Noel and David are quite correct when they say that antimony is almost
always used as an alloying component with lead in type metals, cable
sheathing, solder, bearing metals etc and that it is usually obtained as a
slag from lead softening at 600-800 degC in reverberatory furnaces or
sometimes in kettles. The highest antimony content which can be obtained is
about 50%Sb in the Sb/Pb alloy but historically most of that reported in
Collins and Percy was 10-30% Sb. The Sb slag becomes lower in Sb as the
lead becomes softer and the usual practice was to save some of the later
slags to add to the next batch of lead; this gives a faster reaction than
the use of air alone. Later, countercurrent, continuous softening was
developed.
Very high antimony alloys of around 95% Sb were produced by fractional
crystallisation in reverberatory furnaces and sold as 'star antimony'
because of the crystalline pattern produced on final cooling. Not sure what
these were used for but pigments, chemicals and flame retardants would be
included. Also potassium antimonyl tartrate, tartar emetic was used in as a
pharmaceutical. I know personally, that after all the effort to produce
star antimony, much of it was mixed with lead and used as a master alloy.
Antimony is obtained from Stibnite by iron and other reduction processes;
most of it now comes from China.
Richard Smith
----- Original Message -----
From: "Peter Claughton" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, April 05, 2013 7:42 PM
Subject: The preparation (dressing) of antimony ores in Britain
> Historically very few mines in Britain produced antimony concentrates and
> they appear to have been confined to Cornwall, Cumbria and parts of
> Scotland. Stibnite, the antimony sulphide, was one (perhaps the major) ore
> source but there also appears to have been significant amounts of
> Jamesonite mined.
>
> Jamesonite was a lead/antimony sulphide and I would be interested to know
> what processes were in place to separate the lead and antimony components
> of mixed sulphide ores such as Jamestonite before the advent of froth
> flotation. There is plenty of information of preparing single sulphide
> ores such as Stibnite - but how were mixed sulphides such Jamesonite
> treated?
>
> Peter
>
> Dr Peter Claughton,
> Blaenpant Morfil, nr. Rosebush, Clynderwen, Pembrokeshire, Wales SA66
> 7RE.
> Tel. +44 (0)1437 532578; Fax. +44 (0)1437 532921; Mobile +44 (0)7831
> 427599
>
> Hon. University Fellow - College of Humanities, University of Exeter
> http://people.exeter.ac.uk/pfclaugh/about.htm
> E-mail: [log in to unmask]
>
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>
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