Green steel is far stronger than using coking coal.Pure iron...

Green steel is far stronger than using coking coal.

Pure iron doesnot rust away like steel. Like most pure metals, contact with oxygen produces athin patina of oxide on the surface that is quite stable and effectivelycreates a barrier between the pure iron inside and the oxygen in the air. Steelis simply iron that has been "alloyed" with carbon to produce aharder, tougher material. You don't actually need to add carbon to iron to makesteel because iron ore contains large amounts of carbon in the first place.

The problem withusing carbon from coal is that coal contains all sorts of impurities likesulphur that, when combined with water, create corrosive substances that attackthe iron from within, causing it to rust away.

Using hydrogen asthe reduction agent eliminates the problem of impurities, resulting instronger, tougher steel that is less prone to rust.

Australian-madecars, especially those manufactured in the 1960's and 70's were notorious"rustbuckets" because they used Australian steel that was relativelyhigh in sulphur as a result of coke being used as a reducing agent. Swedishcars, on the other hand, were made with steel produced using charcoal, whichcontains less sulphur. And Swedish cars are renowned for not rusting.