CuO and ZnO addition in the cement raw mix: Effect on clinkering process and cement hydration and properties

One reference and two modified mixtures, prepared by mixing the reference sample with 1.0 wt.% of chemical grade CuO and ZnO, were studied. The effect of the added oxides was evaluated on the basis of the unreacted lime after sintering, the hydration rate, the cement properties and the leaching behavior of clinkers, cements and cement pastes. The added oxides improve the burnability of the Portland cement raw mix and the strength development of the produced cements, without considerably affecting the hydration rate and the physical properties. Cu2+ and Zn2+ are not readily leached from hydrated cement products made from Cu- and Zn-containing clinkers, possibly due to the high incorporation degree of Cu2+ and Zn2+ cations in the main clinker phases.