Quarries in or near Ruardean, Moorwood = Limestone (General)

by Jefff , West London, Middlesex, Saturday, February 06, 2016, 22:19 (3222 days ago) @ Carole Lewis

Hi Carole,
yes, limestone is a key ingredient to add to a blast furnace along with iron ore and coke, to help remove acidic impurities from the iron ore. Limestone contains calcium carbonate, this reacts with the impurities to form molten slag which can then be skimmed off to leave the molten iron behind. Like limestone itself, this slag can then be used for roadmaking, or added to cement. The remaining molten iron is then cast into moulds to produce bulky items, or used to produce tougher wrought iron.

For centuries the Forest was the centre of quality iron-making for all of Britain, until the C18th when overtaken by other areas which had more abundant coke to fuel the new blast furnaces, not charcoal. Even then, Thomas Teague's ironworks at Cinderford (from sinders = slag, leftovers from Roman? processes) opened briefly c1810 and sporadically after that. The Forest iron industry gradually became left-behind by bigger & better-sited areas such as in South Wales. The death knell came when steel became more popular than iron, with it's better strength & durability. Steel is iron which has had the embrittling carbon levels reduced by blowing oxygen thro' the molten mix. At first very expensive to produce, steel became economically viable for mass-production in lieu of iron in the mid C19th, when Henry Bessemer finalised his Convertor Process, albeit by "borrowing" the key ideas from Coleford's own Robert Forester Mushet, a key figure in the development of specialised steel alloys at Darkhill, Coleford.

(Apologies to any bona-fide steelworkers reading this, most of the above is what I recall from college studies 30 years ago, so I may well be "rusty" on a few points).