On the example of waters from Komsomolsk tailings pond (Kemerovo region, Russia) with initial рН=6.5 and content of As and Sb amount to 0.25 mg/l and 0.85 mg/l, respectively, the possibility of using chemical reagents: lime milk, Na2S and FeSO4, for removal of metals and metalloids from the water right up to the maximum permissible concentrations (MPC) was shown. It was experimentally proved that all three used reagents are appropriate for arsenic immobilization. The following sequences of the reagents in increasing order of reagents efficiency for As removal can be constructed: lime milk<Na2S=FeSO4. For Sb removal there is slightly different efficiency: lime milk<Na2S<FeSO4. Detailed chemical and mineral analyses of the newly formed after experiments mineral phases were conducted using X-ray diffraction (XRD) and scanning electron microscopic investigations. Formed reaction precipitates have compound composition. The dominant reaction products for lime milk and Na2S reagents were calcite CaCO3, gypsum CaSO4×2H2O, anhydrite CaSO4, and for FeSO4 reagent was goethite Fе3+О(ОН). Formation of bianchite (Zn,Fe)[SO4]×6H2O and mcnearite NaCa5H4(AsO4)5×4H2O for lime milk; sulfur S0, siderite FeCO3, rezbanyite Pb2Sb6S11, holdenite (Mn,Zn)6(AsO4)(OH)5O2 and sinnerite Cu6As4S9 for Na2S; adamite Zn2AsO4(OH) for FeSO4 were also identified in trace quantity. Iron (III) sulfate is highly effective in precipitation of arsenic and antimony, as 0.5-1.0 g of the reagent per liter of the tailings pond water reduces the concentration of As and Sb to a level below of MPC.
|Журнал||International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM|
|Состояние||Опубликовано - 1 янв 2017|