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The high level of sodium in red mud (RM) is one of the main issues hindering its incorporation as a raw material for construction and building materials. This paper presents a few studies on building materials developed using more than 70% w/w RM content. A proposed industrial process flowchart together with capital (CAPEX) and operational expenditure (OPEX) for a large‐scale plant are presented here. It was estimated that the cost of processing 75 Mton of RM, over a period of 25 years, was US$ 17/ton, including CAPEX + OPEX. The products comprised pellets composed of RM and clay subjected to 1200°C in a straight‐grate kiln. The pellets can be used as road gravel, coarse aggregate in concrete, or converted into supplementary cement material for Portland cement. The collaboration of the construction and building material industry with the alumina industry will be beneficial to mitigate the environmental impacts of RM.

Pyrite is part of the tailings from coal mining and presents a great valorization potential technological, economic and environmental in the production of nanoparticles. In this work, pyrite from coal mining was subjected to high-energy milling and the particle size reduction, electrical and optical properties were evaluated. With the milling parameters used, the apparent size of the crystallites was reduced from 34.7 nm to 23.8 nm, resulting in highly unstable particles and charge carriers with low mobility. Due to this instability, submicron particles were observed, in the range of 300–500 nm, with a hydrodynamic diameter of 1257 ± 36 nm. The processed pyrite showed good visible light absorption and an indirect band gap of 1.51 eV.