Production of hydrogen fluoride and calcium sulfate
US4010245A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 1975 |
| Grant date | Mar 1, 1977 |
| Priority date | — |
| Expiry date | Jul 15, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01F11/46
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
In the production of hydrofluoric acid and calcium sulfate by subjecting sulfuric acid and fluorspar to a partial preliminary reaction in a preliminary reaction zone and the reaction is completed in an after-reaction zone at a temperature from about 100.degree. to 500.degree. C, the improvement which comprises effecting the preliminary reaction by circulating preliminary reaction product through said preliminary reaction zone, adding to the circulating preliminary reaction product at spaced locations in the preliminary reaction zone sulfuric acid preheated to a temperature of about 80.degree. to 200.degree. C and fluorspar preheated to a temperature of about 400.degree. to 800.degree. C, removing from said preliminary reaction zone gaseous hydrofluoric acid and a substantially dry mixture of calcium sulfate, unreacted sulfuric acid and fluorspar, and passing said dry mixture of calcium sulfate, unreacted sulfuric acid and fluorspar to said after-reaction zone. Only some of the necessary sulfuric acid may be supplied to the preliminary reaction zone and the balance supplied to the after-reaction zone. Heating of the preliminary reaction zone can be external or materials can be added…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.