Improvements in and relating to a Process of and a Furnace for Treating Copper and its Alloys.
Year: 1890

page_text: Date of Application, 29th July, 1890-Accepted, 20th Sept., 1890
COMPLETE SPECIFICATION.
Improvements in and relating to a Process of and a Furnace for
Treating Copper and its Alloys.
I, WILLIAM WALLACE KEYS, residing at Waldemere Avenue, near Iraniston
Avenue, in the City of Bridgeport, County of Fairfield and State of Connecticut, one
of the United States of America, Manufacturer, 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 :-
My invention relates to certain new and useful improvements in the method of
treating copper and in a furnace therefor and its alloys, and has for its object to
remove the oxides and suboxides from such metal, so that the latter will thereby be
rendered more dense and homogeneous, as well as stronger and better fitted to withstand
the action of acids.
My said invention consists in a novel construction of furnace and in a method or
process of treating copper and its alloys, with a view to eliminating therefrom
those oxides, sub-oxides, and more or less of such other gaseous impurities as cause
the metal when melted to flow sluggishly and when developed into ingots or castings,
to be more or less porous or open, and to also be quite susceptible to corrosion by
acids and acid solutions, whether used as cast metal, or in a rolled, or in a drawn
condition.
In other words, the prime objects of my invention are to secure large runs of
metal alloys composed mainly of copper (and without zinc or lead) which when
melted, will be of high specific gravity, will flow smoothly and freely, and enable,
for instance, the successful production of solid homogeneous hollow, cylindrical
castings of great size, quite thin, and of very great strength, and also as a matter
of special importance, the metal must have a minimum susceptibility to corrosion by
contact with hot acid solutions.
I have discovered that all of these ends can be attained by purifying and deoxidizing
the metal, and especially the copper, as fully as possible, and I have also discovered
that the metal can be, and is, well deoxidized, by exposing it, while in a melted con-
dition and highly heated, to direct contact with the products of combustion, developed
from the burning of inflammable oils, preferably crude petroleum, although many of
its educts or products will serve a good purpose. The oil is burned either within the
Sinelting furnace or so adjacent thereto, as to admit of the delivery of said products
of combustion to the furnace, and to its contents without being unduly combined with
atmospheric oxygen, it being important that the carbon and hydrogen contained in
the flaming products of combustion, shall pass in contact with the surface of the
highly heated molten metal, accompanied with but little if any atmospheric oxygen,
in order that the oxygen evolved from the metal may be promptly taken up and con-
sumed, the resultant carbonic and hydric oxides, as well as other volatile impurities of
the metal being carried out of the furnace into the usual flue and stack.
The oxygen freely leaves the metal because of its greater affinity for the carbon and
hydrogen than for the metal, and hence the best results accrue when the admission of
atmospheric oxygen to the furnace is carefully guarded and controlled, and at times
it is desirable to exclude it as fully as may be possible, inasmuch as in proportion to
the lack of atmospheric or externally supplied oxygen within the furnace, will the
oxygen be the more freely and effectively eliminated from the metal.
In working my process, I secure the most satisfactory results by using petroleum
as the sole fuel for heating the furnace and melting the metal, because of the complete
exposure of the gradually melted metal to the flaming products of combustion, and
although this result can be fairly well attained by the use of many well known kinds
of furnaces, I have devised one which not only enables the gradually melted metal to

page_text: be continuously exposed, but also thin flowing bodies of the melted metal, as well as
an accumulated mass of highly heated molten metal in the pot of the furnace.
If a furnace of the usual " open hearth" type is to be used, the oil may also be
relied upon as the sole fuel, or the metal may be first well melted and highly heated
by the use of either ordinary or natural gas, and then, while excluding atmospheric
oxygen as fully as may be practical, burning the oil within the furnace, or directly
delivering its products of combustion to the surface of the molten metal, so that in
either case, the oxygen may be freely delivered from the metal.
If the oil be under pressure, and delivered to the furnace in a finely comminuted
or sprayed condition, while the molten metal is highly heated, good results will
accrue but care should be taken to deliver it in small quantities and preferably
intermittingly, so as to avoid the deposit of oil on the surface of the metal and the
consequent danger of defiling the boiling or ebullient metal with carbon. So also
should the spraying be effected without the excessive use of either compressed air or
steam, because of the incident introduction of oxygen, in quantities greater than is
best suited for attaining the results sought.
For more particularly describing my invention, I will refer to the accompanying
drawings in which
Figure 1, in longitudinal vertical section illustrates a novel furnace devised by me
with special reference to operating in accordance with my present invention.
Figures 2 and 3, illustrate the same in lateral vertical sections, on lines, a and y,
respectively.
Figure 4, in longitudinal vertical section illustrates an ordinary form of furnace
adapted to the use of gas for melting the metal, and provided with means for the
introduction of the oil to be burned for deoxidizing the metal.
In my novel furnace, Figures 1, 2, and 3, the pot, A, flue a, and stack b, are
substantially as heretofore in metal working furnaces. In the front wall c, there are
several apertures, c', well guarded by suitable doors, G, and H, the doors, H, are con-
nected with plates, F, and the doors, G, are adjustable and act as dampers. Within
and at the front portion of the furnace, there is a melting shelf or floor, B, which
is slightly inclined towards the pot, A, and at its highest or outer side, it has a raised
ledge, d. Between this floor and the front wall there is an open space or pocket, d'.
Adjacent to each front opening, c¹, inside of the furnace and above said pocket, there
is a cast iron oil burner, C, supplied with oil by way of a vertical duct, e, and below
each burner there is a cast iron drip pan, f, to receive any accidental overflow of oil.
"It sometimes occurs that portions of these burners and pans become melted, and the
object of the pocket, d', is to receive such melted iron, as well as masses of solid
carbon liable to drop from the burners and pans, and also spattering oil, it being
important that all of these he kept from admixture with the metal to be deoxidized.
Suitable well guarded openings, g, are provided in the side walls of the furnace
opposite the melting shelf to admit of charging the shelf, B, with metal which
is piled thereon in one or more loose or open piles as indicated in dotted lines in
Figure 1.
Other side openings, h, also well guarded by doors are provided for affording access
to the pot, A, whenever desirable. The melting shelf having the requisite quantity
of metal piled thereon, the doors to the several openings, c', are opened and oil slowly
"supplied through the ducts, e, to the burners, C, and then lighted the products of
combustion passing directly through and over the pile of metal into and through the
furnace to the stack. As the heat of the furnace increases, the openings, c', are closed
or nearly so. The masses of metal in the pile gradually melt down, and all the while
the products of combustion take up more or less oxygen from the metal, and as the
molten metal flows downward and over the edge of the floor in thin streams it is further
and favourably exposed to the deoxidizing products of combustion, and as the molten
metal accumulates in the shallow pot, its temperature is raised, and its oxygen given
off to the carbon and hydrogen ever present and ready to attract and unite with it, in
combustion, and during this final portion of the operation, little or no atmospheric
oxygen should be admitted to the furnace. The doors of the side openings, h, may be

page_text: provided with mica covered eye-holes to enable observation of the surface of the metal.
When ebullition of the metal ceases, and soon after its surface assumes an oily, glassy,
or reflecting appearance, the deoxidation may be considered as complete, the metal
being then ready to be run off in the usual manner. The time required for the
operation necessarily varies according to the character of the metals used, and the
prevailing atmospheric conditions. About four hours is generally necessary for working
a charge of say from 1:00 to 2000 pounds, commencing with a cold furnace, and while
one charge is being run off, the melting shelf may be reloaded for another run, and a
similar charge would then require but about one hour.
In using a furnace as shown in Figure 4, the pot, A', is directly charged with the
metal by way of the side openings, and the melting operation is performed by means
of gas and hot air, respectively supplied by pipes, i, and k. After the metal has
reached a proper high heat, the gas and air are both cut off, and the oil is very slowly
supplied by way of the duct, e, below which, in the bottom of the firing passage of the
furnace there is a concavity, el, into which more or less of the dropping oil is delivered,
and kept from passing into the pot, A¹.
It is obvious that the time required for the deoxidizing process in using this last
described furnace will be greater than with the one devised by me, because in using
mine, the metal, as it gradually melts will yield up more or less of its oxygen, so that
the molten metal accumulated in the pot requires less purifying than when the
cold metal is placed directly in the pot and partially flooded in molten metal,
or as when after a portion of the metal has been melted, cold metal is dropped
therein.
Although great advantages are derived from the use of my improved furnace, 1
would however have it understood that the carrying out of the process is not absolutely
dependent upon the use of any special form of furnace, nor even to one so far
modified in its construction as to enable it to gradually receive and properly control
the burning oil, inasmuch as the oil may be contained in shallow pans, which
may be introduced, for instance, from time to time into the firing passage of a.
furnace.
It is also to be understood that although the best results will accrue from the use
of the oil as a melting medium as well as for deoxidizing the metal, and while I make
special claim thereto, the main feature of my invention is restricted to exposing highly
heated molten copper and its alloys to contact with the products of combustion
developed by the burning of petroleum or other highly inflammable-hydrocarbon
oils.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. The herein before described method or process of deoxidizing and purifying
copper and its alloys by highly heating the molten metal, and then while practically
excluding atmospheric oxygen, exposing it to the flaming products of combustion
developed from the burning of hydrocarbon oils.
2. The herein before described method or process of deoxidizing and purifying
copper and its alloys by melting the metal by exposure to the hot products of com-
bustion developed by burning hydrocarbon oils, then raising the molten metal to a
high temperature, and then while practically excluding atmospheric oxygen further
exposing the metal to the flaming products of combustion afforded by the oil.
3. In a smelting furnace, a floor whereon the metal is piled, said floor being inclined
toward the pot of the furna e, substantially as set forth.
4. A smelting furnace having an inclined floor whereon the metal to be melted
is piled, burners wherein oil is burned to generate the heat for melting the metal,
and dampers whereby the products of combustion are deflected against the metal,
substantially as described.
5. A smelting furnace, comprising the following features and instrumentalities: a
pot wherein the molten metal accumulates, a floor raised above said pot and inclined

page_text: toward the latter and on which the metal is piled, doors in the walls of the furnace
at the ends of said floor, openings in the front wall of the furnace wherein the
oil burners are located, means for supplying oil to said burners, and dampers
for supplying atmospheric oxygen immediately beneath the burners, substantially
as set forth.
6. The inclined floor having along its top edge a raised ledge, substantially as shown
and set forth.
7. In a furnace as described, having oil burners and drip pans located within the
front wall, a pocket or space in the immediate rear of said wall, whereby any accidental
melting of the burners or pans or accumulation of carbon is prevented from defiling
the molten metal, substantially as set forth.
Dated this 50th low of Lul.. 1800
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.