IMPROVEMENTS IN THE MANUFACTURE
Year: 1874

page_text: LETTERS PATENT to William Black, of Hedworth, near South Shields,
and David Hill, of East Jarrow, South Shields, both in the County
of Durham, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
Sealed the 26th June 1874, and dated the 13th January 1874.
PROVISIONAL SPECIFICATION left by the said William Black and
David Hill at the Office of the Commissioners of Patents, with
their Petition, on the 13th January 1874.
We, WILLIAM BLACK, of Hedworth, near South Shields, and DAVID
HILL, of East Jarrow, South Shields, both in the County of Durham, do
hereby declare the nature of our said Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF SODA IN REVOLVING FURNACES," to be as follows:-
In the ordinary process for obtaining ball soda or black ash from a
mixture of sulphate of soda, carbonate of lime, and small coal in
> revolving furnaces it is customary to heat the carbonate of lime by

page_text: itself or mixed with small coal until a portion of it is converted into
caustic lime, the lime so formed when the balling operation is completed
serves to disintegrate or burst the balls by slaking when brought into
contact with the warm liquors in.the ordinary lixiviating tanks.
Now our Invention consists in heating the mixture of sulphate of
soda, carbonate of lime and small coal in such a way as to prevent the
formation as far as possible of caustic lime, and this may be accomplished
by putting the whole mixture of sulphate of soda, carbonate of lime,
and small coal into the revolving furnace together, or by heating the
carbonate of lime by itself but stopping short in the heating at that
point at which it begins to give off carbonic acid and forms lime, and
then adding the sulphate of soda and small coal, but other modifications
may be adopted in order to obtain the desired result. Ball soda made
in this way will not disintegrate, burst, or fall like ordinary balls
prepared in the usual way when placed in roughly broken lumps in the
ordinary lixiviating tanks. We therefore grind such ball soda to powder
and lixiviate in vessels provided with suitable agitating machinery by
the process of washing known to chemists as that of subsidence and
decantation, using the washings successively from one operation to
another until on the one hand a solution of carbonate of soda of suitable
strength for subsequent operations is obtained, and on the other the
waste sulphide of calcium is freed as completely as possible from
carbonate of soda.
By operating in the manner described the work done in a revolving
furnace is largely increased, accompanied with a large saving of fuel and
of carbonate of lime.
The solution of carbonate of soda obtained is much purer than that
obtainable by the ordinary process, being almost free from caustic soda,
and from the fact that the temperature of the lixiviation is more under
control than in the ordinary tanks there is less risk of the solution being
cantominated with oulnbid, of codin

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Black and David Hill in the Great Seal
Patent Office on the 10th July 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, William
BLACK, of Hedworth, near South Shields, and DAVID HILL, of East
Jarrow, South Shields, both in the County of Durham, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of January, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heir sand successors,
give and grant unto us, the said William Black and David Hill, Her
special license that we, the said William Black and David Hill, our
executors, administrators, and assigns, or such others as we, the said
William Black and David Hill, our 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 SODA IN REVOLVING
FURNACES," upon the condition (amongst others) that we, the said
William Black and David Hill, our executors or administrators, by an
instrument in writing under our hands and seals, or under the hand and
seal of one of us, 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 William Black and David Hill, 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 the ordinary process for obtaining ball soda or black ash from a
mixture of sulphate of soda, carbonate of lime, and small coal in
revolving furnaces it is customary to heat the carbonate of lime by
itself or mixed with small coal until a portion of it is converted

page_text: into caustic lime, the lime so formed when the balling operation is
completed serves to disintegrate or burst the balls by slaking when
brought into contact with the warm liquors in the ordinary lixiviating
tanks.
Our Invention consists in heating the mixture of sulphate of soda,
carbonate of lime, and small coal in such a manner as to prevent the
formation as far as possible of caustic lime, and this may be accomplished
by putting the whole mixture of sulphate of soda, carbonate of lime,
and small coal into a revolving furnace together, or by heating the
carbonate of lime by itself, but stopping short in the heating at that
point at which it begins to give off carbonic acid and forms lime, and then
adding the sulphate of soda and small coal, but other modifications may
be adopted in order to obtain the desired result. Ball soda made in this
way will not disintegrate, burst, or fall, like ordinary balls prepared in the
usual way when placed in roughly broken lumps in the ordinary lixiviating
tanks. We therefore grind such ball soda to powder and lixiviate it in
vessels provided with suitable agitating machinery by the process of
washing known to chemists, as that of subsidence and decantation, using
the washings successively from one operation to another until on the one
hand a solution of carbonate of soda of suitable strength for subsequent
operations is obtained, and on the other that the waste sulphide of
calcium shall be freed as completely as possible from carbonate of

page_text: soda, of carbonate of lime, and of small coal in such a manner and at
such a temperature as to prevent the formation of caustic lime and to
produce carbonate of soda, substantially as herein-before described.
In witness whereof, we, the said William Black and David Hill,
have to this our Specification set our hands and seals, this Eighth
day of July, One thousand eight hundred and seventy-four.