engleski

Assessment of environmental condition in the waste disposal site of ex-aluminum plant near Obrovac in Croatia

The waste disposal site of abandoned alumina plant Obrovac in Croatia contains two basins filled with red mud and waste base. The total amounts of red mud and waste base are estimated to 0.85x106 m3 and 0.65x106 m3, respectively. Red mud was analyzed for its major components, heavy metals content, free base content and leaching properties under different conditions of pH and temperature. Concentrations of 15 elements (Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Rb, Sr, Y, Zr, and Pb) were measured using tube excited EDXRF as an analytical technique. The major compounds were determined by XRD method, while AAS and XRF methods were used for elemental concentration determinations in different types of leachates. It was found that possible treat to the environment from red mud under normal environmental condition could be caused only by leaching of alkalies, and V. On other hand, concentrations of V, Cr, Cu, As, Se in the waste base and pH value are much higher then allowed for technical waste waters discharge directly into the environment. Waste base treatment (neutralisation and heavy metals removal) can be achieved in one step process. During this process neutralisation of acidic red mud would result in the production of gel-like coagulant.

red mud ; heavy metals ; EDXRF

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