Iron ore tailings as a new product: A review-based analysis of its potential incorporation capacity by the construction sector
Lucas Thadeu da Silva Ramos, Rogério Cabral de Azevedo, Augusto César da Silva Bezerra, Leo Maia do Amaral, Raquel Diniz Oliveira
Abstract
Incorporating products from other industries into construction materials has been done successfully in the past, reducing the extraction of raw materials and the disposal of waste from industry. This study analyzes the construction industry's potential to incorporate iron ore tailings (IOT) as a replacement for construction materials through a systematic review to perform a scenario analysis. IOT can be incorporated into different construction materials, such as concretes, mortars, bricks, and blocks, with substitution rates varying from 5% to 100% without losing their standardized required properties. The main property evaluated for using IOT is the compressive strength of construction materials, where most of the results meet or exceed the values for the reference material and the standard requirements for the materials evaluated in the scenario analysis. The replacement of aggregates in concretes and mortars presented results up to 63 MPa and 48 MPa, respectively; when the IOT replaced the cement in concretes and mortars, its results were 56 MPa and 43 MPa, respectively. A cost comparison analysis shows that, at specific replacement rates, the cost of concretes produced using IOT to replace cement or aggregate can even present a cost reduction of up to 40% when replacing the aggregates and up to 35% when replacing the cement. The scenario analysis for the Brazilian IOT production and construction industry indicates that the usage of IOT as a substitution for raw materials could reduce in up to 60% the volume of IOT designated to dams, while following the limitations of the standard for the replacement rates on construction materials. By using the minimum requirements of the compressive strength values for the construction materials instead of the standard allowed replacement rates, the construction industry could potentially consume all IOT generated annually by the mining process and, in a further moment, consume large volumes of IOT stored in dams. Thus, the feasible reduction of the environmental risks and potential damage of dams could present itself as an alternative for a circular economy and assist the mining and construction sector with their decarbonization goal for a more sustainable future. Therefore, the key finding of this investigation can contribute to validating and fostering this strategy as a sustainable option of the industry sector to provide by-products for civil construction in locations in which the IOT source proves to be relevant.