A NEW AND IMPROVED PROCESS FOR TREATING METALS OR METALLIC ORES
Year: 1872

page_text: LETTERS PATENT to Henri Adrien Bonneville, of the British and
Foreign Patent Offices, 18, Rue de la Chaussée d'Antin, Paris,
France, and 6, Piccadilly, in the County of Middlesex, Patent
Agent, for the Invention of "A NEW AND IMPROVED PROCESS FOR TREATING
METALS OR METALLIC ORES."-A communication from Emile Thomas-
Payen, Gentleman, and Hilarion Roux, Banker, residing at
Marseille, France.
Sealed the 18th June 1872, and dated the 9th April 1872.
COMPLETE SPECIFICATION filed by the said Henri Adrien Bonneville
at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 9th April 1872, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRI
ADRIEN BONNEVILLE, of the British and Foreign Patent Offices, 18, Rue
de la Chaussée d'Antin, Paris, France, and 6, Piccadilly, in the County
of Middlesex, Patent Agent, send greeting.

page_text: WHEREAS I am in possession of an Invention for "A NEW AND
IMPROVED PROCESS FOR TREATING METALS OR METALLIC ORES," Communicated
to me by Emile Thomas-Payen, Gentleman, and Hilarion Roux, Banker,
two persons resident at Marseille, France, and have petitioned Her
Majesty to grant unto me, my executors, administrators, and assigns,
Her Royal Letters Patent for the same, and have made solemn
Declaration that it is a communication.
NOW KNOW YE, that I, the said Henri Adrien Bonneville, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the Invention, and
the manner in which the same is to be performed, that is to say:
-
The Invention communicated to me relates to improvements in the
treatment of metals or metallic ores.
The means generally employed in metal works for the treatment and
refinement of other metals than iron are applied at great heats in
reverberatory furnaces or blast furnaces, and except in cases of
pattinsonnage or of the refinement of the precious metals by the
humid way. They present great inconveniences, considerable waste of
combustibles, rapid wearing out of the machines, evident loss in the
quantity of the metals so treated either by the volatization in the
vapours, or by their being carried off, or by their being left in the
scorias; finally, insalubility owing to the metallic exhalations.
The humid way, much more dearer, presents none of these incon-
veniences, but they can hardly ever be applied on account of the
chemical constitution of the minerals themselves or the alloys to be
treated.
The said Invention consists in an entirely new and improved mixt
process which allows to reduce by the dry way, but at a low temperature,
between 300 and 800 degrees centigrades as the cases change, the minerals
to be treated so as to separate on one side the precious metals not
oxydable, and on the oxydable metals from that moment easily and
economically treated and separated by the humid way. The said
process is destined to transform the whole system of metallurgy, not
only in reducing the cost but in ameliorating the treating of ordinary
minerals; but also and above all in allowing to treat and to separate in

page_text: their smallest particles the useful metals from the mineral ores, or
from the most complicated alloys.
Alkaline oxydes, their hydrates, and in a lesser degree their car-
bonates, have the power of oxydising a large number of metals, and of
transforming metallic oxydes into hydrates.
The fundamental idea of this process is to make use of this precious
power by operating in an alkaline bath in a state of igneous fusion,
placed in a tight vessel hermetically closed, and provided with a con-
densing apparatus. The dissolving alkaline bath constitutes a medium
gifted with physical and chemical properties clearly developed.
As chemical medium it causes successively the oxydation of oxydable
metals, and their separations from those which are inoxydable.
As a physical medium it acts as a flux; as a liquid mass, in the
middle of which separations are made by density; as a temperating
mass, to which can be added energetic reactings destined to hasten the
oxydisation or to operate desulfuration, and even the reduction of the

page_text: In almost all cases the most economical bath and the most advan-
tageous is that of hydrate of soda, when to repair losses can be fed with
carbonate of soda, because the reactions to which the said baths are
submitted caustifie the carbonates added, as which will be herein
mentioned. The bath No. 1 melts at 200, bath No. 7 at 800.
CHEMICAL ACTION OF THE BATH.
. The usual metals are attacked by melted alkaline baths in the fol-
lowing order:-1, arsenic; 2, manganese; 3, zinc; 4, tin; 5, iron;
6, molybdene; 7, tungstene; 8, chrome; 9, cobalt; 10, nickel; 11,
antimony; 12, brass; 13, cadmium; 14, bismuth. The three last on
contact with the air or an energetic oxydising reacting.
Metals of platinum, osmium, rhodium, iridium, platinum, palladium,
with the exception of osmium, easily attackable, and in always comparable
to tin, are oxydised in an alkaline bath very rapidly, but not perfectly
without the addition of nitre.
Lead, mercury, silver, and gold are not oxydised by alkaline baths
only, or at least not to a sensible degree. The oxyd of silver however
being a powerful basis and having a great tendency to unite with other
metallic oxyds in presence of very oxydable metals, especially zinc,
or of metals having affinity with silver as copper, a notable proportion
of silver allied with these metals is oxydised in an alkaline bath.
Otherwise it is to be remarked that all very oxydable metals, if in
presence in the bath of metals less oxydable, but with which they were
previously bycatalytic, cause the oxydation of a part of these metals.
When, on the contrary, the different metals are plunged in an alkaline
bath in separate masses they preserve each other reciprocally from
In certain metals the
oxydation in the order of the above series.
preservation is complete; hence, so long as any metallic zinc is in the
bath neither iron nor copper can be attacked.
The metals from 1 to 9 on the series decompose alkaline carbonates
from 200 to 600° centigrade, they oxydise, disengage the oxyd of
carbon, and caustifie the alkaline carbonate.
All metals here above mentioned in the order of the above series
decompose in the bath, the alkaline hydrates disengage the hydrogene,
are oxydised, and take the place in different proportions of the water of
hydrate; the excess of metallic oxyd remains in suspension.

page_text: When alkaline scorias are treated by water, such metals as form
metallic acids (zincates, stannates, arsenites, antemonites, platinates, and
such like metals) produce salts partly soluble but more often insoluble
in the liquid. Others are precipitated in a state of hydratic oxydes
(iron, chrome, cobalt, nikel, copper, and such like metals).

page_text: RECONSTITUTING REACTIFS AND ACCELERATORS OF THE BATH.
Current of Steam.-Under the action of metals in course of treatment,
this bath tending continually to lose the water of combination which is
its active oxydant, and the reaction becoming less and less powerful as
that water becomes decomposed. It is continually restituted by means
of a current of disturbing steam under pression which is introduced at
the bottom of the vessel, passes through the entire bath, and which
besides its chemical and reconstituting action acts mechanically in
multiplying the surfaces and their contact.
Forced Currents of Air.-To obtain a more energetic oxydating action
against a mixture rich in non-oxydable metals, or also when wished to
oxydate lead, the only metal with gold which is unattackable by alkaline
hydrates in a state of fusion, a forced current of air is used through the
bath. This current of forced air serves to obtain for the desulfuration of
the bath, in cases where the minerals contain a little sulpher. In these
cases the sulpher is transformed into alkaline sulphates.
Nitre. The nitrate of soda added in successive small quantities to the
bath at the end of an operation serves to eliminate by oxydating them
the last traces of metal, and also as an energetic desulphurant. The
action of small portions of nitre added to the bath is regular and quiet,
and all the oxygene is utilized. Azote alone is disengaged, and so much
the more caustic alkali remains.
Litharge. Litharge is also sometimes used as an oxydant, but only
when it is useful to increase the lead in a metallic bath.
Filings. Finally to reunite the precious metals sometimes dis-
seminated in particles throughout the bath, or to reduce the oxyd of
silver carried off by the oxydation of the zinc, a feeble proportion of
filings of iron is used either pure or mixed with litharge or filings of
lead, or finally a thin sheet of lead placed flat on the surface of the bath
in order to obtain a minute rain of lead destined to unite the particles or
to produce a reducing action on the oxyd of silver.
"
NATURE AND FORM OF THE APPARATUSSES.
Though the said Invention can be applied to apparatusses of different
forms, and that such form has no influence on the value of the said
Invention, the arrangements which have given the best results will
herein be described.

page_text: For all cases in which the temperature does not depass 5 to 600º. C:
(the dark red) vessels of hard cast iron or Bessemer steel are used.
Where the temperature attains bright red, or 700 to 800°, or up to
1000°, that is to say, when the matters are not susceptible of an
increase of lead to render them more fusible, and it is principally the
case in the separation of silver from lead by this process which takes
the place of cupellation, vessels of beaten íron are used, carefully
covered with brasque or a refractory trimming, in order to avoid them
from being burnt.
The kettle has a flat surface of great diameter in comparison to its
height, in order to offer as much surface as possible. It stands on a
slab of refractory earth or molted iron in order that the bottom may not
be spoilt. It is surrounded by spiral flues which heat it regularly, and
the parts of which uphold it on the sides. The bottom has a tap hole
closed by an obturator operated by a lever or a screw. It receives a
steam pipe supplied with a mud cock and a tube for the forced air,
equally obturated by friction plates.
At the top of the kettle is placed an arched cover to close it, and
which is attached to the body of the kettle either by a surface perfectly
flat or by a groove trimmed with clay. This cover is hung to a pully
and is balanced by a counterpoise. On the upper part of this cover is a
nose for the escape of the gasses, which by, a tube passing through a
cylinder in which are condensed the matters which have been drawn off
(volatilized alkali and dust), and the steam of the water drains off into a
gazometer, the hydrogene or the oxyd of carbon produced if the gas is to
be used or if not to a furnace or to the chimney. This gas thus
produced can be utilized either for lighting or heating.
The gaseous
products being no longer generated, which is proved by the counter of
the gazometer, it is certain that the reactions in the kettle have ceased.
A valve placed on the gas pipe serves to let out the air at the
commencement of the operation, or when the cover has been lifted up
during the operation so as to avoid the formation of explosive mixtures.
in the gazometer.
The tap hole, which must be spacious and very inclined in order to
facilitate the flow of melted matters, is plunged into a little furnace
destined to heat it, to which is attached a moveable channel which

page_text: serves to mould the melted matters. The size of this kettle is variable
according to the quantity of matters to be treated at the same time.
PREPARATION OF THE BATH.
It is necessary to obtain either by purchase or caustification with lime
a first quantity of hydrate of melted soda. This is placed in the kettle |
above described, and is heated to a dark red heat, that is to say, to the
degree in which hydrate of soda commences to be volatilized. There
must be added successively by small quantities, never going beyond as
a whole a third of the weight of the melted hydrate, ordinary carbonate
of soda or of potash of the commerce, as free as possible of sulphur, of
sulphate, and of chlorure (and to obtain this the best is to previously
refine it in the manner of the workers of saltpetre). Steam is then
introduced. This entirely new discovery was then made, that alkaline
carbonates in a state of igneous fusion in the midst of a bath of hydrate
are at this low temperature caustified by a steam current which passes
through them. When the carbonic acid is no longer generated the
steam is stopped, the soda is run out in ingots so as to bring the bath to
its original level, and the operation is recommenced until a sufficient
stock of caustic alkali in ingots is obtained.
The bath can be fed with a carbonate as above stated instead of an 2
hydrate, and in this case all stock of caustic is useless, since the
carbonate added to the bath is precisely in the operation itself caustified
by the current of steam used as a reactif. But in some cases it is best
to feed with caustic so as not to diminish the fluidity of the bath, or the
rapidity of the reactions, or above all because the alkaline carbonates 2
would transform the hydrate of metallic oxyd into carbonates, which
happens for example for zinc and copper, and which would tend to cram
the bath and to slacken the deposit in the consecutive solutions of the
Aux renewed by the water
The metallic matters to be treated, the composition of which are
known, having been placed in the kettle the alkalin flux is added in the
proportions above indicated, according to the nature of the metals, from
3 to 5 of flux for every one of metallic oxyd to carry off. The excess of
flux is besides always useful to obtain fluidity necessary to success.
is never hurtful, for it will be seen that the losses are insignificant. It is
It

page_text: better to increase the proportion of alkali and never to reduce it. Heat
is laid on to the degree required by the nature of the metals, that is to
say, by the point of fusion of the alloys to be destroyed. If the matter
is not an alloy but a mixture of earth and metallic oxyds the heat need
not overpass a commencement of red. As in the cases of an alloy it
must be melted in order to obtain the reactions. It will be always
possible to render it more fusible if it contains too much refractory
metal by adding lead. By this means a lower temperature can be used,
and there would be no inconvenience in this, since the lead would not be
attached, but would be found at the bottom of the bath. Lead also can
be added to the bath when mixtures of oxyds are being treated whenever
the matter treated contains precious metals, gold or silver, which is to be
found in the lead.
'
Care must be taken not to add lead, and a high temperature must
also be used when an alloy difficult to fuse is being treated, and the
concentration of precious metals in a smaller quantity of lead is
required. The violent reaction being terminated (and it takes from half
an hour to an hour) steam can be introduced. A few hours of the action
of the steam are generally sufficient to exhaust the reaction.
If the matters contain very refractory metals a current of air under
pression should be used, or small quantities of nitre should be added to
insure complete oxydation. These same reactifs will be used if the
matters which are being treated contain sulphur, so as to transform it
into alkalin sulphate. When the bath contains lead, which it is not
3 necessary to attack in order to be sure of the end of the reaction,
experiments can be made in the cupel of the laboratory, which is the
most rapid means for assuring oneself that all metals allied to lead have
been oxydated.
A series of acknowledged experiments of lead and metal to be sepa-
rated from it give a scale of cupels less and less crammed with which
the experiment in course of being made should be compared so as to be
assured of the degree of refinement.
If the precious metals are to be united in a bath of lead a thin rain of
lead, by the means explained above, will be used. A light fire can then
be given and the bath will be left in a gentle fusion for one or two hours.
The length of an operation is therefore from 4 to 12 hours. The running
off having taken place, and if it is necessary the lead employed, having

page_text: been separated in the first ingots obtained, the ingots of the flux which
have been cooled aught to be pulverised between cylinders or in a metallic
mill. They are placed in a wooden vessel lined with lead, in which
passes a disturbing steam current, and exhausted by boiling with the
least quantity possible of water as free as can be of sulfates and
chlorine. The condensing water of a steam engine is the best. To
avoid pounding and to obtain an immediate dissolution the fused alkalin
scoria can with necessary precaution be poured at once into the water.
The oxyds obtained by means of deposit, of decanting, and methodical
washing will be carried to the workshop for treating by the humid
way.
Clear fluids must be evaporated and dried up, and the fused alkali, in
spite of a few hundreths of zincates, stannates, antimoniates, and such
like metals, which it retains, will be again used. There will therefore be
lost but that very feeble proportion retained during the washing of the
oxyds or combined with the metallic acids. If however the fluids were
too rich in sulphate of soda these should be got rid of by means of
cristallisation or by precipitating sulphuric acid by nitrate of lead or
baryte.
If the matters to be treated contain arsenic care should be taken to
get rid of this by by the exact addition of its equivalent of monosulphur
of sodium in the clear fluids, or also by the addition of milk of lime.
It is easily seen that the sulphur is the most disadvantageous in the
said new process, because which has to be transformed by all means into
sulphate: It is necessary therefore as much as possible to cleanse the
matters to be treated by means of previous roastings.
Treatment by the Humid Way. It is not necessary to describe the
treating of hydratic oxyds by the humid way, which is already known.
It suffices to state that this new process arriving at this remarkable
result of transforming into hydrates of oxyds all oxydable metals gives a
thus the means, by known processes, to separate them afterwards, to find
them in their smallest particles, and to purify them completely and
economically.
Treatment of Lead containing Precious Metals.-Rich lead, which
has previously been pattinsonned in the usual manner and brought to 3
the highest per-centage possible, is placed in the kettle at a high tem-

page_text: leave the lead rich an pure. In this case it is difficult to avoid the
oxyds from being followed by a certain portion of silver, notwithstanding
the addition of nitre and the rain of lead. It is convenient then to
proceed by the nitric acid, because afterwards precipitating the silver by
copper or by sea salt and the copper by zinc, some nitrate of zinc
cristallized is obtained as a last residue, which suffices by calcinating it
in order to produce again the acid and to obtain the oxyd of zinc white
and pure applicable to paintings. No process hitherto known has
given such results, and has not permitted to thus avoid no loss of silver
and lead, the great obstacle of zinking, and which is more, to find again
the zinc, the antimony, and the copper.
.
Refinement of Old Alloys.-Brass and bronze, to which has been
added a sufficient quantity of lead so as to form a fusible alloy, give by
this new and improved process cement, copper, oxyd of zinc, and stannic
acid, giving pure tin when treated in the brasqued crucible or in the blast
furnace. Old solderings treated direct give copper and tin. It should
be remarked that stanniferous or antimonious alloys can give by the
said process tin or antimony free of iron and arsenic, and consequently
of greater value; also, and above all that henceforward it will be
possible to treat iron alloys of tin which form considerable refuses in the
treatment of the tins of mines.
Treatment of Argentiferous Copper.-The said process will advan-
tageously take the place of that by liquation which only gives leady
copper or coppery lead. In fact by transforming by means of lead the
argentiferous or oreferous copper into a fusible alloy (generally 78 of
lead to 22 of copper), this alloy treated by the said process will give the
pure lead containing the silver and gold and the pure copper by the
cementing of the sulphate by means of the metallic iron.
Complex Minerals.-The most. complex minerals, fáhlers, grey' and
antimonial copper, Bournonite grey and arsenical cobalt, Kupfernikel
and antimony sulphur, the minerals of tin, and such like minerals can
be advantageously treated by the said process which enables to extract
all the metals which are contained in them on condition that by previous
metallurgical operation all silicious gangue shall have been removed
(calcareous gangues are not hurtful if in a small quantity), because the a
silicious earth would absorb the soda which could only be refound after
recarbonating the silicate thus formed, and above all as little sulphur as

page_text: possible, if any. Hence, whether the mineral perfectly roasted be placed
in the kettle in a state of pulverulent oxyds free of gangue, or whether
to separate the gangues the mineral has been fused in raw matts and
then roasted, or whether it has been melted into a metallic alloy of a
complex character, which this process facilitates by allowing large.
additions of plumbago, litharge, or lead in the previous fusion, the
metallic oxyds or the alloys which arise from them will grant to the
metallurgist by this process all the metals separate and pure.
This new and improved process will take the place of that of Wohler
for the separation of arsenic, nickel, and cobalt; and also will be the
probable means of discovering new metals, till now lost in the smoke or
the scorias of metallurgic furnaces.
0
Minerals of Platinum.-These minerals brought to a state of leaden.
alloys, fusible, treated by steam in the said caustic alkalin bath above
stated, and by sufficient additions of nitre will leave the gold with the
lead; the platinum, the iridium, the paladium, the rhodium, and the
osmium oxydated (this last partly volatilised in a state of osmic acid),
will become soluble in chlorhydic acid alone without loss of acid, and
separable by the ordinary process. The considerable expense of re-
galis aqua (eau régale) necessary to chlorurate the metals of platinum,
and the subsequent treatment of osmiure of iridium will thus be
avoided.
Alkalin Chromates.-The said process will advantageously take the
place of the process now known for the treatment of chromic iron. In
fact the mineral in impalpable powder treated in a bath of melted
potash in a closed kettle by an energetic oxydant, such as compressed air
or nitre gives chromate of potash at a comparatively low temperature
and without loss. The liquors concentrated after the crystallisation of
the alkalin chromate can again be used. Chromic iron can also be
treated in a soda bath, and the chromate of soda can be transformed
afterwards into chromate of potash, or else again the liquors can be
precipitated by a milk of lime, afterwards the insoluble chromate of
lime can be transformed into chromate of potash.
Such as herein described are the main applications of the new and
improved process for treating metals or metallic ores.
Having thus described the nature of the said Invention, and the
manner of carrying it into effect, I would have it understood that I do

page_text: not confine myself to the precise details above enumerated, as these may
obviously be modified without departing from the principle of the
Invention, but what I claim is,--
1stly. The use of baths of alkalin flux, either caustic or carbonated,
in a state of igneous fusion as both physical and chemical medium for
the treatment, the separation, the oxydation, and the reduction of
metallic matters in hermetically closed vessels at variable temperatures,
as herein described.
.
2dly. The introduction of currents of steam or air under pression
through the alkaline baths herein described as mechanical agents, or as 1
oxydating reactifs as set forth.
3dly. The successive addition to alkaline baths in a state of fusion
herein described of oxydating, reactifs, desulphuration, or reductifs by
the dry way as above described.
4thly. The caustification of alkalin carbonates in the midst of a 1
mother bath of melted alkaline hydrates by means of a disturbing
current of steam under pression.
In witness whereof, I, the said Henri Adrien Bonneville, have
hereto set my hand and seal, this Twenty-second day of
February, in the year of our Lord One thousand eight hundred 2
and seventy-two.
1
H BONNEVILLE
H BONNEVILLE (L.S.)