Improvements in or relating to the Conversion or Purification of Iron and Steel.
Year: 1893

page_text: Date of Application, 27th June, 1893--Accepted, 14th Oct., 1893
COMPLETE SPECIFICATION.
Improvements in or relating to the Conversion or Purification of
Iron and Steel.
A communication from WILLIAM A. KONEMAN, Metallurgist, CHARLES G.
SINGER, Capitalist, both of 175, Dearborn Street, and AZEL F. HATCH,
Lawyer, of 100, Washington Street, all of Chicago, State of Illinois, United
States of America.
I ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
Chartered Patent Agent, 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 :-
The primary objects of this invention are to convert, by a simple process, scrap-
iron and steel into a highly carburized, high grade, refined and merchantable iron
product, and to recover readily the contained metals in furnace-slag and ores.
Incidentally, the further object of the invention is to save for useful purposes the
gas, generated by the metal treatment, which is of a superior quality, and affords an
especially good fuel-gas.
An improved apparatus for accomplishing the aforesaid objects is illustrated in
the accompanying drawings, in which-
Figure 1 is a view in vertical sectional elevation;
Figure 2, a plan sectional view on the line 2 of Figure 1 ; and
Figure 3, a plan section on the line 3 of Figure 1.
The shell A of the structure is best formed of fire-brick, is preferably of the
generally elliptical shape in cross-section illustrated and should be of considerable
height, say thirty feet or more. Moreover the chamber within the shell should
taper, as represented, both upward and downward from about its transverse center,
the lower taper, however, extending to a point short of the base, from which
the walls of the chamber should be straight and form a pit A' which may be
provided with doors r. A bottom is provided in the pit, of ashes or other inaterial,
the top line of which is indicated at v, whence the molten product flows off at a
spout
About the exterior of the shell near its center is formed a gas-chamber B
communicating through ports y with the interior of the shell and communicating at
one side of the shell through a passage B' with the interior of the shell at its upper
end; and a normally sealed draw-off outlet p may be provided in the passage B¹,
which should also contain a regulating valve B. Within the chamber B, and
flanking the communication therewith of the passage B₁ are walls B*, which
obstruct the flow through that chamber of the gas produced by distillation, as
hereinafter described, from the fuel in the upper portion of the shell, and which
enters the chamber B through the passage B₁; the walls B forcing the gas to
pass through the intermediate incandescent portion of the contents of the chamber
within the shell in order to reach the outlet, shown as a down-take B', extending
from the under side of the chamber B at the side thereof farthest from the passage B₁,
and which is preferably duplicated, as represented.
As will hereinafter more fully appear the use to which the apparatus is put in
recarburizing and recovering metals, causes it to perform three successive functions
in three different freely intercommunicating sections of the interior of the shell;
namely the upper portion or that extending upward from above the plane of the
ports and forming about one-third the height of the shell A, affords a preparing
chamber, in the sense of heating the metal short of the melting point. Below
this preparing chamber, for some distance downward and including the plane of
the ports q, is the intermediate section affording the melting chamber, in which
D

page_text: the metal is reduced to a molten condition, and whence it percolates through the
carbonaceous fuel and protoxide of carbon gas rising from the section below the
melting chamber and which constitutes the percolating chamber, from which
the molten metal flows off through the spout r³.
An air-blast leads into the chamber in the shell near the base of the percolating
chamber portion thereof through tuyeres o, the air being conducted thereto through
branches n of a conduit C encircling the generator-shell and into which leads the
blast-outlet pipe C¹ of a fan D. Another air-conduit C encircles the shell above
the plane of the chamber B and communicates, for its air-supply, with the conduit C;
and from it lead the tuyeres o' for the upper air-supply. The steam-supply may
come through the exhaust-pipe E of an engine serving to drive the fan D and of
which the cylinder F is indicated in Figure 2; and the exhaust-pipe E leads into a
branch E' encircling the shell below the air-pipe C, and from it may lead sub-
branches m into the upper part of the percolating portion of the interior of the
shell, and preferably also branches into the tuyeres o, and branches k downward
through the top of the shell.
At the top of the shell is provided a feed-hopper G of any suitable or known
construction whereby its rotary drum G' is adapted to have its contents dumped,
at will, into the apparatus, the hopper also affording a closure for the top of the
shell against the escape of gas.
Following is a description of the operation:
A fire is built in the shell A and blasted with air through the tuyeres o, and
solid carbonaceous fuel (preferably coal) is supplied through the medium of the
hopper, together with a suitable flux, as limestone, the fuel-bed being raised to
incandescence and the coal being piled on to fill the shell to a height reaching
nearly to the outlet t, at, or about at, which height the bed should be maintained
throughout the operation. Steam is admitted through the pipes m and continuously
into the upper portion of the bed, and air, also, through the uppermost set of the
tuyeres, o, no steam being supplied through the pipes m during the subsequent
metal-conversion, since it would tend to chill the molten metal. The resultant gas
passes through the ports q into the chamber B and thence discharges through the
down-takes B, sufficient, however, rising in the passage B' to the top of the fuel-
bed to exert and maintain a degree of pressure thereon, against the uprising
currents, sufficing to prevent such intense heating of the upper portion of the bed as
would tend too rapidly to disintegrate the fresh coal deposits, the result of which
would be to liberate and drive off the volatile constituents before being subjected
to adequate heat to gasify them sufficiently. The pressure on the top of the bed
of the gas so generated, by preventing the currents generated by the blast from
rising through the fuel above the line of the ports q, causes that fuel to be heated
by conduction from below and by the sensible heat of the gas on top, thereby
effecting slow distillation, or retorting of the fuel above the ports q. The gas-
product of such distillation, which rises through the mass against the gas-pressure
from the passage B' on the top of the bed, enters the passage B' from which the
retorted gas passes through the incandescent portion of the bed to the down-takes B³,
by entering the chamber B, whence the walls B direct it out of that chamber into
the adjacent portion of the bed, wherein it comes in contact with the molten matter
percolating through the incandescent fuel; and owing to its strong reducing and
recarburizing action, it tends to set free metals from metal-bearing compounds and
carburizes such iron as it comes into contact with.
The proceeding thus far described relates mainly to the production of gas, as the
result of generating in the apparatus the requisite differential heat in the different
parts thereof for the metal treatment; and the resultant gas is led off through the
down-takes for such uses as may be desired.
The scrap-metal, furnace-slag, or ore, to be treated is dumped by the hopper,
together with a suitable amount of the fuel and fluxing material, upon the top of
the bed of fuel, thus into the upper "preparing" portion of the shell, wherein it
sinks with the bed by the consumption of the fuel, being heated nearly to fusion by

page_text: the time it reaches the top of the intermediate "melting" chamber, wherein it
encounters the upper air-blast, and is brought to fusion and descends, in a molten
state, through a plane where it encounters the retorted gas from the passage B¹ on
its way to the down-takes, which exerts the above-described effects of reducing and
recarburizing and of setting free metals from metal-bearing compounds. Thence the
molten metal percolates in a subdivided state through the incandescent mass of
carbonaceous fuel in the lower "percolating" chamber and through the protoxide
of carbon gas rising therein. Thus the molten metal in thinly divided proportions
is further subjected to the carburizing effect of the fixed carbon and protoxide
of carbon gas in the percolating chamber, and by the time it reaches the outflow-
spout the scrap-metal is thoroughly recarburized and refined and constitutes a
high grade of iron, and all metals contained in slags or ores are thoroughly reduced
and set free by the reducing action of the carbon and protoxide of carbon gas
through which the fused mass is caused to percolate.
As will be understood, to continue the process the charges of metal, or metal-
containing material, with fuel and flux are repeated as frequently as may be found
necessary to maintain the required height of the bed.
The object of the lower air-blast through the tuyeres o is to maintain the fuel in
the lower percolating portion of the chamber in an incandescent state and at a
temperature greater than the melting point of the material percolating through it;
and the air-supply there should, therefore, not be excessive.
Having now particularly described and ascertained the nature of the said
invention, as communicated to me by my foreign correspondents, & in what manner
the same is to be performed, I declare that what I claim is :-
1. The method of treating scrap-metal, to recarburize it, and furnace-slag and
metal-bearing ores to recover their contained metals, which consists in the continuous
and successively completed steps of melting the material to be treated, causing the
molten mass to percolate through a column of highly incandescent carbonaceous
fuel and through the protoxide of carbon gas generated by the combustion of said
fuel, the carburizing and reducing effect being enhanced by introducing gas distilled
from the upper portion of the bed into the incandescent portion thereof immediately
below it and the fuel being blasted near its base, while the molten metal is so
percolating, with air in quantity sufficient only to maintain the temperature of the
percolation-column of the fuel above the melting point of the metal, substantially
as described.
2. The method of treating scrap-metal, to recarburize it, and furnace-slag and
metal-bearing ores to recover their contained metal, which consists in forming and
confining a deep bed of carbonaceous fuel, blasting it with air, leading off from a
point below the top of the bed the protoxide of carbon gas generated in the lower
portion of the bed and exerting with said gas a pressure on the top of the bed,
leading the gas of distillation from the top of the said bed into the lower incan-
descent portion thereof, introducing the material to be treated upon and allowing it
to sink with the said bed by the fuel-consumption till the said material is melted,
and causing the molten material to percolate downward through the lower incan-
descent portion of said bed of fixed carbon and through the protoxide of carbon
gas rising therein, substantially as described.
3. In an apparatus for the purposes stated, the combination of the shell having a
passage B' leading from the gas-retorting or metal-preparing portion in its upper
end downward into the shell immediately below said upper portion and through
which to maintain the desired gas-pressure from below on the top of the bed of
fuel in the shell, an outlet for the gas leading from the base of said upper portion,
and a blast of air or air and steam, substantially as described.
4. In apparatus for the purposes stated, the combination of the shell having the
walls of its contained chamber tapering in opposite directions from near the
transverse center of the chamber and affording the upper gas-retorting or metal-
preparing section, the lower metal-percolating and gas-generating section and the

page_text: intermediate melting section, a chamber B surrounding the shell near the said melting
section and containing walls B', ports 7 affording communication between the said
melting section and circumferential chamber, a passage B' connecting the chamber B,
from between said walls therein, with the upper end of the said retorting section,
blasting means, and an outlet B2 for the gas from the said circumferential chamber, 5
substantially as described.
Dated this 23rd day of June 1893.
W. P. THOMPSON & BOULT,
London, Nottingham, Liverpool, and Manchester,
Agents for the Applicant.