Effect of Different Physical and Geochemical Parameters on Mobilisation of Metals: A Crucial Step Towards Resource Recovery from Waste




Effect of Different Physical and Geochemical Parameters on Mobilisation of Metals: A Crucial Step Towards Resource Recovery from Waste


The concept of using accelerated supergene processes in repository engineering (ASPIRE) has been proposed to create anthropogenic ores of critical or valuable metals and to supply clean aggregates to meet future needs. This repository concept is a paradigm shift from the historical practice of store and contain to store, contain, clean and concentrate to extract resources from solid wastes that are generated in millions of tonnes per year by the industrial, mining and mineral processing sectors. Resource extraction efficiency largely depends on three processes: metal mobilisation, transport, and trapping within the ore. However, the complexities and lack of comprehensive understanding of the major physical and geochemical processes associated with these three processes (mobilise, transport and trap) in a multiphase geomaterial pose a significant challenge. This paper considers, based on synthesis of the literature, the physical and geochemical processes associated with the mobilisation of elements within an ASPIRE storage. The influence of the several physico-bio-chemical parameters, including pH, particle size, redox state of elements, chemistry of lixiviants, organic matter, mineral composition and aging is highlighted. Particular attention is given to municipal solid waste incinerator (MSWI) ash and coal fly ash, and literature data for this material is used to estimate leachability of metals. It is very challenging to estimate leaching concentration based solely on physico-chemical parameters, and additional kinetic studies are urgently required. Finally, the feasibility of nature-based approach to accelerate mobilisation by supplying root exudates is discussed.



A. Mohammad; D. Sapsford; M. Harbottle; P. Cleall; D. I Stewart; F. Sepulveda


9th International Congress on Environmental Geotechnics (ICEG2023)



Characterisation, Remediation and Management of Contaminated Sites and Wastes



https://doi.org/10.53243/ICEG2023-314