| 摘要 |
<p>The invention relates to converting calcium sulfide to calcium oxide. Particles comprising calcium sulfide are passed (via 14) into one end of a fluidized conversion bed (16) and discharged from the other end thereof. The bed of particles is fluidized by passing an oxygen-containing gas (e.g. air) upwardly into the bottom of the bed (16) via a distributor (17). The oxygen of the said gas reacts exothermically to convert at least some CaS to CaO + SO2, thereby raising the temperature of the particles as they pass towards the said other end. A reducing agent is passed (via 18) into a region of the bed (16) adjacent to the said other end to remove, by chemical reaction, any excess oxygen which might otherwise convert CaS to CaSO4. The reducing agent additionally reduces temperature rises in the said region of the bed (16) so that the particles discharged therefrom are of high chemical reactivity (not having been exposed to excessively high, de-activating temperatures) and contain an increased proportion of CaO than they otherwise might have.</p> |
