and Copper Ores analogous to Copper Matte.
Year: 1886

page_text: Date of Application, 14th Dec., 1886.
Specification Accepted, 21st Jan., 1887.
[Communicated from abroad by JOHN JEREMIAH CROOKE and ROBERT CROOKE, both of
New York, in the State of New York, United States of America, Manufacturers.]
and Copper Ores analogous to Copper Matte.
I HENRY EDWARD NEWTON, of the Office for Patents, 6 Breams Buildings, Chancery
Lane, in the County of Middlesex, Civil Engineer, 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 :-
There are two prominent varieties of copper "matte" or "regulus"; one, the largest
in volume of production is produce by purposely matting the sulphide ores of copper;
the other is a bi-product derived from the smelting of galena and other ores containing
small percentages of di-sulphide of copper. There is also found in some localities
copper ore which in its natural state is analogous to copper matte and which can there-
fore be treated by our process without being previously matted and is therefore to bo
understood as included within the term "matte as used in the following description
and claims. All of these products contain silver and gold associated with antimony,
arsenic, iron sulphur, and other elements. "Stacks or "jacket" furnace matte
besides the above mentioned metals invariably contains large percentages of lead in
combination as sulphide.
"
It is well know that when copper matte is fused with an equal or unequal quantity
of metallic lead the silver and gold and also the antimony and arsenic and a small part
of the copper contained in the matte will at once commence to alloy with the lead and if
the matte is destitute of lead as in the case of Montana matte, a small portion of the
lead will unite with the matte as a sub-sulphide. At the same time, however, that this
takes place a portion of the sulphur contained in the matte will also unite with the lead
forming sulphide of lead and as soon as sulphide of lead has thus been formed to any
considerable extent not only will the silver and gold cease to pass from the matte to the
lead but the copper of the matte will commence to unite rapidly with the lead, thus

page_text: tending to make the whole mass homogeneous. By tapping off the lead however after
it has been in contact with the matte for a few minutes and before sufficient sulphide of
lead has been formed to cause the copper of the matto to unite with the lead to any
considerable extent from 20 to 25 per cent of the silver and gold in the matte may be
withdrawn, and thus by repeated applications of pure lead all of the silver and gold
may be finally extracted.
This, however would be extremely laborious and expensive and would consume a
great amount of time and require the use of a large quantity of lead and would also
involve great expense and labor in refining and desilverizing so large a quantity of lead
to remove the precious metals therefrom.
From the foregoing statement of the reactions which take place between the elements
of the matte and the lead it will readily be seen that if the sulphur of the matte is pre-
vented from remaining in combination with the lead the silver and gold of the matte
will continue to unite with the lead until all of these metals contained in the matte are
withdrawn or until the lead has become enriched to such an extent as to be refined
economically.
It has been discovered that this can be accomplished by introducing iron into the lead
at such a point that it will be out of contact with the fused matte. By this means the
sulphur as fast as it enters the lead is transferred to the iron thereby forming sulphide
of iron which rises and passes through the lead and the matte, thus keeping the lead
free or comparatively free from sulphur so that the silver and gold of the matte will
continue to pass to the lead and the copper of the matte be-prevented from uniting with
the lead. It is upon this discovery that the principal feature of this process is based.
As a full understanding of the process can be best imparted by a detailed description
of a manner in which it may be carried into practice, such description will now be
given, referenco being had to the accompanying drawings which show a furnace of
suitable form for the purpose. In said drawings; Fig. 1 is a cross section through the
furnace body Fig. 2 a longitudinal section taken upon the line X X of Fig. 1 and Fig. 3
is a longitudinal section taken through the furnace body showing the fire box.
Referring to said Figures it is to be understood that the furnace therein illustrated is of
the ordinary reverberatory type having a working body nearly as broad as it is long.
This body is built in a wrought iron pan A standing upon piers of brick-work with
spaces beneath for the circulation of air. The wall on one side of the furnace is pro-
vided with a number of arched recesses B (four as shown in the present case) which
open to the interior of the furnace on a level with the lower edge of the sole D. The
bottoms of these recesses are slightly inclined toward the sole and the recesses are
about six inches high six inches wide and thirteen inches deep. The sole D has an
inclination of about six inches and at its lower side the wall of the furnace is provided
with the usual lead tap a and at its upper side with the usual matte tap b. Commu-
nicating with the recesses B are vertical passages E which extend to the top of the
furnace wall. In each of these passages there is suspended a bar of iron F, the lower
end of which extends downward to the bottom of the recess B. The bars Fare arranged
to be raised and lowered by means of pulleys (not shown) or in any other suitable
manner. It is, of course to be understood that the iron which will commonly be used
in practice will be wrought-iron—such for example as ordinary wrought iron bars-as
the sulphur acts upon such iron much more readily than upon cast iron or steel. When
the work is started the furnace is first charged with a quantity of lead G which reaches
above the tops of the recesses B. After this lead is brought to a red heat a quantity of
the matte, H roughly broken and equal in weight to about half the weight of the lead,
is charged upon the surface of the fused lead. The matte soon fuses and spreads over
the surface of the lead as shown. If it is desired to concentrate and purify the matte
at the same time it is desilverized,.5 per cent of fine sand (silica) is then thrown on the
surface of the matte and the whole is gently rabbled for a few minutes. A series of
reactions now take place. The silver and gold and also the antimony and arsenic in
the matte immediately commence to alloy with lead. At the same time also a portion
of the sulphur in the matte unites with the lead thereby forming sulphide of lead, but
this sulphide of lead as fast as formed is decomposed by the iron of the bars F, the sulphur

page_text: being transferred to the iron of the bars and thereby forming sulphide of iron which
immediately rises passing through the lead and the matte to the surface of the latter.
By this means the sulphur is constantly eliminated from the lead, and the lead con-
sequently remains in such condition that it will continue to receive the silver and gold
from the matte and be prevented from taking the copper from the matte. A portion of
the lead originally contained in the matto or which entered the matte from the volume
of load beneath the matte as before stated at once unites with the silica floating upon
the top of the matte, thereby forming silicate of lead which in turn attacks the sub-
sulphide of iron which is formed by the partial extraction of the sulphur from the iron
in the matte, thereby forming at a low temperature and without previous roasting of
the matte a highly fluid acid slag which is absolutely free from copper and which can
be from time to time skimmed off and removed. By this means and by adding more
silica from time to time as it is skimmed off, a large part of the iron contained in the
matte can be withdrawn and the copper contained in the matte theroby concentrated,
thus avoiding the tedious and expensive process of roasting. This feature is also one
of great importance and may be applied when the iron is not used. The sulphido of
iron formed in the lead by the action of the sulphur on the bars F as it rises through
the matte is robbed of a portion of its sulphur by the cupriferous portion of the matte
and as it arrives at the surface it is attacked by the silicate of lead and converted into
slag and removed as above stated.
The above reactions are allowed to continue for about thirty minutes, during which
time about 90 per cent of the silver and gold, and, if the matte contains lead, the greater
part of the lead will be withdrawn from the matte. If the matte runs for example
200 ounces of silver to the ton, and 30 per cent in lead, there will be transferred to
the lead bath from the inatto during these thirty minutes 175 ounces of silver and
from 450 to 500 pounds of metallic lead free from copper but carrying most of the
antimony and arsenic originally contained in the matte.
If the charge was one ton of matte to two tons of lead the amount of iron consumed
from the bars F to keep the lead free from sulphur and copper will range from 90 to
100 pounds. If 500 pounds of lead was reduced from the matte, there will be consumed
from the ends of the bars 25 pounds for every 100 pounds of lead reduced.
If the lead used was at the commencement of the operation, pure, that is to say, free
from antimony, arsenic &c, all or practically all of the silver and gold might be with-
drawn by the single application. It is desirable however in order to avoid the expense
of refining large quantities of lead, that the same lead should be used two or more
times before it is refined and consequently the lead which will be most commonly used
for the first application will, as in the example stated, be lead which has been already
used and which consequently already contains more or less antimony and arsenic and
also a small amount of copper; and these elements when present prevent the silver and
gold from alloying with the lead as freely and rapidly as they otherwise would. This
is particularly the case after the greater part of the silver and gold have been withdrawn
from the matte. When, therefore, such lead is used, only about 90 per cent of the silver
and gold will be withdrawn from the matte by the first application of lead. For this
reason after the process has continued about thirty minutes as stated, the bars Fare
raised out of the lead and the lead is tapped off. The lead thus tapped off can then
be re-used for the first application with a fresh quantity of matte or can be refined.
Another charge of lead of the same weight as the first but which has not been previously
used and is consequently freer from these objectional elements and poorer in silver
and gold is laundered into the furnace. The bars F are again lowered and the charge
rabbled for a moment and allowed to stand for about ten minutes. This will effect the
withdrawal of all the silver and gold from the matte. The desilverized and concentrated
matte is then tapped off through the matte tap into sand moulds in the usual manner.
The second charge of lead is left in the furnace and a second charge of matte is then
charged in on top of the lead and the process is repeated. Instead of raising the bars F
and tapping off the first charge of lead as above explained the lead may, if preferred
be allowed to remain in the furnace and the matte be tapped off. The matte thus
tapped off will then be treated with a fresh quantity of purer lead and a fresh quantity

page_text: of matte will be charged into the furnace on top of the lead which was allowed to
remain there.
By thus alternating every charge of rich but impure lead with one of poor but purer
lead, the charges can be re-used for the first application with fresh matte until the lead
becomes rich enough to zinc economically. By this method, the furnace bottom will
also be kept poor and loss of silver and gold prevented.
The desilverized matte may be treated for its copper by the process described in the
Specification of English Letters Patent No. 14,853 of 1884 granted to Arthur William
Lovell Reddie or in any other suitable manner.
The particular form of furnace herein shown has been selected merely for the purpose
of illustration. It is to be understood that any other suitable form of furnace may be
used and that the iron may be introduced into the lead in any other suitable manner, it
only being essential that the iron should be in contact with the lead and that it should
be in such position as to be out of contact with the matte.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed as communicated to me by my foreign
correspondents, I declare that what I claim is :—
1. The process of recovering the precious metals from copper matte which consists
in subjecting the matte to contact with a body of lead both being in a fused condition
and at the same time eliminating the sulphur from the lead through the agency of a
body of iron which is in contact with the lead but not with the matte substantially as
described.
2. The process of recovering the precious metals from copper matte which consists
in subjecting the matte to contact with a body of lead both being in a fused condition
and at the same time eliminating the sulphur from the lead through the agency of a
body of iron which is in contact with the lead but not with the matte and then treating
the matte in the same manner with a second body of lead which is poorer in silver than
the first, substantially as described.
3. The process of recovering the precious metals from copper matte which consists
in subjecting the matte to contact with a body of lead both being in a fused condition
and at the same time eliminating the sulphur from the lead through the agency of a
body of iron which is in contact with the lead but not with the matte, and then re-using
the lead in the same manner with a fresh quantity of matte substantially as described.
4. The process of recovering the precious metals from copper matte and at the same
time concentrating and purifying the matte, which consists in subjecting the matte to
contact with a body of lead, both being in a fused condition, to recover the precious
metals and adding silica to the matte to effect the formation of a slag substantially as
described.
.5. The process of recovering the precious metals from copper matte and at the same
time concentrating and purifying the matte which consists in subjecting the matte to
contact with a body of lead both being in a fused condition, and at the same time
eliminating the sulphur from the lead through the agency of a body of iron which is in
contact with the lead but not with the matte and adding silica to the matte substantially
as described.