Monday 30 May 2011

Low carbon steel - and cement?

Browsing through May’s ENDS Report (ENDS 429 p.28-30), I came across an article on the prototype HIsarna blast furnace that is being trialled by Tata Steel at IJmuiden in the Netherlands which promises to cut carbon dioxide emissions by 20% by moving away from conventional coke/sinter/air furnaces to coal/ore/O2 processes. Which, as steelmaking accounts for 6-7% of global CO2 emissions, makes this seem like a very exciting development.

But it wasn’t the potential CO2 reduction that caught my eye, laudable as it is, as much as a comment about one of the benefits of the process being that the top gas from a HIsarna furnace - rather than being a mixture of CO, CO2, hydrogen and nitrogen - is 90% CO2 and no nitrogen, making carbon capture feasible.

Which made me think of Calera cement. (1) I saw this a few years ago – a technique to use hot high CO2 flue gases to produce a cement substitute that sequesters half a tonne of CO2 in every tonne of cement produced. What if the steelmaking industry and the cement industry got together and looked at how the flue gases from these new furnaces could be used to make cement? (Also one of the industries responsible for significant global CO2 emissions.)

Looks like a potential step change for the emissions from construction products to me – I wonder if anyone will ever join the dots and make it happen?

(1) http://www.scientificamerican.com/article.cfm?id=cement-from-carbon-dioxide

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