IMPROVED PROCESS FOR THE CONVERSION OF CHLORIDES AND FLUORIDES OF ALKALINE METALS AND ALKALINE EARTH METALS INTO OXIDES, HYDROXIDES, CARROWING
Year: 1873

page_text: "AN
LETTERS PATENT to Richard Werdermann, of Princes Street, in the
County of Surrey, Civil Engineer, for the Invention of
IMPROVED PROCESS FOR THE CONVERSION OF CHLORIDES AND FLUORIDES OF
ALKALINE METALS AND ALKALINE EARTH METALS INTO OXIDES, HYDROXIDES,
CARROWING
"
Sealed the 25th November 1873, and dated the 29th May 1873.
PROVISIONAL SPECIFICATION left by the said Richard Werdermann
at the Office of the Commissioners of Patents, with his Petition, on
the 29th May 1873.
I, RICHARD WERDERMANN, of Princes Street, in the County of
Surrey, Civil Engineer, do hereby declare the nature of the said Inven-
tion for "AN IMPROVED PROCESS FOR THE CONVERSION OF CHLORIDES AND FLUORIDES
OF ALKALINE METALS AND ALKALINE EARTH METALS INTO OXIDES, HYDROXIDES,
AND CARBONATES," to be as follows:-
:-
This Invention consists mainly in a new process for effecting the direct

page_text: conversion of chloride of sodium into caustic soda without the employ
ment of sulphuric acid.
The said process is as follows:-I first convert by electrolysis
the chloride of sodium Na Cl (common salt) into sub-chloride of
sodium Na, Cl (or Na, Cl³). This sub-chloride of sodium is then
dissolved in water. The reaction which takes place, and during which
hydrogen is liberated, may be represented by the following equation :-
H₂O = Na Cl
Na, Cl
Sub-chloride of sodium. Water.
× H
Hydrogen.
☑
Chloride of sodium.
Na Ho
Caustic soda.
I thus obtain a solution of caustic soda and of chloride of
sodium, which is concentrated in cauldrons of cast-iron until it acquires
a spcific gravity of 1.5. The chloride of sodium is then deposited. The
lye, which is now a pure solution of caustic soda, is next strongly
heated till it acquires a specific gravity of 2. The lye is then drawn off
into tanks, and the soda is left to crystallize. The caustic soda obtained
by this process is absolutely pure.'
I treat in the same manner sub-fluoride of sodium, and also the sub-
chlorides and sub-fluorides of lithium, of potassium, of manganese, and
the alkaline earth metals obtained in like manner by the electrolysis of
the respective chlorides and fluorides.
In acting upon the sub-fluoride of sodium I obtain in due course a
very pure lye of caustic soda, as the fluoride of sodium, which forms is
but slightly soluble in water. If a current of carbonic acid is caused
to pass through the lye, or if it is only exposed to contact with the air,
carbonate of soda is formed.
For obtaining highly concentrated solutions, and consequently econo-
mizing the fuel, I may operate under pressure in dissolving the salts and
afterwards evaporate in a vacuum.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Richard Werdermann in the Great Seal Patent Office
on the 28th November 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD.
WERDERMANN, of Princes Street, in the County of Surrey, Civil
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of May, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Richard Werdermann, Her special licence
that I, the said Richard Werdermann, my executors, administrators, and
assigns, or such others as I, the said Richard Werdermann, my executors,
administrators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend, within
the United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "AN IMPROVED PROCESS FOR THE CON-
VERSION OF CHLORIDES AND FLUORIDES OF ALKALINE METALS AND ALKALINE EARTH
METALS INTO OXIDES, HYDROXIDES, AND CARBONATES," upon the condition
(amongst others) that I, the said Richard Werdermann, my executors or
administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Richard Werdermann, do hereby
declare the nature of my said 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 consists mainly in a new process for effecting the
direct conversion of chloride of sodium into caustic soda without the
employment of sulphuric acid.

page_text: Боти
that is to say:-1 first convert by electrolysis the coride of
Na Cl (common salt) into sub-chloride of sodium Na, Cl (or Na. C12).
This sub-chloride of sodium is then dissolved in water. The reaction
which takes place, and during which hydrogen is liberated, may be 5
represented by the following equation :- Na, Cl
Sub-chloride of sodium.
(Na Cl
+ Na Ho)
:-
+ H
+
H₂O
Water.
=
I thus obtain a solution
Chloride of sodium. Caustic soda. Hydrogen.
of caustic soda and chloride of sodium, which is concentrated in:
cauldrons of cast-iron until it acquires a specific gravity of 1.5. The
chloride of sodium then crystallizes out. The lye which is at this stage
of the process a pure solution of caustic soda is now strongly heated till
it acquires a specific gravity of 70°-72° araeometer Baumé. The lye is
then drawn off into tanks and the soda is left to crystallize. The caustic
soda obtained by this process is absolutely pure. Instead of dissolving
the sub-chloride of sodium in water I may modify my process to effect
its conversion into caustic soda during the process of electrolysis in
passing at the moment when the electric current is acting upon the salt
either as a simple current or as a spark through the heated or molten
mass a jet or jets of common steam or vapour of water.
I treat in the same manner sub-fluoride of sodium, and also the sub-
chlorides and sub-fluorides of lithium, of potassium, of manganese, and
of the alkaline earth metals obtained in like manner by the electrolysis
of the respective chlorides and fluorides.
In acting upon the sub-fluoride of sodium I obtain in due course a
very pure lye of caustic soda as the fluoride of sodium, which is but
slightly soluble in water. If a current of carbonic acid is caused to
pass through the lye, or if it is only exposed to contact with the air,
carbonate of soda is formed.
For obtaining highly concentrated solutions, and consequently econo-
mizing the fuel, I may operate under pressure in dissolving the salts and
afterwards evaporate in a vacuum.
Having thus fully described my said Invention, and the manner of
performing the same, I wish it understood that I claim the production
of oxides, hydroxides, and carbonates of the alkaline metals and alkaline

page_text: earth metals from the sub-chlorides and sub-fluorides obtained by
electrolysis of the chlorides and fluorides of such metals by the process
herein described.
In witness whereof, I, the said Richard Werdermann, have hereunto
set my hand and seal, this Twenty-fifth day of November, in
the year of our Lord One thousand eight hundred and seventy-
three
Witness,
W. ROBT. LAKE,
8, Southampton Buildings,
London.
R. WERDERMANN. (L.S.)