Process of Manufacturing Potash, Soda, Chlorine, and their Deriva- tives by the Decomposition of Alkaline Chlorides, and Apparatus therefor.
Year: 1899

page_text: Date of Application, 22nd Nov., 1899-Accepted, 23rd June, 1900
COMPLETE SPECIFICATION.
Process of Manufacturing Potash, Soda, Chlorine, and their Deriva-
tives by the Decomposition of Alkaline Chlorides, and Apparatus
therefor.
I, REGINALD HADDAN, of the Firm of Herbert Haddan & Co., of 18, Bucking-
ham Street, Strand, W.C., London, Patent Agent, do hereby declare the nature
of this invention, a communication to me from abroad by Paul Jean Jacques
Roubertie, of Bordeaux, in the Republic of France, Chemist, 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 of manufacturing potash, soda, chlorine,
and their derivatives by the decomposition of the alkaline chlorides and apparatus
therefor.
•
This process is based on the following: When in a solution of alkaline
chloride, oxide of carbonate of silver is introduced, the chloride is decomposed,
caustic alkali or alkaline carbonate is formed and the chlorine is united with
the silver in order to form silver-chloride. Subsequently the silver-chloride is
decomposed by appropriate means, the chlorine is collected on the one hand and
the silver again transformed to oxide or silver-carbonate. For instance the
reactions of the chloride are:
1. Ag O+ Na CL + HO = Na O, HO + Ag CL
2. Ag O, CO, + Na CL + HO
=
Na O, CO₂ HO + Ag CL

page_text: from the silver by filtration and then evaporated and dried, sheltered from the
air in receivers or appropriate cylinders.
The desiccation finished, the chloride is introduced in other furnaces com-
municating at their rear part with a principal chamber where the gas produced
begins to cool and where the small amount of volatilized iron-chloride is con-
densed. This chamber is connected by other appropriate pipes with lime-
chambers where the chlorine combines with the lime to form chloride of lime.
Bellows connected with the front of the furnace introduce the air, necessary for
the reaction to the red-hot iron-chloride. This air passes previously through
milk of lime which frees it from its carbonic acid, then it passes through lime in
pieces which dries it and finally into pipes arranged round the furnace so that it
is heated before it enters the latter.
=
Fe., O₁ + 2 Cl.
The formula of reaction is 2 Fe Cl₂ +0,
The chlorine is disengaged and iron oxide remains which I reduce by carbon
mon-oxide, and recover in very fine powder which state is very favourable for
the reduction of silver chloride.
The same furnaces or cylinders can be used for the heretofore described cycle
of operations for the extraction of iron chloride and the recovery of iron. In this
case they are provided with an outlet pipe for the steam produced by the desicca-
tion, and with pipes for the chlorine, the hot air and the carbonic mon-oxide
having valves allowing these pipes to be opened and closed as required.
The silver in the form of powder remaining in the apparatus after the decom-
position of the sodium-chloride and silver chloride, is treated with nitric-acid,
and the silver is thereby dissolved. The solution of silver nitrate is treated with
milk of lime, or of strontia or baryta. The silver oxide is precipitated. The
solution of nitrate of lime or baryta or strontia is ejected, dried up and the nitrate
calcined in appropriate apparatus. The gaseous products of this calcination
introduced in the presence of air and of water steam re-constitute the nitric acid
which is collected in appropriate apparatus.
The residue is alkaline earth which is thus recovered like the nitric acid.
If a current of carbonic acid is brought to the silver oxide the latter would
be transformed to silver carbonate.
Another process which has less advantages than the former is as follows:-
I treat the silver chloride with sulphuric acid of 45°; Baumé silver sulphate
and hydrochloric acid are formed and the acid passes off and is condensed in a
water column. In order to hurry on the reaction and to separate all the hydro-
chloric acid it is necessary to use heat.
1. Ag O, SO, + NH*
NH, SO, + Ag (.
2. AgO, SO, + NH, CO, -,NH, SO, + Ag O, CO,.
The ammonia sulphate eliminated by washing is treated with lime which
removes the ammonia which is retrieved. The residue of the latter reaction is
lime-sulphate which can be sold for agricultural purposes by reason of the small
quantities of ammonia salts which it contains. The hydrochloric acid is collected
by the ordinary means and transformed into chlorine or chloride of lime, chlorate,
or the like by the means in use.
By this second process it is possible with the silver oxide to prepare as desired
either caustic alkalies or carbonate alkalies accordingly as the retrieving is done
by ammonia or its carbonate.
Although the heretofore described operations can be executed in any of the

page_text: known appropriate apparatus, I have devised an apparatus wherein all these
operations with the exception of the retrieving of the ammonia can be effected
without having to remove the silver compositions from the apparatus which
realizes a saving of time, work and money.
The annexed drawing illustrates the apparatus:-
a is a receiver of sheet metal covered with antimonial lead or any other appro-
priate material, b is the bottom of the same which is inclined towards the peri-
phery. I represent in the example a double bottom but this is not indispensable
and if heat is not required it can be suppressed; c is an agitator turning on the
pivot d; e is a cover in two parts which can be bolted on the receiver a. f is a
stuffing box mounted on a cross piece g; h is a cock filter, it is composed of a
cock 1 and the filter. The latter is broader than it is high and formed by the
box 2 the wall 2ª of which is perforated and a plate 3 also perforated but movable
in the box 2 is under the action of the screws 5 in order to permit the filtering
amianthus or cellulose material placed between the bottom 2ª and the plate 3 to
be more or less compressed. The box 2 is fastened on the receiver a in any
appropriate manner. In order to accelerate the filtration an aspiration or force
pump can be used.
are the pipes of the necessary number to bring in the pro-
ducts necessary for the operation and to take away the gas or vapour produced.
Valves are placed at the junction spots of these pipes with the apparatus
allowing them to be put in action or not as required.
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:-
1. The improved process of manufacturing potash, soda, chlorine and their
derivatives by the decomposition of the alkaline chlorides by means of silver
oxide or its carbonate.
2. In the manufacture of soda and potash by silver-oxide or its carbonate,
the decomposition of silver chloride by means of iron for the recovery of the silver
and the extraction of chlorine.
3. In the manufacture of soda and potash by silver oxide or its carbonate,
the treating of silver chloride with sulphuric acid and ammonia sulphate for the
recovery of the silver oxide or its carbonate and the extraction of the chlorine.
4. The apparatus for such treatment substantially as described and represented
in the annexed drawing.
5. The operations-herein described allowing the extraction of soda, potash and.
chlorine contained in the alkaline chlorides, and the recovery of the products
employed.
Datad this 2nd dare of Navamihan 1000.