Let’s say I own some acreage in Georgia with dark red surface clay deposits. It’s my understanding the red color is from iron (or oxides thereof).
How tough/uneconomical would it be to smelt/refine that up into iron/steel?
Any parts of the world where this is done industrially?
clay is clay. the iron stain on it is minor. but where red clay is, there might also be laterite or bog iron. explore some more.
I know the confederates used the iron ore of north Louisiana to make some cannons in the civil war. The cannons however, were of poor quality…too brittle and typically cracked after just a few firings. I know that wasnt the question but sometimes even iron ore is not good enough, much less clay.
Clay is actually a degree of fineness of unconsolidated sediments, rather than a particular compound. However, since various rocks weather to paticular degrees of fineness (e.g, silica generally weathers to sand and stops, not to silt or clay), most “clay is a naturally occurring aluminium silicate composed primarily of fine-grained minerals. Clay deposits are mostly composed of clay minerals, a subtype of phyllosilicate minerals, which impart plasticity and harden when fired or dried.” (Quoted from Wikipedia Clay article). The other components of clay as a soil vary but are generally not concentrated enough to be considered ores – the three exceptions being cryolite (used as a flux in aluminum smelting), kaolin (for porcelain), and some of the rare earths. So while in theory iron could be extracted from the red iron-bearing clay, in point of fact it would be uneconomical to do so.
I think you can, but most of the iron is tied up as silicates, very difficult to reduce. It is not a practical source of iron. Same with the yellow clays common in Pennsylvania, where I grew up, and elsewhere.
There were deposits of iron oxide suitable to make iron places in the South. The Confederates had a large ordinance works South of Birmingham, Alabama where there was coal, iron ore, and linestone close together.
Of course that has nothing to do with quality of the ore. Iron is an element, hence all iron is identical regardless of source. If the metal produced from the ore was brittle, the problem lay with the smelting or casting procedure and had nothing to do with the ore.
Well, in practical terms it did. If there are no feasible smelting procedures available that produce metallurgically pure iron (and AFAIK pre-industrial smelting certainly couldn’t), then the quality of the cast product is naturally going to depend on the amount and type of the impurities in the ore.
The reason that manufacturers avoid using low-grade ores (much less clays) is precisely because it’s much more difficult and/or more expensive to smelt high-quality iron out of them. If the same smelting process produces a high-quality product from one type of ore and an inferior product from another type, I think it’s fair to say that the inferiority is indeed due to the quality of the ore.
(See also: iron ore beneficiation)
how does one reduce the iron in silicates? mighty impossible at that time.
by the time of the civil war, low-quality ore (basically Fe2O3) can already be smelted, casted or bloomed by a competent mettalurgist. high-grade ore (mainly magnetite) was getting exceedingly rare for large-scale exploitation.
weak cannons have more to do with poor casting and annealing.