METHOD OF PURIFICATION OF ACID WASTE WATER FROM ZINC Russian patent published in 2007 - IPC C02F1/62 C01G9/02 C02F103/16 

FIELD: processing of aqueous solutions containing heavy metals; mechanical engineering for purification of acid waste water contaminated with heavy metals, zinc in particular.

SUBSTANCE: proposed method consists in two-stage sedimentation; at the first stage, use is made of calcium hydroxide and at the second stage, use is made of sodium carbonate; at the first stage, solutions of sodium hydroxide and calcium chloride are simultaneously introduced to final magnitude of pH from more than 7 to 8; amount of sodium carbonate is determined through mole ratio to calcium chloride which is close to one. Proposed method makes it possible to clean waste water to thousandth of fraction mg/l. Simultaneous introduction of sodium hydroxide and calcium chloride excludes use of lime milk and metered consumption of sodium carbonate makes it possible to accurately adjust sedimentation pH for obtaining maximum sedimentation.

EFFECT: enhanced efficiency; maximum sedimentation.

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