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Патент USA US3028239

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April 3, 1962
3,028,231
S. KLEMANTASKI ETAL
PROCESSING OF. METALLIC ORES
Filed Dec. 17, 1959
3 Sheets-Sheet 1
ME (+ FLUx)
FUEL GAS
l
PRE — REDUCTION
ZONE
I'- ------------------ --1|
5
I
COAL
HEAT
EXCHANGER
OXYGEN
?
_____________________ .._..'
HIGH
TEMPERATURE
REAcToR
7
J
METAL
F/s. /
SLAG
ms (+ FLUX)
WASTE GAS
‘
E
PRE-HEATING
ZONE
.._---..__________....__A|R
"nun-1
i
FUEL GAS
l
PRE-REDUCTION
ZONE
4-~—--—-—-—-—'-————-~--:
HEAT
I
I
l
-
HIGH
'
"""""""""" "
l
TEMPERATURE
REAcToR
Fla. 2
METAL
SLAG
INY ENTORS
3” Tia/w.
ATTORNEYST
April 3, 1962
s. KLEMANTASKI ETAL
3,028,231
PROCESSING OF METALLIC ORES
Filed Dec. 17, 1959
He. 3.
3 Sheets-Sheet 2
ah“47
FIG. 6.
INVENTQRS
April 3, 1962
s. KLEMANTASKI ETAL
3,028,231
PROCESSING OF METALLIC ORES
Filed Dec. 17, 1959
3 Sheets-Sheet 3
United States Patent O?ice
1
3,028,231
_
PROCESSING OF METALLIC ORES
Sidney Klemantaski, Forest Hill, London, Thomas Wil
ham Johnson, Guisborough, and James Maurice Rid
glon, Normanby, England, assignors to The British Iron
and Steel Research Association, London, England
_
Filed Dec. 17, 1959, Ser. No. 860,218
Claims priority, application Great Britain Jan. 1, 1959
9 Claims. (Cl. 75—38)
_ This invention relates to the reduction of metal bear
1ng_ores and is particularly concerned with, although not
limlted to, the reduction of iron ores for the production
of iron.
3,628,231
Patented Apr. 3, 1962
2
is maintained above the melting point of the metal.
Liquid metal and slag collect at the bottom of the high
temperature reactor and are tapped off.
The gas pro
duced by the combustion of the coal is passed from the
high temperature reactor to a heat exchanger wherein it
is cooled and from which it is passed to the pre~reduction
zone. After contact with the fresh ore in the pre-reduc
tion zone, the gas will usually still have a CO/COZ ratio
such that it can be used elsewhere as a fuel gas. Where
10 the ore to be treated is an iron ore, the temperature in the
high temperature reactor is preferably from 1300° to
1800° C., and advantageously 1500‘? C., and the tempera
ture of the gas leaving the heat exchanger from 1000° to
700° C. depending on the extent to which the ore is to be
An object of the invention is to enable metal-bearing 15 pre-heated in the pre-reduction zone. It is preferred to
ores in a particulate and/or pulverulent state to be re
pre-heat the ore to a temperature of approximately 750°
C., and in this case, if the ore is at room temperature
tlal treatment, such as briquetting or sintering, of the ores
(say 20° C.) when introduced into ’ the pre-reduction
as requires to be done if such ores are to be reduced in a
zone, the temperature of the gas leaving the-heat ex
conventional blast furnace.
'
20 changer is preferably of the order of 1050° C. The gas
duced economically and without the necessity for an ini
1 According to the present invention there is provided a
produced by combustion of the coal in the high tempera
process for the reduction of metal-bearing ores which
ture reactor preferably has a CO/CO2 ratio of at least
comprises passing a particulate metal-bearing ore into a
5/1, and advantageously of about 10/1; after contacting
high temperature reactor wherein a gaseous or particulate
the fresh ore in the pre-reduction zone, the gas preferably
fuel is burnt to produce a gas whose CO/CO2 ratio is such 25 has a (IO/CO2 ratio of from 4/ l to O, and advantageously
that it is capable of reducing the ore to metal and to
of approximately 2/ 1. The extent of partial reduction of
maintain the temperature in the reactor at or above the
the ore passed from the pre-reduction zone to the high
melting point of the metal, ‘whereby liquid metal is pro~
temperature reactor is preferably from 30% to 80%, and
duced.
is advantageously approximately 60%.
30
In a preferred form of the invention the ore is partially
The oxygen is preferably pre-heated before introduc
reduced and pre-heated prior to introduction into the
tion into the high temperature reactor and this may be‘
high temperature reactor. This may be done, and the > conveniently effected in the heat exchanger; a suitable
reducing potential of the gas produced in the high tem
preqheat temperature for the oxygen is, for example,
perature reactor economically utilised, by passing this gas
500° C.
35
from the high temperature reactor to a heat exchanger
The heat abstracted from the hot gas in the heat ex
wherein its temperature is lowered and from the heat ex
changer may, however, be used for other purposes; thus
changer to a pre-reduction zone wherein the gas is con
it may be used for the generation of steam for the even—
tacted with fresh particulate metal~bearing ore in order
tual production of oxygen. Alternatively, ‘fresh ore may
to e?fect partial reduction of the ore and heating of the
be pre-heated to the desired temperature by being passed
latter to an elevated temperature which is below the ag 40 through the heat exchanger without being contacted by
glomeration temperature of the partially reduced ore, the
partially reduced ore at this temperature being passed
from the pre-reduction zone to the high temperature re
the gas passing therethrough; in- this case only partial re
duction of the ore is effected in the pre-reduction zone
because it is already pre-heated.
actor to constitute the ore feed to the latter.
Alternative methods in which pre-heating the ore is ef
The nature of the process will be more readily under 45 fected prior to introduction into the pre-reduction zone
stood from the ?ow diagram forming FIGURE 1 of the
accompanying drawings. in this ?ow diagram, the fuel
employed is ?nely divided coal, this being the preferred
and only partial reduction of the ore is effected in the lat
ter zone are available and one such method, which is in—
deed preferred to pre-heating of the ore in the heat ex
fuel for use in the process according to the invention, but
changer, is illustrated, by Way of example only, in the
other particulate or gaseous fuels, such as conventional, 50 flow diagram forming FIGURE 2 of the accompanying
fuel gas, may equally be employed. FIGURE 1 also illus
drawings.
trates the use of oxygen for combustion of the fuel, but
The process illustrated in FIGURE 2 is generally simi
oxygen-enriched air may also be employed. In the flow
lar to that shown in FIGURE 1, but in this modi?ed
diagram full lines indicate the flow of solids (or liquids
process, fresh particulate ore, together with any ?uxing
in the case of the metal and the slag) and chain lines, the 55 compounds which may be necessary, are passed through
flow of gas.
a’ pre-heating zone before being introduced into-the pre
Referring to FIGURE 1, the ore in particulate form,
reduction zone and gas from the pre-reduction zone
together with any ?uxing compounds necessary is intro
(which may be a part or the whole of the gas leaving
duced into a pre-reduction zone where it is pre-heated
the pre-reduction zone) is passed to the pre-heating zone
60
and partially reduced to a suitable extent by contact with
and burnt therein with air, oxygen or oxygen-enriched
a reducing gas passed into the pre-reduction zone from a
air. In this case it is, of course, essential that the gas
heat exchanger; this gas should, of course, be at such a
leaving the pre-reduction zone should have a CO/CO‘Z
temperature and have such a CO/COZ ratio that the de
ratio such that it can be used as a fuel gas; ratios of
sired degree of pre-heating and partial reduction can be
from 4/1 to 2/1 are preferred,
effected. The ore is then passed to a high temperature 65
Instead of burning gas from the pre-reduction zone in
reactor into which ?nely divided coal and oxygen are also
the pre-heating zone, gas from an external source may
introduced under such conditions that the coal is burnt to
be used and the gas‘from the pre-reduction zone used for
produce a gas whose CO/CO2 ratio is such that the par
other purposes.
'
tially reduced ore is completely reduced to metal by con
A further alternative where a pre-heating zone is em
70
tact therewith and the combustion of the coal also being
ployed’ is to separate particulate carbon from the gas
such that the temperature in the high temperature reactor
leaving the high temperature reactor by the use, for
3,028,231
3
4
example, of a cyclone, and to burn this carbon in the
pre-heating zone with oxygen or oxygen-enriched air.
When ?nely divided carbon is burnt with oxygen, as in
the high temperature reactor, three reactions take place.
bustion thereof into the reactor through one or more
burners which comprise a series of concentric tubes
forming a central supply passage, two annular supply
passages co-axial therewith and passages for the circula
tion of coolant, the ore, fuel and oxygen or oxygen
c+1/2o,-> co
0+0,» (:0
(1)
(2)
c+co2->2c0
(3)
enriched air each being supplied through a different pas
sage. Advantageously one or both of the annular pasa
sages are provided with helical vanes which impart a
swirling motion to the material passing through the
The conditions of combustion in the high temperature
passage(s); if both the annular passages are provided
10
reactor areso adjusted that the sum of these reactions
with such vanes, they are advantageously inclined in op=
is a high CO/CO2 ratio in the gaseous product, but even
posite senses in the two annular passages.
_
with a high CO/COZ ratio of 10/1 or more, there is
One embodiment of such a burner is illustrated, by
always some residual carbon. If this residual carbon is
way of example only, in FIGURE 4 of the accompanying
not separated from the gas leaving the high temperature
drawings. The burner comprises a series of concentric
reactor as described above, it may be deposited in the 15 tubes through which the di?erent materials are fed into
pie-reduction zone or may leave with the gas passing
the high temperature reactor. Thus, the partially re=
from the pie-‘reduction zone, in which case it can be
duced ore from the‘ pre#reduction zone is introduced
through the innermost tune-:14, the fuel, preferably in
residual carbon is readily recycled by‘ either of these
form of pre-‘heated pulveris'ed coal, is introduced
routes and its presence is not in any way disadvantageous. 20 the
through
tube 15, and oxygen, preferably preéheated, is
Where the ore is p're-heated before being introduced
supplied through tube 16. Between tubes 14 and 15 and
into the p’r’e-‘reduc'tion Zone, the gas from the heat ex.
on the exterior of the tube 16 there are passages supplied
changer and the pre-heated ore are introduced intov the
with
cooling water through pipes "17. The coiling of
pre-reductior'i zone at a temperature which is substan
the
burner
by the water passing through these passages
tially that at which the partially reduced ore is passed 25
recovered by' any suitable gas’ cleaning system. The
to the-high temperature? reactor‘; as stated above this tern
protects it from radiated heat from the interior of the
per'a'ture is preferably about» 750° C.
Instead of mixing any ?uxing materials which may be
which the coal and the oxygen pass respectively, are pro;
high temperature reactor. The passages 18, 19 through
vided with helical vanes 21,‘ 22 designed to give the coal
required‘, such as lime in the case if iron-bearing ores,
and oxygen a swirling action as it leaves the burner.
with the ore before the latter is introduced into the pre 30
re'duction zone as described in connection with FIGURE
1 or before it is introduced into the pre-he'ating zone as
As‘ will be seen, the vanes are‘ inclined in opposite senses
in the passages so that, within the reactor, the oxygen
is intimately mixed with the coal and both are intimately
mixed with the ore passing down the centre of the
described in connection’ with FIGURE 2, the fluxing ma
terials may be separately pre-heated, preferably to a
temperature of about 750° C., and mixed with the par 35 burner.
In one actual embodiment of the burner illustrated in
tially reduced ore immediately before introduction of
FIGURE 4, the angles of the vanes 21, 22 were 60° and
the latter into the high temperature reactor or directly
40° respectively and the inlet velocities of the coal and
introduced‘ into the high temperature reactor separately
oxygen were 40 and 500 feet per second respectively.
_
from the partially reduced ore.
The pre-reduction zone and, where employed, the pre 40 The high temperature reactor may take a number of
forms; one suitable embodiment is illustrated, by way
heating zone preferably include at least one ?uidised
of example only, in FIGURE 5 of the accompanying
bed in which the ore is maintained in a fluidised condi
drawings.
The high temperature reactor illustrated in
tion by the upward passage of the gas. One embodiment
this ?gure comprises a vessel 13 into which the reaction
of a pre-reduction chamber incorporating a plurality of
materials enter through a burner 12 which is of the type
?uidised beds is’ illustrated, by way of example only in 45 illustrated
in FIGURE 4. The reactor operates on a dis-'
FIGURE 3 of the accompanying drawings.
persed phase principle and the vessel ‘13 Consists of an
Referring to this ?gure, the pre-reduction chamber com
assembly of water cooled coils, covered by a thin coating
prises a series of ?uidised beds 43 arranged in cascade.
of refractory and contained in a metal shell. The vessel
The warm reducing gas from the heat exchanger is in
troduced at the bottom of the chamber through an inlet 50 13 is self-lining, slag being frozen on to they walls of
the container. At the bottom, the vessel v13 leads through
pipe 44 and passes upwardly through the various beds 43.
a neck 24, which is also water cooled, to a hearth which
The particulate ore is introduced through a pipe 45 to
is
shown generally at 25, metal being tapped through
the ?rst bed 43. Subsequently it passes through con
hole 26 and slag through hole 27. The gases from the
necting pipes 46 to the other ?uidised beds 43 in turn.
The partially reduced ore eventually leaves the chamber 55 ?erce swirling reaction within the vessel 13 pass over
the hearth and leave through a pipe 28 which conducts
through a pipe 47 and is led to the high temperature re
them to the heat exchanger.
~
actor. The tail gas ?nally leaves the top of the pre
Another embodiment of high temperature reactor which
reduction chamber through an exit pipe 48.
may be employed is substantially the same as that illus
The pre-heating chamber may take substantially the
trated in FIGURE 5, but the neck 24 is omitted.
60
same form as the pre-reduction chamber illustrated in
A further form of high temperature reactor is illus
FIGURE 3.
trated in FIGURE 6 and consists of a containerjtl lined
Alternatively both the pre-reduction zone and the pre
with ?re brick or carbon and containing a bed 31 of solid
heating Zone may be located in diiferent parts of the
carbonaceous material, preferably coke, which is replaced
same chamber. Such a combined unit may also take
substantially the same form as the pre-reduction cham 65 as it is used through the charging opening 32. The re
ber illustrated in FIGURE 3, but one or more burners
action materials—the oxygen, coal, ?uxes and ore are
introduced through burners 12 of the type illustrated in
or other devices for the introduction of the fuel and air,
FIGURE 4, located in the side walls of the container
oxygen or oxygen-enriched air for the combustion thereof
30 and the reaction takes place in the adjoining raceway
are provided in the side walls of the chamber, for ex
ample about half way up the chamber, so that the upper 70 area of the packed bed 31. Liquid metal and slag drip
down into the hearth 33 whence they are removed through
part of the chamber constitutes the pre-heating zone and
metal tap hole 34 and slag tap hole 35. The hot re
thelower part, the pre-reduction zone.’
ducing gases from the reaction are led off to pipes 36
In order to obtain the desired conditions in the high
located at the top of the container 30 to the heat ex
temperature reactor it is preferred to introduce the ore,
the fuel, and oxygen or oxygen-enriched air for the com 75 changer. In this case, the water cooling requirement of
n
8,028,231
6
the vessel is very much less than that of the high tem
perature reactor illustrated in FIGURE 5 since the re
fractory of the walls is protected by the bed material 31.
In the case of iron-bearing ores, it is found that in
order to produce 1 ton of metal it is, in general, neces
ticulate ore forms the axial stream, the particulate car
bonaceous fuel forms the inner concentric stream and
sary to use from 0.6 to 2 tons of coal and from 0.6 to 2
tons of oxygen; the amounts of coal and oxygen re
prises the steps of passing a particulate carbonaceous fuel,
3. A process as claimed in claim 2 wherein the par
the gas forms the outer concentric stream.
4. A process for the reduction of iron ores which com
a gas selected from a group consisting of oxygen and
quired depending on the quality and nature of the coal
oxygen-enriched air, and a mixture of partially reduced
and on the design of the high temperature reactor.
particulate iron ore and ?uxing materials into a high
Con
currently with the production of 1 ton of iron, from 0.6 10 temperature reactor, the said three components being in
to 2 tons of slag are produced depending on the nature
troduced into the reactor through at least one port in
of the iron-bearing ore treated. Any suitable carrier
the form of concentrically disposed individual streams
gas may be used to convey the particulate solid materials
whereof one stream is axial and the other two streams
used in the process according to the invention. Air may,
are concentrically disposed with respect to said axial
for example, be employed for the purpose but its use is 15 stream, the three streams uniting within the reactor to
not preferred as it leads to dilution of the gas produced
burn and form a combustion zone within the reactor to
in the high temperature reactor with nitrogen and if it is
produce a gas having a CO/CO2 ratio of at least 5/1
used to convey the ore from the pre-reduction zone to the
and to maintain the temperature in the reactor at from
high temperature reactor there is a danger of re-oxidation
1300” to 1800° C. whereby liquid metal is produced from
of the ore taking place. It is, in fact, preferred to use 20 the partially reduced ore, passing the gas produced in
a small proportion of the gas leaving the high tempera
the high temperature reactor to a heat exchanger wherein
ture reactor for conveying fresh ore to the pre-reduction
its temperature is lowered to from 1000“ to 700° C.,
zone, and partially reduced ore and pulverised coal to
and from the heat exchanger to a pre-reduction zone
the high temperature reactor.
wherein the gas is contacted with fresh particulate iron
Although in the foregoing description, the process ac 25 ore and ?uxing materials in order to effect a 30% to 80%
cording to the invention has been described with particu
reduction of the ore and heating of the ore to an ele
lar reference to the reduction of iron-bearing ores, it
vated temperature which is below the agglomeration tem
may also be used for the production of other metals, such
perature of the partially reduced ore, and passing the
partially reduced ore and ?uxing materials at this tem~
as manganese, zinc, copper and lead, from their ores by
appropriate adjustment of the temperatures and other 30 perature from the pre-reduction zone to the high tem
operating conditions.
perature reactor to constitute the ore ?ux feed to the
We claim:
latter, the gas leaving the pre-reduction zone having a
CO/CO2 ratio of from 4/1 to 0.
prises the steps of introducing a partially reduced par
5. A process according to claim 4, wherein the oxygen
ticulate iron ore, a particulate carbonaceous fuel and a 35 containing gas supplied to the high temperature reactor
gas selected from the group consisting of oxygen and
is pre-heated to a temperature of about 500° C. in the
heat exchanger.
oxygen-enriched air into a high temperature reactor, the
said three substances being introduced into the reactor
6. A process according to claim 4, wherein the high
through at least one port in the form of concentrically
temperature reactor is at least partially ?lled with a bed
disposed individual streams whereof one stream is axial 40 of coke and the combustion of the fuel and reduction of
1. A process for the reduction of iron ores which com
and the other two streams are concentrically disposed
the ore takes place in a raceway formed in the bed of
with respect to said axial stream, the three streams uniting
coke.
within the reactor to burn and form a combustion zone
7. A process for the reduction of iron ores which
within the reactor to produce a gas having a CO/COZ
comprises the steps of passing a particulate carbonaceous
ratio that is capable of reducing the partially reduced 45 fuel, a gas selected from a group consisting of oxygen
actor at not less than the melting point of the metal
and oxygen-enriched air, and a mixture of partially re
duced particulate iron ore and ?uxing materials into a
whereby liquid metal is produced.
high temperature reactor, the said three materials being
ore to metal and maintaining the temperature in the re
introduced into the reactor through at least one port in
2. A process for the reduction of iron ores which com
prises the steps of introducing a partially reduced par 50 the form of concentrically disposed individual streams
ticulate iron ore, a particulate carbonaceous fuel and a
whereof one stream is axial and the other two streams
are concentrically disposed with respect to said axial
gas selected from the group consisting of oxygen and
oxygen-enriched air into a high temperature reactor the
stream, the three streams uniting within the reactor to
said three substances being introduced into the reactor
burn and form a combustion zone within the reactor to
through at least one port in the form of concentrically 65 produce a gas having a CO/CO2 ratio of about 10/0 and
to maintain the temperature in the reactor at from 1300°
disposed individual streams whereof one stream is axial
to 1800° C. whereby liquid metal is produced from the
and the other two streams are concentrically disposed
partially reduced ore, passing the gas produced in the
with respect to said axial stream, the three streams
high temperature reactor to a heat exchanger wherein
uniting within the reactor to burn and form a combustion
zone within the reactor to produce a gas having a CO/COZ 60 its temperature is lowered to about 750° C., and from
ratio that is capable of reducing the partially reduced
the heat exchanger to a pre-reduction zone, wherein the
ore to metal and maintaining the temperature in the
gas is contacted with fresh particulate iron ore and ?ux
ing material which have been pre-heated to a tempera
reactor at not less than the melting point of the metal
whereby liquid metal is produced, passing the gas pro
ture of about 750° C., in order to elfect an about 60%
duced in the high temperature reactor to a heat exchanger 65 reduction of the ore, and passing the partially reduced
wherein its temperature is lowered, and from the heat
ore and ?uxing materials at said temperature from the
exchanger to a pre-reduction zone including at least one
pre-reduction zone to the high temperature reactor to
?uidized bed wherein fresh particulate metal-bearing ore
constitute the ore ?ux feed to the latter, the gas leaving
is maintained in a ?uidized condition by upward passage
the pre-reduction zone having a CO/COz ratio of about
of the gas and is at least partially reduced thereby, and 70 2/ 1.
passing the partially reduced ore at an elevated tem
8. A process according to claim 7, wherein the oxygen
perature which is below the agglomeration temperature
of the partially reduced ore from the pre-reduction zone
to the high temperature reactor to constitute the ore feed
to the latter.
75
containing gas supplied to the high temperature reactor
is pre-heated to a temperature of about 500° C. in the
heat exchanger.
9. A process according to claim 7, wherein’ the high
3,028,231
7
temperature reactor is‘a't least partially ?lled with a bed
of coke and the combustion of the fuel and reduction of
the ore takes place in a raceway formed in the bed of
coke.
References Cited in the ?le of this patent
UNITED STATES PATENTS
538,004
1,815,899
Williamson __________ __ Apr. 23, 1895
Brassert _____________ __ July 28, 1931
2,182,009
2,750,276
2,824,793
2,864,686
2,915,379
2,919,983
2,928,730
2,988,443
8
Wiberg _'_____‘ _________ __ Dec. 5, 1939
Marshall ____________ __ June 12, 1956
I
De Jahn ____________ __ Feb. 25, 1958
Agarwal _____________ .. Dec. 16, 1958
Agarwal _____________ __ Dec. 1, 1959
Halley _______________ __ Ian. 5, 1960
Luerssen ____________ __ Mar. 15, 1960
Metz ________________ __ June 13, 1961
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