| 摘要 |
<p>Chemicals, e.g. phosphates, are pptd. or flocculated from water, esp. waste water, with a precipitant contg. or consisting of metallic Fe pieces which contain or consists of Fe oxide. The precipitant is added to the waste water in a clarifying plant before biological treatment or after clarification. The precipitant can consist of a mixt. of pig iron and/or steel pig and Fe oxide. The precipitant is pref. recovered from Fe smelting and/or rolling mill Fe waste. Fe pieces from blast furnace or steel works waste contains Fe, Fe oxide and weakly alkaline slag. Precipitant use to filter after-clarified water is claimed. The Fe phosphates formed can be used as fertilisers. The precipitant is easily transported and stored and is highly reactive, even in concns. below 1%, without FeSO4 addn. or additional aeration. Water acidification is prevented.</p> |
