within the scope of the titanium dioxide production process. The waste gas and the wash filtrate are passed countercurrently through a series of several washing steps and are contacted with each other by introducing the wash liquid into the waste gas in a finely divided form in scrub towers. The sulphuric acid content of the washing fluid is stepwise changed from washing stage to washing stage. The sulphur dioxide content of the waste gas is reduced to values that may be discharged into the ambient atmosphere. The sulphuric acid-containing process solution is returned to the digestion tank and/or used for dissolving the digestion cake.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.