Analysis of the Release Characteristics of Blast Furnace Lead Smelting Slag by Integrating Mineralogy and Dynamic/Static Leaching

Open piles of lead and zinc smelting slag threaten the environment due to their releasing harmful heavy metals (HMs). However, the unclear relationship between mineral composition and heavy metal release in blast furnace lead smelting slag (BFLSS) has hindered the development of pollution prevention techniques. In this study, a combination of mineral liberation analysis (MLA) and dynamic/static heavy metal leaching tests was used to examine the relationship between the leaching characteristics of HMs and the mineral composition in BFLSS. MLA analysis showed that melilite (58.15%), pyrite (8.82%), magnetite (4.37%), pyroxene (5.77%), and Zn-Fe spinel (3.06%) were the main phases of BFLSS. The morphological analysis results indicate that Pb and Zn are highly migratory and bioavailable. The combined mineralogical and dynamic leaching experiments show that the release of the toxic HMs, Pb and Zn, from the smelter slag under acid rain conditions is mainly controlled by the acidic dissolution of the minerals and the partial oxidation of the pyrite. The combined mineralogical analysis and dynamic/static leaching experiments are significant in explaining the release mechanism of HMs from BFLSS.