CA1071833A - Production of metals and carbides - Google Patents
Production of metals and carbidesInfo
- Publication number
- CA1071833A CA1071833A CA206,077A CA206077A CA1071833A CA 1071833 A CA1071833 A CA 1071833A CA 206077 A CA206077 A CA 206077A CA 1071833 A CA1071833 A CA 1071833A
- Authority
- CA
- Canada
- Prior art keywords
- metal
- carbide
- solid state
- manganese
- carbon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Manufacture And Refinement Of Metals (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
PRODUCTION OF METALS AND CARBIDES
ABSTRACT OF THE DISCLOSURE
Metals in oxide and/or hydroxide form, usually in ores or ore concentrates, are converted to the corresponding carbide by a solid state reaction with carbon, the carbide then is separated in substantially pure form and may be converted to the metal.
ABSTRACT OF THE DISCLOSURE
Metals in oxide and/or hydroxide form, usually in ores or ore concentrates, are converted to the corresponding carbide by a solid state reaction with carbon, the carbide then is separated in substantially pure form and may be converted to the metal.
Description
This invention relates to the recovery of metal values, particularly from ores or concentrates thereof.
In the production of metals from ores, a smelting procedure using coke and a flux generally is practised, with liquid metal being tapped at intervals, followed by solidifi-cation, cleaning and sizing of the metal or alloy. In addition, the process is difficult to control, the slag generally is high in metal values and requires recycling and impure products - often are produced.
In accordance with the present invention, there is provided a method of recovery of metal values in substantially pure carbide form, the metal being selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt and nickel, which comprises subjecting the metal values in oxide and/or hydroxide form in ores or concentrates thereof also containing gangue constituents to a single step solld state reduction and carburization reaction with carbon to convert the metal values to the corresponding carbide and, after completion of the solid state reaction, beneficiating the resultant mass to separate the metal carbide in substan-tially pure form from the gangue constituents.
Metal carbides exhibit distinctly different physical ~ -properties from the various gangue constituents of ores and hence standard beneficiation methods may be used to recover the metal carbides, generally in substantially pure form, when the recovery is made from ores and concentrates thereof.
Such beneficiation techniques include gravity, flotation, magnetic and electrostatic treatments.
The elemental metal may be formed from the separated carbide by another solid state reaction with the metal oxide ~,; - 2 - ~
~071833 in accordance with the equation:
Me3C + MeO > 4Me + C
The conditions utilized to obtain the carbide and the elemental metal may vary widely and depend on the particu-lar metal involved. In general, a shaft or rotary kiln may be employed and the invention may be used on both low and high grade ores.
In instances where the metal, the ore and the conditions are such that large amounts of the metal silicate and aluminate may be formed in preference to the carbide, thereby leading to only low recoveries of the metal values in the form of the carbide, it is preferred to incorporate time into the reaction mixture in order to provide a competing reaction for the silica~and alumina to form calcium silicate -and calcium aluminate rather than the metal silicates and aluminates, thereby resulting in an improved yield of the metal carbide.
The invention is applicable to the formation of a large number of carbides from their ores. The metals are titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt and nickel. Where two or more such metals are present in the ore, selective carburization may be employed to recover -individual metal carbides, such as by varying the quantities of carbon used, temperature, gas composition, catalysts and time.
The present invention has particular application in the production of ferro-alloys which are used as addition agents to steel. Particular ferro-alloys which are commonly employed are high-carbon ferrochromium and high-carbon ferro~
manganese.
.
.
By the i~rocedure of the present invention, an iron-chromium or iron-manganese ore may be carburized to provide a mixture of iron and chromium carbides or iron and manganese carbides. Following beneficiation, the carbides may be converted to the metal. Depending on the degree of complete-ness - 3a --`~ 1071833 of the conversion of carbide to the metal, the resulting metal alloy, either ferro-chrome or ferro-manganese, may have a low-carbon content. In many applications in the steel industry low-carbon alloys are preferred to the currently employed high-carbon alloys.
The invention will be described hereinafter with particular reference to production of manganese and alloys thereof, but it will be understood that the principles described hereinafter with reference thereto also apply to 10 the other elements mentioned above, with suitable modification for the particular element chosen.
- Commonly employed high-carbon ferromanganese has the approximate composition 78 to 82% Mn, 7~C, 1~ Si and the balance Fe, and is produced by submerged arc smelting of manganese ores. Low carbonf i.e. 0.07 to 1.5~ C, materials have been produced in open electric-arc furnaces by reacting -manganese-silicon alloys with the ore. High carbon iron-manganese alloys for the steel-ïndustry also are produced in blast furnace operations.
The production of manganese carbide from the oxide -~
in the ore in accordance with the present invention requires reaction with carbon and removal o~ the carbon monoxide as it is produced. This removal of carbon monoxide may be achieved by flushing the reaction vessel with an inert gas having a - partial pressure of CO below about 0.1 atmospheres, or by maintaining the reaction vessel under a vacuum. The reaction proceeds according to the equation:
7 MnO + 10C ) Mn7C3 + 7CO
The reduction step may be carried out over a wide 30 range of temperatures, preferably about 1100 to 1200C., although higher temperatures up to about 1350Cr ~ or higher may be used. Loss of manganese in the form of stable o~ounds .
- 107~833 such as manganese silicates and aluminates may be prevented by adding a sufficient quantity of lime to the ore as discussed above.
After separation of the carbide from the resulting gangue constitutents by standard beneficiation techniques, there is obtained a manganese carbide product. Since iron oxide generally is present in manganese ores, usually the carbide product consists of a mixture of manganese carbide and iron carbide. It may be possible by selective reduction to obtain pure manganese carbide with the iron oxide being reduced to the metal. Pure manganese carbide then may be recovered.
The recovered carbide may be converted to the metal, or an- alloy of metals where the recovered carbide is a mixture of metal carbides, by reaction with the metal oxide or mixture of oxides in accordance with the equation:
Mn7C3 + 3MnO --~10Mn + 3CO
This reaction is carried out in such a manner as to remove the carbon monoxide as it is formed, typically by flushing with an inert gas, such as argon. Generally,a higher reaction temperature such as about 1100 to 1625C.,-is required than that utilized for the carburization step. -Where the metal involved is chromium, different -~ -temperature conditions may be employed, for example, the carburization step may be carried out at a temperature of about 1025 to 1425C. or higher and the reaction between the carbide and oxide at a temperature of about 1300 C. to 1750C.
or higher.
EXAMPLES
The invention is illustrated by the following Examples:
-` 1071~33 Exa~le I
An ore concentrate containing 26.9% Cr and 22.4%
Fe was mixed with the stoichiometric ~uantity of finely-divided (-400 mesh) graphite containing 95% fixed carbon to form Cr3C2 from the chromium and Fe3C from the iron.
Two separate samples of the concentrate were provided, sized as follows:
Sample 1 Sample 2 wt.g. wt.g.
+200 0.85 ~--200 ~ 4003.90 0.25 -400 + 5001.37 1.20 -500 4.43 4.6 TOTAL 10.55 6.05 The charges for each test were slurried, stirred for -10 minutes, partially dried and pelletized to pellets of approximately 3/4 inch diameter.
The pellets were held for about 7 hours and 20 minutes at a temperature of about 1300 to 1400 C. under a stream of argon flowing at 0.05 CF/min.
The products, after cooling overnight, were observed to be dark gray in colour and strongly magnetic. The product pellets from test 1 weighed 84.6g from a charge of 126g and the pellets from test 2 weighed 56.5g from a charge of 90g.
Part of the products from test 2 was shatter boxed and a sample was found to contain 28.0% Cr, 26.0% Fe, 4.58%
C-and the balance gangue. A recovery of 79.0% of Cr was obtained.
The shatter boxed product from test 2 was subjected to low intensity dry magnetic separation. 73.0% of the chromium values in the original charge were recovered in the magnetic fraction which graded 39.9% Cr, 35.2% Fe and 5.16%C. An 107~833 X-ray diffraction analysis indicated the fraction contained 70% Cr7C3, 20% metallic Fe and the balance minor unidentified substances.
Ex {
An ore containing 49.3% Mn, 2.8% Fe, 5.9% SiO2 and 3.52%Al2O3 was ground to 97% -200 mesh and was mixed with finely ground (100%-150 mesh) graphite containing 70% fixed carbon in a quantity of about 100% excess of the quantity necessary to form Mn7C3 and Fe3C from the manganese and iron values of the ore.
The ore, carbon and a small amount of binder were thoroughly mixed and pressed to form compacts sized about 1" diameter and about 1" long. Samples of compacts were fired at different temperatures under a reduced pressure for different time periods. The conditions are reproduced in the following Table I:
TAB~E I
- Test No. Reduced Pressure Heating Time Temperature mm. Hg. (hrs.) (average) 1 0.8 1 2228F
(1220C) -
In the production of metals from ores, a smelting procedure using coke and a flux generally is practised, with liquid metal being tapped at intervals, followed by solidifi-cation, cleaning and sizing of the metal or alloy. In addition, the process is difficult to control, the slag generally is high in metal values and requires recycling and impure products - often are produced.
In accordance with the present invention, there is provided a method of recovery of metal values in substantially pure carbide form, the metal being selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt and nickel, which comprises subjecting the metal values in oxide and/or hydroxide form in ores or concentrates thereof also containing gangue constituents to a single step solld state reduction and carburization reaction with carbon to convert the metal values to the corresponding carbide and, after completion of the solid state reaction, beneficiating the resultant mass to separate the metal carbide in substan-tially pure form from the gangue constituents.
Metal carbides exhibit distinctly different physical ~ -properties from the various gangue constituents of ores and hence standard beneficiation methods may be used to recover the metal carbides, generally in substantially pure form, when the recovery is made from ores and concentrates thereof.
Such beneficiation techniques include gravity, flotation, magnetic and electrostatic treatments.
The elemental metal may be formed from the separated carbide by another solid state reaction with the metal oxide ~,; - 2 - ~
~071833 in accordance with the equation:
Me3C + MeO > 4Me + C
The conditions utilized to obtain the carbide and the elemental metal may vary widely and depend on the particu-lar metal involved. In general, a shaft or rotary kiln may be employed and the invention may be used on both low and high grade ores.
In instances where the metal, the ore and the conditions are such that large amounts of the metal silicate and aluminate may be formed in preference to the carbide, thereby leading to only low recoveries of the metal values in the form of the carbide, it is preferred to incorporate time into the reaction mixture in order to provide a competing reaction for the silica~and alumina to form calcium silicate -and calcium aluminate rather than the metal silicates and aluminates, thereby resulting in an improved yield of the metal carbide.
The invention is applicable to the formation of a large number of carbides from their ores. The metals are titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt and nickel. Where two or more such metals are present in the ore, selective carburization may be employed to recover -individual metal carbides, such as by varying the quantities of carbon used, temperature, gas composition, catalysts and time.
The present invention has particular application in the production of ferro-alloys which are used as addition agents to steel. Particular ferro-alloys which are commonly employed are high-carbon ferrochromium and high-carbon ferro~
manganese.
.
.
By the i~rocedure of the present invention, an iron-chromium or iron-manganese ore may be carburized to provide a mixture of iron and chromium carbides or iron and manganese carbides. Following beneficiation, the carbides may be converted to the metal. Depending on the degree of complete-ness - 3a --`~ 1071833 of the conversion of carbide to the metal, the resulting metal alloy, either ferro-chrome or ferro-manganese, may have a low-carbon content. In many applications in the steel industry low-carbon alloys are preferred to the currently employed high-carbon alloys.
The invention will be described hereinafter with particular reference to production of manganese and alloys thereof, but it will be understood that the principles described hereinafter with reference thereto also apply to 10 the other elements mentioned above, with suitable modification for the particular element chosen.
- Commonly employed high-carbon ferromanganese has the approximate composition 78 to 82% Mn, 7~C, 1~ Si and the balance Fe, and is produced by submerged arc smelting of manganese ores. Low carbonf i.e. 0.07 to 1.5~ C, materials have been produced in open electric-arc furnaces by reacting -manganese-silicon alloys with the ore. High carbon iron-manganese alloys for the steel-ïndustry also are produced in blast furnace operations.
The production of manganese carbide from the oxide -~
in the ore in accordance with the present invention requires reaction with carbon and removal o~ the carbon monoxide as it is produced. This removal of carbon monoxide may be achieved by flushing the reaction vessel with an inert gas having a - partial pressure of CO below about 0.1 atmospheres, or by maintaining the reaction vessel under a vacuum. The reaction proceeds according to the equation:
7 MnO + 10C ) Mn7C3 + 7CO
The reduction step may be carried out over a wide 30 range of temperatures, preferably about 1100 to 1200C., although higher temperatures up to about 1350Cr ~ or higher may be used. Loss of manganese in the form of stable o~ounds .
- 107~833 such as manganese silicates and aluminates may be prevented by adding a sufficient quantity of lime to the ore as discussed above.
After separation of the carbide from the resulting gangue constitutents by standard beneficiation techniques, there is obtained a manganese carbide product. Since iron oxide generally is present in manganese ores, usually the carbide product consists of a mixture of manganese carbide and iron carbide. It may be possible by selective reduction to obtain pure manganese carbide with the iron oxide being reduced to the metal. Pure manganese carbide then may be recovered.
The recovered carbide may be converted to the metal, or an- alloy of metals where the recovered carbide is a mixture of metal carbides, by reaction with the metal oxide or mixture of oxides in accordance with the equation:
Mn7C3 + 3MnO --~10Mn + 3CO
This reaction is carried out in such a manner as to remove the carbon monoxide as it is formed, typically by flushing with an inert gas, such as argon. Generally,a higher reaction temperature such as about 1100 to 1625C.,-is required than that utilized for the carburization step. -Where the metal involved is chromium, different -~ -temperature conditions may be employed, for example, the carburization step may be carried out at a temperature of about 1025 to 1425C. or higher and the reaction between the carbide and oxide at a temperature of about 1300 C. to 1750C.
or higher.
EXAMPLES
The invention is illustrated by the following Examples:
-` 1071~33 Exa~le I
An ore concentrate containing 26.9% Cr and 22.4%
Fe was mixed with the stoichiometric ~uantity of finely-divided (-400 mesh) graphite containing 95% fixed carbon to form Cr3C2 from the chromium and Fe3C from the iron.
Two separate samples of the concentrate were provided, sized as follows:
Sample 1 Sample 2 wt.g. wt.g.
+200 0.85 ~--200 ~ 4003.90 0.25 -400 + 5001.37 1.20 -500 4.43 4.6 TOTAL 10.55 6.05 The charges for each test were slurried, stirred for -10 minutes, partially dried and pelletized to pellets of approximately 3/4 inch diameter.
The pellets were held for about 7 hours and 20 minutes at a temperature of about 1300 to 1400 C. under a stream of argon flowing at 0.05 CF/min.
The products, after cooling overnight, were observed to be dark gray in colour and strongly magnetic. The product pellets from test 1 weighed 84.6g from a charge of 126g and the pellets from test 2 weighed 56.5g from a charge of 90g.
Part of the products from test 2 was shatter boxed and a sample was found to contain 28.0% Cr, 26.0% Fe, 4.58%
C-and the balance gangue. A recovery of 79.0% of Cr was obtained.
The shatter boxed product from test 2 was subjected to low intensity dry magnetic separation. 73.0% of the chromium values in the original charge were recovered in the magnetic fraction which graded 39.9% Cr, 35.2% Fe and 5.16%C. An 107~833 X-ray diffraction analysis indicated the fraction contained 70% Cr7C3, 20% metallic Fe and the balance minor unidentified substances.
Ex {
An ore containing 49.3% Mn, 2.8% Fe, 5.9% SiO2 and 3.52%Al2O3 was ground to 97% -200 mesh and was mixed with finely ground (100%-150 mesh) graphite containing 70% fixed carbon in a quantity of about 100% excess of the quantity necessary to form Mn7C3 and Fe3C from the manganese and iron values of the ore.
The ore, carbon and a small amount of binder were thoroughly mixed and pressed to form compacts sized about 1" diameter and about 1" long. Samples of compacts were fired at different temperatures under a reduced pressure for different time periods. The conditions are reproduced in the following Table I:
TAB~E I
- Test No. Reduced Pressure Heating Time Temperature mm. Hg. (hrs.) (average) 1 0.8 1 2228F
(1220C) -
2 0.8 2 23790F
(1304C) Following the firing, the products were subjected to elutrlation to obtain samples rich in manganese carbide and at high manganese recoveries.
Example III
A charge of 100 gms of the same ore as used in Example II (100%-200mesh), 26.6 gms of CaO (100%-200 mesh) and 28.7 gms of graphite (100%-400 mesh, 95% fixed carbon) was mixed with water and the resultant slurry was thoroughly stirred and partially dried to give a thick paste which was formed into pellets approximately 1~" in diameter The pellets were allowed to dry overnight.
Samples of the pellets were heated to a reaction temperature while being subjected to a vacuum and held at the reaction temperature for a certain period of time. The conditions are outlined in the following Talble II:
TABLE II
Test No. Heating up Heating Time MaxO Temp. Lowest Time (min.) (min.) C. Pressure attained 1 854 1343 3xlO 3mm Hg.
10 2 76120 1371 46 cm Hg.
After cooling, the~product was subjected to a heavy liquid separation using Clerici solution and the fractions .~ .
analyzed for Mn, Fe and C contents. The results are reproduced in the following Table III:
TABLE III
Fe C Mh Test No. Wt.% Wt.gm. Wt.% Wt.gm. Wt.~ Wt.gm. Wt.% Wt.gm. Distri-_ _ bution %
l Product 100 19 Sink 49.47 9.4 2.12 0.20 6.68 0.62 77.8 7.31 77.7 - -Float 50.53 9.6 1.85 0.17 11.70 1.12 21.9 2.10 22.3 2 Produ~ct 100 10 --Sink 72.0 7.2 4.50 0.324 6.54 0.47 85.80 6.17 82.6 Float 28.0 2.8 3.14 0.087 18.00 0.50 46.6 1.3 17.4 -The present invention therefore provides a process for the recovery of metal values from ores by direct carburization of the metal oxide values of the ore. Mbdifications are possible within the scope of the invention.
- ' ~
(1304C) Following the firing, the products were subjected to elutrlation to obtain samples rich in manganese carbide and at high manganese recoveries.
Example III
A charge of 100 gms of the same ore as used in Example II (100%-200mesh), 26.6 gms of CaO (100%-200 mesh) and 28.7 gms of graphite (100%-400 mesh, 95% fixed carbon) was mixed with water and the resultant slurry was thoroughly stirred and partially dried to give a thick paste which was formed into pellets approximately 1~" in diameter The pellets were allowed to dry overnight.
Samples of the pellets were heated to a reaction temperature while being subjected to a vacuum and held at the reaction temperature for a certain period of time. The conditions are outlined in the following Talble II:
TABLE II
Test No. Heating up Heating Time MaxO Temp. Lowest Time (min.) (min.) C. Pressure attained 1 854 1343 3xlO 3mm Hg.
10 2 76120 1371 46 cm Hg.
After cooling, the~product was subjected to a heavy liquid separation using Clerici solution and the fractions .~ .
analyzed for Mn, Fe and C contents. The results are reproduced in the following Table III:
TABLE III
Fe C Mh Test No. Wt.% Wt.gm. Wt.% Wt.gm. Wt.~ Wt.gm. Wt.% Wt.gm. Distri-_ _ bution %
l Product 100 19 Sink 49.47 9.4 2.12 0.20 6.68 0.62 77.8 7.31 77.7 - -Float 50.53 9.6 1.85 0.17 11.70 1.12 21.9 2.10 22.3 2 Produ~ct 100 10 --Sink 72.0 7.2 4.50 0.324 6.54 0.47 85.80 6.17 82.6 Float 28.0 2.8 3.14 0.087 18.00 0.50 46.6 1.3 17.4 -The present invention therefore provides a process for the recovery of metal values from ores by direct carburization of the metal oxide values of the ore. Mbdifications are possible within the scope of the invention.
- ' ~
Claims (7)
1. A method of recovery of metal values in substantially pure carbide form, said metal being selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt and nickel, which comprises subjecting the metal values in oxide and/or hydroxide form in ores or concentrates thereof also containing gangue constituents to a single step solid state reduction and carburization reaction with carbon to convert said metal values to the corresponding carbide and, after completion of said solid state reaction, beneficiating the resultant mass to separate said metal carbide in substan-tially pure form from said gangue constituents.
2. The method of claim 1 wherein said metal is manganese and said solid state reaction is carried out by heating an ore or concentrate thereof and carbon in intimate admixture at a temperature of from about 1100°C to about 1350°C.
3. The method of claim 2 wherein lime is present in said admixture.
4. The method of claim 1 wherein said metal is chromium and said solid state reaction is carried out by heating an ore or concentrate thereof and carbon in intimate admixture at a temperature of from about 1025°C to about 1425°C.
5. The method of claim 1 including the additional step, after said beneficiation step, of reacting said substantially pure metal carbide with an oxide of the metal in a solid state reaction to form the metal.
6. The method of claim 2 including the further step of reacting said manganese carbide with manganese oxide in a solid state reaction at a temperature of about 1100° to about 1625°.
7. The method of claim 4 including the further step of reacting said chromium carbide with chromium oxide in a solid state reaction at a temperature of about 1300° to about 1750°C.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3728673 | 1973-08-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1071833A true CA1071833A (en) | 1980-02-19 |
Family
ID=10395247
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA206,077A Expired CA1071833A (en) | 1973-08-06 | 1974-07-31 | Production of metals and carbides |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1071833A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001021845A1 (en) * | 1999-09-20 | 2001-03-29 | Unisearch Limited | Solid state reduction of oxides |
| AU772642B2 (en) * | 1999-09-20 | 2004-05-06 | Temco Pty Ltd | Solid state reduction of oxides |
| WO2015100193A3 (en) * | 2013-12-23 | 2015-11-12 | Purdue Research Foundation | Copper based casting products and processes |
-
1974
- 1974-07-31 CA CA206,077A patent/CA1071833A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001021845A1 (en) * | 1999-09-20 | 2001-03-29 | Unisearch Limited | Solid state reduction of oxides |
| AU772642B2 (en) * | 1999-09-20 | 2004-05-06 | Temco Pty Ltd | Solid state reduction of oxides |
| WO2015100193A3 (en) * | 2013-12-23 | 2015-11-12 | Purdue Research Foundation | Copper based casting products and processes |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4018597A (en) | Rare earth metal silicide alloys | |
| US5865872A (en) | Method of recovering metals and producing a secondary slag from base metal smelter slag | |
| US4256496A (en) | Production of metal carbides in pure form | |
| US3999981A (en) | Production and recovery of metallic carbides from ores and concentrates | |
| US4398945A (en) | Process for producing a ferronickel alloy from nickel bearing laterites | |
| CA1071833A (en) | Production of metals and carbides | |
| US3953579A (en) | Methods of making reactive metal silicide | |
| CA1224046A (en) | Process for preparing silicium-based complex ferroalloys | |
| WO2022211640A1 (en) | Ferrosilicon vanadium and/or niobium alloy, production of a ferrosilicon vanadium and/or niobium alloy, and the use thereof | |
| EP0061816B1 (en) | Addition agent for adding vanadium to iron base alloys | |
| US1835925A (en) | Smelting process | |
| GB2030179A (en) | Production of steel from iron sponge in electric furnaces | |
| US1820998A (en) | Smelting of ores | |
| US1863642A (en) | Manufacture of alloys | |
| US5573572A (en) | Process for the production of tantalum-niobium concentrates | |
| US3138455A (en) | Process for the production of low silicon, medium-to-low carbon ferromanganese | |
| US5725631A (en) | Composite charge for metallurgical processing | |
| US2883278A (en) | Process for preparing a sintered agglomerate | |
| US2653867A (en) | Reduction of metal oxides | |
| US2631936A (en) | Process for the production of a ferrochrome-silicon-aluminum alloy | |
| US3271141A (en) | Process for producing a columbium addition agent | |
| US4306905A (en) | Production of ferrochromium alloys | |
| US3024105A (en) | Process for low-phosphorus ferromanganese alloys | |
| US2995455A (en) | Method of recovering nickel and iron from laterite ores by preferential reduction | |
| US3143788A (en) | Columbium addition agent |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |