| 摘要 |
1342227 Coagulating waste water MITSUBISHI JUKOGYO KK 17 May 1972 [17 May 1971] 23149/72 Heading C1C In a process of purifying waste water (e.g. paper pulp mill waste) coagulant is added to the waste water, the resultant sludge and clarified water are separated, the separated sludge is roasted, at least part of the residue after roasting is dissolved in an acidic solution and the solution used for coagulating further waste water. Part of the roasted residue may be directly added to the further waste water to aid settling of the sludge. The sludge may be concentrated and dehydrated prior to roasting. The coagulant may be a salt (e.g. chloride or sulphate) of Mg, Al or Fe. The acidic solution may be HCl, H 2 SO 4 and/or chlorine-containing water. Alkali (e.g. slaked lime, caustic soda or carbide waste) and polyacrylate may be added to the waste water. Material containing coagulant or from which coagulant may be produced may be added at some stage to replenish depleted coagulant in the recycling system. For example, sea water or bittern may be added to the solution; dolomite, magnesite, iron scrap, iron oxide, hematite or limonite may be added at the roasting stage; or magnesia, carnellite or brucite may be added at the dissolving stage. |
