Process and device for manufacturing synthetic anhydrous calcium sulphate and pure hydrofluoric acid
US4460551A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 28, 1982 |
| Grant date | Jul 17, 1984 |
| Priority date | — |
| Expiry date | Dec 28, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01F11/46
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
In the process for the production of synthetic anhydrite and pure hydrofluoric acid, a reaction is initiated using fluorspar with a mixture containing sulphuric acid, oleum and the reflux of the acidic scrubbing. The aim is to produce synthetic anhydrite which contains only the desired small proportion of CaF.sub.2, while the free H.sub.2 SO.sub.4 is completely neutralized, but other desirable accelerators are still retained. The reaction is so arranged that fluorosulphonic acid does not enter the reactor at all or only in minute quantity and the new formation of fluorosulphonic acid is effectively repressed. For this end, the components of CaF.sub.2 and acid mixture are fed into the reactor at an elevated temperature and the reactor intake is so heated, whereby the reaction is initiated at 100.degree. C. and thus new formation of fluorosulphonic acid is arrested. The exhaust gases from the reactor are hot-dried in a first stage and the dust is expelled, before the material is cooled in the subsequent stages.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.