Metallurgical slags from Cu production and Pb recovery in Poland - Their environmental stability and resource potential

摘要

Three different residues from Cu smelting (shaft furnace slag - SFS, and granulated slag - GS) and Pb recovery (Pb slag - LS) in Cu foundries, located in the SW Poland, were examined with respect to chemical and phase composition. The examined materials reveal distinct mineral composition. The Pb slag exhibits crystalline structure, and main phases observed in this slag were sulfides (nukundamite, idaite, sphalerite, troilite), spinel oxides (magnetite and chromite), intermetallic compounds (Cu, Pb and Fe) and non-stoichiometric olivines. The shaft furnace slag and the granulated slag are amorphous apart from the presence of some crystalline phases such as spinels and sulfides in shaft furnace slag. Both shaft furnace slag and granulated slag have metallic Cu and Pb inclusions. The samples are abundant in potentially toxic elements such as Cu, Pb and Zn, as well as critical elements such as REE, Co, Mo and V (up to 308, 1445, 773 and 1228 mg kg(-1) , respectively). Two standardized leaching protocols were applied to illustrate the leaching potential of selected metal(loid)s. The slags were found chemically resistant to leaching by simulated rainfall or water. Six-step sequential extraction revealed that labile forms of metals are present in granulated slag, that exhibits mainly vitreous texture.