Title: Metals in Mine Tailings and Prospects for Use in Cementitious Materials

Author(s): Anne Mette Tholstrup Bagger, Stefanie Lode, Wolfgang Kunther, Pernille Erland Jensen

Publication: Symposium Paper

Volume: 362

Issue:

Appears on pages(s): 966-975

Keywords: cementitious materials, early hydration, lead, metals, mine tailings, retardation, sulfide ore, zinc

DOI: 10.14359/51742022

Date: 6/18/2024

Abstract:

Due to extensive mining activities, mining waste generation accounts for the largest global waste stream. Currently, mining wastes are often deposited and remain an unexploited potential resource, e.g., for the construction industry, which suffers from material scarcity and high CO₂ footprints. Mine tailings, the waste fraction from ore processing, are fine-grained and composed of major oxides like that of cement and come in large quantities, thus having the potential for beneficial use in the construction industry. A systematic approach to match mine tailing properties with cementitious material application could potentially reduce implementation time and cost.

One crucial aspect of implementing mine tailings into cementitious materials is that of unrecovered metals originating from the sulfide mineral ores, which are known to affect early hydration. This study found that lead sulfide is released to a higher degree than zinc sulfide under alkaline conditions despite a higher total initial zinc content. Increasing dosage up to 20% of mine tailings caused a promotion of hydration, while increasing the dosage up to 60% generated a retarding effect. The findings highlight the complex interplay between metal concentrations, dissolution trends, and hydration behavior in alkaline cementitious environments and are crucial for selecting appropriate cementitious material applications for heterogeneous materials like mine tailings.