| 摘要 |
<p>PURPOSE:To obtain Mg(OH)2 by hydrating MgO formed by calcining MgSO3 accumlated in an absorbing liquid for desulfurization with a liquid reactant the MgSO4 concn. of which is diluted with MgCl2-contg. waste liquior after washing calcination furnace gas in a perdetermined temp. range to reduce hydration time. CONSTITUTION:In abosorption tower 1, a slurry contg. Mg(OH)2, MgSO3 and MgSO4 is brought into contact with SO2 in exhaust gas to remove the SO2. The reaction product and unreacted absorbent are then separated from mother liquor by centrifugal separation 2, dried 3, and calcined in calcination furnace 4 at about 1000 deg.C to regenerate MgO as well as to recover SO2. A mixt. of MgO and unreacted MgSO4 formed in furnace 4 is fed to hydration vessel 5. On the other hand, exhaust gas from furnace 4 is fed to washing tower 7 through cyclone 6 and contacted with washing water 8. The concn. of MgCl2 formed and accumulated in the circulating washing water is regulated to 1500-5000 ppm, and the water is fed to vessel 5, where it is mixed with the above calcined product so that the concn. of MgSO4 becomes blow 16 wt%, and the mixt. undergoes hydration at 40-60 deg.C to obtain Mg(OH)2 of below 50 mu in diameter.</p> |
