A new way to clean up the steel industry

Making steel is a dirty business. For every tonne of it some 1.8 tonnes of carbon dioxide (CO) are emitted into the atmosphere. As a result, steelmaking accounts for 7-9% of the world’s anthropogenic greenhouse-gas emissions.Cleaner ways of producing steel are being explored. Mostly, these are based on the use of hydrogen instead of coke as the reagent which extracts the oxygen from iron-oxide ore. But much of the pertinent technology is in its infancy. That, together with the cost of converting from old to new equipment, which might run to several billion dollars per plant, means it could take decades for steelmakers to go green.