| 摘要 |
PCT No. PCT/CH81/00146 Sec. 371 Date Dec. 28, 1982 Sec. 102(e) Date Dec. 28, 1982 PCT Filed Dec. 28, 1981 PCT Pub. No. WO82/03848 PCT Pub. Date Nov. 11, 1982.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 CaF2, while the free H2SO4 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 CaF2 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 DEG 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. |
