Manganese mining waste as a novel supplementary material in Portland cement

Abstract

Manganese ore is one of the most processed in the world and it is considered essential in the manufacture of iron, steel alloys, batteries etc. However, during its mining and processing, a large portion of wastes are deposited in open-air landfills causing vary environmental risks. Here, such residue (MnW) was proposed as a filler material in Portland cement. The effects of partial substitutions of cement by MnW were assessed by compressive strength, water absorption, void index, bulk density, scanning electron microstructure (SEM-EDS). The results showed that replacing cement at 6–8% with the residue increases the compressive strength, bulk density and reduces the voids and water absorption of the samples. By SEM-EDS, MnW seems to stimulate further C-S-H formation by nucleation on the cement surface. The valorization of this MnW as Supplementary Material helps the environment by giving a destination to a mining waste that occurs around the world, encourages a circular economy on the development of new cement-based products with potential local application without harming their mechanical performance.