IMPROVEMENTS IN THE MANUFACTURE OF Sulphite of Soda
Year: 1884

page_text: We EUSTACE CAREY and HOLBROOK GASKELL the Younger both of Widnes in
the County of Lancaster, Alkali Manufacturers do hereby declare the nature of
said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF Sulphite of Soda "
which Invention is partly communicated to us by Ferdinand Hurter, at present
residing in Paris, France, to be as follows:-
Our Invention has for its object to manufacture at a low cost Sulphite of Soda
suitable for use in the manufacture of paper or for other purpose to which it may
be applicable.
According to our said Invention we employ in the said manufacture of Sulphite
of Soda "Salts" or crystallized monohydrated carbonate of Soda.
The said salts may for the purposes of this Invention be obtained in any suitable
way for example by evaporation by heat of those solutions of soda named in the
Specifications of the Letters Patent granted to Eustace Carey, Holbrook Gaskoll
Junior and Ferdinand Hurter on the 18th day of July 1879 N° 2939 the 11th day
of January 1881 N° 608 and the 17th day of March 1881 N° 1161 the said Alkaline
Solutions having been first purified by the processes named in the Specifications of
the said Letters Patent-Or for certain purposes where colour and purity are not
of importance the "Salts" may be those obtained in the Le Blanc process by the
evaporation by heat of the solution of crude carbonate of soda known as vat
liquor" or "tank liquor" or they may be "Salts" obtained by the evaporation by
heat of other solutions of Carbonate of Soda.
st
To the said "Salts" by whichever method obtained we add if necessary a small
quantity of water or of steam and expose the said "Salts" in suitable vessels to
the action of sulphurous acid gas obtained in any convenient way for example by
burning sulphur or pyrites-This treatment of the "Salts" with sulphurous acid
gas is continued until they are sufficiently converted into Sulpbito of Soda which is
applicable for use in the manufacture of paper or other purpose where it is not

page_text: necessary that the Sulphite should be of high test as although the said Sulphite is
very readily and cheaply manufactured by the process constituting our Invention
as herein before described it will not be uncontaminated with bicarbonato of Soda
or other impurities but these impurities will not render the sulphite of Soda
unsuitable for use for certain purposes such for example as for employment in the
manufacture of paper.

page_text: We EUSTACE CAREY and HOLBROOK GASKELL the younger both of Widnes in
the County of Lancaster Alkali Manufacturers do hereby declare the nature of
this Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SULPHITE OF SODA"
which Invention has been partly communicated to us from abroad by Ferdinand
Hurter at present residing in Paris, France, and in what manner tho samo is to
be performed to be particularly described and ascertained in and by the following
statement:-
Our Invention has for its object the manufacture at a low cost of sulphite of
soda suitable for use in the manufacture of paper or for other purpose to which it
may be applicable.
According to our said Invention we employ in the said manufacture of Sulphite
of Soda, "Salts" meaning thereby monohydrated carbonate of Soda. The said
"Salts" may for the purposes of our Invention be obtained in any suitable way,
such for example as by evaporation by heat, of those solutions of soda named in
the Specifications of the Letters Patent granted to Eustaco Carey, Holbrook Gaskell
Junior and Ferdinand Hurter on the 18th day of July 1879 No 2939, the 11th day
of January 1881 N° 608 and the 17th day of March 1881 N° 1161 the said alkaline
solutions having been first purified by the processes named in the Specifications of
the said Letters Patent; or for certain purposes whero colour and purity aro not of
importance the “salts may be those obtained in the Le Blanc process by the
evaporation by heat of the solution of crude carbonate of soda known as
"vat
liquor" or "tank liquor" or they may be "salts" obtained by the evaporation by
heat of other solutions of Carbonate of Soda.
To the said "salts" by whichever method obtained we add if necessary a small
quantity of water or of steam, and expose the said "salts "in suitable vessels to
the action of sulphurous acid Gas, obtained in any convenient way for examplo by
burning sulphur or pyrites. This treatment of the "salts" with sulphurous acid
gas is continued until they are sufficiently converted into sulphite of soda which is
applicable for use in the manufacture of paper or other purpose where it is not
necessary that the sulphite should be of a high test as although the said aulphite is
very readily and cheaply manufactured by the process constituting our Invention
as hereinbefore described, it will not bo uncontaminated with bicarbonate of soda or
other impurities but these impurities will not render the sulphite of soda unsuitable
for use for certain purposes such for example as for employment in the manufacture
of paper.
We do not limit ourselves to any particular form of apparatus in which to carry
ou the process according to our Invention, as any suitable apparatus may be
employed for this purpose, but we will describe a form which is suitable for the
purpose-It is shewn in the annexed sheet of drawings in side elevation in Figure 1,
end elevation in Figure 2, and plan in Figure 3-The iron Cylinder A (which if

page_text: Sulphite of soda of great purity is required may be lined with lead) is capable of
being rotated upon a horizontal axis-The Cylinder is provided with hollow
trunnions or axes supported by and capable of turning in bearings a carried by a
suitable framework a.
The hollow trunnion at one end of the cylinder A is used for admitting
sulphurous acid gas and that at the other end for permitting the exit of excess of
sulphurous acid, of carbonic acid, of nitrogen, and of moisture-The said hollow
trunnions are continued by pipes entering into the interior of the cylinder, and
there turned at or about right angles to the axis of the Cylinder A as shewn at b
for the purpose of avoiding the lodgment therein of solid material and the
consequent stoppage of the free passage of the gas into or from the Cylinder A.
We find it advisable to have an aperture in the Cylinder A and in the exit
pipe C as shown at e e, which apertures can be closed air tight in any convenient
manner, and. through the said aperture which is in the cylinder, the part 6 of the
exit pipe C which is inside the cylinder A, may be cleaned easily and freed from
dust which is sometimes deposited there.
Having described a form of apparatus suited for the purposes of our invention
we will proceed to describe the method of working which we find advantageous.
The charge of "Salts" is introduced into the Cylinder A through an aperture
provided for that purpose which is then closed-The Cylinder is inade to revolve
slowly by any suitable means such for example by means of a pulley F and spur
gearing G driven by any suitable motor.
We find from 2 to G revolutions of the Cylinder per minuto are sufficient.
Sulphurous acid Gas is admitted into the interior of the Cylinder A by the
pipe y and the Sulphurous acid is absorbed by the charge.
The progress of the operation may be ascertained by withdrawing and testing a
sample from time to time-We find that when a sample contains from 36 to 40 per
cent of Sulphurous acid, the product practically answers all the purposes of a mono-
'sulphite of soda, and the process is then stopped and the charge withdrawn.
If strong sulphurous acid be used such as is obtained by treating sulphuric acid
with coke or with sulphur, one such Cylinder A is sufficient, but when sulphurous
acid mixed with nitrogen is used, as it is when obtained by the combustion in
atmospheric air of sulphur or pyrites or sulphuretted hydrogen, then the absorption
is not completo in one cylinder, and the gases leaving the cylinder A by the exit
pipe C still contain sulphurous acid, These gases may be passed through one or
more cylinders similarly constructed and so arranged that any one of them may be
connected directly to the source of supply of sulphurous acid or be made to receivo
the gases from another cylinder of the series or be isolated for discharging and
charging as required, Or the Gas escaping from the Cylinder A may be passed
into a sulphuric acid Chamber.
If the sulphurous acid be obtained by the combustion of pyrites or brimstone, it
is advisable to pass it through a dust chamber before allowing it to enter the
Cylinder A, so that any dust may be first deposited. If the Sulphite of Soda bo
desired of great purity it is also necessary to wash the Sulphurous acid by passing
it through a small tower, (U, Figuro 3,) lined with lead and filled with Coke.
The Gas passes in an upward direction through the tower and meets a very
small stream of hot water-When the gas has thus been washed it must be dried.
For this purpose the gas passes in an upward direction through a similar tower V
filled with coke, where the gas mects a stream of sulphuric acid which absorbs the
moisture.
But when great purity of the sulphite of Soda is not required we omit the
washing and drying of the sulphurous acid gas except when it is obtained by
the combustion in air of sulphuretted hydrogen in which case the gases must be
dried.
When the Cylinders are worked in series it may be found necessary to dry the
gas on passing from one cylinder to the next; for this purpose the gas may be

page_text: passed through a coke tower V as before described which may be placed between
the cylinders, or the gas may be dried in any other convenient manner.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what
we claim is
.
The manufacture of Sulphite of Soda, by exposing "Salts" to the action of
Sulphurous acid gas, substantially as bereinbefore described.