IMPROVEMENTS HAVING FOR OBJECT THE RECOVERY OF THE SULPHUR EMPLOYED IN THE MANUFACTURE OF SODA AND POTASH
Year: 1871

page_text: LETTERS PATENT to Walter Weldon, of 29, The Cedars, Putney, in
the County of Surrey, for the Invention of "IMPROVEMENTS HAVING
FOR OBJECT THE RECOVERY OF THE SULPHUR EMPLOYED IN THE MANUFACTURE
OF SODA AND POTASH.""
Sealed the 2nd February 1872, and dated the 18th August 1871.
PROVISIONAL SPECIFICATION left by the said Walter Weldon at the
Office of the Commissioners of Patents, with his Petition, on the
18th August 1871.
"
I, WALTER WELDON, of 29, The Cedars, Putney, in the County of
Surrey, do hereby declare the nature of the said Invention for
"IMPROVEMENTS HAVING FOR OBJECT THE RECOVERY OF THE SULPHUR EMPLOYED IN
THE MANUFACTURE OF SODA-AND POTASH," to be as follows:-
To recover under- this Invention- the sulphur employed in the -
manufacture of soda I first get that sulphur into the state of sul-
phuretted hydrogen, either by decomposing, either by carbonic acid or
by steam, the residue of that manufacture as at present conducted, or by.

page_text: converting into sulphide the sulphate of sodium which is formed at one
stage of that manufacture, and decomposing this sulphido as aforesaid.
To obtain free sulphur from the sulphuretted hydrogen so produced, I
either treat it with sulphurous acid in a state of solution, either by
injecting it into such solution, or by sending the sulphuretted hydrogen
and sulphurous acid gas simultaneously into a tower such as is used for
condensing bydrochloric acid, and down which water is kept trickling ;
or I treat the said sulphuretted hydrogen with a solution of a persalt of
iron, afterwards injecting air into the resulting solution of protosalt, so
as to obtain a product which will decompose more sulphuretted hydro-
gen, and repeating time after time these alternate treatments, first with
the sulphuretted hydrogen and then with air (by injection thereof); or,
I bring the said sulphuretted hydrogen into contact, in the dry way,
with oxide of iron or oxide of manganese, then treat the product with air,
also by the dry way, then treat again with the sulphuretted hydrogen,
then again with air, and so on time after time, until I have obtained a
mixture of metallic oxide and free sulphur containing a considerable
proportion of the latter, and from which the free sulphur can then be
readily separated. The oxide employed should preferably be hydrated,
though this is not essential.
The same methods as are above described for the recovery of the
sulphur employed in the manufacture of soda are equally applicable to
the recovery of the sulphur employed in the manufacture of potash.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Walter Weldon in the Great Seal Patent Office 2
on the 15th February 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WALTER
WELDON, of 29, The Cedars, Putney, in the County of Surrey, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 3
Letters Patent, bearing date the Eighteenth day of August, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Walter Weldon, Her special licence

page_text: that I, the said Walter Weldon, my executors, administrators, and
assigns, or such others as I, the said Walter Weldon, 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
cxpressed, 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 HAVING FOR
OBJECT THE RECOVERY OF THE SULPHUR EMPLOYED IN THE MANUFACTURE OF SODA AND
POTASH," upon the condition (amongst others) that I, the said Walter
Weldon, my exccutors 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 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 Walter Weldon, 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 :—
To recover under this Invention the sulphur employed in the manu-
facture of soda or potash I first get that sulphur into the state of
sulphuretted hydrogen by converting into sulphide the sulphate which
is produced in the first stage of such manufacture, and then decom-
posing the said sulphide either by carbonic acid or by steam: To obtain
free sulphur from the sulphuretted hydrogen so produced, I cither treat
it with sulphurous acid in the state of solution in water, either by
injecting it into such solution, or by sending the sulphuretted hydrogen
and sulphurous acid gas-simultaneously into a tower packed with either
pebbles, or bricks, or coke down which water is kept trickling, the gases
of course entering at or near the bottom of such tower; or, I treat the
said sulphuretted bydrogen with a solution of a persalt of iron, after-
wards injecting air into the resulting solution of protosalt so as to obtain
a product which will decompose more sulphuretted hydrogen, then
treating again with sulphuretted hydrogen, then again with air, and so
on an indefinite number of times.
:
I do not claim as my. Invention the decomposition of sulphide of
sodium or of sulphide of potassium by either steam or carbonic acid, or the
decomposition of sulphuretted hydrogen by sulphurous acid in any other

page_text: state than that of solution in water, or the oxidation of the protosalt
produced by treating a persalt of iron with sulphuretted hydrogen by
causing a solution of such protosalt to trickle down a tower up which
air
passes; but what I believe to be new and original and useful, and
therefore do claim as the Invention to be secured to me by the herein- &
before in part recited Letters Patent is, the recovery of the sulphur
employed in the manufacture of soda or potash substantially as is
above described.
•
I also claim the treatment by the methods above described of sul-
phuretted hydrogen produced by decomposing by steam or a convenient ]
acid the waste product of the manufacture of soda or potash as at
present conducted.
In witness whereof, I, the said Walter Weldon, have hereunto set
my hand and seal this Fourtcenth day of February One thousand