of the Alkaline Earths, and in Apparatus therefor.
Year: 1887

page_text: Date of Application, 17th Dec., 1887
Complete Specification Left, 16th Oct., 1888
Complete Specification Accepted, 23rd Nov., 1888
[Communicated from abroad by Professor CURT NETTO, of 16, Lindenaustrasse,
Dresden, in the Empire of Germany, Engineer.]
of the Alkaline Earths, and in Apparatus therefor.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature
of this invention to be as follows:-
My invention especially relates to improvements upon the process of manufacturing
sodium, and apparatus therefor, described in the previous Specification filed at the
Patent Office on the 26th of October 1887 and numbered 14602 which contains a
description of an intermittent method of working. Since filing the said former
Specification it has been found that a continuous process is more conveniently worked
and effects a considerable saving in the cost of manufacture.
In the manufacture of sodium by means of caustic soda, and carbonaceous matters,
a portion only of the total amount of sodium contained in the soda, is given off in the
form of vapours, the rest remaining in the crucible, the retort, or the receiver, in the
state of carbonate of soda. This carbonate of soda can only produce sodium,
under the condition of raising its temperature very high, which has the disadvantage
of seriously affecting the retorts or other apparatus in which the reaction takes
place.
Moreover, for the reason above stated, if the temperature is not raised, the reaction
soon stops, and a mass of carbonate of soda remains in the retort which must
be got rid of if it is desired to again place the apparatus in a state to produce
sodium.
My improvement consists in obtaining a continuous production of sodium, by
allowing the carbonate of soda to escape as fast as it is produced, and by introducing
into the receiver or other apparatus continuously, caustic soda, which continually
replaces that which has served for the production of the sodium and the residual
carbonate of soda.

page_text: For this purpose I employ the apparatus hereinafter described which may, however,
be modified in form, or the details of arrangement, so long as a continuous discharge
of the carbonate of soda formed, and a continuous introduction of caustic soda, is
provided for, for the purpose above stated.
DESCRIPTION OF THE APPARATUS.
The apparatus consists in a retort or receiver of any suitable shape, preferably in a
retort of a vertical type, provided with a cover, or any removable means for closing
the same.
In the interior of this receiver are the bodies which are to cause the
reaction. In the upper part is an aperture or hopper by means of which the apparatus
can be fed with carboniferous materials. An arrangement of double doors, or means
for closing, allows this operation to be carried on during the working of the apparatus,
without interfering to any extent with the liberation and condensation of the sodium.
Near the upper part of the receiver is fixed a condenser similar to those usually
employed in the manufacture of sodium, and towards the upper part of the apparatus
an aperture is provided which places the receiver in communication with a reservoir
intended to contain the soda.
It is obvious that precautions are to be taken to prevent the escape of the sodium
vapours anywhere else than through the condenser.
Near the lower part of the apparatus is an aperture in which is fixed a waste pipe,
which allows the residual carbonate of soda to be continuously discharged. This
waste pipe can be bent so as to form a kind of hydraulic joint, preventing the entrance
of air, and allowing a continuous discharge of the carbonate of soda, and of the
caustic soda that may have escaped the reaction, to take place.
In place of the above described arrangement of bent waste pipe, any other
arrangement which accomplishes the same result may be employed.
The apparatus is so arranged that it can be heated, so that the bodies contained
in it may be raised to a suitable temperature, without interfering with the above
mentioned objects.
The above described improved apparatus is equally applicable to the manufacture of
potassium or any of the metals obtained from the alkaline earths.
Dated this 17th day of December 1887.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: If the reaction would actually take place according to this formula, a comparatively
low temperature (bright red heat) would suffice for the reduction.
During the process, however, a gradual but considerable increase of temperature is
required in order to keep up the production of sodium. This necessity of increasing
the temperature is due to the intermediate formation of carbonate of soda; the actual
reaction taking place may be expressed by the following formula :-
That is to say, whilst, at the commencement of the process, caustic soda alone is
decomposed by the carbon ; at a more advanced stage, the reduction is extended also
to the carbonate of soda mixed with the caustic soda.
As the carbonate of soda requires for its reduction a much bigher temperature than
the caustic soda, it is evident that, with the increase of carbonate in the charge, the
temperature for reduction must also be increased.
The required high temperature, however, besides involving great consumption of
fuel, has the considerable disadvantages that only wrought iron or cast steel can be
used for the reducing vessels or retorts, and even these materials suffer so much
that they have to be exchanged after a few operations, and a continuous working
cannot be effected.

page_text: By ny present invention I provide for the production of sodium at a comparatively
low temperature by
(a). The separation of the carbonate of soda at the ratio in which it is formed from
the caustic soda, which is introduced into the retort (or other apparatus) in a continuous
thin stream upon the incandescent or heated coal or coke, thus continually replacing
the caustic soda which has served for the production of the sodium, as well as that
which has been converted into carbonate.
(b). The removal, either intermittently or continuously, from the apparatus, of the
residue of the process (consisting chiefly in carbonate of soda) without interrupting
or even disturbing the reduction process.
I prefer that the removal of the residue should be carried on continuously.
In this manner I ensure that only the first stage of the process of reduction takes
place, that is to say, that the reduction extends only to the caustic soda, consequently
the process may be carried on at a comparatively low temperature and furthermore
the production of sodium effected as long as the apparatus lasts, without other
interruption than that required for the introduction of fresh supplies of carbonaceous
matter, which stoppages may be avoided by the arrangement hereinafter described.
The arrangement for the removal of the residue must be such as to exclude the
possibility of atmospheric air entering the apparatus from below during the process,
because the said apparatus is filled with gases of hydrogen, of sodium and of
carbonic oxide, which in contact with a current of air would easily cause an explosion.
The safest and at the same time the simplest method of accomplishing the desired
result is to employ a hydraulic discharge or trap.
It is necessary, moreover, to provide for the efficient control of the supply or
admittance of caustic soda to the retort, so that the quantity introduced may be
increased or diminished at will according to the greater or less velocity with which
the reduction takes place, or, if required, the admittance of caustic soda may be
entirely stopped.
In the accompanying drawing I have illustrated a convenient form of apparatus
for carrying on my improved process.
Figure 1 is a vertical central section of the said apparatus.
Figures 2, 3 and 4 show modifications of the device for the discharge of the
carbonate. a is the furnace, the retort, which is made of cast iron or other
suitable material and is provided with a cover chaving an opening to
permit the charging of the retort with charcoal;: coke or other suitable carbonaceous
material.
The opening e¹ is closed by a cover c² which need not be fixed, its gravity being
sufficient to hold it down. d is a hopper or funnel for the introduction of the
molten caustic alkali into the retort.
e is a vessel or receptacle for containing the molten caustic alkali to be fed into
the retort. This vessel e is arranged in or above a flue a¹ of the furnace so that
it will be heated to a sufficiently high temperature to melt the caustic alkali. The
receptacle e is provided with an outlet e and with an adjustable plug or valve f
whereby the flow of the caustic alkali therefrom may be regulated or controlled.
Above the receptacle e is arranged a box e, into which the caustic alkali in a
solid state is to be introduced and which is provided with an adjustable bottom
or slide whereby the supply of caustic soda to the receptacle è may be regulated as
desired.
y is the condenser for metallic sodium. is an adjustable plug or valve which is
provided in the funnel d for regulating the flow of the molten caustic alkali into the
retort . This retort is provided with a protecting casing. or jacket j of fireclay or
other suitable material.
k is a tube which extends obliquely upward from the lower end of the retort b so as
to form a hydraulic discharge or trap. This trap is so constructed that the entrance
of air to the interior of the retort will be prevented by the molten slag or carbonate,
whilst a constant or intermittent outflow of the excess of carbonate may be permitted.
The said trap is provided with an adjustable plug or stopper for the purpose of

page_text: regulating or controlling the flow of carbonate through the said trap. 7 is a
receptacle for the metallic sodium. m is a vessel for the reception of the slag or
carbonate.
In carrying on my process with the apparatus shown in the accompanying drawing,
the retort is heated to bright redness, and hot charcoal is introduced through the
opening cuntil the retort is filled to about one third or one half of its height. After
a few minutes, when the charcoal is red hot, molten caustic soda is admitted in a thin
but constant stream upon the glowing charcoal in the retort. Immediately after-
wards, the flame of sodium and the metallic sodium appear at the mouth of the
condenser g.
In commencing the process, when there is no slag in the bottom of the retort to
keep out the air, it is necessary to close the tube k by means of the conical stopper k¹.
After the lapse of about half an hour the said tube may be opened; whereupon the
excess of slag or carbonate will flow out in the same ratio in which it is formed.
Instead. of allowing the slag to flow out continuously, the tube k may, if desired, be
kept closed for some hours and then opened to permit the discharge of the carbonate
collected in the lower part of the retort; the opening of this tube does not interfere
in any way with the process going on in the upper part of the retort.
supply of charcoal in the retort is nearly exbausted, the admittance of caustic soda is
interrupted by shutting the valves fand ; the production of sodium at g will then
cease in a few minutes and the sodium flame disappear. The cover c² is then removed
and a fresh supply of hot charcoal is charged through the opening c¹, which is again
closed by the iron stopper or cover c². As soon as this charcoal has become incandescent,
the valve is opened and the production of sodium recommences.
When the
This interruption for recharging lasts only a few minutes. It is evident, however,
that the charging of the charcoal may be otherwise effected, for instance in a similar
manner to the charging of gas producers, so that the necessity for opening the retort
and interrupting the process is obviated.
Although coal or coke may be used for the reduction, I find the working with
charcoal the most convenient and advantageous; the charcoal containing but a small
quantity of silica, the fluidity of the slag is not diminished thereby.
The slag discharged from the retort, which consists chiefly of carbonate of soda
together with some charcoal dust, may be separated from the charcoal by lixiviation
and then either worked for carbonate of soda or regenerated for caustic soda./
As the caustic soda eats its way at high temperatures through the finest revices or
openings in the iron; it is essential, in order to obtain a good result, to av id the use
of bolts, screws and the like in the lower part of the apparatus ; for this reson the tube
for the discharge of the slag is cast with the retort.
By the employment of an apparatus which permits the removal or scharge, from
the sphere of reaction, of the carbonate of soda formed at the first stage of the reducing
action of the heated coal upon the molten caustic soda, during the operation and without
interfering with the process, I obtain the great advantage, that the reduction is effected
continuously at such a low temperature that cast iron may be used as the material for
the retorts. Moreover as the process is continuous and a great quantity of caustic
soda passes in a given time through the retort, the production is much greater than
that obtained by known processes. Further impure caustic alkali (for instance the
so-called "bottoms"), which could not heretofore be used with economy, may be
advantageously employed.
The retort is not necessarily cylindrical, it may if desired be pear-shaped or be made
in the form of a bottle or of other suitable form.
The discharge for the slag or carbonate may be constructed otherwise than as above
described, provided it allows the withdrawal of the slag without permitting the entrance
of air. There should, however, be no crevices, joints or the like through which the
caustic may find its way.
It is obvious that the above described apparatus can be used in such a manner that
the residual discharges can be allowed to flow intermittently from the retort.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I wish it understood that
I claim:
First The process above described for the manufacture of alkaline metals by
causing the continuous flow of molten caustic alkali upon incandescent carbonaceous
matter, allowing the metallic vapours evolved to escape into suitable condensers, the
residue, consisting chiefly of carbonate of soda, being separated from the caustic
alkali and withdrawn from the retort (or other apparatus), substantially as
described.
Second During the process above described or any similar process for the manu-
facture of alkaline metals, the withdrawal, during the reduction process and without
interrupting the same or interfering therewith, of the residue, chiefly carbonate of
.soda, contained in the retort, so as to enable the operation to be carried on at a low
temperature and continuously, substantially as, and for the purpose, described.
Third The combination, with the retort, of a trap for preventing the entrance of
air whilst permitting the discharge of the residues of the process, as, and for the
purpose, above specified.
Fourth-The apparatus for the manufacture of alkaline metals, consisting of a
retort, a condenser or similar vessel, the arrangement for feeding the caustic alkali at
will into the said retort and the provision for the discharge of the residue (chiefly
carbonate of soda), substantially as, and for the purpose, described.
Dated this 16th day of October 18SS
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.