IMPROVEMENTS IN THE MANUFACTURE OF A DOUBLE SULPHIDE OF CALCIUM AND SODIUM
Year: 1862

page_text: LETTERS PATENT to Peter Ward, of 2, Clouds Hill Villas, St. George's,
Bristol, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF A
DOUBLE SULPHIDE OF CALCIUM AND SODIUM."
Sealed the 3rd March 1868, and dated the 11th September 1862.
PROVISIONAL SPECIFICATION left by the said Peter Ward at the
Office of the Commissioners of Patents, with his Petition, on the
11th September 1862.
I, PETER WARD, of 2, Clouds Hill Villas, St. George's, Bristol, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF A DOUBLE SULPHIDE OF CALCIUM AND SODIUM," to be as follows:-
This Invention has for its object improvements in the manufacture of a
double sulphide of calcium and sodium; this substance is a salt soluble in
water, and of which the solution is strongly alkaline, and may be used for
some purposes for which soda has heretofore been employed. I produce this
material from the substance known as soda-ash waste, an article produced in
the manufacture of soda when sulphato of soda has been roasted with chalk
or limestone, and powdered coal, and the resulting carbonate of soda has been

page_text: dissolved out, there then remains the soda-ash waste, consisting principally
of sulphuret of calcium, lime, and small coal, this material is of little if any
commercial value. According to my Invention I take this substanco when in
a fresh state, (as when exposed to the air it becomes decomposed, and is then
not so suitable for my purpose,) and I mix it with sulphate of soda in suitable
proportion, and heat the mixture so as to obtain a double sulphide of calcium
and sodium. The double sulphide of calcium and sodium may also be obtained
by henting gypsum with sulphate of soda, lime, and carbon, but the soda-ash
waste I consider the more convenient source.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed 1
by the said Peter Ward in the Great Seal Patent Office on the
11th March 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETER
WARD, of 2, Clouds Hill Villas, St. George's, Bristol, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of September, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Peter Ward, Her special licence that I, the said Peter
Ward, my executors, administrators, and assigns, or such others as I, the
said Peter Ward, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after 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 OF A DOUBLE SULPHIDE OF CALCIUM AND SODIUM,"
upon the condition (amongst others) that I, the said Peter Ward, my exe-
cutors 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 Peter Ward, do hereby declare
the uature of the said Invention, and in what manner the same is to be

page_text: performed, to be particularly described and ascertained in and by the fol-
lowing statement thereof, that is to say :—
This Invention has for its object improvements in the manufacture of a
double sulphide of calcium and sodium; this substance is a salt soluble in
water, and of which the solution is strongly alkaline, and may be used for
some purposes for which soda has heretofore been employed. I produce this
material from the substance known as soda-ash waste, an article produced in
the manufacture of soda when sulphate of soda bas been roasted with chalk
or limestone, and powdered coal, and the resulting carbonate of soda has been
dissolved out, there then remains the soda-ash waste, consisting principally
of sulphuret of calcium, lime, and small coal, this material is of little if any
commercial value. According to my Invention I take this substance when in
a fresh state, (as when exposed to the air it becomes decomposed, and is then
not so suitable for my purpose,) and I mix it with sulphate of soda in suitable
proportion, and heat the mixture so as to obtain a double sulphide of calcium
and sodium.
The following is the manner, in which I prefer to proceed:-I tako 144
parts of the crude sulphate of soda, commonly called salt cake, and I mix it
with from 120 to 130 parts of dry black-ash waste; or instead of using dry
waste I use it fresh from the vats, allowing for the water which it may
contain; and after having well mixed these materials I put them into a close
retort (clay retorts are preferred), and I submit the mixture to a bright red
heat for from 12 to 16 hours, or longer, according to the quantity used at a
time for a charge. Afterwards I draw the charge out of the retort, and when
cold it will be found fit for use. The retorts to be used for this purpose
should have a pipe attached to one end to convey the carbonic oxide gas
produced from the decomposition of the materials into the fire to be burned;
the heat thus created is applied in heating the retorts, the quantity of fuel
required in the retorts will thus be considerably lessened. I may here observe
that the proportions of sulphate of soda and black-ash waste will vary
according to the purity of the waste and the quantity of small coke or carbon
it may contain. If there be too much carbon present the double sulphide
will not be formed so perfectly as when the carbon is just enough to deoxidize
the sulphate of soda, which may be ascertained by analysis. Should it happen
that the black-ash waste contains too little carbon, a sufficient quantity must
be added. Fine coke dust will answer for this purpose. Samples should be
taken from the retorts after the first twelve hours, and examined for sulphate of
soda, so as to ascertain the proper time and heat that a charge may require.

page_text: The process should be continued until practically the whole of the sulphate of
soda is decomposed. The proportions of sulphate of soda and black-ash waste
will be best adjusted for a second operation after an analysis has been made of
the compound produced at the previous operation; but I find that generally
speaking the above proportions work very well. To preserve the product from
the action of the atmosphere, I pack it in air-tight casks for transfer or ship-
ment. When it is required to have a product free from impurity, I dissolve
the crude double sulphide in water in iron vessels by a steam heat, or the
vessels may be heated by a fire; thus I dissolve out all the soluble parts from
the crude material; after allowing the liquor or lyes to settle for a few hours
I run them off into iron pans (such as those used in the manufacture of
caustic soda), and I boil down the liquor until it becomes so highly con-
centrated, that if a little be placed upon a plate of iron and allowed to cool, it
will set hard in a similar way to that in which caustic soda does when finished.
After this the concentrated lye is ladled out on to iron plates to cool, previous
to being packed into casks for use. The double sulphide of calcium and
sodium may also be obtained by heating gypsum with sulphate of soda, lime,
and carbon, but the soda-ash waste I consider the more convenient source.
When I use sulphate of lime (gypsum) I take 186 parts of sulphate of limo,
28 parts of lime, and about 24 parts of coke dust, and 144 parts of salt cake,
and when well mixed up I treat them in the same way as I do the former
compounds of salt cake and black-ash waste. Or I use tho materials in the
following proportions:-186 parts of pure sulphate of lime, (or I employ the
hydrate, and allow for the water of crystallization,) 144 parts of sulphate of
soda, and about 24 parts of carbon, or ground coke.
In place of using retorts, as above described, the double sulphide may be
prepared from the above materials in an ordinary black-ash furnace, such as is
used by soda-ash manufacturers. In doing so I prefer to first fuse or flux the
salt cako in the furnace, and afterwards to add the black-ash waste or sulphate
of lime and carbon, or sulphate of lime, lime and carbon; I work the materials
up with a rake until they are all well fluxed and incorporated. I then spread
over the surface of the melted mass a thin covering of fine coke dust, to
prevent the contact of air, and allow the charge to remain as long as any
carbonic oxide is evolved, or until jets of flame cease to be given off from the
surface, or until they become very few in number. After this I draw the
charge out from the furnace in the same manner as black-ash is now drawn
into an iron barrow, and allow it to cool. I then treat it in other respects as
before described. In using a black-ash furnace for this purpose there should

page_text: be dampers, one to shut off the air from the fire-place while working the
materials in the furnace, and another to regulate the draught of the furnace,
as it is desirable to work with as little draught as possible after the furnace
has been beated up and the salt cake fluxed, or during the time the compound
is undergoing decomposition.
In witness whereof, I, the said Peter Ward, have hereunto set my band
and seal, this Fifth day of March, in the year of our Lord One
thousand eight hundred and sixty-three.
PETER WARD. (LS.)