Abstract: A cementitious material was prepared with blended powders including molybdenum tailings, slag, clinker and gypsum.The effect of different types and dosage of super plasticizer on strengths and hydration products of molybdenum-tailing-based mortars was studied.The results indicate that the strength of mortars with the same fluidity is improved when super plasticizer is present in samples.The biggest improvement is PC super plasticizer, next one is FDN and the last one is UNF-5.When the dosage of PC super plasticizer is 0.4%, the compressive strength of molybdenum-tailing-based mortars is high up to 48.8 MPa at 28 d.The ground molybdenum tailings have a certain reactivity in the studied system.The hydration products of cementitious materials prepared with molybdenum tailings are mainly ettringite and C-S-H gel.

Key words: molybdenum tailings;super plasticizer;mortar;hydration product