| 摘要 |
PURPOSE:To reduce the cost of chemicals by neutralizing waste water contg. Cd with calcium carbonate under aeration, adjusting the neutralized water to 8-8.6pH with NaOH to precipitate hydroxide, carrying out solid-liq. separation and treating the resulting supernatant liq. with a chelating agent. CONSTITUTION:Waste water contg. Cd is neutralized to about 6pH with calcium carbonate under aeration and the neutralized water is adjusted to 8-8.6pH with NaOH. A formed hydroxide precipitate is removed by solid-liq. separation, the resulting supernatant liq. is treated by adsorption on a chelating agent and the treated liq. is filtered. By this method, inexpensive calcium carbonate and an alkali agent such as NaOH are utilized to precipitate and remove Zn and Cd, so the cost of chemicals and the stable volume of the formed precipitate can be reduced. |
