An environmental impact of pyritic bauxite from the Dajti Mine, Albania

NOVÁK J.K.,  MINAŘÍK L., PEZA L.H., MELKA K.

Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojová 135, 165 02 Praha 6, Czech Republic

Abstrakt

The accelerated chemical weathering of bauxite due to acid atmospheric deposition and breakdown of pyrite was simulated using short-termed laboratory acid leaching at 20^oC.  Pyrite-bearing gibbsite-boehmitic bauxite giving rise to a number of questions concerning ecology was tested along with oxic boehmitic bauxite from the Dajti mine and that from Mali Korites (Mali Thate Mts.,SE Albania). The leachate of pyrite-bearing and sulphate-producing bauxite is enriched in the following toxic elements: Cd, Be, Zn, Ni, Co, and much less Cr, Cu, As, and Pb. Toxic soluble aluminium ions may be also leached into the aquatic environment, because of high concentration in leachate (563 mg/L). In contrast, the leachates of oxic boehmitic bauxites are commonly depleted in toxic elements with exception of  Cu (Dajti mine) and Be ( new occurrence of Mali Korites ).