U.S. patent application number 12/452850 was filed with the patent office on 2010-05-27 for direct processing of metallic ore concentrates into ferroalloys.
Invention is credited to Glenn E. Hoffman.
Application Number | 20100126311 12/452850 |
Document ID | / |
Family ID | 40429178 |
Filed Date | 2010-05-27 |
United States Patent
Application |
20100126311 |
Kind Code |
A1 |
Hoffman; Glenn E. |
May 27, 2010 |
DIRECT PROCESSING OF METALLIC ORE CONCENTRATES INTO FERROALLOYS
Abstract
A method for producing liquid ferroalloy by direct processing of
manganese and chromium bearing iron compounds, by the steps: of
mixing carbonaceous reductant, fluxing agent, and a binder with
materials such as iron sands, metallic oxides, manganese-iron ore
concentrates and/or chromium-iron ore concentrates and silica
sands, to form a mixture; forming agglomerates from the mixture;
feeding the agglomerates to a melting furnace with other materials;
melting the feed materials at a temperature of from 1500 to 1760 C
and forming a slag and hot metal; removing the slag; and tapping
the hot metal as liquid ferroalloy.
Inventors: |
Hoffman; Glenn E.;
(Lancaster, SC) |
Correspondence
Address: |
RALPH H. DOUGHERTY
4219 KRONOS PLACE
CHARLOTTE
NC
28210
US
|
Family ID: |
40429178 |
Appl. No.: |
12/452850 |
Filed: |
August 12, 2008 |
PCT Filed: |
August 12, 2008 |
PCT NO: |
PCT/US08/10123 |
371 Date: |
January 23, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60967347 |
Sep 4, 2007 |
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|
60997616 |
Oct 4, 2007 |
|
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61126915 |
May 8, 2008 |
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Current U.S.
Class: |
75/508 ;
75/584 |
Current CPC
Class: |
C21B 2100/62 20170501;
C21C 5/527 20130101; C22B 5/16 20130101; C22B 19/10 20130101; Y02P
10/134 20151101; C22B 19/18 20130101; C22B 13/02 20130101; C21B
11/10 20130101; C22B 4/00 20130101; Y02P 10/216 20151101; C21B
13/0013 20130101; C21B 2400/022 20180801; C22B 34/12 20130101; C22B
1/245 20130101; C21C 2007/0062 20130101; C22B 19/04 20130101; Y02P
10/20 20151101; C22B 5/10 20130101; C21B 2100/66 20170501; C21B
13/12 20130101; Y02P 10/136 20151101 |
Class at
Publication: |
75/508 ;
75/584 |
International
Class: |
C21C 7/10 20060101
C21C007/10; B22D 11/10 20060101 B22D011/10; C21B 3/04 20060101
C21B003/04; C21B 3/02 20060101 C21B003/02 |
Claims
1. A method for producing liquid ferroalloy by direct processing of
manganese and chromium bearing compounds (Mn--Fe and Cr--Fe ores),
comprising the steps of: (a) mixing: i. materials selected from the
group comprising: iron sands, metallic oxides, manganese-iron ore
concentrates and/or chromium-iron ore concentrates, silica sands,
and mixtures thereof; ii. carbonaceous reductant; iii. fluxing
agent; and iv. a binder to form a mixture; (b) forming agglomerates
from said mixture (c) introducing said agglomerates to a melting
furnace; (d) maintaining a positive pressure within the melting
furnace: (e) melting the feed materials at a temperature of from
1500 to 1760 C and forming a slag thereon; (f) removing the slag;
and (g) tapping the hot metal as hot liquid ferroalloy.
2. A process according to claim 1, further comprising maintaining a
reducing atmosphere within said melting furnace.
3. A process according to claim 1, further comprising preventing
substantially all air ingress to the melting furnace by providing a
pressure seal.
4. A process according to claim 1, further comprising preheating
the mixture, the agglomerates, or both, prior to introducing them
to the melting furnace.
5. A process according to claim 1, wherein: 100% of the iron sands,
metallic oxides, manganese-iron ore concentrates and/or
chromium-iron ore concentrates and silica sands pass 10 mesh Tyler
Standard (1.70 mm); 100% of the carbonaceous reductant is minus 25
mm; and 100% of the fluxing agent is minus 25 mm.
6. A process according to claim 1 wherein the carbonaceous
reductant is selected from the group comprising coal, coke,
petroleum coke, and char.
7. A process according to claim 1, wherein the fluxing agent is
selected from the group comprising CaO, MgO, CaF.sub.2, SiO.sub.2,
Al.sub.2O.sub.3, and mixtures thereof.
8. A process according to claim 1, further comprising forming a
liquid iron-iron sulfide mixture in the melting furnace; removing
the liquid iron-iron sulfide mixture from the melting furnace,
desulfurizing the iron, and solidifying the resulting iron for
further use.
9. A process according to claim 1, further comprising forming
off-gases in the melting furnace, cleaning and cooling the
off-gases, and utilizing the cleaned off-gases as combustion fuel
to drive a turbine and to generate electricity.
10. A process according to claim 9, further comprising producing
off-gases in the turbine, recovering the off-gases from the turbine
and recovering the sensible heat contained therein as steam in a
waste heat boiler recovery system.
11. A process according to claim 10, further comprising utilizing
the steam to drive a steam turbine and an associated generator to
produce additional electricity, thereby accommodating substantially
all the electrical requirements of the process.
12. A method for producing liquid ferroalloy by direct processing
of manganese and chromium bearing compounds (Mn--Fe and Cr--Fe
ores), comprising the steps of: (a) mixing: i. materials selected
from the group comprising: iron sands, metallic oxides,
manganese-iron ore concentrates and/or chromium-iron ore
concentrates and silica sands; ii. carbonaceous reductant; iii.
fluxing agent; and iv. a binder to form a mixture; (b) preheating
at least a portion of said mixture in a heater to a temperature of
500 to 120.degree. C.; (c) introducing said preheated mixture to a
melting furnace; (d) melting the feed materials at a temperature of
from 1500 to 1760 C and forming a slag thereon; (e) maintaining a
positive pressure within the melting furnace: (f) removing the
slag; and (g) tapping the hot metal as hot liquid ferroalloy.
13. A process according to claim 12 wherein: 100% of the iron
sands, metallic oxides, manganese-iron ore concentrates and/or
chromium-iron ore concentrates and silica sands pass 10 mesh Tyler
Standard (1.70 mm); 100% of the carbonaceous reductant is minus 25
mm; and 100% of the fluxing agent is minus 25 mm.
14. A process according to claim 12, wherein the carbonaceous
reductant is selected from the group comprising coal, coke,
petroleum coke, and char.
15. A process according to claim 12, wherein the fluxing agent is
selected from the group comprising CaO, MgO, CaF.sub.2, SiO.sub.2,
Al.sub.2O.sub.3, and mixtures thereof.
16. A process according to claim 12, wherein the binder is selected
from the group comprising cellulose, bentonite, molasses, starch or
mixtures thereof.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority of the
following applications:
[0002] PCT Application PCT/US2008/010122 filed: 12 Aug. 2008, U.S.
Provisional Patent Application Ser. No. 60/967,347, filed 4 Sep.
2007;
[0003] PCT Application PCT\US 2008\010124, filed: 12 Aug. 2008,
U.S. Provisional Patent Application Ser. No. 60/997,616, filed: 4
Oct. 2007
[0004] PCT Application PCT\US 2008\010123, filed 12 Aug. 2008, and
U.S. Provisional Patent Application Ser. No. 61/126,915, filed 8
May 2008.
FIELD OF THE INVENTION
[0005] The present invention relates to a method and apparatus for
direct processing of manganese, chromite and silica bearing
compounds (Mn--Fe and Cr--Fe ores, and silica) to produce a liquid
ferroalloy and iron, employing the concept of combined cycle power
generation using a gas combustion turbine.
SUMMARY OF THE INVENTION
[0006] Mn--Fe ores, Cr--Fe ores, and silica are cold briquetted to
form compact agglomerates containing a carbonaceous material such
as coal, petcoke, char, etc., iron oxide (either already contained
in the ore or added separately as iron ore fines, mill scale,
metalized iron fines, etc., to the mix), fluxes such as lime,
silica, spar, etc., and binder. An excess amount of carbon is
present in the agglomerate not only to react with the manganese,
chromium, and silica compounds, but also to reduce the iron oxide,
manganese oxide, etc., so that the atmosphere within the melter is
predominantly CO with some liberated H.sub.2 from the
volatilization of the carbonaceous material such as coal. Sulfur in
the system is free to combine with the flux additions (CaO,
CaF.sub.2, MgO, etc.), to form a sulfur-containing liquid slag.
OBJECTS OF THE INVENTION
[0007] The principal object of the present invention is to provide
a method of producing silicamanganese, ferromanganese or
ferrosilicon ferroalloy from ordinary ore materials.
[0008] Another object of the invention is to provide a method of
recovering manganese, chromium, vanadium, and titanium as oxides
from ores.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The foregoing and other objects will become more readily
apparent by referring to the following detailed description and the
appended drawings in which:
[0010] FIG. 1 is a schematic flowsheet of the process, wherein the
reference numerals refer to the items as indicated below.
[0011] FIG. 2 is a schematic flowsheet for handling of
off-gases.
[0012] FIG. 3 is a schematic flowsheet for treating hot metal to
form vanadium and titanium oxides.
[0013] FIG. 4 is a schematic depiction of recovering hot metal in
pig form.
[0014] FIG. 5 is a schematic depiction of slag treatment to recover
vanadium and titanium oxides or to recover concentrated slag for
recycle.
[0015] FIG. 6 is a schematic flowsheet showing an alternative
method for producing a liquid ferroalloy in which the feed
materials are preheated with or without agglomeration, and then fed
to the melting furnace.
[0016] In the figures, reference numerals refer to: [0017]
10--Mn--Fe, Cr--Fe, SiO2, or concentrates--100% passing 10 mesh
Tyler Standard (1.70 mm), preferably 100% passing 100 mesh Tyler
Standard (150 microns) [0018] 12--metallic iron fines, and iron
oxide fines--100% minus 25 mm, preferably 100% passing 10 mesh
[0019] 14--prepared reductant, such as coal, petroleum coke, char,
etc., 100% passing 25 mm, preferably 100% passing 100 mesh Tyler
Standard (150 microns) [0020] 16--fluxing agents--CaO, MgO,
CaF.sub.2, SiO.sub.2, Al.sub.2O.sub.3, etc--100% minus 25 mm [0021]
18--binder such as cellulose, bentonite, molasses, starch--either
organic or inorganic [0022] 20--recycled fines [0023] 22--mixer
[0024] 24--briquetter/agglomerator (size 8 to 100 cc) [0025]
26--water addition (spray) [0026] 28--pelletizer--drum or disc type
[0027] 30--screens--dry or roller type [0028] 32--greenball dryer
(dries pellets to 1% moisture or less) [0029] 34--agglomerate
(briquette) curing/storage hoppers, or preheaters [0030] 36--feed
loss in weight system [0031] 38--electric melter, operating
temperature >1500 C [0032] 40--ladles A and B for liquid
ferroalloy [0033] 42--slag addition for desulfurization [0034]
44--pig iron caster [0035] 46--slag ladle (C) [0036] 48--slag
disposal/quench bunker [0037] 50--recycle slag [0038] 52--offgas
cooling scrubber/bag filter [0039] 54--fan [0040] 56--stack with
combustion to convert CO & H.sub.2 to CO.sub.2 & H.sub.2O
[0041] 58--high pressure compressor (100-350 psig) [0042]
60--optional gas stream, sulfur removal system, such as Selexol
[0043] 62--high pressure gas accumulator tank [0044] 64--gas
turbine (exit gas temp 600-700 C) [0045] 66--generator [0046]
68--waste heat boiler exchanger [0047] 70--high pressure steam
turbine [0048] 72--generator [0049] 74--boiler closed circuit water
conduit [0050] 76--pump [0051] 78--optional chiller upstream of gas
sulfur removal system [0052] 80--pressure sealed chamber [0053]
82--quenching and grinding and electrostatic separation [0054]
84--heater, direct or indirect rotary kiln type
DETAILED DESCRIPTION
[0055] As seen in FIG. 1, feed materials are introduced to mixer
22, the input materials consisting of: metallic iron fines, iron
oxides, manganese-iron ore concentrates and/or chromium-iron ore
concentrates 10, 100% passing 10 mesh Tyler Standard (1.70 mm),
preferably 100% passing 100 mesh Tyler Standard (150 microns);
prepared reductant 14, such as coal, petroleum coke, char, or other
carbonaceous material, 100% passing 25 mm, preferably 100% passing
100 mesh Tyler Standard (150 microns); slag formers or fluxing
agents 16, such as MgO, CaO, Al.sub.2O.sub.3, CaF.sub.2 (fluorspar)
and SiO.sub.2, 100% of which are minus 25 mm; an organic or
inorganic binder 18, such as cellulose, bentonite, molasses, or
starch; recycled fines 20, and water 26 as needed.
[0056] These materials are mixed in mixer 22, then formed into
agglomerates in briquetter/agglomerator 24, or in pelletizer 28
(such as a drum or disc type pelletizer), the agglomerates being in
the form of uniformly sized briquettes or pellets. The agglomerates
are screened by sizer 30, the undersized material being returned to
the agglomerator 24 or to the pelletizer 28.
[0057] Alternatively, material D1 exiting mixer 22 can be fed to a
heater 84 for the purpose of preheating the mixture to about 500 to
120.degree. C., devolatizing the reductant, and producing a
preheated charge to electric furnace melter 38. Pre-reduction of
the iron oxide will occur to levels ranging from about 0 to 90%.
Agglomerated material D2 can also be preheated, if desired, prior
to feeding the material to the melter through the pressure seal 37.
The heater 84 can be an indirectly heated rotary kiln, or a direct
fired kiln, as shown, with off-gases being recycled. The heater 84
can be refractory lined, or it can be unlined, as desired.
[0058] Screened pellets from pelletizer 28 are dried in a greenball
dryer 32 to 1% or less moisture content. The agglomerates are cured
and/or stored in hoppers 34, then fed into an electric melter, or
melting furnace 38 through a pressure-sealed feed system 36. Feed
to the melter is through a pressure-sealed chamber 80, a
conventional feed leg as is used with a shaft furnace, or through
lock valves. The melter off-gas is treated, cooled and scrubbed in
cooler-scrubber 52, compressed in compressor 54 and delivered to
stack 56 which includes combustion means for converting carbon
monoxide and hydrogen to carbon dioxide and water vapor. The melter
38 operates normally under a slight positive pressure. Tapping of
the hot metal and slag is done on an intermittent basis.
[0059] Optionally one or more additional feed materials may be
introduced through a pressure seal to the melter 38, including
metallic iron fines and iron oxide fines 12, 100% of which are
minus 25 mm; prepared reductant 14, such as coal, petroleum coke,
char, or other carbonaceous material, 100% passing 25 mm,
preferably 50% passing 10 mesh; slag formers or fluxing agents 16,
such as MgO, CaO, Al.sub.2O.sub.3, CaF.sub.2 (fluorspar) and
SiO.sub.2, 100% of which are minus 25 mm; and recycled slag 50. The
feed materials are melted in the melting furnace 38 at a
temperature of from 1500 to 1760 C to form a liquid ferroalloy with
a slag thereon;
[0060] Liquid ferroalloy is removed from the melter into ladles 40
and may be cast into ferroalloy pigs at pig caster 44, as shown.
Additional fluxing agents 14 may be added to the hot ferroalloy as
it is discharged into ladles 40 (A and B). A desulfurizing slag
addition 42 is introduced into a hot metal ladle shown as B, the
addition being CaO, MgO, Ca/Mg wire, or a mixture thereof. The hot
metal from either ladle A or B can be cast into pigs.
[0061] The slag from ladle C may contain unreduced oxidized species
of Mn, Cr, V and Ti due to partitioning effects between the liquid
ferroalloy and slag. The slag can then be treated as shown in FIG.
5 by a quenching and grinding and electrostatic separation 82 to
recover MnO, Cr.sub.2O.sub.5, V.sub.2O.sub.5 and TiO.sub.2. This
concentrated slag 50 may then be recycled to the melter, if
desired, in order to increase the desired material concentration of
slag, and improve the efficiency of recovery.
[0062] Recovery of oxidized species, MnO, Cr.sub.2O.sub.5,
V.sub.2O.sub.5 and TiO.sub.2, from the concentrated slag can also
be obtained by solvent extraction techniques.
[0063] The operating parameters of the invented process are as
follows:
TABLE-US-00001 Normal Range Maximum Ferroalloy 1500-1600 C.
1700-1760 C. Melter Temp. Melter Off-Gas 500-1500 C. 1200-1650 C.
Melter Off-Gas 0-0.2'' H.sub.2O gauge <15'' H.sub.2O gauge
Pressure Gas Accumulator 100-350 psig Off-Gas Pressure Gas Turbine
750-900 C. <1000 C. Combined Product Exit Temp.
[0064] Off-gas exiting the melting furnace 36 is cleaned in
cooler-scrubber 52. Optionally, the off-gas may be moved by fan 54
through high pressure compressor 58, which operates in the range of
about 100 to 350 psig, and the cleaned, compressed off-gas is used
as combustion fuel in gas turbine 64, or used for preheating
agglomerates in hopper/preheaters 34 prior to their introduction to
the electric melting furnace 36. Gas turbine 64 drives generator 66
to produce electricity, and sensible heat contained in offgas
exiting the gas turbine is recovered in a waste heat recovery
boiler system 68. The waste heat boiler system 68 steam cycle could
be a "Kalina" cycle based on using 70% ammonia and 30% water for
better range processing and heat recovery efficiency at lower gas
temperatures. Ammonia/water boiling occurs over a range of
temperatures rather that at a specific temperature and pressure.
Steam produced by the waste heat boiler system 68 is then used to
drive a steam turbine 70 and associated generator 72 to produce
additional electricity. A secondary objective of the invention is
to supplement or produce all the required electricity to
accommodate the process and operate the plant so as to be
electricity self sufficient. If sufficient fuel gas is not produced
by the melter, then additional fuel gas, such as natural gas, can
be used to supplement the fuel gas feed to the gas turbine.
[0065] Gas from the compressor 54 can be treated for sulfur removal
in an optional sulfur removal system 60, which may require an
optional chiller 78 upstream of the sulfur gas removal system.
[0066] The agglomerate curing or storage hoppers 34 can be
preheaters, such as a shaft or vessel preheater, as desired. When
used as preheaters, off-gas from the electric furnace or melter 38
can be utilized as shown in FIG. 1. The off-gas is returned to the
gas handling system at cooler-scrubber 52.
SUMMARY OF THE ACHIEVEMENT OF THE OBJECTS OF THE INVENTION
[0067] From the foregoing, it is readily apparent that I have
invented an improved method of producing liquid ferroalloy
(ferrosilicon, ferromanganese, and silicomanganese) from ordinary
ore materials, as well as a method of recovering metallic oxides
contained in the slag, such as manganese oxide, chromium oxide,
vanadium oxide and titanium oxide.
[0068] It is to be understood that the foregoing description and
specific embodiments are merely illustrative of the best mode of
the invention and the principles thereof, and that various
modifications and additions may be made to the apparatus by those
skilled in the art, without departing from the spirit and scope of
this invention.
* * * * *