Sustainable Concrete Bricks Integrating Delithiated Beta Spodumene and Mineral Carbonation

The Challenge 

For every tonne of lithium carbonate produced, approximately 9–10 tonnes of residue, delithiated beta spodumene (DBS), are generated posing significant environmental challenges. Recent studies have shown that DBS contains amorphous aluminosilicate phases and can therefore be utilised in concrete as supplementary cementitious material (SCM), replacing up to 40% of cement due to its notable pozzolanic reactivity. However, the adoption of DBS in concrete has been slow, primarily due to the cautious acceptance among producers, engineers, constructors, and standards. Moreover, the inherently low reactivity of DBS with CO2 has limited its integration with carbon capture and utilisation (CCU) technologies, until now. This research aims to accelerate the practical utilisation of DBS by developing concrete blocks, a product subject to less stringent standard requirements, and integrating CCU using carbonated recycled concrete aggregates (CRCAs). 

Proposed Solution

This research aims to evaluate the mechanical, durability, and microstructural performance of 

concrete incorporating DBS and CRCAs, and to demonstrate its feasibility for concrete blocks. The 

specific objectives are: 

(i) Validate the use of DBS at different cement replacement levels in concrete. 

(ii) Evaluate the impact of replacing natural aggregates with RCAs in DBS-concrete. 

(iii) Treat RCAs with carbon dioxide and assess their CO2 sequestration capacity. 

(iv) Evaluate the mechanical and microstructural performance of DBS-CRCA-concrete. 

(v) Manufacture concrete blocks and evaluate the impact of incorporating these materials. 

(vi) Optimise the mix to comply with the mechanical and durability requirements of Australian 

Standards. 

(vii) Quantify environmental and economic benefits relative to conventional concrete blocks. 

Proposed Benefits to WA

As the world’s leading lithium producer, WA generated about 88,000 tonnes of lithium carbonate equivalent in 2024, producing nearly 1 million tonnes of DBS residue. Valorising DBS as a SCM offers a sustainable solution to reduce waste disposal and cement consumption in concrete. DBS is considerably more economical than other SCMs derived from mining activities, costing roughly 10 % of GGBFS, 4 % of metakaolin, 5 % of silica fume, and only 2 % of cement, while life-cycle analyses show that substituting 30–60 % of cement with DBS can lower concrete’s carbon footprint by 13.5–34.4 %, depending on mix design. This research also addresses Western Australia’s growing construction and demolition waste stream, which accounts for 35% of national waste generation and has increased by 33% in the past six years. By employing RCAs as CO2-sequestering aggregates and DBS as a performance enhancer binder, the project introduces an innovative route for low-carbon, circular construction materials.

Supervisors

Professor Xihong Zhang

DOI

10.71342/590832199202