Assessment of molybdenum mine tailings as filler in cement mortar

Abstract

The present study investigates the mechanical properties and durability of cement mortar incorporating molybdenum mine tailings as a filler material in an effort to report any suitable recycling potential. Molybdenum mine tailings are a type of mineral waste obtained from the mining industry. The proper disposal of mine tailings is an important challenge for sustainable mining practices. These fine-sized mine tailings (<300 μm) can be incorporated into building materials. Cement mortar specimens were fabricated with additions of 0% to 20% of molybdenum mine tailings. The mechanical behavior was observed by compressive strength, flexural strength, ultrasonic pulse velocity, dynamic modulus of elasticity, and bulk and apparent density tests. The durability behavior was tested by assessing the water absorption by immersion, total voids, water absorption by the capillary rise, and resistance to chemical (sulfate and acid) attacks. The addition of molybdenum mine tailings was found to be able to improve the performance of cement mortar according to all parameters examined here. The incorporation of 20% mine tailings resulted in 16% increase for 28 days mechanical performance while 10% mine tailings led to a 20% reduction in total voids in cement mortar. Furthermore, the mine tailings act as a buffer shield to resist aggressive chemical attacks. Based on the outcomes of the present study, the production of cement mortar containing molybdenum mine tailings is a viable solution for the recycling of these materials. Up to 10% molybdenum mine tailings can be used to produce masonry mortar with properties similar to that of conventional mortar.