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Патент USA US2107255

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Feb. 1, 1938.
P. MccoMB
Filed Sept. 4, 1934
. Z
M? 60/77 5,
Patented Feb. 1, 1938
Parker McComb, Monroe, La.
Application September 4, 1934, Serial No. ‘742,624
1 Claim.
(Cl. 263—-53)
top of the stack, it is formed in the shape of a
This invention relates to the reduction of
minerals and ores to oxides and by-product gases.
hollow cylinder.
It is an object of my invention to provide a
roasting oven which will roast stone or ores with
Located inside the stack 2, there is a roasting
chamber 3, which is uniformly rectangular in
5 out permitting the stone, at any place in its
cross sections throughout its entire length. This
chamber is anchored along its. narrow faces to
the stack 2 from points 4 down to the bottom of
the stack 2. From the bottom of the stack 2 to
points 4, gas spaces are provided between the
wide faces of the roasting chamber 3, and stack
2. To prevent any distortion of the roasting
chamber which might result from the condition
of high combustion temperatures, it has been
found advisable to anchor the roasting chamber
3 along its narrow faces to the stack 2. From
travel through the oven, to come into direct con
tact with the products of combustion.
A further object of this invention is to provide
a roasting oven with a vertical type roasting
10 chamber in which the material being roasted
may be lowered as a unit.
Another object of this invention is the pro
vision of a roasting oven having a hopper lo
cated in the path of the products of combustion
15 whereby to dry the charge.
Another object of this invention is to provide
points ll, upwardly, with the exception of the
an improved process of burning stone, ore or the
area at the discharge manifolds 5, the roasting
chamber 3 is spaced from the stack 2 on its
like, and to separate the resulting by-product
gases by allowing them to stratify according to
2 O their various speci?c gravities.
Other objects and advantages of my invention
will be apparent during the course of the follow
ing description.
In the accompanying drawing forming a part
25 of this application, and in which like numerals
are employed to designate like parts throughout
narrow faces as well as its wide faces to permit
products of combustion to contact a greater heat
ing surface.
The roasting chamber 3 is to be constructed
out of suitable refractory materials having a
high thermal conductivity value, such as alu
minum oxide, beryllium oxide, thorium oxide,
silicon carbide, zircon, or from metals such as
the same,
Fig. l is an elevation view in part section of a
tungsten, molybdenum, etc., having high melting
roasting oven embodying my invention,
Fig. 2 is a cross sectional view of the same
on line 2—2 of Fig. 1,
structed by superimposing individual tiles, one
on another, and cementing them together.
Numeral 5 designates discharge manifolds.
Fig. 3 is a cross sectional view of the same on
These manifolds are fabricated from the same
line 3—3 of Fig. 1,
Fig. 4 is a cross sectional view of the same on
35 line 4-4 of Fig. 1,
Fig. 5 is a cross sectional view on line 5-5 of
Fig. 1, showing details of a valve feature of this
In the drawing wherein, for the purposes of
40 illustration, is shown a preferred embodiment of
this invention, numeral I designates the foun
dation of the same. The foundation is fabricat
ed from structural steel or other suitable build
ing materials and is designed to hold up the oven
45 to a sui?cient height to permit dump carts or
The roasting oven is preferably con
materials that the roasting chamber 3 is fabri
cated. These manifolds 5 may be cast as units
but are more preferably constructed in some 35
superimposed hollow tile construction followed
in the construction of the roasting chamber 3.
Exhaust ports 5 are provided in the narrow walls
of the roasting chamber 3. These ports are
slanted upwardly so that they can not get clogged 40
with stone.
Numeral l designates discharge pipes through
which the generated gases may be drawn off
by means of a pump not shown.
Numeral l0 designates a funnel shaped load
other type conveyors to be passed under the
ing hopper. ‘The loading hopper I0 is supported
oven to receive the ?nished product. The outer
wall, forming the stack 2 of this oven, is con
on the top of the stack 2 by means of a frame I I.
structed of ?re brick throughout its entire length.
50 However, other types of material may be substi
tuted for ?re brick toward the top of this oven
where the heat is less intense. From the foun
dation l, upwardly to line :1:—a:, the stack 2 of
this oven is made in the form of a hollow rec
55 tangular prism.
From line :c-—r upward to the
The loading hopper l0 terminates at its lower
end in a rectangular spout I2, which is made
smaller than the mouth of the roasting cham 50
ber 3, into which it extends to provide a clear
ance space through which waste gases may be
?oated o?.
As the temperatures at this part of this oven
are not extreme, I make the loading hopper 55
l0 out of metal of high thermal conductivity ' is supplied with stone or the like from the hop
per H]. The roasting chamber 3 should be kept
The apron HIa of the loading hopper It may
be provided with ports Hlb opening upward and
, outward so as to allow escape of waste gases from
the raw material as it is being dried and heated.
The furnace structure proper of the stack con
sists in the rectangular brick work of the stack
2 from its ?oor up to line x--.r, and is designated
by numeral l3.’ Through holes I4 in the oppo
site narrow walls of the furnace I3, are mounted
burners 15. These burners are mounted, pref
erably, in such a position thatthe flames com
ing from them strike the roasting chamber 3
at right angles on its broad faces. While most
of the combustion takes place in the furnace l3,
it is true that, under some conditions, some of
the combustion takes place at points higher up
in the stack 2. To insure complete combustion,
adjustable dampers l6 (see Fig. 5) are provided
in the ?oor of the furnace l3 to admit excess air
when needed. It has been found advantageous
to carry the burner feed lines l1, both fuel and
air, through the furnace so that both the air
and fuel may be preheated for the sake of econ
omy and for the sake of producing higher burn
ing temperatures in the burner ?ames.
Referring to Figs. 5 and 1, numeral I 8 desig
nates a take-off hopper and 19 a metering valve
mounted at the extreme lower end of the take-off
hopper to enclose the same. The metering valve
I9 is of a cylindrical shape and is provided with
longitudinal pockets 20.
When the metering valve I9 is rotated, the
measures of stone that settle into the pockets 20
are passed out and allowed to fall by gravity into
some suitable container or onto a moving con
The stack 2 is provided with suitable peep
transfer of the heat from the ?ue gases to the
charge through the metal hopper. The hopper’
is made out of an efficient heat conducting'metal, 10
whereby, to more effectively use the waste heat
of the escaping ?ue gases.
The valve 20 at the bottom of the take-off;
hopper acts as a closure for it. Through the
means of pockets 20 in the surface of the valve, 15
de?nite quantities of the burned charge may be
metered out as the, valve is revolved. In this
way the entire chargein the roasting oven is
gently lowered. As the roasting oven 3 is ver
tical, the force of friction of the roasting oven’s 20
walls on the charge will be too slight ‘to stir up
the charge, with the consequence that the entire
charge in the roasting chamber 3 may be lowered
as a unit.
' >
The heat necessary to reduce the charge to
oxides and the by-product gases, S02, CO2, etc.,
is supplied by burning fuel through means of
burners I5. Gas or oil are excellent fuels to use
in this oven ‘because the combustion of these ,_
fuels may be readily controlled.
However, I do'v 80
not limit myself to these fuels since my oven
may be ?red with other fuels successfully.
In the operation of, the preferred?form of this
oven, ?ames from the burners 15 are directed,
against the opposite broad faces of the roasting v'35
chamber 3. This is the hottest point in the oven.
The fuel and air supplies, as previously explained,
are preheated to effect a higher temperature
than would ordinarily occur from the burning
holes 2|, through which the temperatures of the
of a mixture of cold fuel and air, since the heat ‘14.9
products of combustion may be observed at the
various points of its travel.
‘This oven may be constructed in various sizes,’
depending on the volume or materials to be
treated, or may be constructed in a battery of
requisite to bring the‘mixture up to the ?ash
units. It has been found practical that an oven
.of .this type 30 to 40 ft. in height will provide
su?icient contact surface for the preheating and
the separation of gases, complete burning of the
raw material, and also provide a preliminary
cooling chamber in the oven. The burner should
be placed at about one-fourth the height of the
oven, the ports at about two-thirds to three
fourths of the height of the oven.
Among the ores and minerals that can be
burned, roasted, vitri?ed, disintegrated, reduced
or fused in the oven, are: galena, sphalerite,
point has been already partly supplied vto the
fuel and air themselves separately.
To insure complete combustion, excess air'is
admitted through the ?oor of the furnace to the 1145"
stack 2 by means of dampers I6. An occasional
baffle member 2b may be extended inwardly from
the stack’s inner Wall into the ?ue to- create
eddies and prevent the ?ue gas from channel
ling and passing out without giving up its heat.
The temperature in the furnace portion l3 of
the stackv 2' and the other portions of the stack
and the resulting temperature in the roasting
chamber 3 itself will depend on' the material
being treated and the length of time such mate 55
rial remains in the oven.
For example, the temperature range necessary
chalcopyrite, chalcocite, pyrites, gypsum, cerru
to reduce normal ‘carbonates inside the roasting
site, smithsonite, limestone, marble, malachite,
azurite, magnesite, dolomite. The principal by
product gases given off by the above named mate
chamber 3 proper would ‘have to be'from 1200° F.
to 3000° F. to produce metallic oxides and C02. 560
The temperature‘ of the ?ue gases leaving the
rials are sulphur dioxide (SOz),'having a spe
stack should be maintained at about 200° 'F'. ' ' .
ci?c gravity of approximately 2.2, and carbon
dioxide (CO2), having a speci?c gravity of ap
At no place in the stack 2 are the products
of combustion allowed to come in direct contact
with the charge itself. All of the heat that the?
charge in the roasting oven 3 receives from the
combustion of the fuel has to pass through the
walls of the roasting chamber 3. This feature
65 proximately 1.5 as compared with air. The ore
or mineral’ to be treated is ?rst crushed to a
size that will permit it to be readily attacked
by heat. Generally, a ?neness that will pass a
?lled and an extra supply of the stone or the
like should be held in the hopper.
As the ?ue gases issuing from the stack 2 must, 5
by design, impinge on the hopper, the portion
of the charge in the hopper is heated by the
one or two inch screen is sufficient.
If the ore or mineral to be treated isto- be
acted on with a reagent, oxide or silicate, this
oxide or silicate or other agent is then mixed
with the stone charge either before or after
of our invention is very important since it insures '
againstany contamination ofv the charge from 70
the fuel.
From the drying zone A, where the charge is
dried in the hopper by the'esrcaping ?ue gases,
the charge passes into a preheating zone B at
In operating my oven, the roasting chamber 3 ‘ the top of the roasting chamber. In-zone'B “18.3575
charge is being heated both by the heat from
the ?ue gases and also by ascending gases which
have been generated lower down in the roasting
oven 3. In the preheating zone B, exhaust ports
6 provide communication between the roasting
oven 3 and the discharge manifolds 5, provided
with discharge pipes 1, whereby the gases gener
ated in the roasting oven 3 may be drawn o?.
In the generation of S02 or CO2, which have
10 greater speci?c gravities than air moisture and
the other gas impurities, the flow from the ex
haust pipes may be so restricted as to build up
the level of the column of S02 or CO2 with a
resulting increase in pressure to such an extent
15 that the gas impurities, and even a part of the
$02 or CO2 may be ?oated up and out of the
roasting chamber 3. Since the CO2 gas which is
generated at the bottom portion of the vertical
retort is heavier than the air and moisture in
20 the portion of the charge at the top portion of
the retort the volume of CO2 gas and volume of
air and moisture will remain separated along a
natural level in the absence of any stirring action.
To assure that there will be no stirring action
during the carrying out of this process the charge
of ore that is being heated is lowered as an un
disturbed unit. That is to say the individual
lumps of ore in the charge stay in their same
relative position with respect to one another dur
ing their entire travel through the oven. This
type of operation of our oven will insure the pro
duction of a very pure gas. As the charge is
When the temperature of the burners is held
constant, the entire regulation of the furnace
resolves upon the regulation of time under which
the charge is subject to the constant temperature.
The time element is determined by the rate of
?ow of the charge which is in turn regulated by
the metering valve [9. And so I say that, with
a constant temperature maintained, the degree
to which the charge is burned may be controlled
by regulating the meter valve l9.
To insure the purity of the by-product gases,
care must be taken when drawing off the by
product gases to maintain su?icient pressure in
the preheating zone B at the ports 5, so that no
down draft is created in or through the top por 15
tion of preheating vzone B above ports 5 and to
maintain a proper separation zone between the
generated by-product gas and the gas impuri
It is to be understood that the form of my 20
invention shown and described is to be taken as
only a preferred embodiment of the same, and
that various changes in size, shape and arrange
ment of parts may be resorted to without depart
ing from the spirit of my invention or the scope 25
of the subjoined claim.
Having thus described my invention, I claim:
lowered past the exhaust ports 5, any generated
The method of treating carbonates, comprising
applying heated products of combustion to the
exterior of a vertical retort having its upper end
open and in free communication with the at
mosphere so that the heat applied to the retort
decreases upwardly for a?ording a lower reduc
gas which was trapped in the voids of the charge
may be drawn off along with the ascending stream
ing zone and an intermediate pre-heating zone
and an upper drying zone, introducing a 35
of generated gas.
After the charge has passed down through the
preheating zone B, it enters into the reducing
loose charge of a carbonate comprising aggre
gates which are approximately one-inch to two
inches in size and having voids between them
into the upper open end of the retort and grad
zone C in the oven, where the charge in the roast
ing chamber 3 is burned, fused, vitri?ed or
otherwise reduced.
When a charge of normal carbonates is used, it
will be completely reduced in this zone to its
metallic oxides and. CO2.
In leaving the reducing zone C, the charge
passes through the cooling zone D, preparatory
to entering the take-off hopper l8. In cooling,
the charge gives up part of its heat to the incom
ing fuel and air being brought to the burners.
From the cooling zone D the charge, now the
?nished product, enters the take-01f hopper I8,
which, as previously explained, is closed at its
bottom by a metering valve l9.
The metering valve 19 is intended to be rotated
55 by a gear or like means and its speed to be con
trolled by a suitable control means so that the
down ?ow of the charge may be uniformly con
ually moving the charge downwardly through 40
the retort so that it is subjected in succession
to the action of heat in the drying and pre-heat
ing and reducing zones, discharging the gases
from the charge in the drying zone upwardly
through the open end of the retort, preventing 45
any substantial amount of gases other than car
bon dioxide gas from entering the pre-heating
zone by causing a portion of the carbon dioxide
present in the pre-heating zone to pass up
wardly through the voids in the charge in the pre 50
heating zone and drying zone and thereby forc
ing other gases through the voids in the drying
zone and ?nally discharging to the atmosphere
through the upper open end of the retort, and
withdrawing a portion of the carbon dioxide from 55
the pre-heating zone.
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