Delithiated Beta Spodumene (DBS), a by-product of lithium extraction from spodumene, is emerging as a promising supplementary cementitious material (SCM) in concrete. With the rapid growth of the lithium use on the battery industry, DBS is forecast to be produced in large quantities, yet most may end up in landfills if beneficial end uses are not identified. While previous research has demonstrated its potential to enhance concrete performance, its environmental impact has remained largely unexplored. A recent study has conducted a detailed life cycle analysis (LCA) using IPCC 100a method to quantify the embodied carbon emissions of DBS, evaluating its feasibility as a sustainable alternative to traditional cement.

The study examines the carbon footprint of DBS from its extraction to its processing and incorporation into concrete. Since DBS is a byproduct, its environmental burden is shared with lithium carbonate production, and the study applies an economic allocation method to determine the emissions attributed to DBS. Findings indicate that approximately 35% of its carbon footprint comes from the primary extraction process, while 65% is associated with its treatment; specifically drying, grinding, and calcination. These processes, particularly calcination, significantly impact emissions due to their high energy consumption.

Sensitivity analysis further explores how different energy sources influence the carbon footprint of DBS processing. Results show that switching from coal-based electricity to natural gas-based electricity can reduce processing emissions by up to 23.6%. This highlights the role of energy sources in determining the overall sustainability of DBS use. Despite these processing emissions, the study confirms that replacing 30% to 60% of cement with DBS can reduce the overall carbon footprint of concrete by 13.5% to 34.4%, depending on the grade of concrete and the level of cement replacement. Notably, higher-strength concrete grades benefit the most from DBS incorporation due to their higher cement content.

In addition to environmental considerations, the study also evaluates the mechanical performance of DBS-based concrete. Standardized compressive strength data from 41 mix designs were analyzed to ensure that DBS-replaced concrete meets structural requirements. The results indicate that DBS can effectively serve as an SCM without compromising the strength of concrete, making it a viable alternative to conventional cementitious materials like fly ash or slag.

This work was carried out by Gunja Shah, a PhD student at UNSW’s School of Civil and Environmental Engineering, under the supervision of Dr. Ali Kashani and Prof. Stephen Foster. Their research contributes valuable insights into the environmental performance of DBS and its potential role in developing low-carbon concrete solutions.

This article was contributed by Dr. Ali Kashani, Civil and Environmental Engineering, University of NSW.