🇸🇪 Mining tailings are being upgraded – in order to capture carbon dioxide

March 21, 2023
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Press release from Luleå Technical University

Photo: Pixabay

The industrial green transition causes a larger-than-ever demand of metals. Now researchers at Luleå University of Technology will identify for the first time the potential of typical Swedish mine tailings, to be utilized and beneficial for the climate. In this project, researchers will investigate the potential of typical Swedish mine tailings to capture and store (CCS) by using tailings from Boliden Mineral, LKAB, and Copperstone Resources. Two different CO2 sources will be used, industrial emissions and direct air capture (DAC).

“Our previous studies have shown that mine tailings can be a cost-effective alternative for biogenic carbon capture and storage, and for capture of historical carbon dioxide in the atmosphere. The impact of Swedish mine tailings for this task is something that we will investigate in collaboration with the industry”, project leader Ulrika Rova says, Professor of Biochemical Process Engineering, at Luleå University of Technology.

The project “Use of mine tailings to carbonate minerals by a symbiotic CC and DAC bio-stratgy”, is unique in Europe. It is financed by the Swedish Energy Agency and is implemented within the framework of Industriklivet – the Government’s long-term initiative to support climate change – part of the EU’s Recovery and Resilience Facility (RRF). Focus for the researchers in the project are mine tailings, particularly rich in Ca- Si- and Mg-bearing minerals, which are beneficial for CCS. The researchers’ main objective is to reduce the industry’s process-related emissions of greenhouse gases by using solutions that can be implemented rapidly and remain relevant in the long-term.

New method for capturing carbon dioxide

Research, especially from Australia, has shown a strong potential for mine tailings to capture carbon dioxide, by mimicking the natural weathering process. In the TAILOR-MADE project, researchers will use another concept based on the utilization of a novel enzyme assisted carbon dioxide (CO2) hydration step to boost both the carbon capture and the mineral carbonation storage processes.

“The concept’s innovation is that instead of using harsh chemicals as absorbents, we capture CO2 using an enzyme called carbonic anhydrase. The novelty of this process is to utilise this enzyme, which is a biocatalyst, to accelerate the CO2 capture reaction, so the absorption step becomes very fast. Another important advantage is that we can offer a method able to efficiently transport captured COin the form of bicarbonate, which is a prerequisite for making permanent geological storage in Sweden”, Io Antonopoulou says, Assistant Professor in Biochemical Process Engineering, at Luleå University of Technology.

To optimize the enzyme-based carbon dioxide capturing technique, detailed mineralogical and chemical investigations of the ores and their constituents are required.

“We will use several microanalytical methods to characterize and better understand the composition of the geological material since it is crucial for how effective the capture and storage of carbon dioxide will be. Through this understanding, we will be able to optimize the CCS chain and come up with proposals for suitable methods for permanent storage of carbon dioxide “, Glenn Bark says, researcher in Ore Geology at Luleå University of Technology.

Sweden is a country with large metal producers

Sweden is one of Europe’s largest metal producers with currently 12 active mines primarily producing iron, copper, zinc, lead, gold, and silver that generates large amount of tailings. The carbon dioxide processes from mine tailing will be compared with the natural enhanced weathering process that has the potential to sequester carbon dioxide on decadal, to centennial timescales, a 100 year time scale.

“The project is extremely relevant for Boliden. During the autumn, we updated our already ambitious targets for reducing carbon dioxide emissions and we are now aiming for a reduction of 40% by 2030 from the 2021 level. We already know that our mining tailings, have the potential to store many millions of tons of carbon dioxide, but this natural carbonation is a very slow reaction. Catalyzing it, using enzymes, suddenly makes it more feasible”, Erik Ronne says, Head of Sustainability Research at Boliden Mines.

“Since 2015, our research group has built up a unique expertise in the integration of the enzyme carbonic anhydrase, as a biocatalyst to accelerate the capture of CO2 in the form of bicarbonate for use or storage. For us, it is important that our research is relevant to the industry and with this project we get another opportunity to contribute to a more sustainable society”, Paul Christakopoulos says, Professor and Head of Subject of Biochemical Process Engineering, at Luleå University of Technology.

In mining, it is the mineralogical content of the ore and the surrounding bedrock that is directly reflected in the composition of the mine waste.

“When we study an ore body, we do a mineral chemical characterization of the composition of both the ore and the surrounding rocks to understand how the ore was formed. Now, in this climate-related project, we can use that knowledge as part of the assessment of the suitability of a mine waste for catalyzed carbon dioxide storage”, Christina Wanhainen says, Chaired Professor in Ore Geology at Luleå University of Technology.

The project runs for 6 years with a budget of SEK 14.5 million and is a collaboration between researchers in Biochemical Process Engineering and Ore Geology at Luleå University of Technology, together with the mining industry. Mathis Warlo, researcher in Ore Geology, also participates in the project with his expertise in advanced microanalysis of minerals.