Process and Apparatus for the Manufacture of Caustic Alkalies from Alloys of the Alkali Metals.
Year: 1894

page_text: Date of Application (In United Kingdom), 1st Dec., 1894
Complete Specification Left, 31st Aug., 1895-Accepted, 5th Oot., 1895
PROVISIONAL SPECIFICATION.
Process and Apparatus for the Manufacture of Caustic Alkalies from
Alloys of the Alkali Metals.
I, LEON PAUL HULIN, of Modane, (Savoie), France, Civil Engineer, do hereby
declare the nature of this invention to be as follows:-
This invention relates to a process and apparatus for the manufacture of caustic
alkalies by the employment of alkaline alloys.
It has long been known that the alloy formed of a heavy metal and of an alkali
metal is attacked by water, whether in the form of liquid or steam, that the latter
is decomposed, and that the products of the reaction are invariably hydrogen and
alkali and sometimes also the oxide of the heavy metal according to the nature of
the latter.
The process hereinafter described and which forms the subject of the present
application for Letters Patent, consists in causing aqueous vapour or steam to act
indirectly upon alloys containing a large proportion of alkaline metals, under
conditions founded upon a novel principle having for object to prevent the direct
contact either of the steam or of even a drop of water of condensation, with the
rich alkaline alloy.
I have devised this method with the object of effecting the treatment on a
commercial scale, and without danger, of large quantities of alloys rich in alkali
metals, such as those obtained by my electrolytic process forming the subject of
another application for Letters Patent dated the 28th day of November 1894,
No. 23117; for the purpose of extracting therefrom the caustic alkali, concentrated
if desired to a very high degree, and this without causing the oxidation of the
heavy metal or metals present in the alloy, whereas under other conditions the
heavy metal or metals might be oxidized by the vapour or steam at the temperature
of the operation.
This method thus permits of the practical employment of rich alloys of alkali
metals with heavy metals such as copper, zinc, tin, antimony, etc., which would be
very difficult except under the special conditions of my process and apparatus.
The following are the results which I obtain at once and in an almost automatic
manner:-
(1) Absence of violent reactions and dangerous explosions, whereby I am
enabled to act upon large masses on a commercial scale;
(2) Impossibility of oxydizing the heavy metal alloyed with the alkali metal;
(3) Formation of caustic alkali of the desired degree of concentration.
My process consists essentially in introducing at the bottom of a strong closed
receiver filled with hydrogen, an alloy of alkali metal leaving above it a large free

page_text: or less
space for the gas and the alkali to be obtained; within the vessel and towards the
upper part is placed an open tray containing water, the vessel being also provided
with an outlet orifice on top closed by a stop cock at starting. Thus arranged,
I gradually heat the vessel so as to bring the alloy to a state of perfect fusion;
the internal ambient temperature being thus gradually increased the water in the
tray gives off at first weak vapours which diffuse in the hydrogen and while in a
high state of dilution become quietly decomposed in contact with the fused alloy.
There then forms upon the latter a thin layer of caustic alkali more
anhydrous and the vapour continuing to be diffused becomes absorbed at the
surface of the layer of alkali and forms with it an alkaline hydrate. This hydrate
metal of which
immediately reacts upon the subjacent alloy, the alkali
decomposes the water of hydration and becomes oxidized at its expense thus
increasing the layer of alkali whilst the hydrogen is evolved through the layer
in fusion and produces an agitation which promotes the continuation of the operation
as the uppermost layer has absorbed more water by condensing the steam under
pressure generated in the tray and this layer is carried down towards the alloy.
The reaction is thus continuous and regular without violence as it is neither water
nor steam which acts on the alloy but the alkaline hydrate in process of formation,
and therein lies the principle of my system. The alkali metal is capable of
oxidizing under these conditions by decomposing its concentrated hydrate but the
heavy metal is incapable of doing so whereas it might be oxidized by decomposing
the free steam were the latter to act directly upon the alloy at the temperature at
which the operation is to be performed; and such oxidation would increase more
and more in proportion as the alloy becomes impoverished in alkali metal.
The modus operandi which I have prescribed, its effects and advantages, may be
thus summed up :-
(1) The formation of the alkaline oxide is effected by the reaction of the alkali
metal contained in the alloy upon the hydrated alkali which covers it;
(2) The alkaline hydrate entering into the reaction is thereby transformed into
anhydrous oxide to which is added that which becomes formed;
(3) The aqueous vapour or steam which is diluted in the atmosphere of hydrogen
above the alkali regenerates the hydrate as fast as it is destroyed and renders the
operation continuous until the materials under treatment are exhausted;
(4) The hydrogen evolved produces a stirring of the alkali which favours the
above mentioned operation ;
(5) The heavy metal of the alloy thus covered with concentrated alkali and
enveloped by the hydrogen, cannot become oxidized and contaminate the alkali;
(6) The operation is effected without violence or danger by reason of the division
of the reactions;
(7) The final concentration of the alkali by dehydration may be carried to the
highest degree. The alkali may, in fact, be hydrated or concentrated at will
according to the quantitative ratio of the water to the alkali metal under treatment.
By employing an excess of alkali metal relatively to the oxygen of the water
present during the operation, I am enabled to produce alkaline oxide in an almost
anhydrous condition.
To complete the description of the operation and its principle of action, it
should be added that:-
(1) The quantity of water placed in the tray is regulated in proportion to the
quantity of alkali metal contained in the alloy under treatment; in this manner
the operation is naturally brought to a final termination;
(2) The hydrogen generated is allowed to escape by the relief cock in order
that the pressure shall not reach a dangerous point, the pressure being varied at
will (within the practical limits of strength of the apparatus which is provided
with a large safety valve and pressure guage) in order to regulate the absorption
of the steam by the alkali in course of formation and avoid at same time all
entrance of air;
(3) As the hydrogen carries off along with it a certain quantity of steam,

page_text: I cause it to pass through a condenser for the purpose of collecting the water
and returning it to the tray in order to maintain the original proportions;
(4) In order to regulate at will the evaporation of the water in the tray, the
latter is provided with a worm or double bottom in which steam, water, or even
air, is caused to circulate for the purpose of stimulating or moderating the
evaporation as required and so regulate the progress of the operation.
It is evident that without changing the fundamental principle of my process,
the steam might be introduced from an external vessel containing a quantity of
water either proportioned or otherwise, and receiving heat from the apparatus
itself or from an independent source; and also that some of the alkali might be
extracted during the operation provided that a layer is left to prevent direct
contact of the steam with the alloy in conformity with my principle.
The complete apparatus which I have devised for the commercial application
of these principles is illustrated in all its essential parts but only by way of example,
in the accompanying drawing in which A is a strong cylindrical receiver made of
iron or steel in two parts superposed and united to form an hermetically closed
chamber. B is a lateral feed pipe with cap at which the alkali alloy is introduced.
Cis a discharge pipe at bottom, and the vessel A is mounted in a furnace con-
structed of brickwork in the ordinary manner. D is an evaporating tray to
contain the water required in the operation. It is formed with a double bottom d
made steam or watertight and communicating by the pipes e, el, with the pipes ƒ, ƒ¹,
the pipes e, e, serving to support the tray in position. is a thermometer for
indicating the temperature of the water in D. E is a vessel provided with inlet
and outlet cocks for the supply of the regulated quantity of water required for
the operation and for returning during the operation the water carried off by the
hydrogen. F is a cock for regulating the outflow of hydrogen through pipe f.
Gis the condenser through which the gas is passed for the purpose of condensing
the vapour carried off and returning the condensed water through E to D. The
condenser might be modified so as to render the return to D automatic and
continuous. The hydrogen is finally discharged by pipe h. I is a gauge for
indicating the pressure in A and J a safety valve of large area. The crucible
having been charged with alloy at K and with water in the tray D and filled with
hydrogen is gradually heated. The vapour evolved by the water in the tray
spreads slowly at first so as to form a thin layer of alkali which continues to
increase until the water or the alkali metal is exhausted. The progress of the
operation is controlled in the first place by regulating the heat of the furnace
whilst the thermometer i and gauge I indicate the intensity of the evaporation in D
which results from the internal heating of the apparatus and this evaporation is
increased or reduced at will by causing either steam or cold water to circulate
through the double bottom d. The escape of the hydrogen is regulated in
accordance with the readings of the pressure gauge, by the cock F which may be
replaced by a valve opening automatically under a given pressure. The water
separated from the hydrogen is collected in H and returned through the feed
vessel E to the tray D. When the materials are exhausted the residue of
the heavy metal is run off through after which the alkali L is collected. The
apparatus can then be again charged and a fresh operation commenced. The
residue of heavy metal often contains some alkali metal which I generally utilize
in the manufacture of the alloy.

page_text: Process and Apparatus for the Manufacture of Caustic Alkalies from
Alloys of the Alkali Metals.
I, LEON PAUL HULIN, of Modane, (Savoie), France, Civil Engineer, 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:
This invention relates to a process and apparatus for the manufacture of caustic
alkalies by the employment of alkaline alloys.
It has long been known that the alloy formed of a heavy metal and of an alkali
metal is attacked by water (whether in the form of liquid or steam) which is
decomposed, the products of the reaction being hydrogen and alkali and sometimes
also the oxide of the heavy metal.
The process hereinafter described, and which forms the subject of the present
application for Letters Patent, consists in causing steam to act indirectly upon
alloys containing a large proportion of alkali metals, under such conditions as to
prevent the direct contact either of the steam or of even a drop of water of
condensation, with the rich alkali alloy.
I have devised this method with the object of effecting the treatment on a
commercial scale, and without danger, of large quantities of alloys rich in alkali
metals, such as those obtained by my electrolytic process forming the subject of
another application for Letters Patent dated the 28th day of November 1894
No. 23,117, for the purpose of extracting therefrom the caustic alkali concentrated
if desired to a very high degree, and this without causing the oxidation of the
heavy metal or metals present in the alloy, whereas under other conditions the
heavy metal or metals might be oxidized by the steam at the temperature of
the operation.
This method thus permits of the practical employment of rich alloys of alkali
metals with heavy metals such as copper, zinc, tin, antimony, etc., which would be
very difficult except under the special conditions of my process and apparatus.
The results obtained at once and in an almost automatic manner are:-
(1) Absence of violent reactions and dangerous expulsions, which enables large
masses to be treated on a commercial scale;
(2) Impossibility of oxydizing the heavy metal alloyed with the alkali metal ;
(3) Formation of caustic alkali of the desired degree of concentration.
My process consists essentially in introducing at the bottom of a strong closed
receiver filled with hydrogen, an alloy of alkali metal leaving above it a large free
space for the gas and the alkali to be obtained; within the vessel and towards the
upper part is placed an open tray containing water, the vessel being also provided
with an outlet orifice at top which is closed by a stop cock at starting. Thus
arranged the vessel is gradually heated so as to bring the alloy to a state of perfect
fusion; the internal ambient temperature being thus gradually increased the water
in the tray gives off at first weak vapours which diffuse in the hydrogen and while
in a high state of dilution become quietly decomposed in contact with the fused
alloy. There is immediately formed upon the latter a thin layer of caustic alkali
more or less anhydrous and the vapour continuing to be diffused becomes absorbed
at the surface of the layer of alkali and forms with it an alkaline hydrate. This
hydrate immediately reacts upon the subjacent alloy, the alkali metal of which
decomposes the water of hydration and becomes oxidized at its expense, thus
increasing the layer of alkali whilst the hydrogen is evolved through this fused

page_text: layer and
causes an agitation which promotes the continuation of the operation
the uppermost layer having now absorbed more water by condensing the steam
under pressure generated in the tray and this layer being carried down towards
the alloy. The reaction is thus continuous and regular, without being violent, as
it is neither water nor steam which acts on the alloy but the alkaline hydrate in
process of formation, and therein lies the novel principle of operation. The alkali
inetal is capable of becoming oxidized under these conditions by decomposing its
concentrated hydrate but the heavy metal is incapable of doing so, whereas it
might be oxidized by decomposing the free steam were the latter to act directly
upon the alloy at the temperature at which the operation is to be performed; and
such oxidation would increase more and more in proportion as the alloy becomes
impoverished in alkali metal.
The modus operandi which I have prescribed, its effects and advantages, may
be thus summed up :-
(1) Alkaline oxide is formed by the reaction of the alkali metal contained in
the alloy upon the hydrated alkali which covers it ;
(2) The alkaline hydrate entering into the reaction is thereby transformed
into anhydrous oxide to which is added that formed by the reaction above
mentioned;
(3) The aqueous vapour or steam which is diluted in the atmosphere of
hydrogen above the alkali regenerates the hydrate as fast as it is decomposed
and renders the operation continuous until the materials under treatment are
exhausted;
(4) The hydrogen evolved produces a stirring of the alkali which favours the
above mentioned operation;
(5) The heavy metal of the alloy thus covered with concentrated alkali and
enveloped by the hydrogen, cannot become oxidized and contaminate the alkali ;
(6) The operation is effected without violence or danger by reason of the
division of the reactions;
(7) The final concentration of the alkali by dehydration may be carried to the
highest degree. The alkali may, in fact, be hydrated or concentrated at will,
according to the quantitive proportions of the water and alkali metal under
treatment. By employing an excess of alkali metal relatively to the oxygen of
the water present during the operation, almost anhydrous alkaline oxide may be
produced.
To complete the description of the operation and its principle of action, it should
be added that
(1) The quantity of water placed in the tray is regulated in proportion to the
quantity of alkali metal contained in the alloy under treatment so that the operation
comes to an end naturally;
(2) The hydrogen generated is allowed to escape by the relief cock in order that
the pressure shall not reach a dangerous point, the pressure being varied at will
(within the practical limits of strength of the apparatus which is provided with
a safety valve and pressure gauge) in order to regulate the absorption of the
steam by the alkali in course of formation and avoid at same time all entrance
of air;
(3) As the hydrogen carries off along with it a certain quantity of steam it is
passed through a condenser for the purpose of collecting the water and returning it
to the tray in order to maintain the original proportions;
(4) In order to regulate at will the evaporation of the water in the tray, the latter
is provided with a worm or double bottom in which steam, water, or even air, is
caused to circulate for the purpose of stimulating or moderating the evaporation as
required and so regulate the progress of the operation.
It is evident that, without changing the fundamental principle of my process,
the steam might be introduced from an external vessel containing a quantity of
water either proportioned or otherwise, and receiving heat from the apparatus

page_text: itself or from an independent source; and also that some of the alkali might be
extracted during the operation provided that a layer is left to prevent direct
contact of the steam with the alloy.
An example of the complete apparatus which I have devised for the commercial
application of this principle is illustrated in all its essential parts in the drawing
accompanying any Provisional Specification, in which A is a strong cylindrical
receiver made of iron or steel in two parts superposed and united to form an
hermetically closed chamber. B is a lateral feed pipe with cap at which the alkali
alloy is introduced. C is a discharge pipe at bottom. The vessel A is mounted in
a furnace constructed of brickwork in the ordinary manner. D) is an evaporating
tray for the water. It is formed with a double bottom d made steam or water tight
and communicating by the pipes e, e¹, with the pipes f, f, the pipes e, e¹, serving to
support the tray in position. is a thermometer for indicating the temperature of
the water in D. E is a vessel provided with inlet and outlet cocks for the supply of
the regulated quantity of water required for the operation and for returning during
the operation the water carried off by the hydrogen. F is a cock for regulating the
outflow of hydrogen through pipe f. G is the condenser through which the gas is
passed for the purpose of condensing the vapour carried off and returning the
condensed water through E to D. The condenser might be modified so as to
render the return to D automatic and continuous. The hydrogen is finally dis-
charged by pipe h. I is a gauge for indicating the pressure in A, and J a safety
valve of large area.
The crucible having been charged with alloy at K and with water in the tray D
and filled with hydrogen, is gradually heated. The steam given off, spreads slowly
at first so as to form a thin layer of alkali which continues to increase until the
water or the alkali metal is exhausted. The progress of the operation is controlled
in the first place by regulating the heat of the furnace whilst the thermometer i
and gauge I indicate the intensity of the evaporation in D which results from the
internal heating of the apparatus and this evaporation is increased or reduced
at will by causing either steain or cold water to circulate through the double
bottom d. The escape of the hydrogen is regulated in accordance with the
readings of the pressure gauge, by the cock which may be replaced by a
valve connected with the pipe f opening automatically under a given pressure.
The water separated from the hydrogen is collected in II and is returned through
the feed vessel E to the tray 1). When the materials are exhausted, the residue
of the heavy metal is run off through (, after which the alkali L is collected.
The apparatus can then be again charged and a fresh operation commenced.
The residue of heavy metal often contains some alkali metal, which I generally
utilize in the manufacture of the alloy.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what I
claim is:-
1st. The herein described process which consists essentially in treating alloys of
the alkali metals by means of alkaline hydrate at a suitable temperature and in a
reducing or neutral atmosphere in such manner as to oxidize the alkali metal
by the water of hydration and prevent the oxidation of the heavy metal of
the alloy.
2nd. The herein described process of treating alloys of the alkali metals by
means of alkaline hydrate so that the alkali metal of the alloy becomes oxidized
by the water of hydration and of regenerating the alkaline hydrate by steam
diluted in an atmosphere of reducing or neutral gas in a closed vessel and under a
suitable pressure, as specified.
3rd. The herein described process of treating alloys of the alkali metals by
ineans of alkaline hydrate so that the alkaline metal of the alloy becomes oxidized
by the water of hydration and of regenerating the alkaline hydrate by team

page_text: diluted in an atmosphere of reducing or neutral gas in a closed vessel, and under a
suitable pressure, the quantity of water furnishing the steam for hydration being so
proportioned that the oxidizing operation will be automatically determined.
4th. In the process defined in Claims 1, 2, and 3, the employment of a closed
iron or steel vessel formed in one or more parts, placed over a furnace and com-
prising in addition as essential arrangements or constitutive parts, a source of steam,
provision for the escape of the hydrogen, for the introduction of the material to be
treated, and the discharge of the products and residues, and other necessary
adjuncts, substantially as described with reference to the accompanying drawings.
5th. In an apparatus comprising the essential elements defined in Claim 4, the
combination of an evaporating tray located within the crucible and provided with
means of heating and cooling for regulating the generation of steam, an automatic
or hand operated valve for controlling the escape of hydrogen, a condenser for
intercepting the water carried off with, the hydrogen and returning it to the
evaporator so as to maintain the proportion constant, and a water feed apparatus for
increasing the quantity during the operation, all substantially as described.
Dated this 21st day of Act 100%
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.