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I did some experimental bronze making a few years ago, including adding
mined cassiterite (from Geevor) directly into molten copper. The resultant
bronze contained iron (I forget how much, but it wasn't very much.
Certainly nowhere near as high as 8%). Under SEM, we found the iron to be
present as separate particles at the grain boundaries (it had also
absorbed a lot of other impurities from the ore), and not in solution.
Ken Hamilton
On Tue, 16 Mar 1999 08:32:20 +0100 David Liversage
<[log in to unmask]> wrote:
> Remarks for William Quian
>
> Re your messge of March 3rd, I am not a scientist and so I don’t know whether the iron is in solution or not, and the analyses I use do not include Mg, but I have some data about high Fe that may be useful to you.
> Craddock and Meeks write about iron in bronze in Archaeometry 1987, and there is more in Craddock's book "Early Metal Mining and Production". The origin of high Fe seems to be that ferric material was used as flux and was not always removed from the metal afterwards as it ought by a purification process.
> Therefore bronze with several percent iron presumably indicates bad technology, in which purification was skipped. Unpurified bronze does not occur at random, but apparently only at particular times and places. I have been trying to trace these down in the published analyses.
> There are also assemblages with unexpectedly high levels of As, Sb and/or Ni. These might also show omission of the purifying stage. Some of the EBA rib ingot hoards from N of the Eastern Alps are like this. Perhaps the founders rightly suspected they were only going to be buried under the floor in houses of the big farmers in the plains as a form of symbolic wealth, and therefore they didn't bother about purification. Most tools and ornaments at this time seem to have been purified however. In the analyses available to me I see no proportionality between excessive levels of these three on the one hand and of Fe on the other.
> In Hungary and probably Transylvania (from which there are no relevant analyses yet) there is a marked "explosion" of unpurified metal in Moszolic's period Vc (a bit after 1000 B.C.) with Fe (up to 8%) and As, Sb and/or Ni values (up to around 10%). It must mean something. It is based on some very good new analyses by Ernst Pernicka, which I will be publishing. Contemporary Swiss bronze was properly purified, so the phenomenon must be strictly regional. Craddock refers also somewhere to excessive Fe in some Italian bronze.
> I don't know of other occurrences, but my database comprises only about 7000 of the maybe 40,000 published analyses, and there is sure to be lots of exciting information hidden in the others. I could write all the analyses out by hand if I were diligent enough. Unfortunately the people in charge of these sources seem not very keen to make the data available in computerized form, though they have it. I can only see this as an absurd hindrance to research and a big mistake. I am also a little unsure of the ethical side, as the analyses and their computerization must have been paid for by public money. I am told even Germans find it hard to get access! I expect the time will come when everybody finds it natural to have analyses available on the internet. In the meantime I am ready to exchange data with anybody else who might be copying out from the publications. It is a very exciting source about industrial history, but a lot of work! Any reactions?
>
> David Liversage
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Ken Hamilton
c/o Department of Archaeological Sciences
University of Bradford
Richmond Road
Bradford BD7 1DP
West Yorkshire UK
(01274) 235906
http://www.student.brad.ac.uk/kchamil1/
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