I- PROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID, ALKALIS, AND THEIR SALTS
Year: 1853

page_text: LETTERS PATENT to George Robb, of Glasgow, in the County of
Lanark, North Britain, Gentleman, for the Invention of "I-
PROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID, ALKALIS, AND
THEIR SALTS."
Sealed the 22nd September 1853, and dated the 20th March 1853.
PROVISIONAL SPECIFICATION left by the said George Robb at
the Office of the Commissioners of Patents, with his Petition, on
the 26th March 1853.
I, GEORGE ROBB, of Glasgow, in the County of Lanark, North
Britain, Gentleman, do hereby declare the nature of the said Invention
for "IMPROVEMENT IN THE MANUFACTURE OF SULPHURIC ACID, ALKALIS
AND THEIR SALTS," to be as follows:-
This Invention relates to the obtainment of superior economy in the
manufacture or production of sulphuric acid and sulphate of soda. In
making sulphuric acid the vapour of sulphurous acid is passed over per-
oxide of iron mingled with heated air, and the result of this process is
sulphuric acid.
Then to produce sulphate of soda the sulphurous acid is passed along
with heated air and steam over a mixture of common salt and per-
Price 8d 1

page_text: oxide of iron. Another branch of the Invention relates to the pro-
duction of sulphate of sodium for the manufacture of carbonate of soda.
This is accomplished by mixing the materials for the production of the
sulphurate of sodium with sulphurate of calcium or soda waste, so that
the sulphurate of sodium is rendered workable on the large scale, by
being rendered innoxious in its effects upon the apparatus employed in
the process.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Robb, in the Great Seal Patent Office,
on the 24th September 1853.
TO ALL TO WHY
THESE PRESENTS SHALL COME, I,
(EORGE ROBB, of Glasgow, in the County of Lanark, North Britain,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of March, in the
year of our Lord One thousand eight hundred and fifty-three, in the
sixteenth year of Iler reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said George Robb, Her special licence
that I, the said George Robb, my executors, administrators, and
assigns, or such others as I, the said George Robb, 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 OF SULPHURIC ACID, ALKALIS, AND THEIR SALTS," upon
the condition (amongst others) that I, the said George Robb, 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.
tom

page_text: 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 obtainment of superior economy in
the manufacture or production of sulphuric acid and sulphate of soda.
In making sulphuric acid according to my improved process the
vapour of sulphurous acid is passed over per oxide of iron mingled with
heated air, and the result of this process is sulphuric acid.
Then to produce sulphate of soda the vapour of sulphurous acid is
passed along with the heated air and steam over a mixture of common
salt and per oxide of iron. Another branch of my Invention relates
to the production of sulphuret of sodium for the manufacture of car-
bonate of soda. This is accomplished by mixing the materials for the
production of the sulphuret of sodium with sulphuret of calcium or
soda waste, so that the sulphuret of sodium becomes workable on the
large scale by being rendered innoxious in its effects upon the appa-
ratus employed in the process. And in order that my said Invention
may be properly understood, I shall now proceed to describe and
explain the details of my several improvements. In employing per
oxide of iron for the production of sulphuric acid I use, by prefer-
ence, the pyrites cinder, resulting from the combustion of iron
pyrites, as commonly produced in the manufacture of sulphuric
acid at present. The pyrites cinder is first reduced to small pieces,
or to a state of powder, and in this condition it is placed in a fur-
nace or kiln, such a kiln, for example, as is technically known in
Scotland as a "draw kiln." Round this kiln are ranged a set of
pyrites burners, such as are commonly used by sulphuric acid makers;
and these burners are so arranged that all the products of combustion
effected in them may pass into the kiln containing the pyrites powder.
Common pyrites is deposited in these burners, and roasted in the ordi-
nary manner; highly heated atmospheric air being at the same time
admitted at the bottom of the pyrites kiln. By this arrangement the
vapour of sulphurous acid and the oxygen of the atmosphere being
simultaneously brought into contact with the pyrites in the kiln, which
pyrites is kept at a dull red heat, the resultant combination forms
sulphuric acid.

page_text: In making the sulphate of soda by passing the vapour of sulphurous
acid over per oxide of iron and common salt mixed together, and kept
at a dull red heat, I prefer to use the spent cinder from pyrites bur-
ners. Such spent pyrites cinder is reduced to a powder, and the
common salt is mingled with such powder, and the compound is then
placed in such a kiln or chamber as I have already described herein;
and the sulphurous acid generated in the manner which I have also
herein-before described is then passed through the heated materials
producing sulphate of soda. In manufacturing carbonate of soda I
first produce a sulphuret of sodium, and then decompose such material
by the action of carbonic acid. The common sulphate of soda is in
this process decomposed by the action of suitable carbonaceous ma-
terials in a kiln or common furnace. The ordinary materials for the
production of sulphuret of sodium are mixed with sulphuret of calcium
or soda waste, so that I am enabled by this admixture to make the
sulphuret of sodium on the large commercial scale, as that substance
is by this treatment rendered innoxious in its effects upon the appa-
ratus employed in the manufacture, both as regards the furnaces or
operating chambers and the necessary iron tools of the workmen.
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
therefore claim as the Invention secured to me by the herein-before
in part recited Letters Patent, is,-
First, the general arrangements and means for manufacturing
sulphuric acid, alkalis, and their salts, as herein-before described.
Second, the application and use of powdered pyrites cinder or per-
oxide of iron for the purposes herein-before described.
Third, the system or mode of keeping up the heat of the kiln, fur-
naces, or operating chamber by the use of heated air.
Fourth, the decomposition of common salt in a state of admixture

page_text: solely with per oxide of iron or pyrites cinder, by passing the vapour of
sulphurous acid through or over such compound.
Fifth, the system or mode of operating upon pyrites for the produc-
tion of sulphurous acid, wherein the heat involved in the process is
solely derived from the combustion of the pyrites.
Sixth, the system or mode of producing sulphuret of sodium by the
admixture and use of sulphuret of calcium or soda waste.
In witness whereof, I, the said George Robb, have hereunto set
my hand and seal, this Seventeenth day of September, in the
year of our Lord One thousand eight hundred and fifty-three.
GEORGE ROBB. (L.S.)