METHOD OF TREATING INDUSTRIAL SEWAGE WATERS Russian patent published in 1998 - IPC

FIELD: chemical industry; purification of sewage waters from mercury, for instance, in production of chlorine or caustic by mercury method. SUBSTANCE: method includes treatment of industrial sewage waters with freshly settled manganese sulfide taken in the amount of 0.65-0.87 mas.pts per mas. pt of mercury in initial waters. Solid phase is separated. Waters are efficiently purified with production of compact sediment, especially in carrying out of process in several stages, preferably in three stages, using at each stage of the same portions of reagent. The reagent is produced by reaction of excessive salt of manganese (II) with sodium sulfide and/or hydrosulfide in aqueous solution. Mercury content in waters after treatment under optimum conditions is less than 1 mg/l. EFFECT: higher degree of purification (up to 99%). 5 cl, 1 tbl