| 摘要 |
PURPOSE:To crystallization-recover a high quality raw material salt from the title waste water by successively removing mercury, sodium sulfate and CO2<2+> by treatment with a chelate resin, chloride adding reaction and CO2 blowing, respectively. CONSTITUTION:The waste water pretreated to remove SS solids and org. matters such as BOD and COD is treated with a chelate resin in mercury chelate resin tower 5 to selectively remove mercury. The mercury-free water is fed toneutralization precipitation vessel 6, where it is adjusted to pH 10-11 with NaOH to separation- remove heavy metals. The mercury- and heavy metals-free water is then fed to gypsum forming reaction vessel 9 to add a chloride such as CaCl2, and the chloride- added water is supplied to gypsum separator 11 through thickener 10 to separation- remove gypsum 22 and sodium sulfate. This SO4<2->-free water is fed to CaCO3 forming reaction tower 12, where it is adjusted to pH>=7 with NaOH and CO2 is blown to remove Ca<2+> as CaCO3. The resulting water is sent to NaCl crystallizer 18 to rystallize NaCl. Thus, high purity NaCl 24 is separation-recovered 19. |
