Improvements in or relating to the Treatment of Ores, and in Apparatus therefor.
Year: 1896

page_text: Date of Application, 20th Oct., 1896
Complete Specification Left, 29th July, 1897-Accepted, 20th Jan., 1898
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Treatment of Ores, and
in Apparatus therefor.
We, ELIZABETH BARNSTON PARNELL, of 11, Westcroft Road, Carshalton, in the
County of Surrey, Metallurgist, ALBERT SMITH and CHARLES EDWIN MONKHOUSE,
both of 38, Parliament Street, Westminster, in the County of Middlesex, Gentlemen,
do hereby declare the nature of this invention to be as follows:-
This invention relates to the treatment of ores, its object heing to extract the
base metals from auriferous ores, leaving the gold and silver clean and free in the
gangue from which they can be recovered by any of the well-known solvents.
In carrying out our process the ore under treatment should first be crushed and
This concentrated ore is then
and concentrated by any of the well-known means.
subjected to the oxidising action of ozone which may be produced chemically or
electrically, but we have found a convenient method is to mix a suitable portion of
chromic acid or other ozone-producing agent with the concentrated ore. By this
means ozone will be liberated in a nascent condition rapidly attacking the sulphides
and converting them into sulphates and oxidising the ores.
The ore which has thus been treated is next passed into a roasting furnace and
inay be conveyed backwards and forwards by a suitable worm conveyor until the
roasting process is complete. The furnace may be constructed from iron plates
bolted together and arranged preferably to form a triangle in section, though we do
not confine ourselves to this form, and adapted to carry a half muffle hearth.
The upper angle forms a flue-way for the fumes evolved from the roasting ore; the
two lower angles form flues for the fire which thus passes on each side (beneath the
half muffle) to the stack.
The furnace can be converted to a reverberatory by directing the flame over, instead
of beneath the hearth..
After roasting, the acid ore is neutralised with an alkali, such as the waste
ammoniacal liquors from gas works, although caustic soda, or other suitable alkali
may be employed. The ore now passes into an extractor, which is preferably,
though not necessarily of cylindrical form and may be made of any suitable material.
In this extractor the ore is boiled at a considerable pressure, we have found from
2 to 4 atmospheres to give satisfactory results, and this has the effect of dissolving
out the sulphur, which does not occur at the ordinary boiling temperature, leaving
the ore in a fit condition to be acted upon by solvents for the extraction of the
precious metals contained therein.
In extracting soluble sulphates from ore it is advantageous to keep the ore in
motion, and for this purpose the extractor may be seated on a rocker actuated by
cams, or other device worked by gearing; when the rocker is in motion the ore in
the extractor will be thrown from end to end, and every particle effectually
cleansed.
The apparatus employed may be varied without departing from the spirit of our
invention, the main features of our system consisting in the oxidation by ozone or

page_text: an agent producing ozone, and the dissolving out of the sulphur by steam pressure
preferably exceeding two atmospheres.
BOULT & WADE,
Agents for the Applicants.
Improvements in or relating to the Treatment of Ores, and
in Apparatus therefor.
We, ELIZABETH BARNSTON PARNELL, formerly of 11, Westcroft Road, Carshalton,
Surrey, now of Gillmon House, West Street, Carshalton, in the County of Surrey,
Metallurgist, ALBERT SMITH and CHARLES EDWIN MONкHOUSE, both of 38, Parlia-
ment Street, Westminster, in the County of Middlesex, Gentlemen, 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 the treatment of ores, its object being to extract the
base metals from auriferous or argentiferous ores, leaving the gold and silver
clean and free in the gangue from which they can be recovered by any of the
well-known solvents.
In carrying out our process the ore under treatment should first be crushed and:
concentrated by any of the well-known means. This concentrated ore is then
subjected to the oxidising action of ozone, nascent. oxygen or other powerful
oxidising agent, which may be produced chemically or electrically, but we have
found a convenient method is to mix a suitable portion of chromic acid or other
oxygen-producing agent with the concentrated ore. This treatment will partially
oxidise and decompose the ore and prepare it for roasting.
The ore which has thus been treated is next passed into a roasting furnace and may
be conveyed backwards and forwards by a suitable conveyor until the roasting
process is complete. The furnace may be constructed from iron plates bolted
together and arranged preferably to form a triangle in section, though we do not a
confine ourselves to this form, and adapted to carry a half muffle hearth.
The upper angle forms a flue-way for the fumes evolved from the roasting ore; the
two lower angles formn flues for the fire which thus passes on each side (beneath the
half muffle) to the stack.
The furnace can be converted to a reverberatory by directing the flame over, instead
of beneath the hearth.
After roasting, the ore, if acid, may be neutralised with an alkali, such as ordinary
ainmonia or the waste ammoniacal liquors from gas works, although caustic soda, or
other suitable alkali may be employed. The ore now passes into an extractor, which
is preferably, though not necessarily of cylindrical form and may be made of any
suitable material. In this extractor the ore is "boiled" with water at a considerable
pressure, we have found from 2 to 4 atmospheres to give satisfactory results, and this
has the effect of dissolving out the base constituents of the ore more effectually than
occurs at the ordinary boiling temperature, leaving the ore in a fit condition to be
acted upon by solvents for the extraction of the precious metals contained therein.
In extracting soluble sulphates from ore it is advantageous to keep the ore in
motion, and for this purpose the extractor may be seated on a rocker actuated by
cams, or other device worked by gearing; when the rocker is in motion the ore in the
extractor will be thrown from end to end, and every particle effectually cleansed.

page_text: may be of any well known kind but we prefer a conveyor of the following special
construction."
One or more endless chains, preferably of cast-iron, and having ploughs or
conveyors attached, pass along the hearth from end to end. One such chain is shown
at D. At each end where the chain emerges from the furnace it passes over a chain-
wheel D' one of which is caused to rotate and drag the chain in a direction from the
hopper end to the delivery end of the hearth. A return way for the chain is provided
in the brick-work at C, during passage through which it becomes well cooled. The
chain has attached to it at various points, ploughs or conveyors adapted to thoroughly
stir and "turn" the charge without carrying it too rapidly through the furnace.
The ploughs are shown at D2 in Figs. 1 and 2 and one is shown to a larger scale in
Figs. 5 and 6. In these two figs. d are "wings" of the plough which are the most
effective part of the device in bringing fresh portions of the charge to the surface.
The speed at which the ploughs move through the charge may be varied to suit
different kinds of ores requiring roasting for different periods, the usual time
required when the ore has been prepared as hereinbefore described being
8-10 hours.
Provision is made in this furnace for the copious admission of wet steam through
nozzles or holes placed as near to the hearth as conveniently possible so that the
steam can play upon the charge during the process of roasting, the steam being
required for the formation of sulphates. One form of nozzle is shown in the
drawings Figs. 1 and 2 at A being connected to a steam pipe A extending along
both sides of the shell on the outside. Provision for the admission of air or oxygen
is shown at A7. The ore should not be heated to a higher temperature than is
necessary for the formation of sulphates. When the roasted ore has been discharged
into the wagons or other receptacles it may be ground and again roasted or may be
at once treated with alkali if requiring such treatment and transferred direct to an
extractor. A special form of extractor, constructed according to this invention is
shown in Figs. 3 and 4 of the accompanying drawings. E is a cylindrical vessel
closed at each end, to the inside of whose walls E is attached a lining of say
copper E, which is not subject to corrosion or the attacks of any chemicals likely
to be present in the ore, and capable, in conjunction with the walls E', of withstand-
ing a steam pressure of several atmospheres within the vessel E. The ore is mixed
with water to a cream-like consistency, and the whole introduced into the extractor
through a door Es. A steam inlet is provided either by using hollow trunnions or as
shown by the steam pipe E, Figs. 3 and 4, and the charge is "boiled" under a high
steam pressure; we frequently find two to four atmospheres sufficient, though we do
not confine ourselves to this or any particular pressure, but it should not be less than
that of the atmosphere. This operation we term "boiling" and "boiling" under
high pressure thus, has been found by us to effect the extraction far more thoroughly
than at ordinary pressure. A steam gauge and safety valve may be fitted to the
extractor and are shown at E7 and E respectively; E being a blow-off cock. The
whole vessel E is capable of rotation about an axis transverse to that of the cylinder
of which it is formed, and means for oscillating or rocking it about such an axis are
provided as shown in the drawings, F being a crank receiving rotation from a
pulley driven by any suitable source of power, F being a connecting rod hinged
by one end to the extractor at E7, and connected by its other end to the crank.
The extractor is mounted in bearings E which permit of oscillation about the
axis K
The charge is thus thrown to and fro from end to end of the cylinder E and kept
in violent agitation under steam pressure, the result being to get all the sulphates
and other soluble salts thoroughly into solution, the precious metals being subse-
quently thoroughly separated from the sulphates, or "cleaned," by washing in vats
in the usual manner.
When this process has heen carefully carried out and the base metals thus reduced
to a minimum in the gangue, it will be found that an extremely small proportion of
solvent for the precious metals is required as compared with the solvent required

page_text: when the gangue has been prepared by other methods now in use, especially when
copper is among the base metals to be eliminated, and the solvent used is chlorine.
Having now particularly described and ascertained the nature of the
said invention, and in what manner the same is to be performed, we declare that
what we claim is:-
1. In the treatment of refractory ores subjecting them to an oxidising and decom-
posing agent as a preliminary to roasting for the purpose described.
2. In the treatment of refractory ores "boiling" the roasted ore with water under
pressure greater than that of the atmosphere for the purpose described.
3. A process of treatment for refractory ores in which they are first oxidised or
decomposed next roasted and then boiled in water under pressure for the purpose
described.
4. In the treatment of refractory ores a furnace divided by the hearth into flues
and adapted for use either as a inuffle or as a reverberatory furnace or as a half
muffle substantially as described.
5. In the treatment of refractory ores a furnace of substantially triangular form in
cross-section divided by the hearth into flues and adapted for use either as a
muffle or as a reverberatory furnace or as a half muffle substantially as described.
6. In the treatment of refractory ores a furnace hearth curved transversely.
7. The combination and arrangement of parts constituting the complete furnace
substantially as described and illustrated in Figures 1 and 2 of the accompanying
drawings.
8. In the treatment of refractory ores the combination with a furnace hearth of
one or more ploughs or conveyors such as D2 operated by a chain or the like substan-
tially as described.
9. The combination and arrangement of parts constituting the complete extractor
substantially as described and illustrated in Figures 2 and 3 of the accompanying
drawings.
10. The combination and arrangement of parts constituting the plough or conveyor
substantially as described and illustrated in the accompanying drawings.
E. BARNSTON PARNELL.
ALBERT SMITH,
CHARLES EDWIN MONKHOUSE.
Boult & Wade,
Agents for the Applicants.
E. BARNSTON PARNELL.
ALBERT SMITH.
CHARLES EDWIN MONKHOUSE.
Boult & Wade,
Agents for the Applicants.