IMPROVEMENTS 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, Veterinary Surgeon, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID, ALKALIS
AND THEIR SALTS."
Sealed the 29th September 1853, and dated the 2d April 1853.
PROVISIONAL SPECIFICATION left by the said George Robb
at the Office of the Commissioners of Patents, with his Petition,
- on the 2nd April 1853.
I, GEORGE ROBB, of Glasgow, in the County of Lanark, North
Britain, Veterinary Surgeon, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACID,
ALKALIS, AND THEIR SALTS" to be as follows:-
This Invention relates to the manufacture or production of sul-
phuric acid, sulphate of soda, sulphate of potash, and sulphurets of
sodium and potassium and their carbonates, so as to secure superior
economy. In making sulphuric acid, the vapour of sulphurous acid is
passed over or in contact with the per oxide of iron, manganese, or other
metals, with or without the addition of clay or alumina mingled with
heated air; and this produces sulphuric acid. But in order to obtain
[Prise 8d1

page_text: the essentially necessary superior heat, carbonic oxide in a state of com-
bustion, or the products of combustion of any clear bright burning
body, are passed through the materials, so as to ensure a superior result.
To produce sulphates of soda and potash, the sulphurous acid is passed
along with heated air and steam, over a mixture of common salt or
chloride of potassium, and per oxide of iron, manganese, or other oxide,
and with or without clay or alumina, as above; the direct heat of any
clear burning body, as before mentioned, being also used in this part of
the process. In making the sulphurets of sodium and potassium for the
production of the carbonates of soda and potash, the sulphates of soda
and potash are mixed with the sulphates of lime, baryta, stroutia, mag-
nesia, or other sulphates, or the sulphurets of these bodies, or soda
waste, either individually or mixed. The carbonic acid gas may be
obtained from bicarbonate of soda or potash, which has been made
with carbonic acid gas from combustion.
SPECIFICATION in-pursuance of the conditions of the Letters Patent,
filed by the said George Robb, in the Great Seal Patent Office, on
the 30th September 1853.
TO ALL
ALL TO WHOM THESE PRESENTS SHALL COME, I,
GEORGE ROBB, of Glasgow, in the County of Lanark, North Britain,
Veterinary Surgeon, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of April, in the year of
our Lord One thousand eight hundred and fifty-three, in the sixteenth
year of Her 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 J, 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 King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for IMPROVEMENTS IN THE MANUFACTURE OF
SUL

page_text: PHURIC ACID, ALKALIS. AND OTHER 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.
NOW KNOW YE, that I, the said George Robb, 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 manufacture or production of sul-
phuric acid, sulphate of soda, sulphate of potash, and sulphurets of
sodium and potassium and their carbonates, so as to secure superior
economy in the several processes. In making sulphuric acid, the vapour
of sulphurous acid is passed over or in contact with the per-oxide of
iron, manganese, or other metals, with or without the addition of clay
or alumina, mingled with heated air; and this produces sulphuric acid.
But, in order to obtain the essentially necessary superior heat, carbonic
oxide in a state of combustion, or the products of combustion of any
clear bright burning body, are passed through the materials, so as to
ensure a superior result. To produce sulphates of soda and potash, the
sulphurous acid is passed along with heated air and steam over a
mixture of common salt or chloride of potassium and per-oxide of iron,
manganese, or other oxide, and with or without clay or alumina, as
herein-before mentioned; the direct heat of any clear burning body, as
herein-before mentioned, being also used in this part of the process.
In making the sulphurets of sodium and potassium, for the production
of the carbonates of soda and potash, the sulphates of soda and
potash are mixed with the sulphates of lime, barita, strontia, magnesia,
or other sulphates, or the sulphurets of these bodies, or soda waste,
either individually or mixed. The carbonic acid gas may be obtained
from bicarbonate of soda or potash which has been made with car-
bonic acid by a process of combustion. And in order that my said
Invention may be properly understood, I shall now proceed to explain
the details of my several improvements.
८

page_text: In employing oxide of iron for the production of sulphuric acid, I use
by preference the pyrites cinder, resulting from the combustion of iron
pyrites, as commonly produced in the manufacture of sulphuric acid at
present. When oxide of manganese is used, any of the ordinary man-
ganese ores of commerce may thus be employed. The pyrites cinder or
oxide of manganese is first reduced to a coarse powder, and is then com-
mingled with about from one-fifth to one-tenth of its weight of common
clay or argillaceous earth; or, instead of this added matter, alumina
may be used.
The compound so made is then made пр into a paste
with water, when it may be moulded into balls, bricks, or suitable
manageable masses. As the special nature of the incorporated materials
necessarily varies occasionally, the proportions which I have stated are
also equally variable; and in some instances. I prefer to mix a quantity
of ground coke or charcoal, or small coal, in the mass, so that as this
carbonaceous addition burns out in the subsequent calcination of the
balls, the masses will be left in a more highly porous condition, and
better suited for the purpose intended. Some bricks or masses are then
dried in a common stove, until they are hard and difficult of fracture.
In this state they are placed in a furnace resembling an ordinary lime
kiln, or what is technically known in Scotland as a "draw kiln." Round
this kiln are ranged a set of pyrites burners, such as are in ordinary use.
by sulphuric acid makers. These burners are so arranged that all the
products of the combustion effected in them may pass into the composi-
tion kiln. Common pyrites is deposited in these burners, and roasted
in the usual manner; highly heated atmospheric air being at the same
time admitted at the bottom of the composition kiln. By this arrange-
ment the sulphurous acid vapour and the oxygen of the atmosphere,
being simultaneously brought into contact with the composition masses
or bricks at a dull red heat, the resultant combination forms sulphuric
acid. During this process, carbonic oxide or other cheap combustible gas
may be advantageously introduced at different parts of the composition
kiln, so that the kiln may be still better heated throughout. The admission
of surcharged or super-heated steam is also advantageous; and instead
of using pyrites in this way as the source of sulphurous acid, I use as
well sulphur, sulphuretted hydrogen, or artificial sulphuret of iron; or
the sulphurous acid employed may be obtained from any known source..

page_text: In making sulphate of soda, by passing sulphurous acid over oxide of
iron, or manganese and common salt mixed together, and retained at a
dull red heat, the preferable oxide of iron is, as I have already de-
cribed, the spent cinder fiom pyrites burners; or manganese, which may
be used over and over again, may be similarly employed. I make up
the salt and oxide into balls or bricks with clay or alumina, and then
introduce such masses into a kiln, such as I have already described,
passing the sulphurous acid through them. Any artificial mode of
heating may be used, but in the case of pyrites this is unnecessary. The
whole of the common salt is readily decomposed in this way. If steam or
moisture is admitted into the kilu, along with the atmospheric supply,
muriatic acid is given off; but if the air and the materials are
thoroughly dry, chlorine gas is evolved by the process.
In manufacturing carbonate of soda, I first produce a sulphuret of
sodium, and then decompose such material by the action of carbonic
acid. The ordinary sulphate of soda is, in this process, decomposed by
the action of suitable carbonaceous material in a kiln or common
furnace ; but I add to the sulphate of soda a portion of sulphate of
barytes, or strontian, or lime, or magnesia, or other sulphate or sul-
phuret; or a mixture of these said materials, or ordinary vat waste
from the alkali makers, mixed with one or other of these compounds.
By the agency of such additions I obtain a sulphuret of sodium, which
does not corrode the furnace or the iron tools nearly so rapidly as when
the sulphate of sodium is decomposed by itself with carbonaceous
materials; and it is with this object that I use these herein-before
described mixtures. The result of this process is that an easily lixiviable
mass is obtained, and the residue may be continuously used over and
over to assist in the decomposition of fresh sulphate of sodium. Such
sulphuret may be decomposed by the action of bi-carbonate of soda,
according to the process for which Letters Patent for England were
granted to Mr. J. Wilson, in the year 1840. But I especially use the
bi-carbonate of soda as a source of carbonic acid for effecting the
decomposition of sulphuret of sodium, placing the bi-carbonate of
soda in a separate vessel or chamber, and generating the carbonic acid..
by the agency of heat. The bi-carbonate may be produced by causing

page_text: the common carbonate of soda to absorb the products of the combustion
or carbonaceous materials. In practising this process, the sulphuretted
hydrogen evolved may either be turned into sulphurous acid, for the
production of sulphuric acid, or its sulphur may be recovered by
heating it to redness, or by passing it into a chamber where it meets
with sulphurous acid. Or it may be made available by other known
.methods, which must be obvious to the practical chemist.
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 there-
from 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 sul-
phuric acid, alkalis, and their salts, as herein-before described.
Second, the application and use of powdered pyrites cinder, oxide of
iron, or oxide or manganese, formed into masses with clay or alumina,
for the purposes herein-before described.
Third, the system or mode of keeping up the heat of the kiln or
furnace by the use of heated air, by, carbonic oxide or other cheap
combustible gas, or heated products of combustion.
Fourth, the decomposition of common salt in a state of admixture
with oxide of iron, pyrites cinder, or oxide of manganese, by passing the
vapour of sulphurous acid through such compound.
Fifth, the system or mode of operating upon pyrites for the produc-
tion of sulphuric acid, wherein the heat employed is solely derived
from the combustion of the pyrites.
Sixth, the application and use of bicarbonate of soda as the source
of carbonic acid for effecting the decomposition of sulphuret of sodium,
and the node herein-before described of decomposing the sulphuret
of sodium.
Seventh, the application and use of sulphates of lime and the other

page_text: agents herein-before mentioned, in the reduction of sulphate of soda to
sulphuret of sodium, whereby an easily workable mixture is obtained.
In witness whereof, I, the said George Robb, have hereunto set
my hand and seal, this Twenty-seventh day of September, in
the year of our Lord One thousand eight hundred and fifty-
three.
GEORGE ROBB (1.S.)