IMPROVEMENTS IN THE MANUFACTURE OF SODA AND POTASH, AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Max Karl Georg Lieber at the Office
of the Commissioners of Patents on the 4th December 1877.
MAX KARL GEORG LIEBER, of Widnes, in the County of Lancaster, Chemist.
"IMPROVEMENTS IN THE MANUFACTURE OF SODA AND POTASH, AND IN THE
APPARATUS EMPLOYED THEREIN."
This Invention relates to the manufacture of soda and potash, and consists in the
conversion of the sodium and potassium chlorides into sodium and potassium
carbonates respectively, by means of alumina, sulphuric acid and superheated steam,
in the manner and by the apparatus I shall now proceed to describe.
To effect this two different methods may be employed, namely
First. Sodium or potassium chloride, sulphuric acid, aluminium hydrate and
alumina are mixed together with as much water as may be required to make a
paste. The paste obtained is broken into small pieces, dried, and then brought into
the sulphate cylinders, which are heated by the waste heat of the aluminate
cylinders.
Hydrochloric acid is evolved, and to effect a decomposition as complete as
possible superheated steam is passed through the mass towards the end of the
operation. The hydrochloric acid is condensed in the usual way. In the cylinders
the mass obtained is a mixture of sodium or potassium sulphate and alumina,
the whole of which is withdrawn and brought into the aluminate cylinders. Here
superheated steam is passed through, the sulphuric acid (of the sulphate) is de-
composed, and the products of the decomposition, chiefly sulphurous acid, are
evolved.
If no more sulphurous acid is liberated the conversion of the sulphate into
aluminate is completed; then the aluminate is withdrawn and lesiviated with
water, whereby the alumina added in excess is separated.
The liquors containing the sodium or potassium aluminate are treated by means
of carbonic acid gas, which precipitates aluminium hydrate, leaving sodium or
potassium carbonate in solution.
The alumina obtained by the lesiviation of the product drawn from the aluminate
cylinders and the aluminium hydrate precipitated by the carbonic acid, as well as

page_text: the sulphurous acid gas evolved during the heating process, may be used again in
the process in a continuous circuit
Without being converted into sulphuric acid, the sulphurous acid may be used in
the process directly.
To effect this I employ a second method.
Second. Sodium or potassium chloride, aluminium hydrate, and alumina are
mixed with water and prepared as before stated. The mass obtained is brought
into the sulphate cylinders, which are connected with each other by pipes; then the
products of decomposition of the sulphuric acid evolved from the aluminate
cylinders, superheated steam and air are passed through, thus forming, supported
by a slight heating of the cylinders from outside, a mixture of alcali sulphate,
aluminium sulphate, and alumina, whilst hydrochloric acid is evolved. The
resultant mixture then is converted into sodium or potassium aluminato, and after-
wards treated precisely in the before-mentioned manner.
Instead of employing alumina for the before-mentioned purposes may be also
used native compounds, as bausite, diaspore, gibbsite, etc.
=
The apparatus employed for the conversion of the sodium or potassium chlorides
into sodium or potassium aluminates consists in two furnaces, which I call the
sulphate furnace and the aluminate furnace, which may be described as follows:-
The sulphate furnace consists of a series of vessels, which I make of any suitable
material, as cast iron or fire-clay; by preference, I make them of a cylindrical
form.
These vessels which I call the sulphate cylinders are heated either by direct fire or
by the waste heat from the aluminate furnace, and may be either connected with
each other by pipes or worked separately accordingly as I am using either
sulphurous or sulphuric acid to effect the decomposition.
The pipes for carrying away the hydrochloric acid gas evolved may be arranged
in any convenient way.
The aluminate furnace consists in a series of closed vessels or retorts, which I
make of iron or fire-clay, and the superheater for heating the steam, which after
being heated is brought into the retorts.
The heat for the retorts is produced by any known form of gas generator, the
gases of combustion from which are taken round the aluminate retorts, thence to
the steam superheater, thence to the sulphate cylinders, and afterwards, if there is
any available heat left, it may be used for any purposes I may require, such as a
drying the mixtures or evaporating the liquors, and thence to the chimney
1 claim as the principle of my Invention the production of sodium or potassium
carbonates by treating sodium or potassium chlorides in the manner and by the
apparatus herein-before described, but I do not confine myself precisely to the exact
arrangement as herein set forth, which I may vary from time to time without 4
affecting the principle of my Invention.