improvements in or relating to the Treatment of Refractory Ores.
Year: 1895

page_text: Date of Application, 1st July, 1895
Complete Specification Left, 1st Apr., 1896-Accepted, 27th June, 1896
improvements in or relating to the Treatment of Refractory Ores.
A communication from PAUL ARTHUR GASSE, of 3b, Rue La Bruyère, Paris,
in the Republic of France, Clerk.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention to be as
follows:-
:-
This invention relates to a method of preparing ozone and its application for
the treatment of refractory ores and apparatus therefor, whereby the said ores
are desulphurised and oxidised, and thus rendered suitable and non-refractory
for the after-extraction of precious metals. The base metals are left and removed
as oxides and soluble sulphates.
In carrying out the first part of my invention; oxygen or air is driven by
means of a gasometer or by a fan into a dehydrant, which consists of a vat of
slate or wood, containing a solution of sulphuric acid and lump pumice or any
moisture-absorbing chemical. The dried gas then passes to a refrigerator, where
it is cooled down to a low temperature, and thence is led in a cool dry condition
into the ozoniser. The case of the ozoniser will be made preferably of slate,
but my correspondent does not confine himself to this material. On the interior
are arranged horizontally a number of sheets of mica, glass, or other suitable
non-conducting material, which fit into grooves, made in each side of the case,
and extend the whole length thereof. The sheets may be arranged any given
distance apart, and be of any given thickness. On the upper surface of each
sheet, a thin sheet of pure tin, gold, aluminium, or other suitable conductor, is
fastened by shellac or other cement and these metallic sheets fit also in grooves,
so that the upper surface of the mica or glass sheet is covered entirely with the
sheet of metal. This latter is electrically connected by a flap or tongue of the
sheet extending through the side casing, a common conducting bar passing through
the flaps and being fastened to them on the exterior of the ozoniser, the flaps and
bar constituting positive and negative terminals on either side; these terminals
are conveniently placed near the exit end of the ozoniser and so arranged that
the sheets are capable of easy removal or replacement individually, by sliding
them through slits at exit end, and by the above means a good electrical con-
nection is assured. It is desirable that the several electrical connections should
be suitably insulated, and that the glass and metal sheets should be so packed
or insulated or so supported in the casing that there can be no cross-connection
of the current which could destroy the inductive action desired, and so that in,
particular, there is no sparking. The metal sheets are connected alternately with
the positive and negative terminals.
The ends of the ozoniser are open to admit of the entrance and exit of the gas,
the same passing through the spaces between the sheets of non-conducting material.
A high-potential current having a voltage of say about 500,000 and amperage
about 0.0008, alternating say 125 per second, is passed through the ozoniser, being
conducted by the metal sheets from the positive terminal, and passing through the
apparatus and the superposed air spaces to the metallic sheets connected with the
negative pole, thus producing within the ozoniser a silent discharge, which the air
or oxygen in passing through the spaces is subjected to, the oxygen so contained

page_text: being thereby rendered nascent or chemically active, but at the same time if air or
impure oxygen be used, certain oxides of nitrogen are formed. The gas from the
oxoniser is now caused to pass into an acid-deliquescent bath. This may consist of
a wooden or slate vat having perforated or false bottoms. The space between the
false bottoms may be filled with lump pumice or suitable porous material. The
whole vat is filled nearly to the top with cold water, if necessary distilled, which
by means of inlet and exit taps is constantly cbanged or kept circulating as may be
found necessary. By means of the above arrangement, the gas from the oxoniser
passing into the acid-deliquescent bath is brought intimately into contact with the
water and the oxides of nitrogen, contained in the gas, being soluble, are retained
in the vat as nitrous and nitric acids, the nascent gas passing out at the top of the
vat. From thence it passes into the oxidiser. This consists of a wooden or slate
cylindrical vat within which preferably is a fan or stirrer on preferably a wooden
shaft. Attached to the shaft at the exterior of the vat is suitable gear for rotating
it and the fan. The shaft revolves in an aluminium socket or other non-oxidisable
bearing, and its fittings are of non-oxidisable material wherever the ozone has
access to it. The vat is provided with a door for the supply of ore, and an exit
pipe for the gas after its reaction on the orc contained in the oxidiser.
The vat is provided with circulation connections for water and with a door for
the exit of oxidised ore into a shoot for removal. The nascent gas is introduced
by means of a preferably wooden or other non-oxidisable tube passing through the
side of the vat, which tube terminates in a small perforated wooden or Don-
oxidisable box, located immediately beneath the fan or stirrer. When in action
the oxidiser is partly filled with ore to just below the gas inlet.
Water is run in
nearly to the top of the vat. The stirrer is caused to rapidly revolve, producing a
mixing action, the ore being thereby drawn up, thrown about and mixed in the
water, and the nascent gas passed in is brought into very intimate contact with the
floating particles of ore, producing in the presence of sulphur, soluble sulphates
and some oxides, the former being in solution in water, the latter going to the
botton and being passed out at the base of the vat, the gold and precious metal
being of course mixed up in the oxides at the base. I may elect to pass the
nascent gas through one or more oxidisers placed in series, the gas from the first
passing directly into the next and so on.
Although I have hereinbefore referred to alternating electric currents I may if
desired use continuous current.
Dated this 1st day of July 1895.
BOULT & WADE,
Agents for the Applicant.
Improvements in or relating to the Treatment of Refractory Ores.
A communication from PAUL ARTHUR GASSE, of 3, Rue La Bruyère, Paris,
in the Republic of France, Clerk.
I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
Chartered Patent Agent, 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 :-
This invention relates to a method of preparing ozone and applying it to the
treatment of refractory ores and comprises apparatus employed therefor; by this
treatment the ores are oxidised, and thus rendered non-refractory and suitable for
the after-extraction of precious metals therefrom; the base metals being converted
into oxides and sulphates.
Although I herein describe this improved method of preparing and employing

page_text: ozone with reference to a particular construction and arrangement of apparatus
I wish it clearly understood that the method or methods can be carried out in.
other apparatus than that which I shall refer to by way of example.
This improved method of preparing ozone consists in first passing cooled oxygen
or a suitable dry and cooled oxygen-containing gaseous fluid along passages formed'
between sheets of insulating material each sheet bearing on one of its sides a
metallic layer, all the layers being connected to a source of high-potential electric-
current and each having between it and its neighbour a layer of insulating
material.
In utilising for the treatment of ores ozone thus prepared it is preferably first
freed in a bath (hereinafter called a de-acidifying bath) from any oxides of
nitrogen which may be present and then delivered into the vessel in which it is.
brought into intimate contact with the ore on which it is to act.
In the accompanying drawings,
Figure 1 is a diagram illustrating the arrangement of apparatus for the
production of ozone and treatment of ores according to this invention.
Fig. 2 is an enlarged transverse section of the ozoniser on the line 2-2 of
Fig. 1.
Fig. 3 is a vertical central section of a chamber in which is contained a
de-acidifying bath.
Fig. 4 is a vertical central section of an oxidiser.
Like letters indicate like parts throughout the drawings.
In carrying out the first part of this invention; in this apparatus oxygen or air
is driven by means of a gasometer or by a fan A through the tube A' into a vat B
of slate or wood containing a solution of sulphuric and lump pumice B₁or of
any moisture-absorbing chemical. The dried gas then passes through the tube B 2
to a refrigerator C, wherein it is cooled down to a low temperature, say about
freezing point, and thence is led in a cool dry condition into the ozonizer D. The
case of the ozonizer will be made preferably of marble or slate, but I do not
confine myself to this material. In the interior are arranged horizontally a
number of sheets D' of mica, glass, or other suitable nonconducting material,
which fit into grooves D2, made in each side D3 of the case, and extend the
whole length thereof. The sheets D' may be arranged at any suitable distance
apart, and be of any required thickness, the oxygen or the oxygen-bearing fluid
being passed through the spaces between them. On the upper surface of each
sheet, a thin sheet D4 of pure tin, gold, aluminium, or other suitable conductor of
electricity, is fastened by shellac or other cement and these metallic sheets extend
also in the present example into the grooves D2, so that the upper surface of each
mica or glass sheet D', is covered entirely with the sheet of metal. The metal
sheets should be of such dimensions as to extend right across the ozonizer for the
full width of the channel through which the oxygen or oxygen-bearing fluid passes,
in order that no portion of the Huid shall escape the inductive action of the plates.
Instead of having in the ozonizer a non-conducting sheet at only one side of each
metal sheet there may be a glass plate at each side of each metal sheet if desired.
Each of these latter is electrically connected by a flap or tongue D 5 of the sheet,
extending through the side casing with conducting bars alternate sheets such as
the first, third, and fifth being connected to the bar E and intermediate sheets such
as the second, fourth, and sixth being connected to the bar E'. The bars pass
through these flaps and are fastened to them on the exterior of the ozonizer to
obtain a good electrical connection the flaps and bar E constituting a positive
terminal ou one side of the ozonizer and the flaps and bar E constituting a
negative terminal on the other side; these terminals are conveniently placed near
the exit end of the ozonizer and so arranged that the sheets are capable of easy
removal or replacement individually by sliding them out of the grooves and sliding
the flaps D5 out through slits made at the exit end of the walls of the ozonizer.
It is desirable that the several electrical connectious should be suitably insulated,
and that the glass and metal sheets should be so packed or insulated or so

page_text: supported in the casing that there can be no cross connection of the current which
could destroy the inductive action desired, and so that in particular there is no
sparking.
The spaces between the sheets D' of the ozoniser D are open at the ends to
admit of the entrance and exit of the gas by way of the hoods or funnels D7 D8
respectively. A high potential alternating current such as is hereinafter par-
ticularly referred to, is passed into the ozoniser being taken by the 1st, 3rd, 5th etc.,
inetal sheets from the positive terminal E, and a similar high-potential discharge
out of negative sign is delivered to the 2nd, 4th, 6th, etc., sheets by the metallic
tongues connected with the negative pole E thus producing within the ozoniser a
silent discharge to which the air or oxygen in passing through between the
plates D' is subjected, the oxygen being thereby rendered nascent or chemically
active.
It is found that electrical conditions suitable to the economical production of
oxone on a commercial scale by this process are such as may be exemplified as
follows;
For ten square feet of conducting surface in the ozoniser, having say an electrical
capacity of 001256 microfarads, an alternating current of 001 ampères with a
frequency of 100 per second is suitable. In such a case the potential difference
between the terminals of the ozoniser should be about 7000 volts.
In consequence of the high periodicity of the current the plates of the oxone
generator are kept almost constantly in a state of rapidly changing high electrical
stress. This invention is not restricted to the use of the ordinary alternating
current but includes the use of currents known as triphase and multiphase or
polyphase currents with the object of maintaining the plates of the generator in
such a state of electrical stress as above referred to, which is essential to the
proper working of the invention. If air or impure oxygen be used in the ozoniser
certain oxides or nitrogen will be formed. The gas from the ozoniser D is now
caused to pass by the pipe D 9 into a de-acidifying bath contained in the chamber F.
This may consist of a wood or slate vat having perforated or false bottoms F1 F2
above the true bottom F 3. The pipe D9 is led into the chamber F below the
false bottom F1 and delivers the gas into the bath through the perforations of F¹
in fine streams. The space between the false bottoms F1 F2 is filled with lump
pumice F 4 or other suitable porous material. The whole vat is filled nearly to
the top with cold water which may be distilled if desired and is constantly changed
or kept circulating as may be found necessary, F5 F6 are respectively the water
supply and discharge pipes of the chamber F; the supply pipe is connected to the
cistern F 7 whence the water supply pipes of the rest of the apparatus derive their
supply. By the above arrangement the gas from the ozoniser passing into the
de-acidifying bath is brought intimately into contact with the water and the
oxides of nitrogen contained in the gas, being soluble, are retained in the vat as
nitrous and nitric acids the nascent and purified ozone gas passing out at the top of
the vat by the pipe F 8 into the oxidiser G. This latter may consist of a wooden
or slate vat within which is a fan or stirrer G' on a shaft G2 which is preferably
of wood. Attached to the shaft G 2 at the exterior of the vat is suitable gear
such as G 3 for rotating the shaft and the fan. The shaft revolves in an aluminium
socket or other non-oxidisable bearing G4 and its fittings are of non-oxidisable
material wherever the ozone has access to them. The vat is provided with a
door G5 for the supply of ore and an exit pipe G 6 controlled by a suitable valve
through which the gas can be allowed to escape after acting upon the ore.
The vat G is provided with circulation connections for water and with a
door G 9 for the exit of oxidised ore into a shoot H for removal. The nascent
ozone gas is introduced by means of a non-oxidisable tube I forming a continuation
of the tube F 8 and passing through the side of the vat and terminating in a
perforated box I' located immediately beneath the fan or stirrer G' and constituting
the gas inlet. When in action the oxidiser G is partly filled with pulverised ore
to just below the gas inlet 1. Water is then run in nearly to the top of the vat

page_text: by a supply pipe G7 and the fan or stirrer G₁ is caused to rapidly revolve
producing a mixing action, the ore being thereby drawn up thrown about and
mixed in the water so that the ozone gas is brought into very intimate contact with
the particles of ore producing in the presence of sulphur, soluble sulphates and
oxides, the former being soluble in water, the latter going to the bottom of the
vat G and being passed out at the door G 9 the gold and precious metal being
retained in the oxides in a suitable condition for the subsequent treatment with a
solvent or by other known process. G8 is a drain connection for drawing off from
the vat the liquid charged with the sulphates.
I may pass the ozone through one or more oxidisers placed in series the gas from
the first passing directly into the next and so on.
Although I have hereinbefore referred to alternating the polyphase electric
currents I may if desired use continuous current provided the latter is "intermitted"
as by a vibrating contact for example, it will be understood that the strength of
ozone employed will vary with the nature of the ore under treatment, but I prefer
a high percentage such as five per cent. to seven per cent. when practicable.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manuer
the same is to be performed, I declare that what I claim is ;-
1. In the treatment of ores utilising nascent and purified ozone freed from oxides.
of nitrogen for the purpose of oxidation substantially as described.
2. In the manufacture of ozone for the treatment of ores the employment of
electricity in the manner and under the conditions herein before set forth.
3. In the treatment of refractory ores with ozone the combination with an ozone
or generating apparatus of a de-acidifier into which the gases are delivered:
substantially as described.
4. In the treatment of refractory ores an oxidising apparatus such as G
substantially as described and illustrated in Figure 4 of the accompanying
drawings.
5. In the treatment of refractory ores the combination with an ozone generating
apparatus of a de-acidifier and an oxidiser operating in conjunction substantially
as described.
6. The combination and arrangement of parts constituting the complete plant for
the manufacture of ozone and its application to ores.
'ני
LA 1904
BOULT & WADE,
Agents for the Applicant..