IMPROVEMENTS IN THE MANUFACTURE PROVISIONALATION
Year: 1872

page_text: LETTERS PATENT to James Hargreaves, of Widnes, in the County
of Lancaster, Chemist, and Thomas Robinson, of the same Place,
Ironfounder, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
PROVISIONAL SPECIFICATION left by the said James Hargreaves and
Thomas Robinson at the Office of the Commissioners of Patents,
with their Petition, on the 17th February 1872.
We, JAMES HARGREAVES, of Widnes, in the County of Lancaster,
Chemist, and THOMAS ROBINSON, of the same Place, Ironfounder, do
hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE MANUFACTURE OF ALKALIES AND IN APPARATUS EXPLOYED THERRIN,'
be as follows :—
"
to
Our said Invention consists in obtaining carbonates or hydrates of
soda or potassa, or either of them, by reducing chromate of soda or
chromate of potassa, preferably the chromate of soda or chromate

page_text: of potassa produced or obtained in the manufacture of chlorine and
hydrochloric acid, as set forth in the Specification of our Invention,
for which we have applied for Letters Patent simultaneously with this,
with carbonic oxide or hydrogen gas, or hydrocarbon gases or vapours or
other gases, or mixture of gases or vapours, which on combustion with
oxygen yield carbonic acid or water, or a mixture of carbonic acid and
water, and which for brevity we call "reducing gases."
We reduce the said chromates of soda or potassa with hydrogen when
we wish to obtain hydrates, and with carbonic oxide or hydrocarbon
gases or vapours when we wish to obtain carbonates. Steam may be
used along with the said hydrocarbon gases when they are rich in
carbon.
We place the said chromates, or either of them, in a close vessel, and
if not already heated we heat them or either of them preferably to a
dull red heat, but the temperature may be considerably varied, and pass
the said "reducing gases" through the said vessel until the whole or
nearly the whole of the said chromate of soda or chromate of potassa is
reduced and oxide of chromium and soda or potassa in the state of hydrate
or carbonate (and which soda or potassa or either of them we hereafter
for brevity call "alkali") are left in the mass. The closed vessel is
then allowed to cool so far as not to allow its contents to be reconverted
into chromate on coming into contact with the atmosphere. Alkali is
afterwards dissolved out by any suitable means, such for instance as
those at present used in lixiviating ball soda or black ash, or by boiling
by steam in iron vessels and washing the soluble from the insoluble
materials present, using the weaker solution or washing to dissolve the
alkali from the stronger or fresh mixture of oxide of chromium and
alkali.
Another modification of our Invention consists in mixing the chromate
of soda or chromate of potassa with carbon or carbonaceous compounds,
and heating them together in a close vessel, or by mixing the chromate
and carbonaceous matter, and heating them together and then placing
them in a close vessel where they are kept from contact with the air,
and preferably in the presence of some reducing or non-oxidizing gas
till the temperature is so low as not to allow of the oxidation of the g
materials and the re-formation of chromates.
When we reduce by the use of carbonaceous matter in close vessels we

page_text: The oxide of chromium which is left may be used again in the
manufacture of chromates of soda and potassa as set forth, and also in
the manufacture of chlorine specified under even date herewith.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Hargreaves and Thomas Robinson in the
Great Seal Patent Office on the 16th August 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
HARGREAVES, of Widnes, in the County of Lancaster, Chemist, and
THOMAS ROBINSON, of the same Place, Ironfounder, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of February, in the
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto us, the said James Hargreaves and Thomas
Robinson, Her special licence that we, the said James Hargreaves and
Thomas Robinson, our executors, administrators, and assigns, or such
others as we, the said James Hargreaves and Thomas Robinson, our
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 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 "IM-
PROVEMENTS IN THE MANUFACTURE OF ALKALIES AND IN APPARATUS EMPLOYED
THEREIN," upon the condition (amongst others) that we, the said James
Hargreaves and Thomas Robinson, 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.

page_text: what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, that is to say :-
Our Invention consists in obtaining carbonates or hydrates of soda or
potassa, or either of them, by reducing chromate of soda or chromate of
potassa, preferably the chromate of soda or chromate of potassa pro-
duced or obtained in the manufacture of chlorine and hydrochloric acid,
as set forth in the Specification of an Invention for which we have
applied for Letters Patent simultaneously with this, with carbonic oxide
or hydrogen gas, or hydrocarbon gases or vapours, or other gases or
mixture of gases or vapours, which on combustion with oxygen yield
carbonic acid or water, or a mixture of carbonic acid and water, and
which for brevity we call "reducing gases."
We reduce the said chromates of soda or potassa with hydrogen when
we wish to obtain hydrates, and with carbonic oxide or hydrocarbon
gases or vapours when we wish to obtain carbonates. Steam may be
used along with the said hydrocarbon gases when they are rich in
carbon.
We place the said chromates, or either of them, in a close vessel, and
if not already heated we heat them or either of them preferably to a
dull red heat, but the temperature may be considerably varied, and pass
the said "reducing gases" through the said vessel until the whole or nearly
the whole of the said chromate of soda or chromate of potassa is reduced,
and oxide of chromium and soda or potassa in the state of hydrate or
carbonate, and which soda or potassa or either of them we hereafter for
brevity call "alkali," are left in the mass. The closed vessel is then
allowed to cool so far as not to allow its contents to be reconverted into
chromate on coming into contact with the atmosphere. Alkali is
afterwards dissolved out by any suitable means, such for instance as
those at present used in lixiviating ball soda or black ash, or by boiling
by steam in iron vessels, and washing the soluble from the insoluble
materials present, using the weaker solution or washings to dissolve
the alkali from the stronger or fresh mixtures of oxide of chromium and
alkali.
Another modification of our Invention consists in mixing the chromate
of soda or chromate of potassa with carbon or carbonaceous compounds;
and heating them together in a close vessel, or by mixing the chromate
and carbonaceous matter and heating them together and then placing

page_text: them in a close vessel, where they are kept from contact with the air,
and preferably in the presence of some reducing or non-oxidizing gas
till the temperature is so low as not to allow of the reoxidation of the
materials and the re-formation of chromates.
When we reduce by the use of carbonaceous matter in close vessels we
prefer to pass steam through the vessel while the reduction is taking
place.
The oxide of chromium which is left may be used again in the
manufacture of chromates of soda and potassa as set forth, and also
in the manufacture of chlorine specified under even date herewith,
No. 508.
Having now described the nature of our said Invention, and particu-
larized the same in such manner that others will be enabled to carry our
improvements in effect, we claim the manufacture of alkalies substan-
tially in the manner and by the apparatus herein described.
In witness whereof, I, the said James Hargreaves, have hereunto
set my hand seal, this Third day of August, in the year of our
Lord One thousand eight hundred and seventy-two.
In the presence of
JAMES JOHNSON.
JAMES HARGREAVES. (L.S.)