IMPROVEMENTS IN TREATING COPPER MATT
Year: 1884

page_text: COMPLETE SPECIFICATION.
I ARTHUR WILLIAM LOVELL REDDIE of the Office for Patents, 6, Bream's
Buildings Chancery Lane in the County of Middlesex, Patont Agent, do hereby
declare the nature of my invention for "IMPROVEMENTS IN TREATING COPPER
MATT," and in what manner the same is to be performed; to be particularly
5 described and ascertained in and by the following statement :-
These improvements in the treatment of arsenical and other impure copper matt
have in view not only the recovery of the silver and gold usually associated with
all auf

page_text: temperature the lead is entirely absorbed. Oxidization of a portion of the sulphur
now takes place. The temperature increases throughout the mass. It is at this
moment that the reduction and alloying of the silver, gold, antimony and arsenic
with the lead occur. The heat is now kept stationary and the charge again
thoroughly rabbled for about fifteen minutes. During this rabbling about sixty per {
cent of the lead used is liberated and separates from the matt. At the end of a
half hour the furnace is tapped and the lead laundered into one of the ten ton
kettles. The tap is now closed and two tons of fresh lead placed in the furnace.
The pasty mass of matt is again rabbled with this additional lead, and at the
end of a half hour the lead is tapped into the kettle mixing with the load of the
first charge.
Both of these lead applications must be made at a low temperature. The lead
must be kept below a red heat. If the matt is allowed to melt, only a small
portion of the silver, and other metals will be reduced. The success of the operation
depends upon the observance of a low temperature.
The charge which is now in a plastic condition is removed through the doors for
subsequent treatment, leaving the furnace clear for a fresh charge of matt.
The lead used can be built up in silver by boing worked with fresh charges of
matt, but practice has demonstrated that lead once used has not the desilverizing
power of fresh lead, or lend freed from antimony arsenic &c, by zincing; hence we
prefer to use clean lead and make clean work.
The desilverized charge just removed (carrying a large percentage of lead) is
placed in a reverberatory furnace running at a high temperature. While the
charge is still pasty four hundred pounds (or ten per cent) of anthracite coal slack
is rabbled in, and the reduction of a certain portion of the lead allowed to proceed.
This amount of carbon will remove all the lead contained in the matt up to within
about five hundred pounds. This twelve-and-one-half por cent is purposely
retained. The reduced lead containing a little silver is tapped off and recovered.
The melted matt is allowed to fall into sand moulds and is now ready for the
treatment for copper. Of the ten thousand pounds of lead used, ninety five
hundred will be at once recovered as metal, and this metal will contain all the silver
up to within from a quarter to a half ounce of the original assay of the matt
before treatment, together with all the gold, antimony and nearly all the arsenic
with a fraction of one percent of copper which is ultimately recovered. Ten
thousand pounds of lead will treat and desilverize four thousand pounds of matt
running from one to five hundred ounces of silver per ton.
The lend laundered into the kettles parts with the trifling amount of copper
it may contain which is skimmed off as a dry dross. This dross is added to the
next carbon reduction charge and is recovered as sulphide of copper, and the
adhering lead reduced to metal; or the dross may upon the collection of a quantity
be treated alone for copper and lead by fusion with two-and-one-half per cent of
sulphur. The copper will separate as sulphide. The lead as metal alloyed with
whatever silver the dross may have contained.
The kettle lead is treated for silver and gold in the usual manner by the zinc
method.
The lead after zincing can be at once used to desilverize a fresh charge of
regulus. The process being continuous large quantities of matt can be handled with
rapidity and economy. The lead loss will not amount to over one per cent. The
total loss of units of copper contained in the raw matt will not amount to a half
of one per cent. The antimony and arsenic are found in the run slags from the
silver cupellation, which when reduced furnish a merchantable article.
The lead contents of blast furnace matts, usually amounting to twenty per cent
will by this treatment be recovered.
The desilverized regulus which was treated with carbon and tapped into sand
moulds, or non-desilverized copper regulus which has been charged with a small
per cent of lead and submitted to the carbon process, we subject to the following
rapid treatment for copper.

page_text: The stock is broken to allow the largest fragments to pass a half inch mesh.
It is charged into a reduction furnace of five tons capacity. This furnace is one of
reverberation with sido and end door. Upon each side just back of the fire bridge
is an opening each of which openings is furnished with a one inch tuyere. These
tuyeres are arranged to sweep with an air blast over the furnace sole diagonally in
the direction of the end door.
The charge is gradually brought to a red head and occasionally rabbled. It
soon becomes dry. The heat is now increased and the blast is oponed on the
fuming stock The mass will not clot if the temperature is kept somewhat below
the melting point of copper.
At this stage the charge is constantly rabbled. In the course of an hour moss
copper begins to form upon the superficies of every module in the furnace.
The metal gradually thickens running into capillary wire, leaf and sheet copper,
penetrating from the exterior to the interior. This scorifying action between the
lead and sulphide of copper continues until the whole mass apparently becomes
metallic. At this stage samples must be occasionally drawn and plunged into
water.
When the fragments of copper upon trial no longer presont a bright appearanco
owing to the surface formation of protoxide or black oxide of copper (Cu. O) the
blast is shut off from the chargo. The whole operation occupies about four hours
at the longest..
The stock now contains from five to seven per cent of sulphur. The iron is in the
state of protoxide, the load as oxide and sulphate, the copper as metal sulphate and
di sulphate.
For every twelve per cent of iron contained in the original matt eight per cent
of quartzose sand is now added (The addition of silica to the charge converts the
sulphate of lead to oxide and forms a silicate with the iron)
The heat is now raised to a copper fusion. Copper begins to melt and slag to
form. If the slags present a fine pure black color they will be found quite free
from copper, but if they exhibit a red or red black color showing the prosence of
dioxide of copper, the addition of one per cent of desilverized raw matt will at once
clean the sing of copper. The amount of slag made by this process from matts
carrying from fifty five to sixty per cent of copper with twelve per cont of iron will
average about seven hundred pounds to the ton of matt, and should not run at the
maximum over one per cent in copper.
When the slng is found to be of proper color and consequently poor in copper it
is withdrawn by means of a skimming tool in the usual manner through the end
door.
The bath is now watched, and as fast as slag forms it is withdrawn. These
ferruginous black slags carry from thirty-five to thirty-eight per cent of lead.
They are the only slags made and are easily reduced by means of carbon, the metal
being recovered at a slight cost. When the copper from which the slag has been
removed ceases to boil, and oxide of copper begins to form on the surface, the metal
is at once tapped into sand moulds.
This copper occasionally carries some dioxide, but is excellent for brass castinga,
and if tapped at the right moment is as tough as best selected copper.
The tapped metal from the sand moulds is again melted in an ordinary refining
furnace and brought to tough pitch by the reduction of whatever oxide of copper it
may have absorbed.
This copper will then forge, roll into foil, and draw down to hair wire.
It is free from lead and iron and however arsenical the matt may have been, not
a traco of arsenic will be found in the metal.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. In the art of treating copper regulus, the process consisting in first bringing a
quantity of lead to a state of incipient redness, then combining therewith a quantity

page_text: of ground argentiferous copper matt by agitation, and thereby bringing the mass to
a temperature producing dull redness without fusing the matt, and then tapping off
the freed lead for further treatment substantially as described.
2. In the art of treating copper regulus, the process consisting in first bringing
a quantity of lead to a state of incipient redness, then combining therewith a
quantity of ground argentiferous copper matt by agitation and thereby bringing
the mass to a temperature producing dull redness without fusing the matt, then
tapping off the freed lead, then again combining a quantity of lead with the matt,
again agitating the mass until brought to a state of dull redness, and tapping off the
freed lead, substantially as described.
3. In the art of treating copper regulus, the process of separating the excess
of lead from the charge resulting from the removal of silver, gold, antimony, and
arsenic from copper matt, by combining lead therewith, rabbling the mass and
drawing off the freed lead, the same consisting in rabbling into the mass at high
temperature a quantity of coal whereby the greater portion of lead contained in the
matt is reduced and the matt melted, substantially as described.
4. The process of treating copper regulus for the recovery of copper the same
consisting in combining a small por cent of lead with the regulus, then roasting the
same while subjected to a blast and under agitation at a temperature slightly less
than that at which copper melts, substantially as described.
•
5. The process of refining copper regulus combined with lead substantially as
described the same consisting in scorifying the mass by subjecting the same to a
blast until it becomes metallic, then adding silica thereto and then subjecting the
stock to a temperature producing copper fusion until the melted copper ceases to
boil, substantially as described.
6. In the art of treating copper regulus, the process consisting of the following
steps:-
In first bringing a quantity of lead to a state of incipient redness and combining
therewith a quantity of ground argentiferous copper matt by agitation and heat at
a temperature that will not fuse the matt, then after removing the freed land,
rabbling into the mass a quantity of coal while the whole is subjected to a melting
temperature less than that at which copper melts, then scorifying the mass by
subjecting it to a blast until it becomes metallic, then adding silica thereto and
subjecting the mass to a heat producing copper fusion until the melted copper
ceases to boil substantially as described.
Dated this 11th day of November 1884.