Carbon dioxide mineralization of mine tailings for permanent CO2 storage

Dr Juerg Matter, Dr Matthew Cooper, Dr Phil Renforth (Heriot Watt)

Achieving the Paris Agreement goal of limiting the post-industrial increase of global surface temperature to 1.5°C requires drastic reduction in current CO2 emissions into the atmosphere. If the UK is to meet the legislated target of net-zero carbon emissions by 2050, approximately 130 MtCO2/yr may need to be removed from the atmosphere. Direct air capture (DAC) has a nearly unlimited potential to capture CO2 from the atmosphere, provided that the captured CO2 can be stored permanently and its overall cost can be reduced significantly. A promising option for reducing cost and guarantee of permanent storage of the capture CO2 is through integration of DAC with CO2 mineralisation. Alkaline industrial waste, such as steel slag, mine tailings and demolition waste readily reacts with CO2 to form stable carbonate minerals.

This project will provide important constraints for a novel hybrid DAC-mineralisation system by quantifying the rate of CO2 mineralisation of different type of mine tailings by conducting first a series of laboratory experiments, followed by a large scale field trial in a novel engineered heap reactor system. The main outcomes of this project will contribute to the development of a pilot-scale demonstrator for greenhouse gas removal at one of Anglo American’s mine sites. The collaboration with Anglo American is under an existing NDA between University of Southampton and Anglo American.


The student will characterise representative alkaline industrial waste materials (including steel slag, demolition waste and mine tailings) with regard to physical properties, mineralogy and chemistry using different analytical methods (SEM-EDS, XRD, XRF, mass spectrometry, micro-computer tomography, grain size and surface area analyzer). Reaction kinetics of these materials will then be defined at well-controlled experimental conditions by laboratory experiments. Results from these laboratory experiments will be key for defining the experimental conditions in the novel heap reactor system (80 kg CO2/day) based at one of Anglo American’s mine site. By analyzing leachate samples from the heap reactor (major/trace elements, alkalinity, d13C, d18O, Sr-isotopes) rates of dissolution and CO2 uptake by carbonate precipitation will be determined in the field-scale heap reactor system. These data will then be used to evaluate the overall CO2 capture efficiency of this system.


University of Southampton

The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at the National Oceanography Centre Southampton. Specific training will include: (i)physical and chemical characterisation of alkaline industrial waste material via micro-CT, grain and surface area analyzer, XRD, XRF, mass spectrometry and SEM-EDS; (ii) the collection of leachate samples from laboratory and field based experimental reactors, and associated in-situ micro-sensor measurements (pH, CO2 etc); (iii) Laboratory and field-based experimental approaches for quantifying the rate of alkaline waste material dissolution and carbonate precipitation.

In addition to exchanges associated with INSPIRE, the student will have opportunities to work closely with national and international collaborators on the DAC-Hybrid Mineralisation project (Phil Renforth & Mjindert van der Spek, Heriot Watt; Aidong Yang & Richard Darton, Oxford; Anglo American).


Eligibility & Funding Details: 

Please see for details.

Background Reading: 

Matter et al. Rapid carbon mineralization for permanent disposal of anthropogenic carbon dioxide emissions. Science, Vol 352, 6291 (2016)

The Royal Society & Royal Academy of Engineering. Greenhouse Gas Removal. (2018).

National Academies of Sciences. Negative Emissions Technologies and Reliable Sequestration. (National Academies Press, 2019). doi:10.17226/25259.

Renforth, P. The negative emission potential of alkaline materials. Nat. Commun. 10, 1401 (2019).