I agree with Thilo that the sulphur is most likely from the coal but why not
the iron too!
Iron pyrite inclusions are not that uncommon in some coals and if they were
heated in a reducing atmosphere then prills of iron sulphide would result.
cheers
roger
**********************
Dr R.C.P. Doonan
Archaeology Group
University of Bournemouth
Bournemouth
Dorset BH12 5BB
UK
t 01202 595452
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f 01202 595255
**********************
> Thilo
>
> > how about some of that sulphur being picked up from mineral coal in the
> > smithy?
>
> I wondered about this, but haven't been able to locate any
> documentation or published description of what such reaction
> would look like.
>
> The iron fragment richest in the inclusions is about 3 x 1.5mm in
> the plane of the polished section and bears numerous inclusions of
> rounded outline up to about 80 microns across, but more typically
> about 30 microns, and foming 1-2% of the material (estimated not
> point-counted). The inclusions bear a fine structure with a scale of
> much less than a micron (with phases not determinable therefore
> on the BSEM).
>
> Although the piece is very small, the structure is more
> homogeneous than I would have intuitively expected through
> reaction with the coal. On the other hand some of the smithing
> slags from the site were certainly produced in a coal-fired hearth.
> The S (only determined by XRF therefore likely to be too low) at
> 1800ppm and the Mo at around 30ppm in this slag are sufficently
> elevated to make coal firing a possibility with this particular
> specimen.
>
> I'd like to find some comparative data, as I mentioned in my first
> message, otherwise I'm going to have to try to persuade the
> blacksmith to use some nasty high S coal in his forge and find out
> what happens...
>
> Tim
>
> Dr Tim Young
> Email: [log in to unmask]
> Web: http://www.geoarch.demon.co.uk/
> Phone: 02920 747480
> Fax: 08700 547366
> Mobile: 0802 413704
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