or of otherline Earth.
Year: 1884

page_text: Calcium or of other Alkaline Earth.
I, JOSIAH WYCKLIFFE KYNASTON of 149, Kensington, in the City of Liverpool,
Manufacturing Chemist, do hereby declare the nature of my said invention for
"IMPROVEMENTS IN OR RELATING TO THE MANUFACTURE OF BISULPHITE
CALCIUM OR OF OTHER ALKALINE EARTHS," to be as follows:-
OF
Bisulphite of lime has hitherto I believe only been made, at least on a manufac-
turing scale, up to twelve degrees Twaddle. Bisulphite is largely used in paper
mills; owing to the great bulk of water in the solution, it is requisite to save
expense to manufacture it on the spot. It is therefore a great desideratum to get
a highly concentrated solution, as then it would be possible to manufacture it in
ordinary chemical works, and carry it to the consumers, instead of the paper
makers and others having to manufacture what they severally require.
Now my invention consists in a method by which I am able to get the con-
centration up to about twenty one to twenty two degrees Twaddle.
In the present most improved methods of manufacture, sulphurous gases from
sulphur or pyrites burners are passed through milk of lime, or through water into
which lime is stirred. Now as these gases are largely nitrogen, containing only
about 9 to 11 per cent of SO, the nitrogen has the effect of mechanically driving
off with it the SO,, and it is found impracticable to concentrate further than to
about ten degrees to twelve degrees Twaddle. I find however, that if puro S O₂ be
passed through instead of the mixed gases, a solution of vastly higher concentration
can be obtained. I accordingly form a neutral sulphite of calcium in any well
known method, such as by passing sulphur burner or pyrites burner gas through
water in which lime is agitated, but when the neutral point is reached, instead of
continuing the action, I pass pure SO, through. This I form by treating ordinary
neutral sulphite of lime with hydrochloric acid in a retort or other suitable
vessel. The fumes from this treatment I pass through the mixture of neutral
sulphite of calcium and water till all the neutral sulphite that the acid will take
up is dissolved. Thus, while the ordinary process is a single process, mine is
a double one.

page_text: I first form the neutral sulphite or a weak solution of bisulphite with neutral
sulphite, and second, I add to it the SO, obtained from a further quantity of
neutral sulphite, by treating it with a strong mineral acid.
If this process be objected to on the ground that there is a loss of valuable H Cl,
in the resulting chloride of calcium liquor which is a waste commodity, this loss
can be obviated by making sulphite of magnesia instead of lime for the source
of S O₂, and driving off the sulphurous acid for use by means of heat in a retort.
This process is equally applicable for manufacturing the bisulphites of other
alkaline earths, but these are in but small demand.
WM P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, and
323, High Holborn, London,
Agents for the Applicant.

page_text: Improvements in or relating to the Manufacture of Bisulphite of
Calcium or of other Alkaline Earth.
I, JOSIAH WYCKLIFFE KYNASTON of N° 149 Kensington, Liverpool in the
County of Lancaster Analytical Chemist do hereby declare the nature of my
said invention for "IMPROVEMENTS IN OR RELATING TO THE MANUFACTURE OF
BISULPHITE OF CALCIUM OR OF OTHER ALKALINE EARTH and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement :-
23
The production of bisulphite of calcium of the very highest possible degree of
concentration and at a very low cost has, through its recent introduction as an
agent in obtaining paper pulp from wood, become a matter of vast importance.
All attempts hitherto made to produce it at a sufficiently low cost, and of such
high strength that it would bear the cost of carriage from the chemical manufac-
turer to the paper mill, have hitherto failed, and the paper maker has been
compelled, at much inconvenience to produce it on the spot.
By my new process, now to be described, I obtain bisulphite of calcium of a
higher density than it has hitherto been produced on a manufacturing scale,
namely, from 24 to 26 degrees Twaddle, or of specific gravity from 1.120 to 1·130
and I can use as the source of sulphur the very cheapest substances containing it
such as ordinary sulphur pyrites blende coal brasses or gas lime.
The dilute sulphurous acid gas obtained by calcination or burning of any of
these substances or by the combustion in air of brimstone sulphur, in the ordinary
burners or kilns in common use for the purpose is brought into contact with milk
of lime of a density of from 5 to 6 Twaddle when newly agitated, either by
drawing it through the mixture by means of an aspirator, an ejector or an air
pump, or by forcing air into specially constructed burners at such pressure as will
overcome the resistance of the column of absorbing liquid, or, and this is the mode
I prefer, I use as the absorber a flag stone tower constructed exactly as the
hydrochloric acid towers in common use in Alkali Works, except that in place of
the usual coke packing, the packing must be of open or pigeon-hole brickwork, the
alternate layers crossing each other, and the one layer partially obstructing the
free passage left in the course below. The milk of lime is pumped up to a cistern on
the top of the tower and must be kept in agitation. The arrangement for running
it down the tower may be any kind of distributor which will not permit of the
separation or deposition of the lime from the water. The dilute sulphurous gas
then passing into the tower at the bottom ascends through the open brickwork
packing and meeting the descending current of lime mixture the sulphurous acid is
abstracted from the other gases, and the latter are drawn away from the top of the
tower by a connection with a chimney stack which maintains a draught through
the whole apparatus.
The proportion of milk of lime run down the tower may be so regulated that
from the bottom there runs an aqueous mixture of neutral sulphite of calcium,
but I prefer that, as it issues from the tower it contain a small proportion of
sulphurous acid in excess,

page_text: The mixture of the very insoluble neutral sulphite of calcium and water is
caught in a lead cistern placed near the bottom of the tower, when the sulphite
quickly settles down and the supernatant liquid, (which if the mixture running
from the tower was slightly acid, holds in solution any arsenic absorbed from the
gases) may be run away.
The pasty mass of neutral calcium sulphite is then removed from the settler and
divided into two equal parts. The one part is transferred to a stone or lead lined
iron vessel and there mixed with so much water as that the mixture when
thoroughly agitated shall contain eight and a balf to nine lbs of real calcium
sulphite (Ca SO₁) per cubic foot. The other portion of the pasty mass is trans-
ferred to a stoneware still constructed similarly to the chlorine stills in common
use in Bleaching powder works, but more strongly braced, so as to withstand
pressure. A pipe connection from the top of this still leads to the bottom of the
vessel containing the mixture of the first portion of calcium sulphite and water
where it is terminated by a distributor. The openings now being securely closed,
hydrochloric acid is run into the still either from a cistern placed at a sufficient
height above, or by means of a force pump, in sufficient quantity to completely
decompose the calcium sulphite, and the sulphurous acid is finally driven off by
blowing steam into the mixture. The pure sulphurous acid gas liberated passing
into the watery mixture of sulphite is absorbed, and there is obtained a solution of
bisulphite of calcium completely saturated and testing about 25 degrees by
Twaddle's hydrometer. After being allowed to stand at rest until the insoluble
matters have settled down, the clear solution of bisulphite is drawn off.
If, this process be objected to on the ground that there is a loss of valuable H CI,
in the resulting chloride of calcium liquor which is a waste commodity, this loss
can be obviated by making sulphite of magnesia instead of lime for the source
of S O₂, as then. magnesium chloride is the residuum from which the hydrochloric
acid can be extracted in well known ways. This process is equally applicable for
manufacturing the bisulphites of other alkaline earths, but these are in but small
demand.
This process is also applicable for the manufacture of other bisulphites but they
are rarely wanted. It must be understood however throughout this specification
that when the word calcium is used other alkaline earth metals could be substituted
if their bisulphites be required, and also that I do not bind myself to the exact
details of working herein set forth.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
The production of a highly concentrated solution of bisulphite of calcium by
producing first a neutral sulphite of calcium by means of dilute sulphurous acid
gas, and afterwards converting the neutral sulphite into bisulphite by the use of
concentrated sulphurous acid gas in the manner substantially as described.