Recovery of gypsum from sludges from desulphurising plants - for use as raw material in cement mfr. to control setting of cement

摘要

Gypsum dihydrate is recovered in solid form from the sludge formed during the desulphurisation of flue gases with milk of lime. The sludge is mechanically dewatered. A part is removed from the main stream, heat treated to form (partially or completely) gypsum hemihydrate which is returned to the main stream and the mixt. agglomerated. The recovery of gypsum from the sludges is made ear easier and the prod. is less damaging to the environment.