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Iron and Steel – Greenhouse Negative


Steel is manufactured from non-renewable resources such as iron ore, alloy metal ores, coal and limestone.

Although the supply of those resources at current rates of usage is guaranteed for many hundreds of years, the same may not be true for some of the minerals (chromium, nickel, cobalt, vanadium) needed to form the alloys which give steel its special properties.

In the manufacture of iron and steel, there are emissions to air of carbon monoxide, sulphur dioxide, and nitrogen oxides (totalling 40 kg per tonne of steel), and to water of heavy metals and oils.

Large quantities of solid waste (mainly slag, such as metal oxides) are created during manufacture.

This is in addition to smaller quantities of hazardous waste, which may require disposal to landfill.

About 15,000 litres of contaminated water (containing hydrocarbons and other organic compounds: sulphides, phenolics, ammonia, metals, cyanide, oil and grease) are produced for each tonne of steel*.

* Williamson et al 2001.