IMPROVE MENTS IN THE MANUFACTURE OF CAUSTIC SODA AND CARBONATE OF SODA
Year: 1862

page_text: LETTERS PATENT to James Dickson, of 66, Tollington Road, Holloway,
in the County of Middlesex, Gentleman, for the Invention of "IMPROVE
MENTS IN THE MANUFACTURE OF CAUSTIC SODA AND CARBONATE OF SODA."
Sealed the 13th January 1563, and dated the 17th July 1862.
PROVISIONAL SPECIFICATION left by the said James Dickson at the
Office of the Commissioners of Patents, with his Petition, on the
17th July 1862.
I, JAMES DICKSON, of 66, Tollington Road, IIolloway, in the County of
Middlesex, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC SODA AND CARBONATE OF SODA,"
to be as follows:-
My method consists, 1stly, in employing heated aqueous solution of
chloride of sodium, cominon salt, sea water, or other suitable salts of soda,
such for instance, as sulphate of soda, sulphite of soda, or nitrate of soda, and
decomposing the same by the agency of voltaic electricity, in which case I pro-
duce caustic soda direct; any of the products obtained in this case 1 utilize so
as to assist in the further production of soda or carbonate of soda; or, 2ndly,
in obtaining from any of the above heated materials by means of voltaic elec-
tricity acetate of soda or other products that are salts of soda, and igniting the
same, if necessary, either alone or in combination with carbonaceous matter,
whereby I produce carbonate of soda; or, 3rdly, in obtaining from certain of

page_text: the said heated materials by means of many of the modifications of the voltaic
battery, for which I received Provisional Protection for six months on or about
the 18th February 1862, and numbered 340, certain salts, such for instance,
as sulphate of soda, or sulphite of soda, and igniting the same in combination
with carbonaceous and calcareous matter, by which means I obtain carbonate
of soda. The positive poles or anodes which I employ immersed in the salts
above alluded to, are iron, zinc, tin, lead, copper, carbon, or other metallic
substances, and as negative poles or cathodes, I employ carbon, wrought or
cast iron, copper, lead, or other suitable metals, or metallic substances. In
conducting the said operations I find that by employing certain sub-
stances in one or other, and, in some instances, in both of the compart-
ments of the decomposition cell employed, the decomposition of the said
materials is accelerated, as for instance, by placing in the positive compart-
ment a carbon anode, and pouring into the same compartment an aqueous
solution of any of the sulphides of the metals of the alkalies, or of the
sulphides of the metals of the alkaline earths, or by using therein a similar
solution of sulphurous acid, or other suitable acids, or metallic salts, to any of
which may be added common salt or sea water. So also, for instance, by
adding to the fluids of the negative compartment of the said decomposition
cell, in which latter it must be understood that in this and in all or most of the
cases already described, a porous medium or mediums is used, metallic oxides
or metallic acids, such oxides, for instance, as those of copper, tin, lead, and
zinc, there being also opposed to them in the said positive compartment any
suitable salt of soda and a positive pole or anode, then the said voltaic decom-
position is similarly effected. In some instances I employ lime or other suit-
able alkaline substances mixed with the fluids employed in the positive
compartment of the said decomposition cell. I find that at a temperature of
about 212° Fahrenheit, or at still higher temperatures, the said voltaic decom-
position of the salts employed may be very readily effected in producing soda
or carbonate of soda, but as many of the said modifications of my own battery
already alluded to aro very inexpensive sources of voltaic electricity, I can also,
by employing a sufficient number of them, produce caustic soda or carbonate
of soda with advantage, at temperatures much lower than the temperatures
alluded to. Or, 4thly, I obtain soda from fused sulphate of soda or from other
suitable salts or compounds of soda, by passing a current of voltaic electricity
through the said fused salts or compounds, by means of carbon or other suit-
able anodes and cathodes immersed therein and connected with the terminal
poles of a voltaic battery.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Dickson in the Great Seal Patent Office on the 17th
January 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
DICKSON, of 66, Tollington Road, Holloway, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of July, in the year of our
Lord One thousand eight hundred and sixty-two, in the twenty-
year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said James Dickson, Her special licence that I, the said James
Dickson, my executors, administrators, and assigns, or such other's as I, tho
said James Dickson, 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 "IMPROVEMENTS IN
THE MANUFACTURE OF CAUSTIC SODA AND CARBONATE OF SODA," upon the condition
(amongst others) that I, the said James Dickson, my executors or adminis
trators, 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 James Dickson, 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, that is to say:-
My method consists, firstly, in employing heated aqueous solution of certain
salts alluded to in my Provisional Specification, but of those named or alluded
to therein, I have since found as most preferable in yielding caustic soda or
carbonate of soda, those salts or substances hereunder given.
"SALTS."
§ 1. Chloride of sodium or common salt, rock salt, the brine liquor of salt
pits, sea water, kelp, crude nitrate of soda from Chili and other localities;
carbonate of soda contaminated with chloride of ammonium, as when common
salt is decomposed by Dyer and Hemming's process for producing carbonate

page_text: § 2. Mono-sulphide or bisulphide of sodium, or the solution of sodium
formed by igniting to bright redness a mixture of either sulphate or sulphite
cf soda, with about two-thirds of their respectivo weights of coal dust, and then
lixiviating the same with water; also the impure black ash and other soda
liquors formed as in the intermediate stage of the manufacture of ordinary
caustic soda or carbonate of soda.
The terms "battery cell" or "battery cells" used in this Specification, are
in a general sense used to signify a charged battery cell or charged battery
cells capable of yielding voltaic electricity.
In stating the date of Letters Patent in the Provisional Specification which
precedes this my Final Specification, an error occurs in the words "on or about
the 18th day of February, 1862; "the said date should have been stated and
will be hereinafter stated as the 10th day of February, 1862, instead of the
said 18th day of February, 1862.
Fig. 1 represents one form of the decomposition vessel or cell to be used
in the production of caustic soda by my method. A, A, A, A, represents the
rim or upper part of the said decomposition cell, which may be of cast iron;
a vertical section of the said decomposition cell taken through the dotted
line D, E, Fig. 1, is given in Fig. 1b; r, r, r, r, Fig. 1, represent the upper
part of an ordinary porous cell to be used as the positive compartment in the
cast-iron decomposition cell; Crepresents a carbon anode immersed into the
said porous cell; Pis a metallic conductor to be metallically connected with
the said carbon anode; Nis also a metallic conductor soldered to or connected
by binding screw with the said cast-iron vessel. The said cast-iron vessel has
a tap at its lower part to draw off the soda liquor formed by battery action.
A cover formed of glazed stoneware, if chlorine be evolved in the processes to
be hereafter described,may be fitted to the said decomposition cell, as shewn
in Figs. 1° and 1°. The same letters in each of the said Figures correspond to
the same parts of the said Figures. This decomposition cell may be heated
with its contents by means of steam applied to its external sides when con-
tained in a chamber formed of wood or of brickwork set in or coated
externally with pitch, tar, petroleum, or asphalt, mixed, if desirable, with sand
or other similar carthy matter; or the said decomposition cell may be heated
by forcing into it at its lower part a jet or jets of steam by suitable piping and
taps connected with the said decomposition cell and a steam boiler; or the
said cell may be heated by setting it in brickwork over a common fire.
To produce caustic soda from an aqueous solution of common salt, the said
solution is conveyed into the said cast-iron decomposition cell A, A, A, A, as
also into the said porous cell r, r, r, r, until it reaches the level V, V, Fig. 1b;

page_text: the whole arrangement is then heated by means already described to about
212° Fahrenheit. The carbon anode C, and the cast-iron vessel or cathode
A, A, A, A, are respectively connected by the metallic conductors P and N,
with the negative and positive poles of a series of charged battery cells
capable of effecting the said decomposition of the said common salt; when
soda and hydrogen gas are transmitted into the fluid contained in the negative
compartment lettered y, y, in Figs. 1ª and 1', while chlorine gas is evolved
from the said carbon anode in the positive compartment of the said decompo-
sition cell. An aqueous solution of caustic soda, capable of freely conducting
the electric current.may, in the first instance be employed in the said negative
compartment yy, instead of the said aqueous solution of common salt already
described as used therein. I find that the number of battery cells arranged in
single series that are capable of effecting the already described decomposition
of common salt varies according to the relative energies of the said battery
cells so arranged; for instance, in one of the forms of the voltaic battery for
which I have obtained Letters Patent(Number 340) on or about the 10th day
of February,1862, in which iron is used as a positive metal in a double porous
cell,the inner porous cell of which is filled with aqueous solution of common
salt, and the outer porous cell thereof with sulphuric acid water 1 to 10 or 1 to
15,thesaiddoubleporous cell being immersed into oil of vitriol of specific gravity
1-846 contained in a glazed stoneware vessel, inwhich is also a carbon negative
pole, I find that four of such battery cells heated to 212° Fahrenheit will
evolve chlorine and soda at the anode and cathode respectively, butwherezine
positive poles are substituted for the said iron positive poles, in the form of
battery last alluded to, then from two to three such battery cells arranged in
single series arequite capable of producing the decomposition of common salt.
Again, where in the form of battery last alluded to, the ordinary nitricacid of
commerce, to which sulphuric acid may be added, is substituted for the said
oil of vitriol, a single porous cell being used, the said temperature and said
other conditionsbeing maintained; then astillless number of such battery cells
is required to effect the said decomposition of common salt; indeed, even one
such batterycellwill effect the decomposition of the said common salt, but the
said decomposition is more readilyeffected with two such battery cells arranged
in single series. So also, by arranging in single series a sufficient number of
any of the other forms of the voltaic battery, for which I have received Letters
Patent as aforesaid, and by applying the electric current derived therefrom to
the said aqueous solution of common salt as already described, chlorine gas
and soda and hydrogen gas may be eliminated; endless examples might be
given of thevarying numbers of each distinct form of the said battery required

page_text: to effect the said decomposition, especially in the cases in which the different
forms of the said voltaic battery, or some of the said forms thereof, are used
united together in single series asmixed batteryarrangements; the size of the
poles of each form of battery being made to vary according to the relative
voltaic energy of each of the said forms used; but the numbers of batterycells
required to effect the decomposition of any of the solutions named under
heading salts," may be readily arrived at by comparing the relative energies.
of each form of battery cell with the energies of the battery cells whose
decomposing powers have been already described.
When by the said continued battery action on the said solution of common
salt thesodaliquorcontained in the said negative compartment yy,has become
of the required specific gravity, it may be drawn off into an iron boiler by means
of a tap connected with the lower part of the said decomposition cell,and may
then undergo concentration by boiling it in iron vessels until of sufficient
density to solidify on cooling, and while in its fused state is run into moulds
as caustic soda, the said soda liquor may be exposed to carbonic acid passed
into chambers, wherein the said acid becomes absorbed by the said liquor
forming carbonate of soda, which latter may now be evaporated, so as to
ultimately yield crystals of carbonate of soda by the ordinary method of
crystalizing the said carbonate. As the solution of common salt in the said
porous cell r, r, r, r, becomes exhausted by continued battery action, fresh
portions of common salt may be added to the said porous cell, and the said
decomposition continued, or the said exhausted solution may then be drawn
off, and a fresh supply of aqueous solution of common salt be conducted into
the said porous cell, or a constant stream of the said solution may be made to
percolate slowly but constantly through the said porous cell during the battery
action described, and in either case the battery current is passed through the
said solution, as already described. Any of the other salts or substances
named under heading "salts," $ 1,may be subjected in the said decomposition
cell to the said battery current in a similar manner to that already described
with reference to the said decomposition of common salt. When the soda of
the said salts or substances is also transferred to the negativecompartmenty,y,
of the said decomposition cell, the said sodaisto bedrawn off and concentrated
to the state of caustic soda, or converted into carbonate of soda, as heroin-
before described. Any iodine or bromin derived from whatever iodides or
bromides exist in the aqueous solution of the said salts or substances will be
determined by the battery action to the carbon or other anodes used. During
the said batteryaction the chlorine from the carbon anode can be prevented if
desired from escaping as gas by keeping the temperature of the sea water.or

page_text: aqueous solution of common salt acted on at about 150° Fahrenheit, while the
said solution is caused by means of taps to percolate into, and are at the same
time syphoned out of the said porous cell, so as to keep the said porous cell
full of the fluid to be operated on, in this way the chlorine remains absorbed
in the fluid of the said porous cell; the said fluid may when syphoned into
proper vessels be heated, and the chlorine expelled therefrom as gas, to be
used as desired. Or a porous cell similar to that represented in Fig. 10 may
be used in the said decomposition cell; the chlorine evolved as gas from the
carbon anode within the said porous cell is conducted away by the pipe l'
attached thereto; the same system of percolation, butwithout the saidreduction
of temperature may be employed where any of the other aqueous solutions of
the salts or substances named under heading "salts" are to be decomposed by
the said battery action in the said porous cell r, r, r, r, when either a carbon or
metallic anode is used, as already described. Or instead of a carbon anode
used as already described I substitute in the said porous cell r, r, r, r, any of
the said metals, viz., wrought or cast iron, zinc, lead, copper. The other
conditions in the formation of caustic soda already described remain unaltered
and apply as much to the aqueous solution of the other salts or sub-
stances stated under heading "salts," § 1, as to the said aqueous solution
of common salt, I avoid using an iron or zinc anode when nitrate of soda is to
be decomposed; with the other salts or substances named or described under
heading "salts," § 2, a carbon anode only is to be used. The use of either iron,
zinc, lead, or copper as anodes, considerably assists the production of the
caustic soda, and less battery power is then required than when a carbon
anode is used, especially if common salt is to be decomposed; used as anodes
the said metals are dissolved as protochlorides, but copper as dichloride of
copper, if
solution of common salt be used, and as a nitrates or
nitrites, if the nitrate of soda be subjected to battery action; during the said
solution of each metal soda is transferred to the negative compartment of the
said decomposition cell, and is to be concentrated as already stated. Tho
decomposition of common salt by battery action, as already described, is
facilitated by adding to the said common salt in the positive compartment of
the said decomposition cell. kelp, which contains besides chloride of sodium
and of potassium a considerable portion of an iodide or bromide.
increased effect is due principally to the decomposition of the said iodide at
the anode; when the iodine is released in its free state, the said increased
effect begins to subside. Now, I avail myself of such presence of an iodide
by passing into the said positive compartment from the commencement of the
battery action on the said fluid therein, a stream of sulphuretted hydrogen gas
aqueous
And the

page_text: or sulphurous acid gas constantly passed during the said battery action; the
effect of the former gas is to give up its hydrogen rapidly to the iodine at the
anode, reforming the hydriodic acid as fast as it is decomposed at the said
anode by battery action, sulphur is at the same time released in the said
positive compartment. The effect of the said sulphurous acid gas is also to
reform the hydriodic acid, while the said sulphurous acid itself becomes con-
verted partly into hyposulphuric or sulphuric acid. By continued battery
action both the potash and soda of the said kelp are determined to the
negative compartment, from which the said potash and soda may be drawn off,
and sufficient common saltadded there to toconvert the said potash into chloride
of potassium, and release a further quantity of soda; the soda liquor may
now be concentrated and further treated for caustic soda. By operating on
a large portion of kelp in the manner described, the iodine and bromine which
it contains is ultimately determined to the fluid of the positive compartment of
the said decomposition cell as hydriodic and hydrobromic acids, and the said
acids last named may now be extracted therefrom by the chemical reagents
usually employed for that purpose. Or by arresting the supply of the said
sulphuretted bydrogen or sulphurous acid, and continuing the said battery.
action, the said iodine and bromine may be finally evolved as vapour, and
condensed in suitable receivers; in this case the form of porous cell represented
in Figure 10 may be used in the said decomposition cell. A, E, G,F,D, in
the said Figure represent the porous cell, to whose rim A, B, D; is fitted a
ground or glazed stoneware cover, as represented in the said Figure; in the
centre of the said cover an oblong opening is formed, surrounded by a collar
X, X, into the said opening is placed a carbon pole C, C, the continuity of
which within the said porous cell is shown by the dotted lines c, c, c, c; the
said oblong opening is wider by about ths of an inch at its upper part than it
is at its lower part; but the said opening is only just wide enough at its lower
part to admit the said carbon pole through it. To the intermediate space
existing between the said carbon pole and collar an intimate mixture of
hydrate of silex, precipitated sulphate of baryta, and filaments of asbestos, is to
be packed, so as to form, as far as possible, an air-tight joint, or the said joint
may be made with finely-ground Roman cement. R is a tubuture by which
any gas or gases from the interior of the said porous cell pass into the pipe P,
which is ground so as to fit tight into the said tubuture; X is also a tubuture
by which the fluids operated on may be drawn off by a syphon.; Y, a stopper
fitted into the said tubuture X. In operating, as already described, on sea
water or similar solutions which contain iodides or bromides, and which will at
the same time afford-soda at the said cathode, it is advisable to pass, either

page_text: constantly or at intervals, sulphuretted hydrogen or sulphurous acid; but
soluble sulphite or hyposulphite of soda may be used in the said positive com-
partment instead of the said gases, the object of such additions being to retain
the hydriodic acid in the fluid of the said positive compartment until the said
battery action is completed. The aqueous solution of either mono-sulphide or
bisulphide of sodium, or the other substances which contain the said sulphides
named or described under heading "salts," § 2, are to be subjected, in the
positive compartment of the said decomposition cell, to the battery current,
and into the negative compartment of the said decomposition cell aqueous
solution of soda is to be conducted; the said snlphides which they may contain
then become ultimately converted into penta or polysulphide of sodium in the
said positive compartment; and if sufficient battery power be employed, the
carbon anode ultimately becomes thickly covered with sulphur; if the said
battery action be further continued, sulphuretted hydrogen is evolved; but at
about the time that this effect takes place the said action is arrested and the
hotsolution from the said positive compartment drawn off and allowed to cool,
when a large proportion of the sulphur of the said fluids crystallizes out and
may be separated by stirring and subsequent decantation of the supernatant
liquor, which may now be decomposed by exposing it in suitable chambers to
the influence of carbonic acid, so as to form carbonate of soda and sulphur;
the said carbonate of soda may be further purified and crystallized in the
usual manner. The whole of the sulphur and sulphuretted hydrogen formed
is collected, burned, and converted into sulphuric acid, to be used in any or
some of the battery cells described, as used in the method 2ndly herein-after
given. Any hyposulphite or sulphate which remains after separating the said
carbonate of soda from the said supernatant liquor may be treated for the
further production of carbonate of soda by the ordinary method. During the
said battery action the oxides of either lead, tin, copper, or antimony may be
added to tlie soda liquor contained in the said negative compartment, but only
in such quantity as to leave none of the said oxides dissolved in the said soda
liquor after the said battery action has been finally interrupted. The said
oxides may be placed ou perforated shelves or on small trays, conveniently
formed, and placed at the upper part of the said negative compartment; or
the said oxides and soda liquor may be freely agitated together by a jet
or jets of steam passed into the said liquor; also, in any of the cases herein-
before described with reference to the decomposition of any of the other salts
or substances stated under the heading "salts," § 1, in which said cases the
said soda liquor exists in the negative compartment of the said decomposition
cell used, the said metallic oxides may be also, with the precaution stated,

page_text: added to the said negative compartment during the continuance of the battery
action described in such cases.
The black ash liquor, as also the impure caustic soda of soda works, is also
to besimilarlysubjected, in the positive compartment of the said decomposition
cell, to the said battery current until the said liquor or liquors become clear
or nearly colorless. I find that where the said sulphides are treated as last
described but little battery power is required up to the period of the said
decomposition, at which the said sulphides become peutasulphide; for
instance, one of the battery cells already described in which zinc is used will
produce the effects alluded to. I find that when sulphide of sodium or black
ash liquor is much impregnated with silex and oxide of iron, both of these
substances are determined to the said anode, and in this case the form of
decomposition cell, in which the anode may be made to revolve, may be
used, and thus be cleansed of the black slime, sulphur, or other matter
so determined to its surface. If sulphur or the said other impurities on
the surface of the said anode impede the passage of the said battery current
such impurities may be burnt off the surface of the said revolving anode by
fixing near its surface a row of gas jets whose flames will ignite the said
sulphur.
It frequently occurs that the metals, when reduced by the ordinary method
of smelting them from their ores, contain, as alloy, such quantities of
certain metals, such as copper, silver, or gold, as would render the complete
extraction of the last-named metals from them a source of profit. Now
it occurs, where the metals, iron, zinc, and lead, are used as anodes, as
described, and do not contain such an excess of either copper, or silver, or
gold, as will arrest the influence of the said battery current, that these impu-
rities of the said anodes remain undissolved in the fluid of the said
without arresting the said production of the soda, and the same remark applies.
porous cell
to copper when similarly contaminated with silver or gold. In these cases.
the said metallic impuritics, with any other insoluble matter, remain either on
the surface of the anode or fall off the said anode to the bottom of the said
porous cell, from which the said impurities may be collected from time to.
time. Where it is desired to, collect the more precious metals during the
solution of the said anodes by battery action, a decomposition cell is employed:
similar to that represented in Fig. 6, in which B, B, represents a circular flat
plate of any of the said impure anodes put on in two halves, as indicated by
dotted line c, d, and firmly fixed to the flauchf, f, formed ou an iron shaft S,
and metallically connected thereto by means of bolts, nuts, and screws, as
shewn in the said Figure. When in action, the said plate is made to revolve

page_text: continually, or at intervals, on the said shaft in the direction shewn by the
arrow, against a thin iron scraper i, i, bent a little towards the said plate; the
said scraper is firmly fixed to the endof aguide board,t, of the form represented
in the said Figure; R is a tap to draw off the soda liquor; v, v, v, is a wooden
cover formed so as to admit into the said decomposition cell the said circular
plate, from the surface, of which latter the said scraper i, i,scrapes and collects
thesaid impurities of the anode, the said impurities collect on the surface of the
board t, t, which is screwed orbolted on to the upper part of the decomposition
cell A, A, A,A; the cast-iron decomposition cell and its contents may be heated
by any of the means described; the iron of the said decomposition cell A, A,
A,A, and the end of the shaft S are connected respectively with the positive
and negative poles of the voltaic battery employed; the dotted lines 1, 1, 1, 1,
represent the porous cell, which as well as the outer compartment of the
said decomposition cell is to be charged as already directed with reference to
charging the decomposition cell represented in Figures 12, and 1". It is
evident that any number of such decomposition cells may be arranged side
by side,and that the circular anole of each cell, being insulated from the said
shafts, by meansof glass or other non-conducteous substance may be connected
by means of a metallic spring, which presses on its periphery or surface, with
the iron of the next adjoining decomposition cell, the circular anode of which
latter revolving in common with all the other anodes, is also connected in
the same manner with the iron of the next adjacent decomposition cell so that
a single series of the said decomposition cells is thus formed, and may be
arranged in single series with any desired number of battery cells. Any of
the metals of the chlorides, formed by the solution of the respective metallic
anodes named, maybe recovered from their said solutions to the metallic state
by precipitating them as oxides by means of cream of lime added to their
respective solutions; the precipitates of the said metallic oxides thus formed
are to be washed,collected,and mixed with carbonaceous matter, and reduced
to the metallic state by the usual mode of reducing such oxides. I also
recover zinc, lead, and copper from their respective solutions formed in these
operations by the means to be described in the Specification of the Inventions
for which I have received Provisional Protection, viz., for Improvements in
Treating Copper Ores,and Solutions of Copper to Obtain Copper therefrom."
No. 2101, dated on or about 24th day of July 1862, also for "Improvements
in Treating Zinc Ores, and Solutions of Zinc, to Obtain Zinc therefrom,"
No.2253,dated an orabout 12th day of August 1862, also for "Improvements
in Treating Ores,and Solutions of Lead to Obtain Lead therefrom," No. 2254,
dated on or about 12th day of August, 1862. Any sulphurous salt of soda

page_text: which remains dissolved in the fluid of the said negative compartment last
alluded to after continued battery action is boiled down to dryness, and con-
verted into carbonate of soda by the ordinary method of manufacturing the
said carbonate.
The battery cells which I employ in my method, 1stly, 2ndly, and 4thly
described are those to be further described or alluded to in my method 3rdly
described.
The method 2ndly alluded to in my Provisional Specification is as
follows: When carbonate of soda is contaminated with chloride of amino-
nium as described under heading "salts," the said carbonate and chloride are
dissolved in water, and then transferred into the negative compartment y, y,
of the decomposition cell represented in Figures 1, 1°, and into the positive
compartment 1, 7, 7, 7, aqueous solution of common salt is conducted, into
which latter an anode of either carbon or any of the metals already described
as anodes is placed, any of the said anodes, and the cathode of the said decom-
position cell are then respectively connected with the negative and positive
poles of the said battery cell or cells in the manner already described, the
said decomposition cell, and its contents are then heated to about 212° Fahr.,
or gently boiled, when the ammonia of the said chloride of ammonium is
evolved at the said cathode, and chlorine or a chloride, as the case may be,
is formed in the said negative compartment. By continuing the said battery
action as described the whole or greater part of the said chloride of ammonium
may be extracted from the said carbonate of soda, which is then to be boiled
for a short time, drawn off, evaporated and crystallized. The said ammonia
escapes by the pipe from the said decomposition cell, and may be conveyed
with carbonic acid gas into iron chambers, in which it may be absorbed as
sesqui or bicarbonate of ammonia in cold water. During the said battery
action, oxide, or dioxide of copper may be added to the said ammonia fluid
of the said negative compartment.
In any of the cases herein-before stated in which the various salts have been
described as subjected to battery action in the decomposition cell already
alluded to, the operation is modified without other alteration by adding acetic
acid or pyroligneous acid to the negative compartment of the said decom.
position cell, until the aqueous solution of common salt contained therein gives
an acid reaction; the said battery action is then continued, the formation of
acetate of soda readily takes place, and by continued battery action accumu-
lates in the said negative compartment, whence it is ultimately drawn off,
evaporated to dryness, and ignited to a dull red heat in suitable vessels or
furnaces, and what acetic vapours or a portion of them that are given off

page_text: during the said ignition, are condensed in water, and are again supplied to the
negative compartment of the said decomposition cell to again form acetate of
soda, as before described; the said acetate is to be heated to a dull red heat,
to form carbonate of soda, as described, and the acetic vapours again absorbed
and used as already explained; the same proceeding is to be repeated so long
as sufficient acetic acid is recovered to be practically available for the purpose
described. To the acetic acid in the said decomposition cell a portion of
common salt, with the oxides of either lead, or copper, or other suitable oxides
may be added during the said battery action, and the acetate of soda formed
inay be finally drawn off, separated by crystallization from impurities, and is
then converted, as described, into carbonate of soda.
In employing acetic or pyroligneous acid as described, I wish it to be under-
stood that I only use the said acid under such conditions of its manufacture as
warrantits remunerative employment in the production of carbonate of soda;
or, instead of using acetic acid as described, sulphurous acid is substituted for
it in the said aqueous solution of common salt contained in the negative com-
partment of the said decomposition cell, and a portion of dioxide or oxide of
copper, or the sulphite of the said oxides with excess of common salt may be
added thereto. The sulphite of soda or similar salt of soda which remains
dissolved in the fluid of the said negative compartment, alter continued battery
action, is boiled down to dryness and converted into carbonate of soda by the
ordinary method of manufacturing the said carbonate.
The products of the decompositions already specified are to be utilized in the
further production of caustic soda and carbonate of soda, in the mannerhere-
under represented. Let a, b, c, d, represent four of the battery cells treated
to 212° Fahr., in which zinc, common salt, oil of vitriol, and a carbon negative
pole have been already described as used; let E represent a decomposition
cell, similar in its construction to the decomposition cell used in the operations
already described; let E contain common salt in both of its compartments; lot
frepresentan additional uncharged ballery cellin which the negativecompart-
ment consists of a porous cell with appurtenances, as represented in Figure 10;
the said porous cell is to be placed into an iron vessel, which is to act both as
a positive pole and as the outer compartment of the said uncharged battery
cell into both of the said compartments of the said additional battery cell is
now to be poured aqueous solution of common salt, and the said iron vessel
and its contents are to be heated to about 190° Fahr.; the said four battery
cells and the said decomposition cell heated to about 212° Fahr. are connected
together as already described, so as to continually decompose the said common
salt into chlorine, soda, and hydrogen, as previously specified; the said

page_text: chlorine as it is evolved from the pipe, Fig. 1', representing the said
decomposition cell, is conducted by the said pipe into the said aqueous solution
of common salt contained in the porous cell of the said additional battery cell;
as soon as the said chlorine or a sufficient portion thereof is absorbed by the
said solution of common salt, the battery connexion between the terminal
carbon pole of the said four battery cells and the carbon anode of the said
decomposition cell is interrupted, and the said terminal carbon pole of the said
four battery cells is then metallically connected with the said iron vessel or
positive pole of the said additional battery cell; the carbon negative pole of
the said additional battery cell is then metallically connected with the said
carbon anode of the said decomposition cell; thus a single series of five instead
of four battery cells are connected with the said decomposition cells. By this
method of utilizing the chlorine from the said decomposition cell, the produc-
tion of the soda liquor in the negative compartment is facilitated. Instead of
iron, either zinc or lead may be used as the positive pole in the said additional
battery cell; or, instead of any of the said metals, a carbon positive pole may be
used, there being at the same time added tothe said solution of common salt in
which the said carbon pole is immersed a portion of monosulphide of either
sodium, potassium, or of calcium; or any known suitable positive electrolyte may
be added thereto which will effectually assist the said production of the soda
liquor in the said decomposition cell. Again, in order to still further assist the
production of the said soda liquor in the said decomposition cell, the said soda
liquor that is transferred to the negative compartment of the said decompo-
sition cell is to be extracted therefrom, and heated, aqueous solution of
common salt supplied to the said negative compartment of the said decompo-
sition cell; the said soda liquor is then boiled with monosulphide of calcium
or with the soda waste (oxysulphide of calcium) of soda works; the said
liquor is then used in a second additional battery cell gas a positive electro-
lyte in contact with a carbon positive pole in a porous cell, around which may
then be poured any known inexpensive negative electrolyte, such as sesqui-
chloride of iron or oil of vitriol, in which as negative pole carbon may be used;
the said battery cell and its contents are heated to abont 212° Fahr.; the said
battery cell is now connected in single series as a sixth battery cell with the
said 5 battery cells and decomposition cell, in the same manner as that already
described with reference to connecting the said five battery cells and said
decomposition cell. The soda liquor is again transferred by the said united
battery action of the six battery cells to the negative compartment of the
said decomposition cell. What pentasulphide of sodium is formed in the
said 2nd additional battery cell during the said battery action is to be

page_text: decomposed by carbonic acid gas into carbonate of soda, and the sulphur
and sulphuretted hydrogen given off are to be converted into sulphuric acid.
This method of utilizing the said products may be repeated, as desired, until
more than one of the said decomposition cells may be arranged in single
series with the battery cells thus producible; but to make up for any loss
of chlorine, I connect any required number of such battery cells as are to be
used in these operations with the said series of battery and decomposition
cells. Chloride of potassium may be similarly decomposed, and its chlorine
and potassa utilized, as described with reference to the said decomposition
of common salt; but in this case a decomposition cell in which soda is elimi
nuted from common salt is to be included in the series of battery and decom-
position cells used:
The same method is put in force when nitrate of soda or of potassa is sub-
jected to battery action, a carbon or copper anode being used in the decom-
position cell employed.
The method 3rdly alluded to in my Frovisional Specification conjoins the
production of voltaic electricity and carbonate of soda.
The operations 1stly,2ndly, and 4thly described, depend partly or entirely on
the voltaic power produced by this method.
The substances from which the voltaic electricity is producible consist of,
NEGATIVE ELECTROLYTES.
Oil of vitriol of from specific gravity 1.846 to specific gravity 1.52;
sulphurous acid dissolved in sulphuric acid of about specific gravity 1.4;
sulphurous acid dissolved in aqueous solution of common salt,either of which
said negative electrolytes are to be used with carbon as negative pole;
also a
negative electrolyte in which are used the ingredients stated in the following
proportions, viz. :-Oil of vitriol of specific gravity 1.846, mixed with about
twice its bulk of water, to a quart of which said mixture is then added two
ounces of powdered peroxide of iron and from 6 to 8 ounces of powdered
peroxide of manganese; the said substances are heatedtoabout 212°Fahrenheit
stirred together and maybe heated as described and used as negative electrolyte
with carbon as negative pole; such ingredients favor the formation of a
manganate or permanganate of the oxide of iron added. I also employ as
negative electrolyte the nitric acid of commerce, to which about a third of its
volume of oil of vitriol is added, with carbon as negative pole. The said
negative electrolytes and the positive electrolyteshereafter stated are of course
to be used at a temperature of about 212° Fahrenheit. Iron, zinc, and lead
are the soluble positive poles used.
When oil of vitriol of greater specific

page_text: gravity than 1.52 is to be used as negative electrolyte I prefer to employ a
double porous cell, the outer compartment of which is to be charged as
described in my method 1stly given, but where amalgamated zinc is to be used
as the positive pole in sulphuric acid water the said outer compartment may
be filled with a mixture of equal volumes of oil of vitriol and water, which
greatly prevents the precipitation of sulphate of zinc in the pores of the
porous cells and a durable battery action is maintainable; also with an
amalgamated zinc positive pole in sulphuric acid water a single porous cell
may be used, if the oil of vitriol of the negative compartments be of about
specific gravity 1.55. Aqueous solution of common salt is to be used in the
positive compartment of the battery cells in which iron, amalgamated zinc, or
lend, are to be used as positive poles and when iron or amalgamated zinc are
the positive poles used, their respective oxides (F20, HO), (ZnO, HO;) are
to be mingled with the said solution of common salt in which the said poles
are immersed.
POSITIVE ELECTROLYTES.
.
The following substances are the positive electrolytes used in aqueous
solution with carbon as positive pole in the battery cells in which any of the
said negative electrolytes, with the exception hereafter stated, are also to be
used. Mono or bi-sulphide of sodium; sulphide of calcium; the soda waste
of soda works or oxysulphide of calcium; soda-lime, or the waste calcareous
matter used to convert carbonate of soda into caustic soda; the said soda-lime
is to be boiled with aqueous solution of common salt and the said sulphides of
calcium. The said exception is that the said last-named sulphides of calcium
are only to be used with solution of sesquichloride of iron formed in the
operations hereafter described, or with nitric acid as negative electrolytes at
about 212° Fahr.; but neither of the said last-named negative electrolytes are to
contain sulphuric acid. Although oil of vitriol and the said other negative
electrolytes may be used as negative electrolytes with any of the said sulphides
of calcium mixed with aqueous solution of common saltas positive electrolytes,
yet from the precipitation of the sulphate of lime in the pores of the porous
cells employed, I avoid using them.
Carbonate of soda is to be produced as the result of battery action by the
following proceedings:-Let a hundred battery cells be arranged in single
series in which iron positive poles, common salt, double porous cells, and oil
of vitriol are used, as in method 1stly specified; the terminal positive and
negative poles of such a battery cell are to be respectively connected with the
cathode and anode of such a number of the decomposition cells which have

page_text: been already described as will allow the residual voltaic current of the said
battery cells to pass with such intensity and power as will produce the voltaic
flame, heat, light, and other effects producible by electricity. By the entire
voltaic energy of the said battery cells can be used for any other desired
purpose without being connected with the said decomposition cells; in either
case when the said oil of vitriol of the said hundred battery cells has become
sufficiently exhausted by continued battery action, and then it should not
be of less specific gravity than that of about 15,the said oil of vitriol is to
be drawn off by leaden siphons into stout leaden tubes or gutters,and thereby
conducted into large hemispherical pans of lead constructed and set in the
brickwork of a furnace as the leaden pans used for the manufacture of salt.
cake are constructed and set. But in order to expel the sulphur and sulphur-
ous acid from the said oil of vitriol which is conveyed into the said pan the
latter with its contents is heated by a fire beneath it to a temperature of about
300° or 320° Fahrenheit; the said sulphur liquifies and floats on its surface.
During the said heating the most of the sulphurous acid which it contains is
expelled, and to expel it the more readily a current of heated air may be forced
rapidly through the said oil of vitriol, and thus both the sulphur and sulphurous
acid inaybeat once expelled into the sulphur furnace or burner attachodtothe
leaden chainbers in which sulphuric acid is manufactured. The said sulphuris
burned therein and again converted, with the said sulphurous acid, 'into
sulphuric acid; an iron pan may be similarly used instead of the said leaden
pan. The said oil of vitriol of the hundred battery cells thus freed from:
sulphur and sulphurous acid as described is now to be used for the purpose.
of manufacturing carbonate of soda in the manner usually practised at soda
works. While the said exhausted oil of vitriol is drawn off at one end or
part of the battery cell fresh oil of vitriol is constantly supplied at the other
end thereof.
:
To aid the manufacture of the oil of vitriol which is to be formed partly or
entirely from the said sulphur and sulphurous acid last alluded to, several of
the battery cells in which' nitric acid is used as negative electrolyte is to be
arranged in single series, or as otherwise desired, with the said hundred
battery cells; about a dozen such nitric acid battery cells may be arranged as
described, and the uitrous vapours evolved during battery action, are to be
conveyed by glazed stoneware pipes,into the leaden chambers, in which the
said sulphurous acid, and burned sulphur have been already described as
conveyed. The said nitric acid battery cells may be formed of glazed stone-
ware, into each of which are placed porous cells with a carbon negative
pole, as represented in Figure 10, which has been already to. I prefer to

page_text: use as positive electrolyte in the said nitric acid battery cell, thesaidsulphides
of calcium, which by the continued battery action, become converted into
pentasulphide, from which latter the excess of sulphur and sulphuretted
bydrogen may be driven off by carbonic, hydrochloric or sulphuric acid; or to.
the said sulphides last named, chloride of iron, of the battery cells, may be
added, the said sulphur and sulphuretted hydrogen may then be converted
into sulphuric acid.
In manufacturing the said carbonate of soda from the exhausted oil of
vitriol derived from the battery cells, hydrochloric acid is driven off and is to
be condensed in towers in the manner generally practised, the said hydro-
chloric acid is to be allowed to percolate over peroxide of iron or hydrate of
peroxide of iron, such as bog iron ore or other suitable iron ores, and the
percolation is to be effected while the said hydrochloric acid is hot, either in
the said towers, or in reservoirs built of fire-brick and silicious cement, and
covered in so as to prevent the escape of the vapour of the hydrochloric acid.
The said peroxide of iron may be placed in the said reservoir in masses or
lumps of any convenient size so as to unite with the said hot acid, and form
sesquichloride of iron. The said acid when sufficiently saturated is while hot
to be conveyed by glazed stoneware pipes into battery cells of the said ware
kept heated to 212° Fahrenheit, and used therein as negative electrolyte. In
these sesquichloride of iron battery cells, I prefer to employ, as positive
electrolyte, either soda waste (oxysulphide of calcium) or sulphide of sodium,
if the said soda waste be used as the positive electrolyte ; the effect of the
battery action is to convert the said soda waste into pentasulphide of calcium,
which may be treated for its sulphur as before stated,and the said sulphur is
to be converted into sulphuric acid. If the said sulphide of sodium be used the
samereactions occur, but in this case I prefer to decompose the pentasulphide
of sodium formed by the said battery action as far as possible into carbonate
of soda, by exposing the last-named sulphide to the action of carbonic acid,
when a portion of carbonate of soda is obtainable.The said sesquichloride of
iron battery cells may be arranged in single series or otherwise with the said
decomposition cells and the said hundred battery cells. During the battery
action of the saidhundred battery cells a portion of sulphate of soda is formed
in the fluid of the outer compartment of the double porous cells used, the said
fluid is to be drawn off by siphons, or allowed to percolate from the said
porous cells by means of the battery apparatus represented in Figures 7, 8,
and 8,the said fluid of the outer porous cells is then concentrated by evapora-
tion until it is sufficiently saturated to allow its sulphate of soda to crystallize
out; the mother liquor is to be drained off, and the said sulphate washed with

page_text: a small portion of water mixed with coal dust, and converted into carbonate
of soda.
T
. In Figures 7, 8, and S*, A, B, C, D, E, F, represent a battery trough of
any requisite dimensions; the said trough has six divisions, to each of which:
a lip S is formed capable of carrying off into the leaden gutter g, 9, 9, at
separate periods of time either the oil of vitriol of each of the said divisions
or the respective fluids of the outer and inner porous cells, the forms of which
latter are represented in Figures 8 and 8. When a supply of oil of vitriol is
needed in the said trough the said oil of vitriol is conveyed by leaden pipes,
to which are attached glazed stoneware taps; by turning the said taps a
supply of oil of vitriol, of about specific gravity 1-846, is run into the said
troughs, the exhausted oil of vitriol is thereby displaced, and overflows by the
lips S, S, S, S, S, S, drop by drop (if the said battery cells be in action) into
the gutter g, 9, 9, whence it is conveyed into the leaden pan first already
alluded to. The lower end of the gutter g,g, g, is now placed so that it will
discharge its fluid into another vessel, and by means of leaden pipes and taps,
as described, the fluids of either the said outer or inner porous cells a, a, a, a, .
b, b, b, b, may be made to overflow drop by drop at separate periods of time
into their respective nozzles a and y, whence the said fluids are conveyed by
the lips S, S, S, S, S, S, into the gutter g, g, g; the dotted line in Figure 8,
and the Drawing Figure 8, shew the position of the inner porous cell b, b, b, b,
when placed within the outer porous cell a, a, a, a. The fluid of the inner
porous cell contains chiefly chloride, of iron, which latter may be first neu-
tralized with a small portion of cream of lime, then boiled down in a suitable
boiler, from which the crystals of the said chloride may be removed and
exposed to a red heat in a reverberatory furnace, similar to those used in
forming the black ash of soda works; the fire of the said furnace is to be
supplied with coke, and free access of the atmosphere is allowed during the
ignition, so as to convert the said chloride, as far as possible, into sesqui-
chloride of iron, which is allowed to pass over with the hydrochloric acid
formed into a large chamber, where the said sesquichloride and other vapours
are to be condensed in the hydrochloric acid water previously formed in the
operations described. Iron and oil of vitriol to be used respoctively as positive
pole and negative electrolyte in the battery cells may be produced as fol-
lows: Iron pyrites of any suitable description may be first burned in a
pyrites furnace, the whole or greater part of its sulphur converted into oil of
vitriol, which latter is to be used in the battery cells, and then converted into
carbonate of soda, as already stated; the positive iron poles to be used in the
said battery cells last named, are to be derived from the peroxide of iron

page_text: formed in the said pyrites furnace by smelting the said peroxide in the
ordinary way.
When zinc is used as positive pole in the battery cells the
same proceedings may be adopted, as described, in reference to the employ-
ment of the oil of vitriol of the negative compartment in the formation of
salt cake or sulphate of soda, and the 'subsequent conversion of the said
sulphate into carbonate of soda. The same remark applies also as to the said
employment of the oil of vitriol used in the negative compartiment of the
battery cells when lead is used as positive pole in aqueous solution of common
salt, or when, as positive electrolytes, aqueous solution of the monosulphide or
bisulphide of sodium is used with oil of vitriol as negative electrolyte. Tin
and copper and other metallic substances, although capable of acting as
positive poles in common salt with oil of vitriol, and the other negative
electrolytes described, I do not employ in this method on account of their
costliness. When sulphurous acid is used in the battery cells as negative
electrolyte, whether dissolved in aqueous solution of common salt or diluto
oil of vitriol, the battery action determines the sulphite or sulphate of soda
formed to the negative compartment.
Figure 11 represents a section of a battery cell charged with the last-
named fluids, into which the sulphurous acid gas is to be passed. a, b, c, d,
represent the outer. vessel of glazed stoneware; c, c, the carbon pole, which
as also the porous cell R, R, R, and the glass tube g, are fixed air-tight by
means of Roman or other suitable cement at their respective joints into the
upper part of the said battery cell, as represented in the said Figure; a
tubulure, not represented in the said Figure, conducts the said gas after
passing through tho said fluids into suitable pipes to leaden chambers, in
which it is finally converted into sulphuric acid. O, in the said' Figure,
represents a positive pole; v, a piece of vulcanized tube. The said negative
electrolytes after battery action has ceased are to be siphoned off, and the
salts of soda last named treated so as to yield carbonate of soda by the usual
method of manufacturing the said carbonate. The sulphurous acid may be
supplied to the said battery cells by burning sulphur in a tubulure cast-iron
vessel set in brick work the said vessel is cast so as to have three openings
a, b, c, d, as represented in Figure 12, in which v, v, v, represent melted
sulphur, which latter is supplied by the funnel-shaped opening b; a supply of
air is forced through the pipe C over the sulphur, which is to be ignited by
putting a red hot rod of iron into it through the opening it, into which a small
plug fits; the air and sulphurous acid are propelled through the pipe a into
the battery cells last described. The negative electrolyte, in which peroxide
of manganese is used, is to be drawn off and mixed with sufficient common

page_text: salt and water to form with the whole of its sulphuric acid a saturated solu-
tion of sulphate of soda; the said solution is allowed to cool, and the crystals
of sulphate of soda drained, washed, and then converted into carbonate of
soda, as before described. In order to recover the sulphur from the soda
waste sesquichloride of iron is forined by mixing with the exhausted oil of
vitriol of the battery cells, the necessary quantity of peroxide of iron to
convert it into persulphate of iron (Fe2 03, 3S, 03), and heating the same
as a thick paste to about 400° Fahrenheit; or instead of using the said
peroxide, as described, any suitable basic persulphate of peroxide of iron is to
be substituted for it and heated, as described; the said mixture is then added
to aqueous solution of common salt, the sulphate of soda allowed to crys-
tallize out, and the solution of sesquichloride conveyed to the battery cells,
in which the said soda waste is to be used as positive electrolyte; the
sulphate of soda is then to be converted into carbonate of soda. Lead used
as positive pole requires to be well supplied with aqueous solution of common
salt, and the solution of lead formed by battery action may be precipitated as
sulphide of lead from the said aqueous solution by exposure to sulphuretted
hydrogen, which is formed in the operations already described, or formed by
adding sulphuric acid to sulphide of iron. The said sulphide of lead is to be
reduced to metallic lead, and the said aqueous solution of common salt, which
now contains hydrochloric acid, is to be conveyed.
In witness whereof, I, the said James Dickson, have hereunto set
my hand and seal, this 17 day of January, in the year of our Lord
1000
JAMES DICKSON. (LS.)