Potential utilization of copper tailings in the preparation of low heat cement clinker

•Copper tailings can be used as a raw material for LHC production.•LHC with copper tailings addition showed low hydration heat (72.1 J/g) at 7 d.•The heavy metal leachability of LHC and its paste were much below safe limits. In order to avoid environmental pollution from copper tailings (CT), this paper presented a study on potential utilization of CT in the preparation of low heat cement clinker (LHC). The effect of CT addition on the properties of LHC was investigated by using free lime (f-CaO) content test and X-ray diffraction (XRD). Furthermore, to study the hydration properties of LHC paste, the produced LHC samples were mixed with 0.37 wt% gypsum to prepare the LHC paste at a water/binder ratio of 0.30. The compressive strength, hydration process, hydration products of LHC paste and solidification of heavy metals in LHC and the hydrated paste were analyzed. The experimental results showed that CT can be used as a raw material for LHC production. The CT is beneficial for the formation of 2CaO•SiO2 (C2S) during the sintering process of LHC. Furthermore, LHC paste with higher CT addition showed lower hydration heat during the first 7 d hydration. With 2 wt% CT added, the hydration of LHC paste can be promoted and the compressive strength was higher than the blank group at the age of 60 d. The leaching tests indicated that heavy metals in CT can be stabilized in LHC and LHC paste during the sintering process and the hydration process.