Reuse of base-metal tailings as aggregates for rendering mortars: Assessment of immobilization performances and environmental behavior

• We studied environmental behavior of mortars that used base metal tailings as aggregates.
• Good mechanical and durability performances of tailings-based mortars were obtained.
• All leaching tests results indicated that risks of metals release from tailings-based mortars are minor.
• The use of base-metal tailings as aggregates may constitute a sustainable alternative method for efficient tailings management.

The management of mine tailings has become a worldwide environmental concern. In essence, with the increasing ecological disruptions related to tailings storage facilities, there is a pressing need to develop sustainable alternative methods for the management of these hazardous materials. In parallel, abandoned base-metal tailings that contain residual metals are increasingly used in some developing countries as aggregate for mortars without any control or environmental concern. Consequently, there is an additional necessity for improved knowledge of tailings eco-compatibility when reused as construction material. This paper approaches these issues by assessing the geochemical behavior and immobilization performances of two low sulfide tailings-based mortars, commonly used in the upper-Moulouya region (eastern Morocco) as surface finishing mortars. The mechanical and durability performances of these mortars were also presented to endorse their reuse potential. The obtained results showed firstly that the reuse of base-metal tailings with low sulfide content and relatively minor residual-metal concentrations (As ≈ 30 mg/kg, Cr ≈ 60 mg/kg, Pb ≈ 4500 mg/kg, Zn ≈ 250 mg/kg) generates mortars with good mechanical and durability performances. Additionally, all leaching tests results (batch test, acid neutralization analysis, selective dissolution, tank leaching test and weathering cell test) indicated that risks of metals release from tailings-based mortars are minor and their reuse as surface finishing renders may constitute a sustainable alternative method for efficient tailings management.