US3224871A - Process of preheating ores for reduction in smelting furnace - Google Patents

Process of preheating ores for reduction in smelting furnace Download PDF

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Publication number
US3224871A
US3224871A US173450A US17345062A US3224871A US 3224871 A US3224871 A US 3224871A US 173450 A US173450 A US 173450A US 17345062 A US17345062 A US 17345062A US 3224871 A US3224871 A US 3224871A
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United States
Prior art keywords
charge
gas
kiln
shaft
rotary kiln
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Expired - Lifetime
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US173450A
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English (en)
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Collin Frederik Christen
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Elektrokemisk AS
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Elektrokemisk AS
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/14—Multi-stage processes processes carried out in different vessels or furnaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/28—Moving reactors, e.g. rotary drums
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/08—Making spongy iron or liquid steel, by direct processes in rotary furnaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00054—Controlling or regulating the heat exchange system
    • B01J2219/00056—Controlling or regulating the heat exchange system involving measured parameters
    • B01J2219/00069—Flow rate measurement
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
    • B01J2219/00099—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor the reactor being immersed in the heat exchange medium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/0015—Controlling the temperature by thermal insulation means
    • B01J2219/00155—Controlling the temperature by thermal insulation means using insulating materials or refractories
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00159—Controlling the temperature controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00164—Controlling or regulating processes controlling the flow
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00186—Controlling or regulating processes controlling the composition of the reactive mixture
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/18—Details relating to the spatial orientation of the reactor
    • B01J2219/187—Details relating to the spatial orientation of the reactor inclined at an angle to the horizontal or to the vertical plane

Definitions

  • the charge In the rotary kiln the charge is heated by combustion of gas rich in CO which is formed by reaction between oxygen in the charge and a carbonaceous reducing agent and additional heat is ordinarily supplied at the discharge end of the kiln.
  • the charge which is preheated and at times prereduced in the rotary kiln is then fed into the electric furnace in which final reduction and smelting take place.
  • the heat content of the gas leaving the feed end of the rotary kiln is most effectively utilized by passing the gas in countercurrent flow through a bed of charge moving downwardly in a shaft.
  • the hot gas in passing through the interstices in the bed of charge contacts a large surface area of the charge to provide a much greater transfer of heat than that obtained in the rotary kiln without sacrificing the advantages of pretreatment in the rotary kiln.
  • the preheating shafts increase the heat efliciency of the rotary kiln operation and many other advantages may be achieved by the combined shaft and rotary kiln system of the present invention.
  • the off gases from the kiln may be at a temperature of about 500 to 900 C. or more.
  • the charge in the shafts may be heated to a temperature of about 500 to 800 C. before it is fed into the rotary kiln.
  • Such a hot charge makes it possible to reduce the length of the rotary kiln which is of advantage in reducing the cost of installation.
  • the temperature of the off gas from the rotary kiln may be further increased to about 1200 C. by feeding all of the carbon required for reduction of the charge as coal into the high temperature zone of the rotary kiln.
  • the charge in the shafts may be heated to about 1000 C. This is of particular advantage in connection with the production of calcium carbide as in such case the limestone will be heated and precalcined in the shafts while the final calcination and coking of the raw coal will take place in the rotary kiln.
  • a combination of preheating in the shafts and prereduction in the rotary kiln is especially advantageous for treating pellets or briquettes.
  • Raw pellets of finely ground metal oxide, bituminous coal and a binding agent such as Portland cement must be heat treated to provide the necessary mechanical strength for prereduction in a rotary kiln.
  • the pellets are heated treated in the shafts at a temperature of about 600 to 900 C. At this temperature the coal is converted to coke and during this process a coke lattice is formed which reinforces the pellets to provide the mechanical strength required. for treatment in the rotary kiln. In the rotary kiln the pellets are heated to about 900 to 1100 C.
  • the temperature and composition of the gas used in the shafts In certain applications it is important to control the temperature and composition of the gas used in the shafts. In general this is done by controlling the amount of heat supplied at the discharge end of the kiln and by controlling the amount of air and coal fed into the high temperature zone of the kiln. Final control of the temperature and composition of the gas in the'shaft is achieved by providing an air lock at the mouth of the shaft and by withdrawing the gas below the air lock by means of fans which may be employed for recycling the gas.
  • FIG. 1 shows a side view of the combined shaft and rotary kiln system of the present invention
  • FIG. 2 is a section on line 22 of FIG. 1.
  • Shaft 16 with refractory lining 18 is provided with a conventional type air lock valve 20 for feeding charge into the shaft.
  • Valve 22 controls the flow of charge from the discharge end of the shaft where the charge is fed into the kiln by pipe 24.
  • the off gas from the kiln is collected in box 26 and fed into the bottom end portion of the shaft by the pipe 28 and a conventional gas feeder 30 which distributes the gas to the charge in shaft 16.
  • the gas is collected at the top of the shaft by a conventional gas collector 32 and fan 34 overcomes the pressure drop in shaft 16 to suck the gas through the charge.
  • Valves 36 and 38 control the flow of gas from the fan and the gas is either returned to the exhaust stack or recycled through pipe 39 to chamber 26 for adjusting the temperature and composition of the gas fed to the shaft.
  • each shaft 16 is equipped with its own individual fan and gas feeding and recycle pipes connected to chamber 26 as described for shaft 16.
  • the rotary kiln may be equipped with one or more devices for feeding coal or other high volatile carbonaceous material into the kiln.
  • One such device is illustrated in the drawings and as there shown the device comprises a hopper 40 with conveyor 41 which feeds coal into the open container 42.
  • a plurality of pipes 44 which extend into the interior of the furnace are bent at their outer end in the direction of rotation of the kiln to provide scoops which pick up the coal from container 42 and feed it onto the charge in the kiln which is at a temperature of 800 C. or more.
  • the heat of the charge will quickly drive off the volatiles and convert the coal to coke.
  • the volatile material is burned above the charge with a luminous heat radiating flame.
  • Air for burning the volatiles may be introduced through the same pipes used for introduction of the coal or additional air pipes (not shown) may supply air to the kiln near the discharge end in conventional manner or excess air may be supplied by a burner if such is employed for introducing heat into the discharge end of the kiln. If desired coke or other low volatile carbonaceous material may also be fed into the kiln by means of pipes 44.
  • the material treated in the kiln is discharged through a conventional so-called front wagon 46 and it may be fed directly into an electric furnace 48 by the inclined chute or pipe 50.
  • the kiln discharges into an intermediate hopper (not shown) and the discharged material is then transferred from the hopper to the electric furnace.
  • furnace gas rich in CO is supplied to the discharge end of the kiln by pipe 52- and the gas is burned in the kiln to supply heat at this end of the kiln.
  • a conventional gas burned (not shown) may be used for supplying heat at the discharge end of the kiln.
  • iron ore and the usual limestone flux are charged to the preheating shafts and all of the carbon required for reduction of the charge is fed into the kiln as coal by pipes 44. Air fed into the kiln is so adjusted that the off gas of the kiln is at a temperature of about 1000 C. and contains about 3% oxygen.
  • the iron ore and limestone flux are heated to a temperature of about 900 C. in the shafts and as a result FeS in the ore will be oxidized to Fe O and the limestone flux calcined to lime. Under these conditions about 30% of the oxygen is removed from the ore in the rotary kiln.
  • powdered iron ore 50 to 90% of which passed through a 200 mesh standard Taylor screen is pelletized with slightly more than the stoichiometric proportion of bituminous coal necessary for reduction and about 5% Portland cement as a binder.
  • the raw wet pellets were hardened by storing for three days at atmospheric temperature whereby the point pressure strength of the pellets increased from 3 kgs. to 15 kgs.
  • the mechanical strength of the hardened pellets of 15 kgs. is adequate for pretreatment in the shafts but insufficient for treatment in the rotary kiln.
  • the pellets are fed into the shaft.
  • gas supplied by the furnace to the discharge end of the rotary kiln contains 45% CO and 55% CO.
  • the gas is burned in the rotary kiln and the supply of air is so controlled that the off gas from the kiln is at a temperature of about 900 C.
  • the off gas contains about 13% CO 0.2% oxygen, 1.0% CO and the remainder N
  • the pellets in the shaft are heated to about 800 C. by the hot off gas whereby the point pressure strength of the pellets is increased from 15 kgs. to about kgs. to provide the desired mechanical strength for treatment in the rotary kiln.
  • the hardened pellets are transferred to the kiln where they are heated to a temperature of about 900 C.
  • the charge in the shaft is heated to a temperature of about 500 to 900 C. in order to provide the pellets with the necessary mechanical strength for treatment in the rotary kiln and for best results the oxygen content of the gas utilized in the shaft is below about 1.0% and the CO content is also below about 1.0%. Care is taken to limit the depth of the charge column in the shafts to about 1.0 meter because of the low mechanical strength of the pellets charged to the shafts.
  • system of the present invention may be used for pretreatment of ores or other oxides or materials of the type which are customarily treated in a submerged arc smelting furnace.
  • oxides or materials of the type which are customarily treated in a submerged arc smelting furnace.
  • iron oxides various oxides for producing ferro alloys such as ferromanganese or ferro silicon and also can be used in the production of calcium carbide.
  • the method of treating ores in a rotary kiln having at least one shaft associated therewith for feeding charge into the kiln which comprises the steps of introducing charge into the shaft to establish a column of charge therein which is relatively short with respect to the length of the kiln, moving the charge in the column downwardly in the shaft, collecting hot off gas from the rotary kiln, introducing at least a portion of the hot off gas into the lower end portion of the shaft, passing the introduced off gas upwardly in the shaft in countercurrent flow through the interstices in the column of charge, withdrawing the introduced off gas from the upper portion of the shaft and feeding the charge heated by the introduced off gas into the rotary kiln.
  • the method specified in claim 1 which includes the step of providing a flow of oxidizing gas countercurrent to the bed of charge containing from about 1 to 5% oxygen at a temperature of not more than 900 C.
  • the method specified in claim 1 which includes the step of providing a flow of gas which contains not more than about 1% oxygen, and not more than about 1% CO, such gas being at a temperature of about 500 to 900 C.
  • the method of treating ores in a rotary kiln having a plurality of stationary shafts associated therewith for feeding charge into the kiln comprising the steps of introducing charge into the shafts to establish vertical columns of charge therein which are relatively short in comparison with the length of the kiln, moving the charge in each column downwardly, passing hot off gas from the rotary kiln upwardly through the interstices in each column countercurrent to the movement of the charge to heat the charge, withdrawing from each column the gas passed upwardly through the column, passing said withdrawn gas upwardly through the columns along with off gas from the rotary kiln and introducing charge so heated into the rotary kiln.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US173450A 1961-02-24 1962-02-15 Process of preheating ores for reduction in smelting furnace Expired - Lifetime US3224871A (en)

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Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3328161A (en) * 1962-12-07 1967-06-27 Metallgesellschaft Ag Process for reducing iron ore pellets
US3407059A (en) * 1965-04-22 1968-10-22 Selas Corp Of America Reducing a mixture of ores and carbon
US3486883A (en) * 1964-10-09 1969-12-30 Metallgesellschaft Ag Process for the production of iron sponge
US3831913A (en) * 1971-08-12 1974-08-27 Nippon Kokan Kk Apparatus for direct iron reduction
US3864122A (en) * 1971-05-29 1975-02-04 Krupp Gmbh Method for producing steel
US3887360A (en) * 1969-03-26 1975-06-03 Skf Svenska Kullagerfab Ab Methods and furnaces for steel manufacture by direct reduction and melting of iron ore
US3894865A (en) * 1970-07-10 1975-07-15 Wienert Fritz Otto Production of metallurgical pellets in rotary kilns
US3918958A (en) * 1968-06-24 1975-11-11 Guenter Heitmann Method for the production of sponge iron
US3929459A (en) * 1974-03-13 1975-12-30 Us Interior Charging an electric furnace
US3945817A (en) * 1973-12-17 1976-03-23 Nippon Kokan Kabushiki Kaisha Method for the collection of dust of a high zinc content during the production of reduced iron pellets
US3976472A (en) * 1973-05-17 1976-08-24 Rolf Linder Method and an electrically heated device for producing molten metal from powders or lumps of metal oxides
US3996045A (en) * 1972-09-01 1976-12-07 Pacific Metals Co., Ltd. Method for producing high-grade ferro-nickel directly from nickeliferous oxide ores
US4002465A (en) * 1974-04-16 1977-01-11 Ugo Brusa Process for continuously heating and melting prereduced iron ores
US4076954A (en) * 1973-05-17 1978-02-28 Rolf Linder Method and an electrically heated device for producing molten metal from powders or lumps of metal oxides
US4156102A (en) * 1975-10-22 1979-05-22 Societe Metallurgique Le Nickel -Sln Method for producing ferro-alloys
US4280836A (en) * 1980-06-02 1981-07-28 Kyoei Steel Ltd. Method of preheating iron scraps in steel-making by the electric arc furnace
US4396181A (en) * 1980-11-19 1983-08-02 Inspiration Consolidated Copper Company Converter for refining liquid metal
US4416689A (en) * 1980-10-15 1983-11-22 Asea Ab Process for the manufacture of crude iron and energy-rich gases
US4487399A (en) * 1980-11-19 1984-12-11 Inspiration Consolidated Copper Company Converter for refining liquid metal
US4490168A (en) * 1983-01-13 1984-12-25 Metallgesellschaft Ag Process of making steel by melting sponge iron in an electric arc furnace
US4514219A (en) * 1983-02-03 1985-04-30 Institut De Recherches De La Siderurgie Francaise Method of producing molten metal
US4551172A (en) * 1983-08-25 1985-11-05 Metallgesellschaft Aktiengesellschaft Process of producing liquid carbon-containing iron
US4613363A (en) * 1985-12-11 1986-09-23 Wienert Fritz Otto Process of making silicon, iron and ferroalloys
US4981510A (en) * 1988-08-06 1991-01-01 Fried.Krupp Gesellschaft Process and apparatus for the production of ferrochromium
US5074906A (en) * 1988-03-16 1991-12-24 Abb Flakt Ab Method and installation for recovering energy in metallurgical processes
WO2009032111A1 (en) * 2007-09-04 2009-03-12 Cardero Resource Corporation Direct processing of ferrotitania ores and sands
US20120107759A1 (en) * 2010-10-27 2012-05-03 Christopher Moran Flameless impingement preheating furnace

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1786999A (en) * 1925-11-25 1930-12-30 Granular Iron Company Reduction of metals from ores
US1864593A (en) * 1929-05-15 1932-06-28 Gustafsson Emil Gustaf Torvald Method of producing metal sponge
US1971815A (en) * 1931-01-30 1934-08-28 Halvorsen Birger Fjeld Treatment of sulphurous iron ores
US2484911A (en) * 1945-04-21 1949-10-18 Seil Frances Merritt Rotary kiln
US2593398A (en) * 1943-06-11 1952-04-22 Kalling Bo Michael Sture Method of reducing ores without melting
US2754197A (en) * 1952-09-26 1956-07-10 Wienert Fritz Otto Method and a rotary kiln for the manufacture of sponge iron
US3007690A (en) * 1960-02-03 1961-11-07 Chemical Construction Corp Self-sealing rotary kiln
US3033673A (en) * 1960-05-03 1962-05-08 Elektrokemisk As Process of reducing iron oxides

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1786999A (en) * 1925-11-25 1930-12-30 Granular Iron Company Reduction of metals from ores
US1864593A (en) * 1929-05-15 1932-06-28 Gustafsson Emil Gustaf Torvald Method of producing metal sponge
US1971815A (en) * 1931-01-30 1934-08-28 Halvorsen Birger Fjeld Treatment of sulphurous iron ores
US2593398A (en) * 1943-06-11 1952-04-22 Kalling Bo Michael Sture Method of reducing ores without melting
US2484911A (en) * 1945-04-21 1949-10-18 Seil Frances Merritt Rotary kiln
US2754197A (en) * 1952-09-26 1956-07-10 Wienert Fritz Otto Method and a rotary kiln for the manufacture of sponge iron
US3007690A (en) * 1960-02-03 1961-11-07 Chemical Construction Corp Self-sealing rotary kiln
US3033673A (en) * 1960-05-03 1962-05-08 Elektrokemisk As Process of reducing iron oxides

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3328161A (en) * 1962-12-07 1967-06-27 Metallgesellschaft Ag Process for reducing iron ore pellets
US3486883A (en) * 1964-10-09 1969-12-30 Metallgesellschaft Ag Process for the production of iron sponge
US3407059A (en) * 1965-04-22 1968-10-22 Selas Corp Of America Reducing a mixture of ores and carbon
US3918958A (en) * 1968-06-24 1975-11-11 Guenter Heitmann Method for the production of sponge iron
US3887360A (en) * 1969-03-26 1975-06-03 Skf Svenska Kullagerfab Ab Methods and furnaces for steel manufacture by direct reduction and melting of iron ore
US3894865A (en) * 1970-07-10 1975-07-15 Wienert Fritz Otto Production of metallurgical pellets in rotary kilns
US3864122A (en) * 1971-05-29 1975-02-04 Krupp Gmbh Method for producing steel
US3831913A (en) * 1971-08-12 1974-08-27 Nippon Kokan Kk Apparatus for direct iron reduction
US3996045A (en) * 1972-09-01 1976-12-07 Pacific Metals Co., Ltd. Method for producing high-grade ferro-nickel directly from nickeliferous oxide ores
US3976472A (en) * 1973-05-17 1976-08-24 Rolf Linder Method and an electrically heated device for producing molten metal from powders or lumps of metal oxides
US4076954A (en) * 1973-05-17 1978-02-28 Rolf Linder Method and an electrically heated device for producing molten metal from powders or lumps of metal oxides
US3945817A (en) * 1973-12-17 1976-03-23 Nippon Kokan Kabushiki Kaisha Method for the collection of dust of a high zinc content during the production of reduced iron pellets
US3929459A (en) * 1974-03-13 1975-12-30 Us Interior Charging an electric furnace
US4002465A (en) * 1974-04-16 1977-01-11 Ugo Brusa Process for continuously heating and melting prereduced iron ores
US4156102A (en) * 1975-10-22 1979-05-22 Societe Metallurgique Le Nickel -Sln Method for producing ferro-alloys
US4280836A (en) * 1980-06-02 1981-07-28 Kyoei Steel Ltd. Method of preheating iron scraps in steel-making by the electric arc furnace
US4416689A (en) * 1980-10-15 1983-11-22 Asea Ab Process for the manufacture of crude iron and energy-rich gases
US4396181A (en) * 1980-11-19 1983-08-02 Inspiration Consolidated Copper Company Converter for refining liquid metal
US4487399A (en) * 1980-11-19 1984-12-11 Inspiration Consolidated Copper Company Converter for refining liquid metal
US4490168A (en) * 1983-01-13 1984-12-25 Metallgesellschaft Ag Process of making steel by melting sponge iron in an electric arc furnace
US4514219A (en) * 1983-02-03 1985-04-30 Institut De Recherches De La Siderurgie Francaise Method of producing molten metal
US4551172A (en) * 1983-08-25 1985-11-05 Metallgesellschaft Aktiengesellschaft Process of producing liquid carbon-containing iron
US4613363A (en) * 1985-12-11 1986-09-23 Wienert Fritz Otto Process of making silicon, iron and ferroalloys
US5074906A (en) * 1988-03-16 1991-12-24 Abb Flakt Ab Method and installation for recovering energy in metallurgical processes
US4981510A (en) * 1988-08-06 1991-01-01 Fried.Krupp Gesellschaft Process and apparatus for the production of ferrochromium
WO2009032111A1 (en) * 2007-09-04 2009-03-12 Cardero Resource Corporation Direct processing of ferrotitania ores and sands
US20120107759A1 (en) * 2010-10-27 2012-05-03 Christopher Moran Flameless impingement preheating furnace

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ES274866A1 (es) 1962-05-01

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