Improvements in or connected with the Obtainment of Metals or Alloys by Electrolysis or Hydro-electro-chemical Action.
Year: 1896

page_text: Date of Application, 5th Dec., 1896
Complete Specification Left, 26th July, 1897-Accepted, 4th Sept., 1897
Improvements in or connected with the Obtainment of Metals or
Alloys by Electrolysis or Hydro-electro-chemical Action.
I, PASCAL MARINO, of 77 Rue des Foulons, Brussels, in the Kingdom of Belgium,
Engineer, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to obtain metals or alloys by electrolysis, by the
wet method; or hydro-electro chemical action, and either in a massive form or in the
form of an electro-deposited layer; the deposit being obtained either on the metals
of the same or of different kind or upon alloys, or, upon conducting surfaces of any
description.
The electrolytic deposits of the various metals and alloys, obtained by these
operations are distinguishable by :-
(a) Perfect adhesion to-all but amounting to affinity for-the metals whereon
they are deposited.
(b) Perfect cohesiveness; and
(c) A fine metallic lustre.
According to my invention, a solution of a salt of the metal, which it is proposed
to deposit by electrolysis, is first prepared; such solution containing, say, one
equivalent; and there is further prepared another solution of a salt of either barium,
calcium, strontium or lead, containing one equivalent or less.
The two solutions are then mixed and by double decomposition, there are formed
an insoluble precipitate and a saline solution constituting the basis of the electrolyte.
This saline solution is prepared by either a complete or an incomplete double
decomposition the object in the latter case being, to obtain mixtures of salts, such
as sulphate and chloride, sulphate and acetate, sulphate and nitrate, chloride and
acetate, chloride and nitrate and the like.
The following are examples of the ways in which my invention can be carried out
bnt I do not limit myself to the precise details given in these examples.
1. Take a solution containing one equivalent of sulphate of magnesia, and mix with
it a solution containing less than one equivalent of barium chloride. An insoluble
precipitate of sulphate of baryta, and a solution of sulphate and chloride of
magnesium will form. The fluid is separated from the precipitate which may be
done either by decantation or by filtration, or by both filtration and decantation.
2. Mix a solution of a chloride (or a nitrate, or an acetate, of the salt of which
it is desired to precipitate the metal) with the solution of a salt which, as on double
decomposition, gives an insoluble precipitate and a solution to be electrolyzed. Thus,
one solution might contain one equivalent of chloride of aluminium, and the other
solution less than one equivalent of acetate of lead. Then the mixture of the two
solutions will yield insoluble chloride of lead and a solution of acetate of alumina and
of chloride of aluminium which, after being freed from traces of lead by sulphurous
hydrogen, is ready for use as a basis for the electrolyte whereby deposits of metallic
aluminium are to be obtained.

page_text: 3. Mix a solution containing one equivalent of sulphate of chrome with a solution
containing less than one equivalent of chloride of calcium. There will form some
insoluble sulphate of lime and a solution of chloride and sulphate of chrome which
may serve for the preparation of chrome.
4. Mix a solution containing one equivalent of sulphate of manganese with a
solution containing less than one equivalent of chloride of strontium. A precipitate
of sulphate of strontium will form while the fluid will contain chloride of
manganese along with sulphate of manganese, which may serve as a basis for the
electrolyte.
Or, on the other hand, the solution to be electrolysed may be prepared, and 1
formed by double decomposition, in the following manner :-
If it be desired to extract copper from ore, the electrolyte is formed by taking a
solution of sulphate of copper; and to this is added an alkaline sulphate, and then
a solution of an alkalino-earthy chloride, of which there should not, however, be a
sufficient quantity to precipitate the whole of the sulphuric acid combined with the
copper and the alkali. There will form an earthy alkaline sulphate and a solution
which, on being separated by decantation or filtration, will contain a mixture of
sulphate and chloride of copper, and also some sulphate and some alkaline chloride.
To this solution a mineral acid, is added (either hydro-chloric or sulphuric acid
being suitable) for the purpose of causing the solution to become a better conductor
and of facilitating the attack to which the ore which is employed as a soluble anode is
to be subjected.
The practicability of preparing an electrolytic bath by means of double decom-
position, and the obtainment by this method of preparation, of results which are
totally different from any that were ever obtained before, may not be self evident,
inasmuch as they have not, hitherto, received any recognition or corroboration from
theory, but I have ascertained by numerous experiments that my theory is correct.
In fact my method is an application of the well known laws laid down by
Berthollet.
According to Berthollet's law the reaction taking place in a mixture of solutions
of two different salts is complete wherever an insoluble precipitate is the result.
This phenomenon will readily be accounted for when it is remembered that the
particles of the precipitate destroy the chemical equilibrium which is restored
between two inverse reactions.
It has, moreover, been shewn that there takes place an exchange-though an
incomplete one-even where the result of the mixture of two different salts is not
an insoluble precipitate; as, for example, where a colourless solution of sodium-
chloride is mixed with a blue solution of sulphate of soda; which is discoverable

page_text: owing to the green colour of the mixture. But in these cases reaction is never
complete. A very characteristic change of colour will become noticeable if an
electrical current be sent through a mixture of solutions of chloride and of sulphate of
copper; which shews that the laws referred to apply to mixtures of different salts
of the saine metal.
According to Berthollet's law, the reaction would be complete if the
chemical equilibrium were upset by the falling particles of the precipitate; and the
same will be the case where the same effect is produced by some other-say
electrical-power.
This theoretically explains the instance above given. When the metallic
particles, under the influence of the electric current, pass from one chemical
combination to another, they become exposed, and ready to be precipitated upon the
cathode.
It has long been known that the weakest electric currents are capable, of traversing
conducting liquids and that, such currents follow. Ohm's law. Clausius hence
concluded, in 1857 (see "Poggendorf's" Journal, 101st year, p. 338), that any
hypothesis, such as the one of Grotthus-according to which the two constituent
parts of an electrolyte are considered to be united, and connected together to form
a molecule was inadmissable and altogether at variance with Ohm's law.
;
Relations have been established between osmotic pressure and the fixing of the
freezing point, and the lowering of such freezing point and the raising of the boiling
point of the solutions. It was shewn that these reductions and elevations were.
directly proportionate to the osmotic pressure of the solutions and also, consequently.
to the number of molecules contained in them (Van't Hoff's "Zeitphysik," Chem. 3..
115. 10. 51). The molecular lowering of the freezing point, i.e., the product
obtained, may be calculated by multiplying the lowering of such point produced by:
one gramme of substance dissolved in 100 grammes of solvent, by the molecular.
weight. Now the bodies, the aqueous solutions of which are conductors of electricity,
always give higher results than those indicated by theory; and the same applies to.
osmotic pressures.
To account for these anomalies, Arrhenius (1887 "Zeitphys." Chem. 1. 631)
admits that the eletrolytic molecules are already decomposed into their constituent
elements before the current passes and then only contain electro-positive and electro-
negative ions. Such decomposition may not be complete, especially in the case of
solutions of medium concentration; hence the term "electrolytic dissociation." It
follows that when an electrolyte is decomposed by an electric current, this means
that the molecules have previously been divided into their ions; all the current does,
being, to convey such ions to their respective poles; it does not separate them,
but on the contrary, if it can pass at all, it is owing to the previous division of
the ions; and owing to this disssociation, the value of the osmetic pressure
increased.
bas.
If N molecules have been dissolved in a given volume, and if a be the relation
the number of disssociated molecules to the molecules originally dissolved, the total
number of dissociated molecules will be N.a, while the total number of non-
dissociated molecules will be N (1-a). Now if each of the Na dissociated
molecules be decomposed into parts or ions, the solution will contain Na (1—a)
Nn a molecules or ions, instead of N.
The absorption spectra of the diluted solutions confirm this hypothesis (Gladstone,
Phyl. Mag. (4) 14, 418) (Oswald, "Zeitphysik," Chem. 9, 584). These spectra are
merely superpositions of the spectra of absorption of the ions.
The colour of the solutions of yellow chromates and red bichromates is. due to the
ions CrO, Cr20 7.
According to Arrhenius, when KCl is mixed with Azo³/Na, the solution does not
contain the four salts NaCl, KCl, Azo³/Na, the solution will contain not the four
salts NaCl, KCl, Azo³/Na and Azo³/K, but the ions K, Na, Cl, Azo³.
The same applies to the mixture CuCl, and CuSO*.

page_text: Now if an electrical current should pass, copper will be deposited and, inasmuch
as the anions will attack the anode, the equilibrium will again be interrupted, and
so on.
Whatever may be the manner of this exchange between the ions and the two
salts of the same metal, such an exchange is necessary and conformable to Arrhenius'
theory. This theory satisfactorily explains the anomalies presented by the electrolytes,
as contrasted with the laws of Raoult and the investigations of Pfeffer (Osmotische
Untersuchungen, Leipzig, 1877). This continuous double exchange taking place between
the ions enables the results attained by my invention to be understood. Should either
of the two anions SO Cl be more readily transferrable than other ions, which attack
the anode with greater energy, then my purpose is accomplished; I have saved
electrical power and have rendered the formation of the metallic deposit more
uniform; while at the same time I have obtained a coherent deposit, perfectly well
adhering to the cathode.
The novelty of my process, therefore, rests upon the fact that by my experiments
and invention I have rendered the abstract hypothesis of great scientists applicable in
practice.
In any case I add to the liquids obtained in accordance with the examples above
given, viz.-by double decomposition'; and also to the same liquids obtained by any
other process; or to similar liquids in the natural state, a solution of an alkaline
salt, such as ammonium, potassium, sodium, or a mixture of two or three such salts,
in the proportion of 1/6 at least of the metal contained in the solution to be
electrolysed; except where such salts have had metallic salts simultaneously added
to them, before double decomposition has been resorted to; and then an equal
proportion of either a free organic acid, or if free boric acid is superadded.
M. Roseleur, in nickel-plating, employed chloride of ammonium. Mr. E. Weston
added boric acid, either free or in combination, to his bath; and M. Hainantz added
tartarates and tannic acid. But in these different cases the object was to employ
alkaline solutions and solutions of organic or boric acids separately, and in baths of an
entirely different composition; whereas in my process the object is to form the novel
combination herein before defined which is applicable to all metals occurring under
the conditions specified.
If the object be to obtain a deposit, either on the same or on a different metal,
or upon any good conductor which it is desired to cover, chloride of ammonium,
potassium, or sodium may be employed as an electrolyte, and an organic acid, or
boric acid, equivalent in quantity, may be added.
The bath is thus formed, and the metal to be deposited is used as an anode. If
it be desired to cover, say, an article made of iron or copper or any other metal
with aluminium, the bath is prepared with chloride of ammonium and oxalic acid;
the anode to be employed is aluminium.
EXAMPLE.

page_text: like; and upon the cathode of iron or other metal there is deposited an electrolytic
alloy of magnesium with zinc, tin, lead, or the like. The process will be the same
if it be desired to deposit iron, manganese, chrome, cobalt, tungsten, copper, or the
like. The electrolytically deposited metal will be, adhesive and have a metallic
lustre.
These re-actions are applicable whether it be proposed to deposit metals by
electrolysis either separately or mixed, to constitute alloys in predetermined
proportions.
Supposing it be desired to obtain an alloy of aluminium and chrome, a solution
will be taken for the electrolyte, containing salts of aluminium, magnesium, and
chrome. To this will be added an organic acid, or boric acid, and an alkaline salt,
or several alkaline salts that are not capable of giving insoluble precipitates with the
metallic salts from which it is desired to obtain deposits of metals.
The electrolytic process is performed in air-tight wooden tubs, or vats of other
substances, proof against the action of the solutions.
The anodes are carbon or other conducting material proof against the influence of
the products of the re-action; or they may be made of carbon or conductors proof
against any influence through contact or of an agglomeration with the salts or the
insoluble oxides of the metals constituting the baths. These salts or oxides will be
attacked, with the formation of soluble salts intended to preserve the original
concentration of the bath. The anodes may also be formed of the metals of which it
is desired to obtain electro-deposits.
Where it is desired to manufacture a metal or alloy, the cathodes are formed by
conducting surfaces of the same metal or alloy which it is proposed to produce or
of any other materials from which the metal or alloys deposited may subsequently be
separated for the purpose of melting, casting, or otherwise utilising it.
If it be intended to apply the metal or alloy to any article, as is the practice
in the silvering, gilding and kindred trades, such an article is used as a cathode.
The baths are fed by the addition of solutions of the salts of the metals to be
deposited by electrolysis, according to the composition of the electrolyte or by soluble
metallic anodes which may also be ores of the metals which it is desired to obtain or
by oxides or salts placed at the anodes, or in the bath itself.
Dated this 5th day of December 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
Improvements in or connected with the Obtainment of Metals or
Alloys by Electrolysis or Hydro-electro-chemical Action.
I PASCAL MARINO of 77 Rue des Foulons, Brussels, in the Kingdom of Belgium,
Chemist, 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 :-
The object of this Invention is to obtain metals or alloys by electrolysis by the wet
method or hydro-electro chemical action.
According to my Invention I provide electrolytic baths, for working by the wet
method, which have a more radical electrolytic action than the baths hitherto known
in that the extraction of metals from their natural or artificial salts in these baths
and the metallic deposits or alloys obtained have a more perfect adhesion or cohesive-
ness as well as a finer metallic lustre than has been obtained hitherto.

page_text: By observation and experiments I have found that these results are due to the
employment of baths prepared in the manner hereinafter described by double
decomposition which considerably assist the migration of the ions with very
beneficial results.
By observing the effects of double decomposition in the preparation of the baths
I have found that the simple mixture of salts of various metals does not give any very
marked results but that when a mixture is prepared of different salts of one and the
same metal so that the different acids of these salts are of almost the same strength,
as for example sulphate and chloride, sulphate and nitrate, chloride and nitrate,
of the said metal, very much better results are obtained in the subsequent
electrolysis.
I have found that still better results are obtained when one of the salts in the
solution of two salts of the same metal is replaced by a smaller proportion of a
solution of a salt of an alkaline earth or of lead.
By working in this last mentioned manner an incomplete double decomposition
takes place with the formation on the one hand of an insoluble precipitate and on
the other hand of a saline solution (containing different salts of the same metal)
which is then removed by filtration or decantation, and which constitutes the electro-
lyte possessing the superior qualities I have mentioned.
Proceeding in the manner indicated for another salt of the same metal and then
mixing together the two solutions obtained from the incomplete.double decomposition,
yields a still better result for electrolysis.
By preparing separately by incomplete double decomposition the solutions of salts
of different metals and then mixing together the different saline solutions when
decanted, an electrolyte would be obtained for making alloys possessing the same
qualities as the mixtures of saline solutions of the same metal and this has been
confirmed by practical tests. Thus the particular method described of incomplete
double decomposition enables an electrolyte to be prepared suitable for any desired
working by electrolysis by the wet method.
It will therefore be understood, speaking generally, that the electrolytes are
prepared, according to my invention, by the inixture of the solution of any salt of
the metal to be extracted with a solution of a salt of barium or of calcium or of
strontium or of a salt of lead, the two solutions having unequal proportions of the
chemical equivalents of the two salts, so as to bring about the incomplete double
decomposition with the formation of an insoluble precipitate and a saline solution
which is recovered by decantation or filtration.
The electrolysis of the baths formed of the liquids obtained by incomplete double
decomposition as described or by equivalent liquids may be further improved by the
addition thereto of a solution of an alkaline salt such as sodium ammonium or
potassium or a mixture of two or three of these salts in the proportion of 1/6 at least
of the metal contained in the solution to be electrolysed with the further addition in
the same proportion of a free organic acid or free boracic acid.
Instead of proceeding in the manner already indicated for the preparation of the
baths the order of operations may be changed as follows:-
The saline solution of the metal to be deposited may be first mixed with one or
several alkaline salts of the same acid as that of the metal salt and the solution of the
alkaline earth salt which is capable of producing by incomplete double decomposition
the insoluble precipitate already mentioned is then added and to the electrolyte
thus obtained the free organic acid or free boracic acid is added after decantation
or filtration.
The baths so obtained may be fed and kept at their original degree of concentration
in different ways without injury to their action by merely adding thereto as they
become exhansted saline solutions for example of metals in conformity with those of
the metal to be deposited. But these optional additions of salts and of their solutions
can only be made in baths obtained by the double decomposition of salts of the same
metal.
For obtaining alloys of two or more metals the electrolyte is prepared as already

page_text: described by incomplete double decomposition for the salts of each of the metals to
be alloyed and the different saline solutions are then mixed together after
decantation or filtration. The bath so formed can be kept at its original degree of
concentration by employing as soluble anodes the metals with which it is desired to
form the alloy.
This method of alloying metals may also be effected with a bath formed by means
of a salt of one of the metals according to the process by incomplete double
decomposition, in which bath the other metals may forin soluble anodes.
The following are examples for the formation of electrolytic baths according to my
invention for the extraction of the metals named.
The metals in the Examples 1 and 2 viz, magnesium and aluminium may also be
obtained by taking for the bath solutions of the sulphates of the metals and mixing
them with chloride of calcium. By incomplete double decomposition an insoluble
sulphate of lime will be obtained as the precipitate with solutions containing a mixture
of sulphate and chloride of the above mentioned metals.
In this modified operation an alkaline sulphate is added to a solution of sulphate
of magnesia and the whole mixed with a solution of a chloride of an alkaline earth.
An alkaline earth sulphate forms the insoluble precipitate, the bath containing in
solution a mixture of chlorides and sulphates of magnesia and of an alkali.
In a similar manner baths may be formed for obtaining any other metals which
can be recovered by electrolysis.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :--
In baths obtained by double decomposition for obtaining metals or alloys by
electrolysis by the wet method,

page_text: 1. For the extraction of a single metal the preparation of an electrolyte, by double
decomposition, of a mixture of two solutions of salts of different acids of the same
metal substantially as described.
2. For the extraction of a single metal the preparation of the electrolyte by
incomplete double decomposition in which one of the saline solutions of the same
metal is replaced by a solution of an alkaline earth salt or of a salt of lead of less
than one equivalent the saline solution of the metal being of one equivalent,
substantially as described.
3. For the extraction of a single metal the preparation of the electrolyte by the
mixture of two or more electrolytes, obtained by incomplete double decomposition, of
two or more saline solutions of different acids of the metal to be deposited each being
treated separately with a solution of an alkaline earth salt or of a salt of lead of a less
equivalent substantially as described.
4. For obtaining alloys the preparation of the electrolyte by the mixture of two or
inore electrolytes obtained by incomplete double decomposition of two or more saline
solutions of different metals each being treated separately with a solution of an
alkaline earth salt or of a salt of lead of an equivalent less than the solutions of the
metal salts substantially as described.
5. The modification in the preparation of electrolytic baths, obtained by incomplete
double decomposition, of a saline solution or of several saline solutions by the addition
to the baths of suitable alkaline salts either before or after the incomplete double
decomposition and lastly the addition to these baths of free organic acids or free
boracic acid substantially as described.
Dated this 26th day of July 1807
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.