IMPROVEMENTS IN OR RELATING TO THE TREATMENT OF COMPLEX ORES FOR THE SEPARATION OR EXTRACTION OF THE METALS CONTAINED THEREIN
Year: 1883

page_text: LETTERS PATENT to William Phillips Thompson of 6, Lord Street Liverpool,
in the county of Lancaster, Chemical Patent Agent for an Invention of
"IMPROVEMENTS IN OR RELATING TO THE TREATMENT OF COMPLEX ORES FOR
THE SEPARATION OR EXTRACTION OF THE METALS CONTAINED THEREIN
a communication to him from George T. Lewis a person residing at
Philadelphia in the state of Pennsylvania, United States of America
PROVISIONAL SPECIFICATION left by the said William Phillips Thompson
at the Office of the Commissioners of Patents on the 25th July 1883.
WILLIAM PHILLIPS THOMPSON, of 6, Lord Street, Liverpool, in the county of
Lancaster, Chemical Patent Agent "IMPROVEMENTS IN OR RELATING TO THE
TREATMENT OF COMPLEX ORES FOR THE SEPARATION OR EXTRACTION OF THE
1>
METALS CONTAINED THEREIN a communication to me from George T Lewis,
a person residing at Philadelphia, in the state of Pennsylvania, United States of
America
This invention has for its object the treatment of complex and refractory ores
containing lead zinc, and copper with very often antimony arsenic and other base
metals, besides a valuable quantity of silver and gold, together or singly.
It has hitherto been found very difficult or impracticable to smelt such ores in
the dry way, as the large amount of silica, zinc, antimony, and arsenic which they
contain will at a low temperature prevent the valuable metals from smelting down,
and only a slaggy, waxy ass will be formed; if on the other hand the temperature
be raised sufficiently high, the bulk of the metal including much of the gold and
silver, instead of smelting down will be carried off as fumes and escape into the

page_text: stack or chimney. This is owing to the tendency which antimony and zinc have,
even where reducing agents such as coal or charcoal are freely used, to pass off as
fumes, carrying off or "ballooning" the non-volatile but finely divided precious
metals.
On the other hand, if these complex ores be reduced to a fine powder and treated
by the wet method for separation of the metals they contain with sulphuric or
muriatic acids, it is often difficult to get them into a sufficiently fine state of
division by ordinary grinding to be readily acted upon by the acid. In addition
to this the other substances they contain, forming the matrix of the ores, such as
silica, alumina, lime, magnesia, and iron, often combined with sulphur sulphuric
and carbonic acid, besides being bulky to convey to the place of treatment,
generally interfere with the separation by the wet process, oither retarding or
neutralizing the action of the acid, or rendering a greater amount necessary for
the purpose.
Now it is found that instead of roasting or smelting these ores as carefully as
possible in order to avoid volatilization of the metals they contain, the best way
is to use as high a temperature as possiblo with a highly oxidizing atmosphere, so
as to volatilize them as completely as possible, thus separating them from the
matrix they contain and the non-volatile metals. The fumes thus obtained are
afterwards condensed by forcing them through a series of cooling pipes, and after-
wards straining them through flannel or other fibrous bags, or other means of
condensation and separation from the gaseous products of the furnace in which the
fumes of the volatilized metals are susponded.
This object is best attained by bringing a heated blast of air to bear upon the
complex ores, either with or without fluxes and mixture of fuel, depending upon
the class of ore to be treated.
For instance in the case of an ore consisting chiefly of sulphurets of lead, zinc,
and antimony, with silver and gold, the ore is best treated by being subjected
whilst in a fine state of division to a heated blast of air without the admixture of
fluxes, fuel, or the gaseous products of combustion. The metals will be largely
oxidized, sublimed, and separated from their solid impurities, which will be left in
the furnace or fall to the ground shortly after passing from the furnace, leaving
the fumes, consisting chiefly of the sulphates of the oxidized metals, to pass on and
be condensed.
In the case of refractory complex cupreous ores containing much silica and other
impurities, it will be found best to employ a cupola furnace supplied with a heated
blast of air at the bottom, and add a mixture of coal, coke, or charcoal, and fluxes,
in order to remove the impurities as slag, at the same time separating the slag
from the fluid non-volatile metals and yet volatilizing and separating as far as
possible the volatile metals.
In either case the object to be attained is just the reverse of the ordinary
smelting process, that is to say, to drive off as completely as possible the metals as
fumes, obtaining none or the minimum amount of actual metal in the furnace
itself, by the employment of a highly oxidizing atmosphere, preferably obtained
by the use of a heated blast of air at a high temperature forced through the
furnace in which the complex ores are treated and sublimed; subsequently, the
condensation and separation of the metallic fumes from the gases in which they
are suspended by a series of cooling pipes and flannel bags or some other effective
device for effecting this purpose.
The metallic fumes so obtained are in an impalpable powder, and consequently in
a state peculiarly suitable for separation by lixiviation or by treatment with acids,
or any of the well known wet methods of separating them from each other, or they
can be smelted in the dry way, an operation which will be much easier now that
they are deprived of their earthy and silicious ingredients.
An experimental plant which has proved very successful is as follows. First,
a low cupola furnace with feed opening for ore and fuel and sloping bottom.

page_text: Second, a box into which the metal is tapped or runs while the slag passes into a
water box. Third, a water back tuyero for the blast. Fourth, four blowers to blow
in the heated blast carrying the fumes formed in the furnace into, fifth, a hood, and
through that into, sixth, the cooling pipes and exhausting fan. Seventh, a sheet iron
receiving bin where the solid fumes collect while the gases pass out through the
interstices of, eighth, a bag or bags fastened by collars or connecting flues to the
bin. Most of the lead, gold, and silver, collects in the bin. The remainder of these
metals with most of tho arsenic, zinc, and antimony, are found in the bag or bags,
while a regulus containing most of the copper runs out of the furnace into the box
aforesaid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Phillips Thompson in the Patent Office on the
25th January 1884.
WILLIAM PHILLIPS THOMPSON of 6 Lord Street Liverpool in the County of
Lancaster, Chemical Patent Agent, IMPROVEMENTS IN OR RELATING TO THE
E
TREATMENT OF COMPLEX ORES FOR THE SEPARATION OR EXTRACTION OF THE
METALS CONTAINED THEREIN "-A communication to me from George T. Lewis
a person residing at Philadelphia in the state of Pennsylvania United States of
America.
-
This invention has for its object the treatment of complex and refractory ores
containing lead, zinc and copper with very often antimony, arsenic and other base
metals, besides a valuable quantity of silver and gold, together or singly.
It has hitherto been found very difficult or impracticable to smelt such ores in
the dry way, as the large amount of silica, zinc, antimony, and arsenic which they
contain will at a low temperature prevent the valuable metals from smelting down,
and only a slaggy waxy mass will be formed; if on the other hand the temperature
be raised sufficiently high, the bulk of the metal including much of the gold and
silver, instead of smelting down will be carried off as fumes, and escape into the
stack or chimney. This is owing to the tendency which antimony and zinc have,
even where reducing agents such as coal or charcoal are freely used, to pass off as
fumes, carrying off or " 'ballooning" the non-volatile but finely divided precious
metals.
On the other hand, if these complex ores be reduced to a fine powder and treated
by the wet method for separation of the metals they contain with sulphuric or
muriatic acids, it is often difficult to get them into a sufficiently fine state of
division by ordinary grinding to be readily acted upon by the acid. In addition to
this the other substances they contain, forming the matrix of the ores, such as
silica, alumina, lime, magnesia and iron, often combined with sulphur, sulphuric
and carbonic acid, besides being bulky to convey to the place of treatment, generally
interfere with the separation by the wet process either retarding or neutralizing the
action of the acid, or rendering a greater amount necessary for the purpose.
Now it is found that instead of roasting or smelting theso ores as carefully
as possible in order to avoid volatilization of the metals they contain, the best way
is to use as high a temperature as possible with a highly oxidizing atmosphere
so as to volatilize them as completely as possible, thus separating them from the
matrix they contain and the non-volatile metals. The fumes thus obtained are
afterwards condensed by forcing them through a series of cooling pipes and after-
wards straining them through flannel or other fibrous bags, or other means of
condensation and separation from the gaseous products of the furnace in which the
fumes of the volatilized metals are suspended.
This object is best attained by bringing a heated blast of air to bear upon the
complex ores, either with or without fluxes and mixture of fuel, depending upon
the class of ore to be treated.
For instance in the case of an ore consisting chiefly of sulphurets of lead, zinc
and antimony, with silver and gold, the ore is best treated by being subjected whilst
in a fine state of division to a heated blast of air without the admixture of fluxes,
fuel or the gaseous products of combustion. The metals will be largely oxidized,
sublimed and separated from their solid impurities, which will be left in the furnace
or fall to the ground shortly after passing from the furnace, leaving the fumes,
consisting chiefly of the sulphates of the oxidized metals, to pass on and be
condensed.
the case of refractory complex cupreous ores containing much silica and other

page_text: impurities, it will be found best to employ a cupola furnace supplied with a heated
blast of air at the bottom, and add a mixture of coal, coke or charcoal and
fluxes, in order to remove the impurities as slag, at the same time separating the
slag from the fluid non-volatile metals and yet volatilizing and separating as far
as possible the volatile metals.
In either case the object to be attained is just the reverse of the ordinary
smelting process, that is to say, to drive off as completely as possible the metals as
fumes, obtaining none or the minimum amount of actual metal in the furnace itself,
by the employment of a highly oxidizing atmosphere, preferably obtained by the
use of a heated blast of air at a high temperature forced through the furnace in
which the complex ores are treated and sublimed; subsequently, the condensation
and separation of the metallic fumes from the gases in which they are suspendod,
by a series of cooling pipes and flannel bags or some other effective device for
effecting this purpose.
The metallic fumes so obtained are in an impalpable powder and consequently in
a state peculiarly suitable for separation by lixiviation or by treatment with acids,
or any of the well known wet methods of separating them from each other, or they
can be smelted in the dry way, an operation which will be much easier now that
they are deprived of their earthy and silicious ingredients.
An experimental plant which has proved very successful is as follows. First, a
low cupola furnace with feed opening for ore and fuel and sloping bottom, second,
a box into which the metal is tapped or runs while the slag passes into a water box.
Third, a water back tuyere for the blast. Fourth, four blowers to blow in the heated
blast, carrying the fumes, formed in the furnace into the hood hereafter mentioned.
Fifth, a hood which receives the gases and passes them on to the cooling pipes.
Sixth, the cooling pipes and exhausting fan. Seventh, a sheet-iron receiving bin,
where the solid fumes collect, while the gases pass out through the interstices of
(eighth) a bag or bags fastened by collars or connecting flues to the bin. Most of
the lead, gold, and silver collects in the bin. The remainder of these metals with
most of the arsenic, zinc and antimony, are found in the bag or bags, while a
regulus containing most of the copper runs out of the furnace into the box aforesaid.
The drawing shows a sketch of a plant for the purpose-the only important point
requiring attention and delineated in detail is the filter. In this A is the fan.
B long box or flue. CC filter bags. D smaller bags immediately beneath them to
collect the dust. The upper ends of the bags Care attached to a frame capable of being
shook vertically or horizontally at intervals so as to shake the dust off and cause it
to descend into the bag below from whence it is from time to time removed.
E branch from main.
Having now described the invention and the best mode known to me of carrying
it into effect, I wish it to be understood that I do not claim broadly under this
patent the catching of metallic fumes in bag filters, as that is protected in the
patent granted to Mr William Robert Lake No 687 of 1879, but that what I claim
under the Letters Patent is :-
=
The process of treating complex ores and of separating the metals contained
therein, which consists in treating the ores at a high temperature with excess of air
sufficient to thoroughly oxidize and volatilize the more volatile metals, and collecting
the fumes in air filtering apparatus for subsequent treatment.
In witness whereof I the said William Phillips Thompson have heraunto set
my hand and seal this twenty fourth day of January in the year of our Lord
one thousand eight hundred and eighty four.
P MEARNASE