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Slag heaps could help pull carbon from the atmosphere

2 May 2017

Slag heap

A Cardiff University scientist has been awarded £300k to lead a project looking into possible global warming intervention strategies using slag heaps.

It is estimated that waste material could be used to pull 90 to 155 billion tonnes of carbon dioxide (CO2) from the atmosphere over the next century.

Dr Phil Renforth, from the University’s School of Earth and Environmental Sciences, has been awarded the money as part of a UK-wide £8m investment by the Natural Environment Research Council (NERC) focusing on the removal of dangerous greenhouse gases from the atmosphere.


Previous research has shown that due to their chemical make-up, slag heaps are able to absorb CO2 from the atmosphere through a process known as sequestration.

Dr Renforth’s study will look to find ways in which this process of absorption can be accelerated, with the overall goal of reducing dangerous levels of CO2 in the atmosphere.

Dr Renforth will study the internal chemistry of historic slag deposits in order to better understand the absorption process, as well as undertake field trials by injecting CO2 into large controlled reactors.

Dr Renforth said: “First, we will drill into one of these old, historic slag heaps and see what has been happening there over the years and understand what chemical processes have been going on as rainwater has brought carbon dioxide into the heap.

“And then we will start the second stage...”

“We will create our own mini-heap – about the size of a skip – and play with its chemistry to try to optimise its ability to sequester carbon from the atmosphere.”

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