Experienced industrial gases expert Stephen B. Harrison delved into an area considered one of the most exciting in current CO2 applications – utilisation, specifically in the area of mineralisation.
Enthused by the prospect of CO2 for mineralisation, Harrison provided some background information about the exciting new area.
Stating that some rocks, such as limestone and magnesite are saturated in CO2, cement making converts limestone to calcium oxide, releasing CO2 in the process. Two specific ultramafic rocks, serpentinite and olivine are able to absorb CO2 during mineralisation.
“These ultramafic rocks are interesting because they can help us to absorb CO2 to take CO2 out of the atmosphere.”
“We can use these rocks to help decarbonise industrial processes,” he added.
To move these rocks from where they were mined to where the CO2 needs to be captured, they require mass-transport and cost effective logistics infrastructure. Harrison explained that the rocks, once on location, must be milled to powders to react quickly with CO2 in mineralisation reactions.
An energy-intensive process, Harrison reminded us that, “Carbon capture through any technology doesn’t come for free.”
Mine tailings – grit, dust, dirt, sediment – is already ground up and is used to extract metals from mined ore, could be a potential source of minerals to absorb CO2.
Slag can also be used to help absorb CO2 using CO2 mineralisation to help reduce emissions for blast furnaces.
Giving another example of slag that can be utilised, Harrison said, “Waste incineration slag is also suitable to absorb CO2 from industrial processes.”
To make cement, limestone is required and a huge amount energy is needed to grind the limestone. Through the use of calcium carbonate, produced from mineralisation, industry can avoid the energy-intensive grinding process and reduce transportation and energy costs.
Harrison gave examples of other uses of mineralised CO2, such as baking soda.
Sea-level rise and climate change
As sea-levels continue to rise and sea defences become ubiquitous in more coastal areas, Harrison explained that concrete will have to be used in construction of the defences.
“If we’re using that captured carbon to make cement, we’re capturing, utilising, and permanently storing carbon dioxide.”
All sessions of gasworld’s virtual ‘Europe CO2 Summit’ will be available to watch on-demand.