IMPROVEMENTS IN THE MANUFACTURE OR PRODUCTION OF ALKALIS PROVISIONALIRTS,LINE SALTS
Year: 1853

page_text: LETTERS PATENT to Alexander Cuninghame, of Glasgow, in the
County of Lanark, North Britain, Iron Master, for the Invention
of "IMPROVEMENTS IN THE MANUFACTURE OR PRODUCTION OF ALKALIS
PROVISIONAL SPECIFICATION left by the said Alexander Cuning-
hame at the Office of the Commissioners of Patents, with his
Petition, on the 20th August 1853.
I, ALEXANDER CUNINGHAME, of Glasgow, in the County of Lanark,
North Britain, Iron Master, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OR PRODUCTION OF
ALKALIS AND THEIR SALTS, OR ALKALINE SALTS," to be as follows:-
This Invention relates to the manufacture or production of alkalis
and their salts, or alkaline salts, from alum schist, alum slate, gentle slate,
and what is technically known in some parts of Scotland as "black
stone," which is found lying in connection with the alum schist or gentle
slate, together with any and all of those substances containing sulphur
found in the coal measures, with the exception of iron and copper pyrites.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Cuninghame in the Great Seal Patent
Oflice, on the 20th February 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
ALEXANDER CUNINGHAME, of Glasgow, in the County of Lanark, North
Britain, Iron Master, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of August, in the year
of our Lord One thousand eight hundred and fifty-three, in the seven-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alexander Cuminghame, Her special
license that I, the said Alexander Cuninghame, my executors, adminis-
trators, and assigns, or such others as I, the said Alexander Cuninghame,
my executors, administrators, or 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
"IMPROVEMENTS IN THE MANUFACTURE OR PRODUCTION OF ALKALIS AND
THEIR SALTS, OR ALKALINE SALTS," upon the condition (amongst others)
that I, the said Alexander Cuninghame, by an instrument in writing
under my hand and seal, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and 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 Alexander Cuninghame, 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:
My said Invention relates to the employment and use of new
materials or substances in the manufacture or production of alkalis and
their salts, or alkaline salts. The materials or substances which I thus
employ are alum schist, alun slate, gentle slate, and what is technically

page_text: known in some parts of Scotland as "black stone," which last substance
is a hard species of alum schist commonly found lying in connection
with the ordinary alum schist; and the products which I obtain by the
use of these substances are the sulphates of soda and potash.
In manufacturing sulphate of soda by the aid of such substances and
by such general process I prefer to grind or reduce the schist or
black stone to a disintegrated condition or to powder. To such reduced
matters I then add a quantity of common salt, the proportion of such
added salt being variable, according to the constitution of the schist or
stone, which varies in different specimens, the requisite proportions being
ascertainable only by positive experimental examination. For every
sixteen parts of sulphur in the schist or stone I add about fifty-nine
parts of common salt; but I prefer to have an excess of schist or stone,
as a loss of sulphur frequently arises from using too high a working
temperature.
In some instances I find it to be advantageous to add to this mixture
a quantity of oxide of iron or oxide of manganese. I also prefer iu
some instances to add to the mixture a quantity of ground coke, char-
coal, or coal; but none of these matters are, in my opinion, essential
to the success of the process. For every part of sulphur contained in
the schist or stone I add two parts or less of peroxide of iron, or
instead of such addition oxide of manganese may be used. I add those
matters for the reason that they combine with the sulphur, which, in
case of the heat being too high, might be driven off and lost. The
addition of the carbonaceous matters renders the mass more open and
porous by reason of the combustion so caused; hence, the access of
air is facilitated, and the decomposition is increased. This composite
mass is then amalgamated or mixed up into a paste with the addition
of water, and such plastic mass is then moulded or shaped into balls,
bricks, or other conveniently manageable masses for further treatment.
These bricks or masses are then dried, cither wholly or in part, and
they are afterwards placed in a furnace, kiln, or other heating appa-
ratus, by the agency of which heating apparatus they are calcined or
roasted. This calcination or roasting process may be effected either
by the heat derivable from a coal or coke fire, or by the application of

page_text: heated air or carbonic oxide or other convenient inflammable matter in
a state of combustion, with the free admission of atmospheric air, and
also steam, which is of advantage when the materials are very dry,
and which then facilitates the evolution of the muriatic acid, as herein-
after mentioned. In this calcining or roasting process I prefer that
the heat should be moderate, more especially at the commencement of
the process. In practice I find that the system works well with the
use of a dull red heat throughout. The result of this routine of
manufacture is the production of sulphate of soda, the common salt
being decomposed, whilst muriatic acid, mixed with chloride of iron, is
evolved. The sulphate of soda is dissolved out of the treated mass
with water, and is crystallised or obtained by evaporation. 'The
muriatic acid is conducted away by a pipe leading from the chinuucy,
and is condensed in the usual way, as is well understood by practical
men. The sulphate of soda which I prepare in this manner is obtain-
able in a particularly pure state, and is applicable for the manufac-
ture of soda ash of fine quality, as well as for the other purposes
for which this salt is used. If in this process the air and materials
were kept thoroughly dry, chlorine instead of muriatic acid would be
evolved.
The sulphate of soda may also be obtained from the herein-before
described materials, by placing such materials, either in masses or in a
reduced state, in a reverberatory furnace or in a retort or other con-
venient and suitable chamber or receptacle, and applying heat. When
sulphate of potash is to.be made according to my Invention the heroin-
before described process is pursued, except that chloride of potassium
is added to the mass instead of common salt. The muriatic acid is a
product common to both processes.
Having.now described and particularly ascertained the nature of my
said Invention, and the manner in which the same is or may be used
or carried into effect, I may observe, in conclusion, that I do not
confine or restrict myself to the precise details or arrangements which
I have had occasion to describe or refer to, as.many variations may be
made therefrom without deviating from the principles or main features
of my Invention; but what I consider to be novel and original, and

page_text: therefore claim as the Invention secured to me by the herein-before in
part recited Letters Patent, is,-
First, the general arrangement of apparatus or means for the manu-
facture or production of sulphate of soda and sulphate of potash, as
herein-before described.
Second, the employment and use of alum slate, alum schist, and
black stone in the manufacture or production of sulphate of soda and
sulphate of potash.
In witness whereof, I, the said Alexander Cuninghame, have
hereunto set my hand and scal, this Seventeenth day of
February, in the year of our Lord One thousand eight hundred
and fifty-four.
A. CUNINGHAME. (L.S.)
A. CUNINGHAME. (L.S.)