Novel carbon dioxide mineralisation initiated by direct air capture

September 26th, 2023

Waste to treasure: Novel hybrid carbon dioxide mineralisation initiated by direct air capture

Project duration: July 2023–June 2026

Image: DALL E with prompt: a close up of some alkaline magnesium and calcium material left over from mining ore. It is reacting with carbon dioxide molecules in the air resulting in a gold halo effect

Project lead

Dr Song Zhou

Research Scientist


Liang Li, Paul Feron, Hai Yu, Miao Chen, Pingan Song, Ali Kiani, Tara Hosseini, Claudia Echeverria and Mihaela Grigore.


The progress of carbon dioxide (CO2) mineralisation is plagued by its high operation cost, primarily due to three factors. First, there are no appropriate chemicals that can self-regenerate without external energy input. Second, there’s a lack of beneficial applications for the carbonated residue, which ends up as a secondary waste product. Third, CO2 mineralisation using natural rocks is limited by its slow reaction rates that require demanding operating conditions and the use of highly concentrated and high-cost CO2 gas.

Similarly, direct air capture (DAC) using liquid absorbents, which may be the most promising method for large-scale applications, requires large energy inputs for deep regeneration of the capture agents. Moreover, the evaporative losses of chemicals that happen in most CO2 mineralisation and DAC technologies are economically and environmentally undesirable.

Our recent research showed that the integration of industrial carbon capture with carbonation of alkaline solid wastes offers a unique, low-cost solution to CO2 mineralisation. But, at present, it can only capture concentrated CO2, produce low-value solid mixtures with few market prospects, and doesn’t enable a closed process. There’s an opportunity to advance the science to a novel DAC-initiated hybrid CO2 mineralisation method that would make large-scale carbon capture, usage and storage a reality, and convert atmospheric CO2 and alkaline solid wastes into value-added products.


We aim to develop a highly innovative and effective ex-situ CO2 mineralisation process using atmospheric CO2 as the carbon source, with 100% waste in and 100% treasure out.

Building on our recent discoveries, we’ll combine DAC and mineralisation into one short, efficient, low-cost process by eliminating CO2 regeneration/compression, and directly turning ambient CO2 and solid wastes into two valuable products – a high-value/low-volume fire retardant material, and low-value/high-volume construction materials. This cutting-edge technology will use a single ‘smart’ chemical that links the system and can self-regenerate after each cycle without extra energy or chemicals. We’ll also establish a database designed to facilitate the application of AI and machine learning, which could predict, guide and improve carbon capture performance in the future. Ultimately, the research will lead to the development of a scalable, cost-effective, long-term negative carbon emissions technology that utilises problem waste as feedstock for products in a closed-loop system.


Due to its low technology readiness, there are high technical risks, but great potential to deliver significant social, economic and environmental impacts.

One of the most challenging aspects of the project involves the exploration of a smart chemical that must fulfill triple roles, including efficient atmospheric CO2 capture, effective mobilisation of magnesium (Mg) and calcium (Ca) ions from solid reactants, and efficient carbonation reactions enabling self-regeneration. The chemical also needs to have low vapor pressure and good stability when exposed to high levels of oxygen in the air. Another challenge is the supply of alkaline solid wastes and their composition.

We’ll deal with these challenges through exhaustive characterisation, comparison and determination of potential chemicals, and thorough assessment of alkaline solid wastes. A number of factors need to be considered, such as the abundance of wastes in Australia (or the world), modes of occurrence of elements, and the content of Mg,Ca and other compounds. Based on previous research results, however, we’ve identified potential chemicals and alkaline solid wastes that could be suitable. Some other challenges we may encounter include cost or complexity of manufacture, technology availability, regulations, scalability, sequestration timescale and verification. We’re confident that the depth of experience and expertise in the project team will ensure these challenges are met.


Ji, L., Zheng, X., Zhang, L., Feng, L., Li, K., Yu, H., & Yan, S. (2022). Feasibility and mechanism of an amine-looping process for efficient CO2 mineralization using alkaline ashes. Chemical Engineering Journal, 430, 133118.

Kiani, A., Feron, P., Conway, W., Pourkhesalian, A., Bennett, R. D., Grillmeier, D., … & Puxty, G. (2022). Direct Air Capture of CO2 using Amine-based Capture Technology. Available at SSRN 4283785.