| 摘要 |
A process is disclosed for reducing Hg content of industrial waste water. Total Hg present is first converted to ionogenic, divalent oxidn. step, by setting up, in the waste water, an active Cl concn. of 2-50 mg/l. This is achieved by adding Cl2, HCl or NACL to the inorganic acid medium. Fe (II)-ions are then added until their concn.in waste water reaches 0.1-1.5 g/l.- A redox potential of -0.1 to -0.8 v, w.r.t. standard H electrode, is then set up, by adding pH-raising chemicals. Hg is reduced, pptd. and deposited together with the Fe hydroxides generated at the same time.Pptn. products are finally sepd.- Process is partic. suitable for treating waste waters from chlor-alkali electrolysis by amalgam process. Good results, e.g.99.97% Hg removal, are obtd. even with a 14000 times NaCl excess w.r.t. Hg wt./ml. waste water.- The Hg (I) salts obtd. are flocculated by mixt. of Fe hydroxides formed. Setting of redox potential and separation of pptd. products pref. take place in an O2-free atmos
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