PROCESS AND APPARATUS FOR THE PRODUCTION OF CHLORIDE GAS AND OF METALLIC SODIUM BY THE DECOMPOSITION OF CHLORIDE OF SODIUM THROUGH THE AGENCY OF DYNAMIC ELECTRICITY
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by André Léopold Nolf at the Office
of the Commissioners of Patents on the 12th September 1882.
ANDRÉ LÉOPOLD NOLF of Brussels in the Kingdom of Belgium, Chemist
PROCESS AND APPARATUS FOR THE PRODUCTION OF CHLORIDE GAS AND OF
METALLIC SODIUM BY THE DECOMPOSITION OF CHLORIDE OF SODIUM THROUGH
THE AGENCY OF DYNAMIC ELECTRICITY
"
My Invention relates to certain means and apparatus for decomposing Chloride
of Sodium by dynamic electricity into two constituent elements, viz-Sodium and
Chlorine, the decomposition being effected by means of a special form of vat
or trough into which is placed the solution of Chloride of Sodium to be acted
upon.
The various effects produced simultaneously by the "Nolf" apparatus are as
follows: The Sodium is reduced to a metallic state and prevented whilst in that
state from decomposing the water in the solution in which it is placed; the
Chlorine is allowed to disengage itself in a gaseous state so that it may be easily
collected; all polarization of the electrodes in the bath which is subjected to
decomposition is prevented; the solution of Chloride of Sodium is always main-
tained at the same degree of concentration without the necessity of stopping the
decomposition for a single moment.
The following is a description of the apparatus, reference being had to the three
Figures of the annexed drawings.
A is a trough made of hard wood its interior being coated with a varnish which
will resist the action of the Chlorine.
B is the bottom of trough formed of sheet iron perfectly flat.
C is a rin or flange of sheet iron which encircles the whole of the vat or trough
forming a rim or ledge on its outside of about 8 or 10 centimetres onto which the
cover of the apparatus is bolted.
D is the cover also formed of sheet iron slightly domed and perfectly adjusted
to the rim or flange.
E are bolts placed at equal distances around the whole circumference of the
cover and which when once tightened up should ensure a hermetic closing. An
•
17

page_text: india rubber ring is placed between the cover and the rim or flange to secure this
perfect closing.
G is a vertical iron shaft or axle passing through the centre of the apparatus
cover.
H is an axle or shaft formed of hard wood perfectly true and fixed solidly to
the iron axle of which it forms the continuation.
I is a stuffing box in which the axle G revolves freely whilst at the same time
maintaining a hermetic closing.
J is a cast iron sleeve enclosing the lower end of the wooden axle H, the upper
part L L of the sleeve is arranged in the form of a cross to support four wooden
arms, hereinafter described.
K is a bearing fixed to the bottom of the vat or trough.
M M are arms formed of hard wood strongly fixed by means of bolts N N, to
the cross of the iron sleeve. 0, 0, are pieces of gas-retort carbon 30 centimetres
long, 10 centimetres wide and 3 or 4 centimetres thick; passing through the
wooden arms M they project a short, distance above the upper part and are
fastened to the arms in such a manner as not to move in any way. These carbons
form the positive electrode of the decomposing bath.
ii represent a layer of mercury one centimetre in thickness resting on and
covering the bottom of the apparatus and forms the negative electrode of the bath.
P is an iron tube of 5 centimetres interior diameter bent like a syphon and
provided with a cock also made of iron, for emptying the Mercury when required.
Qis a Mercury pressure guage for indicating the pressure which may be formed
inside the apparatus.
R is an iron tube 1 centimetre in diameter rigidly fixed to the cover which it
traverses and passes down to within 2 millimetres of the bottom of the apparatus.
This tube is for the purpose of charging the apparatus with Mercury when
necessary and its upper part is widened out in the form of a funnel.
S is a leaden tube 3 centimetres interior diameter fixed on the cover and serving
for the escape of the Chlorine gas.
T is the gearing for communicating a slow and regular rotary motion to the
verticle axle.
U is a partition of thin wood fixed rigidly to the inside of the wooden trough
and serving to produce a continuous stirring of the solution when the agitator is
in motion. This partition is called a "depolariser" because the stirring it
produces presents any adherence of bubbles of gas to the surface of the
electrodes.
V is a glass tube of small diameter passing through the apparatus cover and
resting on the layer of Mercury on the bottom. In this tube is a copper wire
which puts the layer of Mercury in the apparatus into communication with the
negative pole of a dynamo-electric machine.
X is a copper ring fixed to the axle G but at the same time completely insulated
therefrom by an intermediate sleeve of india-rubber or gutta percha.
Y is an iron piece fixed at its base to the cover but completely insulated there-
from, its upper part carrying a flat brush of silvered copper wire which impinges
against the circumference of the ring X. This brush is put into communication
with the positive pole of the dynamo-electric machine by means of a copper
conducting wire.
a is a small vertical groove on the iron axle commencing at the place where the
ring X is fixed and terminating at the lower end of the iron axle.
b is a platinum wire fitting into the groove a from which it is insulated, and
serving to conduct the electric current from the ring X to the upper part of
all the carbons 00 to which it is firmly fastened by means of clips or fasteners
of any kind. When the contacts are perfectly established, the platinum wire, the
clips or fasteners, and all the other points of contact are carefully covered or
coated with a mastic varnish not affected by the Chlorine. It is also essentially
necessary to ensure the perfect insulation of the platinum wire froin the cross LL

page_text: of the pivot sleeve. e e are tubes of vulcanized india-rubber 8 centimetres
interior diameter fixed to and passing through the cover. The bottoms of these
tubes are made very thick and they are pierced with a number of small holes up
to about 10 centimetres from their bottom. The upper part of these tubes is
slightly widened or funnel shaped. They are kept constantly filled with Chloride
of Sodium and are called "alimentary tubes" their object being to always maintain
the solution under decomposition at the same degree of concentration.
manner.
Having thus completely established the apparatus, the cover is well bolted on,
and a concentrated solution of Chloride of Sodium in a cold state is allowed to
flow into the apparatus by means of an india-rubber tube arranged in any suitable
When it has reached a height of 20 centimetres the inlet cock is closed
and a dynamo-electric machine (which should be placed as near as possible to the
apparatus) is put in motion. A slow and regular motion is imparted to the
axle G when the decomposition of the Chloride of Sodium instantly cominences.
The liberated Sodium is attracted to the negative electrode : e: the Mercury,
with which it forms an amalgam which preserves it from any decomposing action
on the water; whilst the Chlorine in a gaseous state finding no body at the positive
electrode with which it can combine, disengages itself abundantly, flowing through
the escape tube S in the cover.
The Sodium or the amalgam of Sodium is collected by simply opening the cock
on the small emptying tube P at the bottom of the apparatus. This amalgam is
very fluid when care is taken not to allow it to become charged with too much
Sodium, and it flows of itself towards this tube by slightly tilting the whole
apparatus.
When the Mercury charged with Sodium has been extracted and the apparatus
placed upright, the inlet tube R is opened allowing a fresh charge of pure Mercury
to flow to the bottom of the apparatus. The general arrangement of the apparatus
is such that the two operations effected by one attendant are completed without
the necessity of stopping the dynamo-electric machine. The Sodium contained in
the amalgam is then utilized as required.
As regards the gaseous Chlorine, it is conducted by the escape tube S to the
place where it is required to be used.