IMPROVEMENTS IN THE MANUFACTURE OF SODA AND ALKALI."
Year: 1855

page_text: LETTERS PATENT to James Cochran Stevenson and John Williamson,, of
South Shields, Alkali Manufacturers, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF SODA AND ALKALI."
PROVISIONAL SPECIFICATION left by the said James Cochran Stevenson
and John Williamson at the Office' of the Commissioners of Patents, with
'their Petition, on the 31st December 1855.
We, JAMES COCHRAN STEVENSON and JOHN WILLIAMSON, of South Shields,
Alkali Manufacturers, do hereby declare the nature of the Invention for "Im-
PROVEMENTS IN THE MANUFACTURE OF SODA AND ALKALI" to be as follows:-
Our improvements relate to that part of the process of manufacturing soda
or alkali called balling, or black ash making. The plan hitherto in use has been
to introduce a mixture of certain proportions of sulphate of soda, coal, and
chalk (or limestone) into a reverberatory furnace or other suitable apparatus,
and heat them. together until the desired decomposition has been effected.
We propose to heat together at first only the coal and chalk (or limestone),
reserving the sulphate of soda until a high temperature has been attained,
and we prefer that they should be so heated until a portion of the chalk (or
limestone) is converted into caustic lime; we then throw in the sulphate of
soda, incorporate it well with the materials already in the furnace, and finish

page_text: the operation in the usual manner; we may vary this by adding a portion
of additional coal with the sulphate of soda when the mixture appears to
require it.
The advantages we attain are, that a smaller portion of sulphate of soda is
carried away by the draught of the furnace and less soda volatilized by the heat
and oxydation; there is less tendency to form cyanide of sodium and other
objectionable impurities, and the ball soda or black ash resulting is more
easily soluble in water.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Cochran. Stevenson and John Williamson in the
Great Seal Patent Office on the 30th June 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
COCHRAN STEVENSON and JOHN WILLIAMSON, of South Shields, Alkali Manu-
facturers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirty-first day of December, in the year of our
Lord 'One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us, the
said James Cochran Stevenson and John Williamson, Her special licence that
we, the said, James Cochran Stevenson and John Williamson, our executors,
administrators, and assigns, or such others as we, the said James Cochran
Stevenson and John Williamson, 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 "IMPROVE-
MENTS IN THE MANUFACTURE OP SODA AND ALKALI," upon the condition (amongst
others) that we, the said James Cochran Stevenson and John Williamson, our
executors or administrators, by an instrument in writing under our or their
hands and seals, or under the hand and seal of one of us or them, 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said James Cochran Stevenson, on behalf of
myself and John Williamson, do hereby declare the nature of the said Inven-

page_text: tion, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement thereof, that is
to say:-
Our improvements relate to that part of the process of manufacturing soda
or alkali called "balling," or black ash making, in which sulphate of soda is
decomposed by being heated in contact with coal and chalk (or limestone).
The process, as heretofore performed, has been to introduce into the ball
furnace the sulphate of soda at the earliest stage of the operation along with
the coal and chalk.
:
Our improvements consists in keeping back the sulphate of 'soda until the
chalk and coal have been heated together to a high temperature, and then
adding the sulphate of soda and finishing the operation in the usual manner.
In the first or heating stage of the operation, we expose, the mixed chalk
and coal to the heat of the furnace, until they have attained a strong red heat,
and a considerable portion of the chalk has been converted into lime; and we
shorten the second or decomposing stage of the operation, during which the
sulphate of soda is in the furnace, as much as possible, consistently with proper
decomposition.
Our improvements require no alteration in the construction of the furnace,
and the proportions of the materials employed remain nearly the same as
heretofore.
In operating in an ordinary double-bedded ball furnace, we charge into the
upper bed every hour about 2 cwts. of dried chalk and 1 cwt. of coal, pre-
viously ground together, and at the end of about an hour these materials,
having been heated to a good red heat, are transferred to the working bed of
the furnace, on which they are spread level, and a mixture of about 2 cwts.
of sulphate of soda and of a cwt. of coal, previously ground together, is in-
troduced, and immediately carefully and intimately mixed and incorporated
with the highly heated coal and chalk. The process is then conducted in
the ordinary way, and is completed in about another hour, during which time
chalk and coal for the succeeding charge are undergoing the heating stage on
the upper bed of the furnace.
In operating in the revolving ball furnace known as Elliot and Russel's
patent furnace, we proceed as follows:-We introduce into the cylinder as
much undried chalk as would be equal to 15 cwt. of dried chalk, and 7 cwt.
of small coal, and cause the cylinder to revolve at the rate of one revolution in
12 minutes; at the end of an hour the cylinder is stopped, and a charge of
15 cwt.. of sulphate of soda and 2½ cwt. of small coal is added, and the cylinder
is again set in motion at the same speed, which is continued for half an hour

page_text: '
longer, after which time there is no tendency for the materials to be blown
away in dust into the flue. We then increase the speed of the cylinder to one
revolution in a minute and a quarter, which is maintained for half an hour, by
which-time the operation is completed, and the charge withdrawn: In working
in the cylinder we do not grind, or take any pains in mixing the materials,
previous to their being introduced into the cylinder. But to avoid lumps of
excessive size, we pass all the materials through a grating: formed of iron bars,
placed 5 inches apart. And we would state, that we find a strong draught
in such furnace necessary.
Having thus described the nature of our Invention, and, the manner of
carrying it into effect, wo would have it to be understood, that we do not con-
fine ourselves to the precise details here given, nor to the use of any particular
apparatus for carrying out the same; but what we claim is, the heating of the
chalk and coal, and reserving the introduction of the sulphate of soda until the
materials for its decomposition have attained, a high temperature..
In witness whereof, I, the said James Cochran Stevenson, have hereunto
set my hand and seal, this Thirtieth day of June, in the year of our
Lord One thousand eight hundred and fifty-six.
Witness,
S. CARPMAEL.
JAMES C. STEVENSON. (L.S.)