IMPROVEMENTS IN THE MANUFACTURE OF SODA AND POTASH AND "
Year: 1871

page_text: LETTERS PATENT to James Hall, of the Town and County of New-
castle-on-Tyne, Thomas Gibb, of Jarrow-on-Tyne, in the County of
Durham, and Charles Gelstharp, of the same Place, for the In-
vention of "IMPROVEMENTS IN THE MANUFACTURE OF SODA AND POTASH AND
"
PROVISIONAL SPECIFICATION left by the said James Hall, Thomas
Gibb, and Charles Gelstharp at the Office of the Commissioners of
Patents, with their Petition, on the 21st November 1871.
We, JAMES HALL, of the Town and County of Newcastle-on-Tyne,
THOMAS GIBB, of Jarrow-on-Tyne, in the County of Durham, and
CHARLES GELSTHARP, of the same Place, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SODA
AND POTASH AND OF THE CARBONATES THEREOF," to be as follows :—
In carrying this Invention into effect chloride of sodium or potassium
is decomposed by means of sulphuric acid, thus producing sulphate of
soda or potash and hydrochloric acid, as is well understood.

page_text: The sulphate of soda or potash is reduced to sulphide by any known
method, and the sulphide thus obtained is decomposed in such a manner
as to produce caustic or carbonated soda or potash and sulphuretted
hydrogen. For this decomposition it is preferred to employ carbonic
acid and to act thereby on the sulphide dissolved in water. The sulphu-
retted hydrogen produced in decomposing sulphide of sodium is employed
to decompose sulphate of copper, thereby forming sulphide of copper
and sulphuric acid. The sulphuric acid thus obtained is employed to
decompose chloride of sodium or potassium, thereby forming sulphate
of soda or potash to be reduced to sulphide, from which soda or potash
and sulphuretted hydrogen are again produced. The sulphide of copper
formed by the action of the sulphuretted hydrogen on the sulphate of
copper is oxidised so as to reproduce sulphate of copper, which is again
decomposed by sulphuretted hydrogen formed in decomposing sulphide
of sodium or potassium, the sulphuric acid being used in decomposing
the chlorides, and the sulphide of copper re-oxidised as before. Thus the
sulphur of the sulphuric acid used in decomposing chloride of sodium or
potassium is continually recovered in combination with copper, the
sulphide of copper re-oxidised, and sulphuric acid reproduced in con-
nection with the production of soda or potash from chloride of sodium or
potassium.
Instead of employing sulphuric acid in a direct manner to decompose
chloride of sodium or potassium, sulphate of copper may be mixed with
the chloride in solution, and the copper precipitated from this solution
by sulphuretted hydrogen. On evaporating the residual solution
sulphate of soda or potash is obtained, which is reduced to sulphide
to be decomposed into caustic or carbonated soda or potash and
sulphuretted hydrogen as above described, the sulphuretted hydrogen
being used to decompose sulphate of copper in mixture with chloride of
sodium or potassium, the sulphide of copper being oxidised for the repro-
duction of sulphate of copper, to be again decomposed in mixture with
chloride of sodium or potassium, thus continually recovering the sulphur
employed in the production of soda or potash from chloride of
sodium or potassium, in the same manner as that previously described in
connection with the direct decomposition of chloride of sodium or
potassium by sulphuric acid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Hall, Thomas Gibb, and Charles Gelstharp
in the Great Seal Patent Office on the 20th May 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
HALL, of the Town and County of Newcastle-on-Tyne, THOMAS GIBB,
of Jarrow-on-Tyne, in the County of Durham, and CHARLES GELSTHARP,
of the same Place, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of November, 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 us, the said James Hall, Thomas
Gibb, and Charles Gelstharp, Her special licence that we, the said
James Hall, Thomas Gibb, and Charles Gelstharp, our executors,
administrators, and assigns, or such others as we, the said James
Hall, Thomas Gibb and Charles Gelstharp, our executors, adminis-
trators, 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 "IMPROVEMENTS IN THE MANU-
FACTURE OF SODA AND POTASH, AND CARBONATES THEREOF," upon the condition
(amongst others) that we, the said James Hall, Thomas Gibb, and
Charles Gelstharp, our executors or administrators, by an instrument
in writing under our, 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 we, the said James Hall, Thomas Gibb, and
Charles Gelstharp, do hereby declare the nature of our 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:
In carrying our said Invention into effect chloride of sodium or
་་

page_text: sulphate of soda or potash and hydrochloric acid, as is well understood,
and which process we do not of course claim as part of our Invention.
The sulphate of soda or potash is reduced to sulphide by any known
method, and the sulphide thus obtained is decomposed in such a manner
as to produce caustic or carbonated soda or potash and sulphuretted
hydrogen. For this decomposition we prefer to employ carbonic acid,
and to act thereby on the sulphide dissolved in water. The sulphuretted
hydrogen produced in decomposing the sulphide of sodium or potassium
is employed to decompose sulphate of copper, thereby forming sulphide
of copper and sulphuric acid. The sulphuric acid thus obtained is
employed to decompose chloride of sodium or potassium, thereby forming
sulphate of soda or potash to be reduced to sulphide, from which soda or
potash and sulphuretted hydrogen are again produced. The sulphide
of copper formed by the action of the sulphuretted hydrogen on the
sulphate of copper is oxidised so as to reproduce sulphate of copper,
which is again decomposed by sulphuretted hydrogen formed in decom-
posing sulphide of sodium or potassium, the sulphuric acid being used
in decomposing the chlorides, and the sulphide of copper re-oxidised as
before. Thus the sulphur of the sulphuric acid used in decomposing
chloride of sodium or potassium is continually recovered in combination
with copper, the sulphide of copper re-oxidised, and sulphuric acid
reproduced in connection with the production of soda or potash from
chloride of sodium or potassium.
Instead of employing sulphuric acid in a direct manner to decompose
chloride of sodium or potassium, sulphate of copper may be mixed with
the chloride in solution, and the copper precipitated from this solution
by sulphuretted hydrogen. On evaporating the residual solution
sulphate of soda or potash is obtained, which is reduced to sulphide to be
decomposed into caustic or carbonated soda or potash and sulphuretted
hydrogen as above described, the sulphuretted hydrogen being used to
decompose sulphate of copper in mixture with chloride of sodium or
potassium, and the sulphide of copper being oxidised for the reproduction
of sulphate of copper to be again decomposed in mixture with chloride of
sodium or potassium, thus continually recovering the sulphur employed
in the production of soda or potash from chloride of sodium or potassium
in the same manner as that previously described in connection with the
direct decomposition of chloride of sodium or potassium by sulphuric
acid.

page_text: Having thus described and ascertained the nature of our said
Invention, and in what manner the same is to be performed, we would
observe in conclusion that what we consider novel and original, and
therefore claim as constituting the Invention secured to us by the said
herein-before in part recited Letters Patent are, the processes and
methods of treatment of the chemical agents herein-before mentioned
in the manufacture of soda and potash and carbonates thereof,
substantially as herein-before described and set forth, or any mere
modifications thereof.
In witness whereof, we, the said James Hall, Thomas Gibb, and
Charles Gelstharp, have hereunto set our hands and seals, this
JAMES HALL.
THOMAS GIBB.
(L.8.)
(L.S.)
CHARLES GELSTHARP. (L.S.)