Effect of CO 2 on the Desulfurization of Sintering Flue Gas with Hydrated Lime.

The effect of carbon dioxide (CO 2 ) on the desulfurization of sintering flue gas with hydrate (Ca(OH) 2 ) as an absorbent was investigated, and the formation of calcium carbonate (CaCO 3 ) and its effect on the desulfurization was discussed. The competitive relationship between carbon dioxide (CO 2 ) and sulfur dioxide (SO 2 ) with the deacidification agent in sintering flue gas is discussed thermodynamically, showing that sulfates are more likely to be generated under high oxygen potential conditions and that SO 2 reacts more preferentially than CO 2 under a thermodynamic standard state. The amount of produced CaCO 3 increases under the condition that the CO 2 concentration is absolutely dominant to SO 2 in the sintering flue gas atmosphere. The effect of temperature, humidity and CO 2 concentration on the desulfurization of Ca(OH) 2 are discussed experimentally. The increasing temperature is not conducive to desulfurization, and the humidity can promote desulfurization, while excessive humidity could inhibit desulfurization. The suitable relative humidity is 20%. In situ generated calcium carbonate has a certain desulfurization effect, but the desulfurization effect is not as good as Ca(OH) 2 . However, a large proportion of CaCO 3 was produced in the desulfurization ash under the condition that CO 2 concentration was absolutely dominant to SO 2 in the sintering flue gas atmosphere.