Improvements in or appertaining to the Manufacture of Alkali.
Year: 1891

page_text: Date of Application, 4th Apr., 1891
Complete Specification Left, 4th Jan., 1892-Accepted, 13th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in or appertaining to the Manufacture of Alkali.
We, ARTHUR GEOFFREY HADDOCK of Ditton, in the County of Lancaster,
Fellow of the Institute of Chemistry, and JoHN LEITH of Knowsley Road,
St. Helens, in the same County, Manufacturing Chemist, do hereby declare the
nature of this invention to be as follows:-
:-
In our Specification No. 11296%, we have described a process for obtaining
carbonate of soda, sulphate of lime & sulphuretted hydrogen.
The present application is for improvements thereon.
In order to avoid having to wash the refuse of the Le Blanc alkali waste or other
calcium compounds used after having been treated with sulphuretted hydrogen, we
drain off the calcium sulphydrate liquor, agitate the residue with an equal quantity
of water, which is drained off & used to make another batch of vat waste or
other cream; and then add to the residue a further quantity of water sufficient to
make into a thick cream. We then pass CO, (the lime kiln gas on its way to the
carbonators) through it.
The H,S & CO, which escape pass into the carbonators. The water is drained
off & may be used repeatedly for a similar purpose or any other convenient
purpose. The residual waste is quite free from any smell of H₂S (sulphuretted
hydrogen).
We treat the sulphate of lime in a similar manner. When the calcium
sulphydrate & sodium sulphate liquors are mixed, sulphate of lime is precipitated
very quickly. We then draw off the clear sodium sulphydrate liquor & add water
to the precipitate & agitate, this will wash most of the sodium sulphydrate out &
the weak liquor is drawn off. We then add a further quantity of water to the
precipitate & pass CO2 (the lime kiln gas) through the mixture until it is free
from smell of HS. The escaping HS & CO, are passed through the carbonators
& the calcium sulphate freed from the weak liquors by a centrifugal machine, filter
press or other convenient means.
It is most important for our process & others similar that the CO, from the lime
kiln be free from oxygen before reaching the carbonators.
To effect this, we bring the CO, to a high temperature, either by circulating it
round the hot part of the lime kiln, or it may be passed through pipes or a stove
heated externally. Just previous to heating, we add a quantity, sufficient to take
up the oxygen, of water gas, coal gas, petroleum, or other inexpensive hydro-
carbons. The oxygen combines with the combustible matters in passing through
the heated pipes or chambers & is replaced by CO₂ or water.
When Le Blanc alkali waste or other calcium compounds are not conveniently
obtained, we heat the sulphate of lime produced (as before described) intimately
mixed with ground coal in a furnace or kiln out of contact with air to beyond the
decomposing point, CO, is produced which may be passed to the carbonators &
sulphide of calcium which can be used for the further production of sulphydrate of
calcium.
The advantages of using the sulphate of lime in this way are:-
1st. A pure article is used for the production of sulphydrate of calcium, conse-
quently there is no waste sludge left behind.
2nd. The manufacturer is independent of a Le Blanc process or other supply of

page_text: 3rd. If our process comes into very extended use, the supply of calcium sulphate
would probably exceed the demand. By adopting this modification, the amount
of calcium sulphate placed in the market can be regulated according to the demand
for it.
Dated this 3rd day of Anril 1891
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in or appertaining to the Manufacture of Alkali.
We, ARTHUR GEOFFREY HADDOCK of Ditton, in the County of Lancaster,
Fellow of the Institute of Chemistry, and JOHN LEITH of Knowsley Road,
St. Helens in the same County, Manufacturing Chemist, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
In our Specification No. 11296, we have described a process for obtaining
carbonate of soda, sulphate of lime, and sulphuretted hydrogen.
The present application is for improvements thereon.
In order to avoid having to wash the refuse of the Le Blanc alkali waste, or
other calcium compounds used, after having been treated with sulphuretted
hydrogen, we drain off the calcium sulphydrate liquor, agitate the residue with
water which is also drained off and may be used to make another batch of vat waste
or other cream, we then add to the residue a further quantity of water sufficient
to make into a thick cream and pass carbonic acid gas (on its way to the
carbonators) through it.
The sulphuretted hydrogen and carbonic acid, which escape, pass into the
carbonators. The water is drained off and may be used for any convenient purpose.
The residual waste is quite free from any smell of sulphuretted hydrogen.
We treat the sulphate of lime in a similar manner. When the calcium
sulphydrate and sodium sulphate liquors are mixed, sulphate of lime is precipitated.
After settling, we draw off the clear sodium sulphydrate liquor, and add water to
the precipitate and agitate; (this will wash most of the sodium sulphydrate out)
and the weak liquor is drawn off. We then add a further quantity of water to
the precipitate and pass carbonic acid through the mixture until it is free from
smell of HS. The escaping sulphuretted hydrogen and carbonic acid are passed
through the carbonators, and the calcium sulphate freed from the weak liquors
by a centrifugal machine, filter press or other convenient means.
It is most important, for our process and others similar, that the carbonic acid
used be free from oxygen before reaching the carbonators.
To effect this, we add, to the carbonic acid at a high temperature, water gas or
hydrogen, coal gas, petroleum or any inexpensive oils or hydrocarbons. The gas
or oil may be added to the carbonic acid in the hot lime kiln chamber, injected into
a pipe or chamber heated externally. The oxygen combines with the combustible
matters in passing through the heated pipes or chambers, and is converted into
carbonic oxide, carbonic acid or water.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
:―
1. The treatment of the residues from the calcium sulphydrate liquor, and of
the hydrated sulphate of lime, to remove sulphur remaining in them, as sulphuretted
hydrogen, by means of carbonic acid gas, in excess, such excess afterwards being
absorbed in the soda carbonating vessels.

page_text: 2. The elimination of free oxygen from carbonic acid gas by the addition to it
of petroleum or other hydrogenous fuel, such as described, at a sufficiently high
temperature to bring about the union of the free oxygen with the hydrogen, or
with the hydrogen and carbon, for the purposes specified.
Dated this 2nd day of January 1892.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.