Preliminary life cycle assessment of CO2 sequestration in construction materials by accelerated carbonation of mineral waste – The Mineral LOOP project.

Mineral waste is one of the largest waste streams in Europe. Despite their potential to partially replace primary raw materials in construction (e.g., natural aggregates), mineral wastes are still largely landfilled and rarely reused or recycled. Among these wastes, alkaline mineral materials have the additional ability to capture and store CO2 from the atmosphere, through the reaction of mineral carbonation. The Mineral LOOP project, funded by the GreenWin Pole of Wallonia (Belgium), aims to produce and commercialize new types of fillers and aggregates obtained from carbonated mineral wastes. Thereby, it intends to tackle the following environmental challenges: (1) the circular management of mineral waste streams, (2) the reduction of construction-related CO2 emissions, and (3) the reduction of primary raw materials consumption.

Many waste streams (including thermal process residues, mining and quarrying wastes, construction and demolition wastes) are investigated to identify the ones with the highest potential for carbonation and valorization. An industrial pilot plant will be designed, developed, and operated for the processing of mineral wastes into secondary products. In particular, it will implement an accelerated carbonation process with the purpose of capturing and fixing industrial CO2 (e.g., from cement manufacturing). The obtained products will then be valorized by the industrial partners on the project. Throughout the project, the Life Cycle Assessment (LCA) methodology will be used as a decision-support tool to assess the environmental impact of the various waste processing operations.
Commercialized products are expected to be both low-impact and cost-competitive while promoting a local circular economy. Moreover, the accelerated carbonation process could contribute to a significant portion of the negative emissions required to reach future climate targets. Such a strategy will hopefully pave the way for more sustainable initiatives in the Walloon region construction sector.