EVAPORATING AND CONCENTRATING METHOD OF SULFURIC ACID- CONTAINING WASTE WATER AND DEVICE THEREFOR

摘要

PROBLEM TO BE SOLVED: To prevent the deterioration of scaling suppressing efficiency due to the volume increase of seed crystals by grinding the seed crystals in the circulating concentrated liq. of an evaporative concentrator and using in circulation the ground seed crystals. ;SOLUTION: The waste water whose pH is adjusted is supplied to the evaporative concentrator 2 by interposing a waste water supply pump 9. The concentrated liq. concentrated in the evaporative concentrator 2 is concentrated by always being circulated by interposing a concentrated liq. circulating pump 10. The concentrated liq. is supplied to a seed crystals grinding machine 16 by a transferring pump 11 to grind the seed crystals in the circulating concentrated liq. The concentrated liq. containing the ground seed crystals is transferred to a circulating liq. regulating tank 7. The circulating concentrated liq. containing the ground seed crystals is stirred and mixed in the circulating liq. regulating tank 7 and returned to the evaporative concentrator 2 by interposing a circulating regulated liq. transferring pump 15. Since the surface area per unit volume of the circulating concentrated liq. is increased by grinding the seed crystals, the scaling suppressing efficiency of the seed crystals is maintained. Further, the waste water concentrated to a prescribed concn. is sent to a concentrated liq. tank 4.;COPYRIGHT: (C)2000,JPO