Study on the Preparation of Glass-Ceramics by All-Solid Waste of Lead-Zinc Tailings and the Stabilization Mechanism of Heavy Metals

Abstract

Today a large number of tailings are piled up and not utilised, which has a great impact on the environment and ecology. How to effectively use tailings is a challenge for mankind. In this paper, a method using 100% lead-zinc tailings to fabricate glass-ceramics was successfully proposed. Which can completely consume tailings as well as effectively solidify heavy metals. First of all, a reasonable proportion of glass-ceramics was designed based on thermodynamics, then the heat treatment process was determined by kinetics. The mechanism of heavy metal solidification and migration during high temperature calcination was investigated, and finally, the risk of heavy metal leaching was analyzed. The results show that the main crystalline phases of the samples were pyroxene and spinel by calculations based on the thermodynamic fit ratio. The lead-zinc tailings contained a large amount of Fe, which was cured in the glass-ceramics mainly in the form of CaFeSi2O6 and Fe3O4. Cu and Zn were efficiently cured in the spinel, while Pb was uniformly distributed as ions in the glass matrix. Leaching concentrations of heavy metals in glass-ceramics were well below standard thresholds, and curing efficiencies can exceed 99%.

Keywords: lead-zinc tailings, heavy metals, solid waste, glass-ceramics, transformation and stabilization