30 SEP 2026 (WED) 14:35 - 15:05

Harnessing Alkaline Wastes for Carbon Sequestration: Mineral Carbonation and Life Cycle Assessment

Miss SHAO Zi

( Supervisor: Prof Kuishuang Feng )

Abstract:

Alkaline wastes, generated in excess of 20 Gt annually as byproducts of mining, metallurgy, and chemical industries, remain underutilized, despite their enrichment in calcium- and magnesium-bearing silicate minerals. These minerals offer significant negative-carbon potential through natural and accelerated mineral carbonation processes, which could sequester more than 1 Gt CO₂ per year, a mitigation potential equivalent to offsetting approximately 10% of industrial and fossil-fuel emissions. By integrating carbonation kinetic models with LCA-based carbon emission accounting methodologies, the study characterizes pathways of CO₂ uptake at the global scale under both natural and engineered conditions thereby elucidating differences in sequestration potential, pathways, and associated environmental benefits. It also assesses the strategic role of alkaline solid wastes within the broader portfolio of carbon neutrality and negative emission technologies. Under natural conditions, alkaline wastes can gradually capture atmospheric CO₂ through mineral carbonation, whereas accelerated carbonation technologies can markedly enhance both sequestration efficiency and resource utilization. Although recent research has advanced understanding of mineral carbonization mechanisms, kinetics, and enhancement strategies of mineral carbonation, existing studies are often limited to specific minerals or case studies and lacks a systematic framework integrating diverse utilization pathways across regions. In addition, the baseline contribution of natural carbonation is often overlooked, leading to uncertainties in offset estimates and constraining the integration of alkaline wastes into climate mitigation policies and carbon capture, utilization, and storage (CCUS) strategies. The findings are expected to deepen understanding of the global carbon cycle and provide both theoretical and empirical support for waste valorization and CCUS technologies, thereby contributing to industrial emission reduction and sustainable development.