Integrated valorization of silver mine tailings through silver recovery and ceramic materials production

Abstract

The use of mine wastes as alternative materials to finite natural resources in the construction sector is a sustainable solution to better protect the environment and manage solid wastes. This paper aims to investigate the integrated valorization of silver mine tailings (RST) through the recovery of residual silver by froth flotation and ecofriendly use of the resulting treated tailings (SMT) to manufacture ceramic materials. Treated silver mine tailings (SMT) sample was mixed with natural clays in different proportions to prepare the desired formulations. Samples were then pressed, dried and sintered at various temperatures (900, 950, 1,000 and 1,050 °C) for 3 h with a heating rate of 2 °C/min. The mineralogical compositions, physical, mechanical, microstructural and environmental properties of the sintered ceramics were assessed. The main results show that the mechanical resistance of sintered ceramics decreases with the addition of SMT. However, increasing the sintering temperature allows to improve the mechanical performance of ceramics. Also, water absorption was improved with the increase of sintering temperature due to the decrease of open pores. The leaching behavior of pollutants from sintered ceramics was also evaluated according to the Toxicity Characteristic Leaching Procedure (TCLP). The released concentrations of As, Ba, Cd, Cr, Cu, Mo and Pb were below the requested limits for non-hazardous waste set by US-EPA regulations.