Improvements in the Beds or Tests of Cupellation Furnaces, Assay Cupels and the like.
Year: 1896

page_text: VISIONAL SPECIFICATION.
Improvements in the Beds or Tests of Cupellation Furnaces, Assay
Cupels and the like.
We, THOMAS BURNS MCGHIE of 116, Camberwell Grove, Camberwell, London,
S.E., and EDWARD GEORGE BALLARD of Newton Lane, Chester, in the County of
Chester, Chemists, do hereby declare the "nature of this invention to be as
follows:-
This invention has for its object the making of beds or tests of cupellation
furnaces, assay cupels and the like cheaper than heretofore, and yet of materials
that will easily smelt up afterwards, and the invention consists mainly in sub-
stituting sulphate of baryta for the usual bone ash. The sulphate of baryta
can be simply the raw barytes ground up, or can be precipitated sulphate of
barytes as preferred. For a binding we prefer to use sulphate of soda, but of
course sulphate of potash or the ordinary binding salts can be used if desired.
When the cupels or tests are so saturated with lead as to be no longer useful
they are smelted so as to utilise the oxide of lead and what silver has been
absorbed. For this purpose we make use of fluorspar which at once combines
with the barytes forming a very liquid slag.
Dated the 19th day of November, 1896.
WM. P. THOMPSON & Co.,
Of 6 Lord Street, Liverpool, Patent Agents for the Applicants.
Improvements in the Beds or Tests of Cupellation Furnaces, Assay
Cupels, and the like.
We, THOMAS BURNS MCGHIE of 116, Camberwell Grove, Camberwell, London,
S.E., and EDWARD GEORGE BALLARD of Newton Lane, Chester in the County of
Chester, Chemists, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
This invention has for its object the making of beds, hearths, bottoms or tests
of cupellation furnaces, the linings of furnaces in which litharge corrosion has
to be combated, assay cupels and the like cheaper than heretofore, and yet of
materials that will easily smelt up afterwards, and the invention consists mainly
in substituting sulphate of baryta for the usual bone ash. The mineral barytes
is at present the cheapest source of this material the barium sulphate in the

page_text: raw mineral generally occurring in a massive crystalline form. The sulphate
of baryta can be simply the raw barytes ground up or can be precipitated sulphate
of barytes as preferred and can be either simply compacted by pressure with or
without moisture or admixed with other materials.
In making tests, cupels and the like of the raw barytes, we have, found that
the compacted material has invariably fissured and often flown to pieces on sub-
jection to heat. We obviate this difficulty by submitting the mineral (preferably
ground) to calcination prior to its use. The calcination probably acts in part
as a decrystallising and in part as an annealing operation.
In carrying the invention into effect for assay cupels, the mineral prepared
as above is mixed and made up with water, preferably without the admixture
of saline substances. I
For refinery tests we have found the admixture with the barytes of 5-10 %
of Portland or other lime cement to be a suitable formula, the mixture being
moistened with water and beaten into the ring in the ordinary manner.
A good formula for linings such as of lead "improving pans," battery furnaces,
and the like, is 3 parts (by measure) of Barytes with 1 part of cement, the
mixture being gauged with a moderate amount of water and laid on with a trowel.
If desired a binding of sulphate of soda, or sulphate of potash or the ordinary
binding salts may be employed with the barytes.
When the cupels or tests are so saturated with lead as to be no longer useful,
they are smelted so as to utilise the oxide of lead and what silver has been
absorbed. For this purpose we make use of fluorspar which at once combines
with the barytes, forming a very liquid slag.
Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed, we declare that what we
claim is:-
1. The application and use of barium sulphate with or without admixture of
other materials in the making of hearths or tests of cupellation furnaces, the
linings of furnaces in which litharge corrosion has to be combated, assay cupels,
and the like, substantially as hereinbefore set forth.
2. The making of cupels of ground and preferably calcined barytes mixed and
made up with water, substantially as described.
3. The making of refinery tests of barytes with an admixture of Portland
or other lime cement the whole being moistened with water and beaten into
the ring in the ordinary manner, substantially as described.
4. A lining for lead "improving paus" battery furnaces, and other furnaces
in which litharge corrosion has to be combated, consisting of barytes with an
admixture of cement gauged with moderate amount of water and laid on with
a trowel, substantially as described.
Dated this 21st day of August 1897.
WM. P. THOMPSON & Co.
Of Liverpool, Manchester, Birmingham and London, Patent Agents.