###### Abstract  
This research investigated the possibility of using metallurgical slags from the copper and lead industries as partial replacement for cement. The studied slags were fayalitic, having a mainly ferro-silicate composition with minor contents of Al2O3 and CaO. The slags were treated at 1200-1300 \({}^{\circ}\)C (to reduce the heavy metal content) and then granulated in water to promote the formation of reactive phases. A full hydration study was carried out to assess the kinetics of reactions, the phases formed during hydration, the reactivity of the slags and their strength activity as supplementary cementitious material (SCM). The batch-leaching behaviour of cementitious mixtures incorporating treated slags was also investigated. The results showed that all three slags have satisfactory leaching behaviour and similar performance in terms of reactivity and contribution to the strength development. All slags were found to have mediocre reactivity and contribution to strength, especially at early ages. Nonetheless, they passed the minimum mechanical performance requirements and were found to qualify for use in cement. s +
Footnote †: journal: Medical  
are produced compared to iron slag (5.5 and 68.7 million tons for lead and copper slags, respectively [7; 8], compared to 320-384 million tons for iron slag [9] on a global basis), they often incorporate considerably higher amounts of heavy metals and corrosive anions [7; 10], which makes their disposal more critical and costly. Their use in concrete also comes with the risk of disturbing the cement hydration reactions (due to the presence of sulphates, other anions and heavy metals) and leaching of contaminants to the environment in the long term. As such, a separate pyrometallurgical treatment can be applied to such slags to recover the valuable heavy metals such as metallic lead and zinc, reduce the toxic heavy metals such as arsenic and antimony and remove the anions. The application of this step is intuitively crucial for converting such slags from wastes into secondary resources with the potential for being used in the cement and concrete industry as SCMs or precursors of alkali-activated materials [7; 8; 11; 12; 13]. The thermal treatment usually involves melting the slags intermixed with coke at up to 1200-1300 \({}^{\circ}\)C, followed by dwelling at such temperature for a length of time to fume off volatile elements and reduce others to a metallic state that can be tapped. To promote the reactivity of the slags, they are rapidly granulated in water to avoid crystallisation and the formation of stable phases [14; 15]. Some additives such as silica and limestone may be added to the slag prior to the thermal treatment as flux to reduce the ultimate temperature, optimise the melt viscosity and/or increase the reactivity as SCMs or in alkaline media in general [3; 7; 16; 17; 18]. [PERSON] and [PERSON] [3] studied the effects of using a source of copper slag on the mechanical properties of concrete and found out that replacement of 10% of Portland cement with rapidly cooled granulated slag resulted in a slight increase in the compressive strength. [PERSON] et al. [19] used two sources of slowly cooled and rapidly cooled copper slag (milled for two different milling times) in combination with Portland cement up to 20% replacement. They concluded that low replacement levels can enhance the hydration reactions, while higher levels of replacement can cause some retardation. Rapid cooling was found to slightly enhance the strength activity of the slags, and the fineness was found to have a mild influence on the strength activity index (SAI) of the slags. [PERSON] et al. [20] studied the effect of fineness of a non-ferrous metallurgical slag (NFMS) on the reactivity of blended cements [20]. They also reported a slightly higher long-term strength for finer slag despite the retarding effect of the fineness on early-age hydration. The R3 heat release results of the NFM slags studied by [PERSON] et al. [20] and [PERSON] et al.