Construction materials such as cement have, for many years, contributed to climate change largely due to the amount of carbon dioxide (CO2) emitted in their production. The new research led by Dr Phil Renforth from Heriot-Watt’s Research Centre for Carbon Solutions has found this might not always be the case.
The study, funded by the Greenhouse Gas Removal Programme and published today (28th March) in Nature Communications shows that future production could instead help capture a significant amount of CO2 from the atmosphere.
The study, Greenhouse gas removal in the iron and steel industry, also reveals materials including cement as well as steel slag and lime, may be able to react and trap more CO2 than previously thought thanks to their alkaline content.
Industrial alkaline materials are composed of calcium silicate minerals chemically similar to naturally occurring minerals found in igneous rocks such as basalt, the study points out. The chemical make-up of artificial materials makes them much more reactive with carbon dioxide and research is ongoing to better understand the most cost-effective way of achieving this.
Traditionally, the potential for building materials to help combat climate change was considered to be relatively low given their intensive production process.
However, the research suggests that if, for example, industries were to cut emissions in this process by using renewable energy, the extra carbon dioxide reacted with alkaline minerals may be enough to make the companies carbon neutral or even carbon negative.
Renforth said: “We found the forecasted global potential of these materials to capture carbon dioxide may be three to seven times greater than previous estimates based on current production.
“This will not be enough to make a drastic difference on current emissions but if industries combined this with an extensive reduction in emissions, it may be enough to tip the balance.”
The study suggests the storage potential of up to 7.5 billion tonnes per year of CO2 could be ‘hidden’ in existing industries but would only be realised if current emissions are drastically reduced.
Renforth continued: “Preventing climate change will require a range of technologies, as well as changes in our lifestyle. Locking up carbon dioxide using alkaline materials may be an important part of our toolbox.”