Improved Process for the Manufacture of the Hydrates of the Alkalies, of the Alkaline Earths, and of their Carbonates, which Process is also Applicable to the Dissociation of Alloyed Metals.
Year: 1888

page_text: Date of Application, 18th Oct., 1888
Complete Specification Left, 18th July, 1889-Accepted, 31st Aug.,
1889
PROVISIONAL SPECIFICATION.
[Communicated from abroad by FRANÇOIS THEODORE ROMIGUIÈRES, of No. 6, Boule-
vard de Strasburg, Paris, in the Republic of France, Manufacturing Engineer.]
Improved Process for the Manufacture of the Hydrates of the Alkalies,
of the Alkaline Earths, and of their Carbonates, which Process is
also Applicable to the Dissociation of Alloyed Metals.
I, HENRY HARINGTON LEIGH, Fel. Inst. P.A., Assoc. M. Inst. (.E., practising as
Phillips & Leigh, of No. 22, Southampton Buildings, Chancery Lane, in the County
of Middlesex, Engineer & Patent Agent, do hereby declare the nature of this inven-
tion to be as follows:-
The principal object of this invention is the manufacture of any caustic alkali,
sodium, potassium, barium, ammonium, and other, hydrates as well as the carbonates
of the same bases. It is likewise also applicable to the treatment of certain metals
and alloys in respect of their refining and dissociation. It comprises a series of
operations which shall be described by way of explaining the manufacture by my
invention of sodium hydrate and carbonate.
If a mixture be prepared of sodium chloride or sulphuret and sodium plumbite
solutions, there will be precipitated plumbic chloride or sulphuret with remanent
sodium hydrate, thus
The process comprises two principal operations.
1. The preparation of the sodium plumbite solution.
2. The precipitation of the lead by means of a compound of sodium one of whose
elements combines with the lead to form with it an insoluble salt.
PREPARATION OF THE SODIUM PLUMBITE.
Two boilers are placed side by side, and in communication with each other so that
the liquor drawn from the bottom of one can be made to enter through the top of the
other of them. They are fitted with self closing apertures adapted to allow of the
introduction of the materials at the top and their withdrawl at the bottom. They are
also furnished with a coil, or a double bottom, for the purpose of applying steam-heat,
liquid and pressure gauges, and a suitable complement of cocks. In general construc-
tion they assimilate to the type used in the gelatine manufacture.
Each boiler communicates with an air-compressor and a suitable number of
reservoirs.
Both boilers are charged about three parts full with finely divided lead, and a con-
centrated solution of caustic soda, to which a little sodium sulphate or equivalent
chemical has been added, sufficient to cover the lead is led in. Heat is then applied
till a pressure of from 1 to 2. kilos is attained, when the heating is stopped, and the
compressed air supply turned into the bottom. As soon as a pressure of from 4 to 5
kilos is attained, the liquor is run off into the next boiler through the top thereof.
When the whole has been transferred, the communication between the boilers
interrupted, the further supply of air to the first one stopped, and the compressed air
already in allowed to escape.
The temperature of the caustic solution in the second boiler is kept up, at the same
time that compressed air is injected.
When the right pressure is attained, communication with the first boiler is re-
established so as to re-conduct the caustic solution thereinto.
This solution is passed

page_text: backwards and forwards from one boiler into the other, and air injected as described
until all the lead is oxidised, dissolved, and in combination with the sodium oxide.
The load in the presence of the caustic soda takes oxygen from the sodium sulphate,
and then combines with the soda to form sodium plumbite, thus :-
All the sodium salts, all the binary compounds of sodium the acids or the metalloids
of which are capable of forming with lead a sodium. plumbite, may be used for the
production either of caustic soda or of sodium carbonate.
Under the action of caustic soda (to which a little sodium sulphate has been added)
and of atmospheric air, lead is not the only metal which dissolves in a state of com-
bination with soda. Zinc, antimony, arsenic, and tin, all act in the same way, either
alone or in a state of mutual alloy, or even if alloyed with metals incapable.of forming
with soda a compound in which they play the parts of acids.
So if there be introduced into the oxidation boilers, an alloy of lead, tin, and
zinc, with a certain proportion of silver, for example; there results the solution of the
alloy, the silver only excepted, which latter is precipitated. The solution of a complex
composition will be treated according to the following equations:
Na, Pb O, +
2 Na Cl
Na, Zn O, +
Na, Sn O + CO₂
=
2 Na, O+ Pb Cl₂.
Na, S = 2 Na, O + Zn S.
=
Na, CO,
Sn O₂.
That is to say, the lead is to be precipitated first, by sodium chloride, (chlorine
precipitating neither zinc nor tin), and next the zinc, by sodium sulphide. The solu-
tion containing only the tin is concentrated so as to make it give up the sodium
stannate in a crystallised state. This stannate treated with carbonic acid yields sodium
carbonate and binoxide of tin. From sodium stannate and sodium pyro-phosphate
mixed in solution and treated with carbonic acid there will be precipitated pyro-
phosphate of tin

page_text: The three metals will then co-operate to form caustic soda and sodium carbonate
with chloride, sulphuret, and pyrophosphate of sodium. As soon, therefore, as it
becomes practicable, according to my invention, to dissolve lead, tin, zinc, as well as
antimony, arsenic, and other metals, it is possible to extract them from their respective
alloys; and, consequently, this process will be applicable to the treatment of lead-,
tin-, or zinc-coated irons, and the like; of alloys of copper and tin; of copper and
zinc to the treatment of argentiferous, antimonial, arsenical, and other leads, as well
as similar artificial or natural metallic mixtures.
Dated this 18th day of October 1888
HENRY H. LEIGH.
COMPLETE SPECIFICATION.
Improved Process for the Manufacture of the Hydrates of the Alkalies,
of the Alkaline Earths, and of their Carbonates, which Process is
also Applicable to the Dissociation of Alloyed Metals.
I, HENRY HARINGTON LEIGH, Fol. Inst. P.A., Assoc. M. Inst. C.E., practising
as Phillips & Leigh of No. 22, Southampton Buildings, Chancery Lane, in the County
of Middlesex, Engineer & Patent Agent, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :—
The principal object of this invention is the manufacture of any caustic alkali ;
sodium, potassium, barium, ammonium and other hydrates; as well as the carbonates
of the same bases. It is likewise also applicable to the treatment of certain metals
and alloys in respect of their refining and dissociation. It comprises a series of
operations which shall be described by way of explaining the manufacture by my
invention of sodium hydrate and carbonate.
If a mixture is prepared of sodium chloride or sulphuret and sodium plumbite solu-
tions, there will be precipitated plumbie chloride or sulphuret with remanent sodium
hydrate, thus:
The process comprises two principal operations.
1. The preparation of the sodium plumbite solution.
2. The precipitation of the lead by means of a compound of sodium one of whose
elements combines with the lead to form with it an insoluble salt.
PREPARATION OF THE SODIUM PLUMBITE.
Two boilers are placed side by side, and in communication with each other, so
that the liquor drawn from the bottom of one can be made to enter through the
top of the other of them. They are fitted with self closing apertures adapted to
allow of the introduction of the materials at the top and their withdrawal at the
bottom. They are also furnished with a coil, or a double bottom, for the purpose of
applying steam-heat; liquid and pressure gauges; and a suitable complement of
cocks. In general construction they assimilate to the type used in the gelatine
manufacture.
Each boiler communicates with an air-compressor and a suitable number of
reservoirs.
Both boilers are charged about three parts full with finely divided lead; and a
concentrated solution of caustic soda, to which a little sodium sulphate or equivalent
chemical has been added, sufficient to cover the lead, is led in. Heat is then applied
till a pressure of from 1 to 2 kilos is obtained, when the heating is stopped, and the
As soon as
compressed air-supply turned into the bottom.
a pressure of from
4 to 5 kilos is attained, the liquor is run off into the next boiler through the top

page_text: thereof. When the whole has been transferred, the communication between the
boilers is interrupted, the further supply of air to the first one stopped, and the
compressed air already in allowed to escape.
The temperature of the caustic solution in the second boiler is kept up at the same
time that compressed air is injected. When the right pressure is obtained, com-
munication with the first boiler is re-established, so as to re-conduct the caustic
solution thereinto. This solution is passed backwards and forwards from one boiler
into the other, and air injected as described, until all the lead is oxidised, dissolved,
and in combination with the sodium oxide.
The lead in the presence of the caustic soda takes oxygen from the sodium sulphate,
and then combines with the soda to form sodium plumbite, thus :—
All the sodium salts, all the binary compounds of sodium the acids or the metalloids
of which are capable of forming with lead a sodium plumbite, may be used for the
production either of caustic soda or of sodium carbonate.
Under the action of caustic soda (to which a little sodium sulphate has been added)
and of atmospheric air, lead is not the only metal which dissolves in a state of
combination with soda. Zinc, antimony, arsenic, and tin, all act in the same way,
either alone or in a state of mutual alloy, or even if alloyed with metals incapable
of forming with soda a compound in which they play the parts of acids.
So if there be introduced into the oxidation hoilers an alloy of lead, tin, and
zinc, with a certain proportion of silver, for example, there results the solution of
the alloy, the silver only excepted, which latter is precipitated. The solution of a
complex composition will be treated according to the following equations:

page_text: That is to say, the lead is to be precipitated first by sodium chloride (chlorine pre-
cipitating neither zinc nor tin), and next the zinc, by sodium sulphide. The solution
containing only the tin is concentrated, so as to make it give up the sodium stannate
in a crystallised state. This stannate treated with carbonic acid yields sodium
carbonate and binoxide of tin. From sodium stannate and sodium pyro-phosphate
mixed in solution and treated with carbonic acid, there will be precipitated pyro-
phosphate of tin.
The three metals will then co-operate to form caustic soda and sodium carbonate
with chloride sulphuret and pyrophosphate of sodium. As soon, therefore, as it
becomes practicable, according to my invention, to dissolve lead, tin, zinc, as well as
antimony, arsenic, and other metals, it is possible to extract them from their respective
alloys; and, consequently, this process will be applicable to the treatment of lead-,
tin-, or zinc-coated irons, and the like; of' alloys of copper and tin; of copper and
zinc; to the treatinent of argentiferous, antimonial, arsonical and other leads, as well
as similar artificial or natural metallic mixtures.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is
1. The process as hereinbefore described of oxidising and dissolving lead, tin, zinc,
antimony, arsenic, sodium, or other metals of analogous chemical properties, by
immersing them in a lye of caustic alkali (e.g., potassic, sodic, baric, strontium, or
lime), and then passing through the lye or bath a current of air by any suitable
means.
2. The manufacture of caustic alkalies, (e.g., sodium, potassium, barium, or
strontium hydrates), or their carbonates, by means of the precipitation of a metal
combined with the caustic alkali, by a binary compound or salt of the same or a
different alkali.
Dated this 18th day of July 1880
HENRY H. LEIGH.