Exploring the Potential for Utilization of Medium and Highly Sulfidic Mine Tailings in Construction Materials: A Review

Abstract

Medium and highly sulfidic tailings are high-volume wastes that can lead to severe environmental damage if not properly managed. Due to the high content of sulfide minerals, these tailings can undergo weathering if put in contact with oxygen and water, generating acid mine drainage (AMD). The moderate-to-high sulfide content is also an important technical limitation for their implementation in the production of construction materials. This paper reviews the use of sulfidic tailings as raw material in construction products, with a focus on cement, concrete, and ceramics. When used as aggregates in concrete, this can lead to concrete degradation by internal sulfate attack. In building ceramics, their implementation without prior treatment is undesirable due to the formation of black reduction core, efflorescence, SOx emissions, and their associated costs. Moreover, their intrinsic low reactivity represents a barrier for their use as supplementary cementitious materials (SCMs) and as precursors for alkali-activated materials (AAMs). Nevertheless, the production of calcium sulfoaluminate (CSA) cement can be a suitable path for the valorization of medium and highly sulfidic tailings. Otherwise difficult to upcycle, sulfidic tailings could be used in the clinker raw meal as an alternative raw material. Not only the SO3 and SiO2-rich bulk material is incorporated into reactive clinker phases, but also some minor constituents in the tailings may contribute to the production of such low-CO2 cements at lower temperatures. Nevertheless, this valorization route remains poorly explored and demands further research.

Additive-Free Aqueous Extraction of Copper and Zinc from Sulfidic Tailings Using Fast Microwave-Assisted Pre- and Post-Treatments

“…This solid residue, however, still contains small quantities of residual metals and offers potential for further extraction processes before being stored or, given its rich mineral content, reused as a replacement for raw materials in building material or inorganic polymers. 13,15,16 • MW-assisted hydrothermal iron-precipitation: in previous works, it has been shown that MW-assisted hydrothermal reactions are more efficient through enabling rapid, uniform, and selective heating and a simpler, more environmentally friendly performance. Compared to conventional hydrothermal methods, which often require harsh temperature and pressure conditions, as well as longer times (hours to days), MWassisted hydrothermal processes operate under lower temperatures and pressures as well as shorter times (minutes to hours).…”

“…The removal of sulfur in the form of SO x gases (during roasting) and sulfates (during leaching) in a controlled manner significantly reduces the environmental risks of sulfidic tailings since it decreases the risk of AMD after depositing the produced leaching residues. This solid residue, however, still contains small quantities of residual metals and offers potential for further extraction processes before being stored or, given its rich mineral content, reused as a replacement for raw materials in building material or inorganic polymers. ,, MW-assisted hydrothermal iron-precipitation: in previous works, it has been shown that MW-assisted hydrothermal reactions are more efficient through enabling rapid, uniform, and selective heating and a simpler, more environmentally friendly performance. Compared to conventional hydrothermal methods, which often require harsh temperature and pressure conditions, as well as longer times (hours to days), MW-assisted hydrothermal processes operate under lower temperatures and pressures as well as shorter times (minutes to hours). − When applied to the aqueous leachates generated in our process, selective precipitation of Fe with adsorbed As was achieved within 1 h at 150 °C.…”

“…The removal of sulfur in the form of SO x gases (during roasting) and sulfates (during leaching) in a controlled manner significantly reduces the environmental risks of sulfidic tailings since it decreases the risk of AMD after depositing the produced leaching residues. This solid residue, however, still contains small quantities of residual metals and offers potential for further extraction processes before being stored or, given its rich mineral content, reused as a replacement for raw materials in building material or inorganic polymers. ,, …”

“…Sulfidic Cu–Zn–Pb tailings not only contain a significant amount of Cu, Zn, and Pb, but they also pose a threat to the environment (due to their As content) either by acid mine drainage (AMD) , or dam failure. , Lastly, extraction of valuable metals from such materials, as well as removal of toxic elements, also makes one step forward toward closing the loop of a circular economy according to near-zero-waste principles . Thereby, the leftover matrix can be valorized as a product, such as inorganic polymers, supplementary cementitious materials, aggregates, ceramic products, etc. − …”

Prospective Environmental Assessment of Reprocessing and Valorization Alternatives for Sulfidic Copper Tailings

“…The presence of ye'elimite (Ca 4 (AlO 2 ) 6 SO 3 ) as active clinker phase instead of alite (Ca 3 SiO 5 ) brings advantages in decreasing firing temperature by 100 • C -250 • C during clinkerization of CSA cement (Telesca et al, 2019). The inventory input for clinker materials is modeled based on Martins et al (2020Martins et al ( , 2021, where highly sulfidic tailings constitute 14%-wt of raw meal mixture. To generate the entire life cycle model at a large scale, we combine our design mix with the industrial CSA plant data.…”