Michael Shaw asked:
>Is it possible to economically
>produce sulphuric acid from sulphide copper ores?
Yes, it has been normal practice since the late 1960's and if you count
Ducktown, Tennessee and Rio Tinto as copper ores, since perhaps the 1940s or
even much longer (some of the real historians on this list will know). In the
cases of Rio Tinto and Ducktown, as the mines aged the copper content of the
pyrite ores dropped, and the companies found that they could still make money by
making and selling acid. For at least the last 20 years of Ducktown's life
sulphuric acid was its only product. There were other, less famous, mines
close to consuming industries that never produced much else but acid, but I
forget their names.
Even on the Zambian Copperbelt the companies were making their own acid for the
electrolytic refineries by at least the mid 60s, and as Bernard said, the
environment around the acid plant was fairly hellish, especially during an
atmospheric inversion. They may also have been selling acid: I have a vague
memory that that was the case. Even though the acid plant was hellish, part of
the reason for making acid was to keep the sulphur out of the atmosphere - this
was one of the earliest effects of environmental awareness (even 70 miles
downwind of Ducktown there was an enormous excess of SO4 ion accumulating in the
soil). The effect on the sulphur industry was fairly dramatic - it was in
huge surplus for years. Just as the Frasch process sulphur production in Texas
had closed down the Sicilian mines, acid production from base metal mines
severely stressed the Texas industry.
Bernard Moore said:
>It would be interesting to know what was contributed by the W.Cumberland and
> Barrow Iron Works. Sulphur would have been produced as a by product from most
> if not all Iron Smelters for a very long while I would imagine
I have a question: why would sulphur be a by-product of iron smelting? Almost
all the ores are oxide ores (Haematite/Magnetite), so the only sulphur would be
from impurities in the coke, the ore or the flux. Or am I missing something?
John Mason said:
> Example: Elbaite, a specimen-grade version of tourmaline, from and named for
the Island of Elba, near Italy, whose only other claim to fame was as the island
>of Napoleon's exile.
I beg to differ with John's writing-off of Elba: for several hundred years it
was (one of) the Mediterranean world's main sources of iron. Mussolini carted
away 11,000,000 tons of ancient (Etruscan) slag from Populonia, on the mainland
opposite Elba, to re-smelt: it ran over 50% iron. Underneath up to 12 m of
slag were the Archaic age (600BC) tombs of the early ironmasters(?), now open to
the public and famous for their art work. Most of the ore came from Elba, but
some was from iron and base metal mines in the Colline Metalifere on the
mainland of Italy nearby. The slag, however, represents only a part of Elba's
production, since they smelted on-island until they ran out of wood to burn. I
calculate that Elba supplied about 25% of the ancient world's iron for about 400
years, and the operations kept a fleet of at least 20 large (for the times)
ships going back and forth, employed several thousand laborers (slaves?), and
probably deforested a fairly large chunk of central Italy. All of which I would
love to have the time and money to do field research on. Ilvaite is also named
from Elba.
All of which leads to MY question: does anyone on the list know (or know
someone or some book who knows) quantitatively what the inputs (FeOx+carbon) and
outputs (Fe metal plus slag) would have been for iron age bloomeries such as
these? In my calculations referred to above I had to make a lot of assumptions
that I would like to refine.
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Subject: mining-history Digest - 26 Jan 2003 to 27 Jan 2003 (#2003-26)
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