IMPROVEMENTS IN THE MANUFACTURE OF ALUMINOUS AND SILICEOUS COMPOUNDS
Year: 1856

page_text: LETTERS PATENT to Henry Davis Pochin, of Salford, in the County of
Lancaster, Manufacturing Chemist, for the Invention of "IMPROVEMENTS
"
PROVISIONAL SPECIFICATION left by the said Henry Davis Pochin
at the Office of the Commissioners of Patents, with his Petition, on the
6th March 1856.
I, HENRY DAVIS POCHIN, of Salford, in the County of Lancaster, Manu-
facturing Chemist, do hereby declare the nature of the said Invention for
IMPROVEMENTS IN THE MANUFACTURE OF ALUMINOUS AND SILICEOUS COMPOUNDS to
be as follows:-
I take clay containing various proportions of silica and alumina and dry it
well by exposure to heat for some time; I then grind it to powder in an
ordinary clay or other suitable mill, and afterwards mix it well together with
various proportions of powdered charcoal, peat, pitch, pitch-coke, soot, sawdust,
spent dye wood, or other carbonaceous matters which leave little ash or iron after
combustion. I find that about one part by weight of powdered charcoal will
do to burn with about six parts of clay, and when I use pitch I find it desirable
to use about equal weights of clay and pitch, but I do not confine myself to
those proportions. I then heat in a furnace the clay so prepared until the

page_text: whole of the carbonaceous matter is burnt away. Other minerals containing
variable proportions of silica and alumina may be used in the place of clay
with like results.
By means of the above improved method of roasting clay or other mineral
in contact with carbonaceous matters, I find that it not only more readily
combines with acids, but I liberate more completely the silica united with it.
The whole of the alumina contained in the clay or other mineral so prepared
will combine with sulphuric as well as with other acids, which has not hitherto
been effected. The clay prepared by my improved-mode-of-treating it can be
employed with advantage in the manufacture of sulphate of alumina, the alums
of commerce, and other aluminous compounds, whilst the silica afforded can be
used for those purposes for which pure silica is required.
SPECIFICATION in pursuance of the conditions of the Letters 'Patent, filed
by the said Henry Davis Pochin in the 'Great Seal Patent Office on the
5th September 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
DAVIS POCHIN, of Salford, in the County of Lancaster, Manufacturing Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the 'Sixth day of March, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of 'Her reign,
did, for Herself, Her heirs and 'successors, give and grant unto me, the said
Henry Davis Pochin, Her special licence that I, the said Henry Davis
Pochin, my executors, administrators, and assigns, or such others as I, the
said Henry Davis Pochin, my executors, administrators, and assigns,, should
at any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF ALUMINOUS AND SILICEOUS COMPOUNDS," upon the
condition.(amongst others) that I, the said. Henry Davis, Pochin, my executors
or administrators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed, and

page_text: cause the same 'to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters. Patent.
NOW KNOW YE, that, I, the said Henry Davis Pochin, do hereby
declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement (that is to say):
By the methods hitherto in use for roasting clay and other minerals con-
taining variable proportions of silica and alumina, a part only of the alumina
contained in the minerals so treated will combine with acids. Now, I have a
method of treating a mineral consisting of alumina and silica without iron, so
that the whole of the alumina of the minerals containing variable proportions
of silica and alumina shall combine with acids. For this purpose I take a
mineral consisting of some proportions of silica and alumina, such as the
mineral known as china clay, and dry it well by exposure to heat for some
time in any convenient manner; I then grind such mineral to powder in an
ordinary clay or other suitable mill, and afterwards mix it well together with
one or more of the following substances, namely, powdered charcoal, peat,
pitch, pitch-coke, that is to say, coke from pitch, soot, sawdust, spent dye-
woods, or other carbonaceous matters which leave little ash and no iron after
combustion. I find that about one part by weight of powdered charcoal will
do to burn with about six parts of clay; and when I employ pitch I find it
desirable to use about three parts by weight of clay and one part of pitch; and
with sawdust, spent dye-woods, and other such matters, equal weights of clay
and those substances but I do not confine myself to those proportions. I then
heat in a reverberatory or other furnace, which will supply oxygen to the
roasting substance, the clay so prepared, until the whole of the carbonaceous
matter has been burnt away, which should be done by keeping the furnace at
a dull red heat, and will occupy about an hour and a half. The mineral, pre-
pared by the above method, can be employed with advantage in the manufacture
of aluminous cake, pure sulphate of alumina, the alums of commerce, and
other aluminous compounds, whilst the silica afforded can be used for those
purposes for which pure silica is required.
Having now described the nature of my said Invention, and in what manner
the same is to be performed, I hereby declare that what I claim as my In-
vention is, the treating of a mineral containing variable proportions of silica
and alumina with powdered charcoal, peat, pitch, pitch-coke, soot, sawdust or
other carbonaceous matter, leaving but little ash and no iron after combustion
in a reverberatory or other furnace, as above described, for the manufacture of

page_text: aluminous and silicious compounds in such manner as that the alumina may
be brought into a condition to be more easily acted on by sulphuric and other
acids, and the silica of which can be obtained in an almost pure state suitable
for the ordinary purposes for which that mineral is employed.
In witness whereof, I, the said Henry Davis Pochin, have heretofore
set my hand and seal, this Fourth day of September, in the year of
our Lord One thousand eight hundred and fifty-six.
Witness,
P. F. SWANN,
Clerk to John Stuart, Sol",
Grays Inn.
HENRY D. POCHIN. (L.S.)