| 摘要 |
<p>PURPOSE: To improve the desulfurization efficiency without increasing the consumption of calcium carbonate and obtain highly pure gypsum as a by-product by separating a diluted fine slurry from a concentrated slurry with increased particle size under the presence of an ammonium salt in the slurry. CONSTITUTION: A combustion flue gas 1 is led to a desulfurization apparatus 2 and the flue gas 3 purified by the desulfurization apparatus 2 is released to air. Since SO2 is continuously absorbed in the desulfurization apparatus 2, calcium carbonate in a quantity corresponding to the absorbed SO2 is supplied to a supply line 4, thus a slurry consisting of gypsum as a main component is taken out through a discharge line 5. The taken out slurry is sent to a classifier 6. The slurry is concentrated in the classifier 6 and, at the same time, since the particle size of gypsum is rather large as compared with that of calcium carbonate, calcium carbonate in the gypsum decreases in the concentrated liquid line 7 of the classifier 6. That is, the purity of gypsum is improved. Meanwhile, in the dilution line 8 of the classifier 6, a slurry in which calcium carbonate is increased in gypsum is obtained.</p> |
