Apologies if I have sent this twice, but I think my first reply went only to
Alan.
Just to make it clear, in case anyone is tempted to try it:  Barium sulphate
(barytes, barite) is non-toxic, because it is very insoluble.  Barium
carbonate (witherite) is highly toxic, as it dissolves readily in the
hydrochloric acid in your stomach.   Do not try this at home.
And there is no general rule about toxicity of sulphates as against other
salts.  It's the metal part that counts, so long as it is soluble,
especially in acid.  Epsom Salt is magnesium sulphate, and Andrews Liver
Salts, for instance, contains quite a lot.  If you took  as much barium
carbonate as a typical dose of Epsom Salt you would be quite ill, or worse.


Mike

Dr M Worsfold,
Principal Scientist,
Charles Salt Research Centre


-----Original Message-----
From: Alan Campbell [mailto:[log in to unmask]]
Sent: 25 September 2004 10:46
To: [log in to unmask]
Subject: Uses of barium


A couple of points, which I hope will expand on the useful info from
various contributors.

I also had barium to facilitate an X-ray, if I remember correctly it was
the carbonate, and fortunately it had some flavouring added to make it
more pleasant. (Maybe practice varies between hospitals, or according to
budget?) But getting a litre of it down quickly was not easy. Sulphates
are usually toxic or at least irritant, small quantities tend to have a
powerful laxative effect, carbonates of relatively non-toxic metals are
also relatively non-toxic and will linger in the system long enough to
facilitate contrast enhancement in X-rays.

In the nuclear industry I think it is used for neutron, rather than
gamma absorbtion, but my memory on that subject is slightly vague. I was
told, many years ago, probably late 1960s, that they keep a stockpile of
it at nuclear plants for emergency use. I think I was shown sacks of it
at Hunterston power station, on an open day. The Windscale problem would
have quickly exhausted the emergency stockpile and needed urgent
replenishment. But as others are agreeed, it does go into the concrete,
not the major structural components, because it is a very weak aggregate
compared to the usual assortment of pebbles found in washed gravel, or
the crushed whin, or even recycled crushed concrete sometimes used for
normal purposes. But layers used only for shielding don't necessarily
need to be very strong.

The official Windscale report contains a number of major factual
inaccuracies, and downright lies, supposedly in the interests of
national security, more recent reports are likely to be more truthful.
It is now common knowledge that Polonium was involved, and as a result
the death toll from cancer etc will be many times higher than the
official estimate. I would not take anything in the original report too
seriously.

Barytes is widely used in the oil industry for making a heavy mud to
lubricate the drill and, by being heavy, help prevent blow-outs. But I
don't know where it is still mined in the UK, maybe some as a by-product
of fluorspar in the Peak District and Pennines? Of the main Scottish
sources, Muirshiel is now a country park and Gasswater is simply closed.
It is abundant, but in small widely-dispersed and uneconomic veins, in
the Ochils, where my interest in mining began. In that locality it is
invariably pink, and so very easy to recognise, apparently the colour
varies a lot elsewhere.

Alan