IMPROVEMENTS IN THE MANUFACTURE OF HYPOSULPHITE OF SODA, HYPOSULPHITE OF POTASH, AND HYPOSULPHITE OF AMMONIA
Year: 1877

page_text: COMPLETE SPECIFICATION filed by William Moody at the Office of the
Commissioners of Patents on the 2nd February 1877.
WILLIAM MOODY, of Walker-on-Tyne, in the County of Northumberland, Agent.
"IMPROVEMENTS IN THE MANUFACTURE OF HYPOSULPHITE OF SODA, HYPOSULPHITE
OF POTASH, AND HYPOSULPHITE OF AMMONIA."
This Invention has for its object improvements in the manufacture of hypo-
sulphite of soda, hyposulphite of potash, and hyposulphite of ammonia. For these
purposes I convert the sulphides of sodium, potassium, and ammonia respectively
into hyposulphite of soda, hyposulphite of potash, and hyposulphite of ammonia.
When I desire to manufacture hyposulphite of soda or of potash, I first prepare a
sulphide of the alkali by heating the sulphate at a blood red heat in an ordinary
reverberatory or other suitable furnace, with an admixture of coal or other carbon-
aceous matter, by which the sulphates are deoxidized and reduced to sulphides.
In practice I mix the sulphate with about one-third of its weight of coal and
with a charge of four hundred weight I continue the heat for about one hour. I
then draw the charge out into boxes or waggons. When cold I break the lumps
into fragments and dissolve in water in such manner as to obtain a solution of
1,300 specific gravity.
The sulphides of sodium and potassium may also be obtained in the following
way-I take the soda or potash liquor resulting from the lixiviation of the balls
produced by the well known balling process of Leblanc in the manufacture of soda
ash or carbonate of potash. This liquor consists of carbonate, sulphide, and caustic
alkali in variable proportions, and the carbonate and caustic alkali I convert into
sulphide by boiling with a considerable excess of sulphur in a fine state of division.
To effect the combination I mix the sulphur with the liquor and boil the same in an
ordinary pan until the carbonate and caustic alkali are changed to sulphide. The
undissolved portion of sulphur I separate by settling.
To obtain the sulphide of ammonium I take the ordinary gas water produced in
the manufacture of coal gas, which contains the sulphide in solution in variable
quantities mixed with tar oil and other organic products of coal distillation. I
allow these to separate as far as practical by their specific gravities, and then I run
the clear liquid containing the sulphide off into tanks conveniently placed for the
purpose.
To convert the sulphides of soda, potassium and ammonium respectively into hypo-
sulphite of soda, potash and ammonia, I expose them to the action of sulphurous

page_text: acid. To effect this I prefer using a tower similar in construction to those used in
soda manufactories for the condensation of hydrochloric acid gas. They consist of
erections 20 to 80 feet high by 4 to 12 fect square, according to the quantity of gas
to be condensed, and built of tarred wood, stone, brick, or other substances not acted
on by acids, and having a foundation impervious to water. This tower I fill with
hard burnt coke, flints, or other substances unacted on by sulphurous acid gas, and
in pieces of such sizes as will allow a current of gas to pass freely between them.
A tower 20 feet high by 5 feet diameter, fitted in the usual way, is sufficient to
produce 10 tons of hyposulphite of soda per week.
To the bottom of the tower I connect by means of a flue or pipe the kilns,
burners, or furnaces usually employed in chemical works for the conversion of
sulphur or the sulphur contained in metallic sulphides into sulphurous acid gas in
the production of sulphurous acid.
The burners or furnaces are charged with sulphur or sulphur ore and ignited, and
the resulting sulphurous acid is made to pass into the tower, on the top of which I
run a current of the solution of the alkaline sulphides, which percolates amongst the
packing in the tower, and coming in contact with the ascending gas absorbs it, and
is converted into hyposulphite of soda, of potash, or of ammonia, according to the
alkaline sulphide used, and then is run from an opening provided at the bottom of
the tower into a cistern to allow any solid matter or sediment to settle. It is then
run into concentrating pans and brought to a specific gravity of 1,400, and then
run into glass or earthenware vessels to crystallize.
In order to explain my Invention as completely as possible I now proceed to
describe the Drawing hereunto annexed, and to the letters of reference marked
thereon.
Figuro 1 is a sectional elevation of the plant required for combining the sul-
phurous acid with the sulphides; a is the tank to contain the solution of sulphide to
be run or pumped on the tower; b is the tower containing coke or other materials
not actod on by acids; c is the flue or pipe to convey the sulphurous acid gas from
the furnace, kiln, or other generator of the gas to the tower; d is the outlet for
the gases not absorbed by the sulphide solution; e is the outlet for the solution of
hyposulphite; and the tank in which to settle the solution previous to concen-
tration and crystallization. This tank is heated by a fire underneath to prevent
crystallization taking place in the liquor before the impurities have settled.
I would state that at the present timo the mercantile demand for hyposulphite of
potash and byposulphite of ammonia is but small, whilst the demand for hypo-
sulphite of soda is very considerable, but an increased demand for the first-
mentioned salts may hereafter spring up.
Having thus particularly described my said Invention and the manner in which
the same may be carried into effect, I have to state that I do not restrict myself to
the preciso details herein described or delineated, but that what I consider to be
novel and original and claim as my Invention is,-
First. The manufacture of hyposulphite of soda, or of potash, or of ammonia
by the treatment of the sulphide of the alkali with sulphurous acid, substantially
as described.
Second. The manufacture of hyposulphites of soda, or of potash, or of ammonia
by causing a solution of the sulphide of tho alkali to trickle over an extended
surface over which a current of sulphurous acid gas is caused to pass, substantially
as described.
In witness whereof, I, the said William Moody, have hereunto set my hand and
seal this Second day of February, in the year of our Lord One thousand