WO2007026192A1 - Production of ferroboron in direct current electrical arc furnace - Google Patents
Production of ferroboron in direct current electrical arc furnace Download PDFInfo
- Publication number
- WO2007026192A1 WO2007026192A1 PCT/IB2005/053499 IB2005053499W WO2007026192A1 WO 2007026192 A1 WO2007026192 A1 WO 2007026192A1 IB 2005053499 W IB2005053499 W IB 2005053499W WO 2007026192 A1 WO2007026192 A1 WO 2007026192A1
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- WO
- WIPO (PCT)
- Prior art keywords
- ferroboron
- charge
- boron
- arc furnace
- direct current
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
- C21C5/5264—Manufacture of alloyed steels including ferro-alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/56—Manufacture of steel by other methods
- C21C5/562—Manufacture of steel by other methods starting from scrap
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
- C21C5/5229—Manufacture of steel in electric furnaces in a direct current [DC] electric arc furnace
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Definitions
- This invention is related with the production process of ferroboron in direct current electrical arc furnace.
- Ferroboron is used in several areas of the industry.
- ferroboron In production of ferroboron several methods can be used. Production process is determined by the usage area of ferroboron. Ferroboron, added to steel in order to improve its mechanical properties, is being usually produced with the aluminothermic method. In this method, iron oxide, boron oxide and aluminium powder are put in a laddie, specific for aluminothermy, to interact with each other. Ferroboron produced with this method usually contains 16-20% boron and 1 ,5-6% aluminium, and the boron recovery is 40-60%. In this process ferroboron can be produced to blocks of 1 ton weight.
- ferroboron concentration in ferroboron increases to 20%, aluminium concentration remains at 2-4% and the boron recovery is 50-68%.
- the usage of ferroboron produced by this process is limited because of the impurities it contains.
- ferroboron is planned to be used as an electrical or magnetic material
- the production method is carbothermic process.
- the raw material feed consisting of boron oxide or boric acid, pre-reduced or sintered iron and coke, yields some ferroboron suitable for metallic glass.
- the boron recoveries are low (38,5-73%), and the high percentage of carbon makes a decarburization necessary.
- boron shows similar thermodynamic behaviour as carbon and gets lost increasing the cost of the process.
- the published patent application JP1177334 describes a ferroboron production method using a direct current girod furnace with a ladle of 100-500 mm height.
- boron raw material boron oxide or boric acid has been used.
- the ferroboron production in direct current arc furnace can be used.
- the ladle of the furnace is being charged with the feed material (4) consisting of boron carrying raw materials (such as boron oxide, boric acid, borax and borax anhydrite), iron and iron oxide carrying raw materials (such as low silica hematite ores, iron oxide containing minimill wastes and metallic iron as lubricant free lathe shavings), charcoal as reductant and wood shavings (in order to decline the bulk density of the charge, to prevent sintering and to obtain a macro-porous carbon skeleton.) Because of the low amount of carbon, slag formation doesn't occur. Thus, the boron yield increases to 98% and the energy consumption decreases.
- the aim of the invention is to decrease the consumption of electrode and energy and also the abrasion of refractory lining by using DC arc furnace in ferroboron production.
- Another purpose of the invention is to provide an homogeneous product by means of homogeneously heat distribution in the charge and owing to the mobility of the molten phase. Furthermore a slag-free production is aimed.
- Figure 1 is a side view of the DC arc furnace ladle.
- the DC arc furnace comprises the furnace ladle (A), the tapping hole (7) which is opened to the bottom part of the side edge (9) of the furnace ladle (A), the moveable upper electrode (3) and the stationary bottom electrode (5).
- the ladle (A) of the furnace is being filled with the charge (4) comprising boron carrying raw materials selected from the group which comprises boron oxide, boric acid, borax and borax anhydrite; low silica hematite ores; iron oxide containing minimill wastes; iron and iron oxide carrying raw materials selected from the group which comprises metallic iron, charcoal as reductant and wood shavings in order to decline the bulk density of the charge, to prevent sintering and to obtain a macro- porous carbon skeleton.
- the charge (4) comprising boron carrying raw materials selected from the group which comprises boron oxide, boric acid, borax and borax anhydrite; low silica hematite ores; iron oxide containing minimill wastes; iron and iron oxide carrying raw materials selected from the group which comprises metallic iron, charcoal as reductant and wood shavings in order to decline the bulk density of the charge, to prevent sintering and to obtain a macro- porous carbon skeleton.
- the ratio of boric acid (H 3 BO 3 ) to iron oxide (Fe 2 O 3 ) is to be kept between 0,3-2; H 3 BO 3 to iron oxide (FeO) between 0,3- 2,1 and H 3 BO 3 to iron (Fe) between 0,3-2,4.
- the charcoal amount in the charge (4) is about 5-25% of total charge weight and the amount of wood shavings is about 10- 20% of total charge weight.
- the moving upper electrode (3) is submerged, vertically to the furnace base (8), into the charge (4) fed into the DC arc furnace ladle (A).
- the boron concentration in ferroboron can be increased. With increasing boron concentration, the percentage of carbon in ferroboron can be reduced to 0,2%. Calcium compounds in the charge lead to slag formation so a slag-free production is made by the decrease of calcium compounds in ferroboron.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Silicon Compounds (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Vertical, Hearth, Or Arc Furnaces (AREA)
Abstract
Ferroboron is produced in direct current electrical arc furnace by melting the charge (4) mixture, consisting of boron carrying raw materials (such as boron oxide, boric acid, borax and borax anhyrite), iron and iron oxide carrying raw materials (such as low silica hematite ores, iron oxide containing minimill wastes and metallic iron), charcoal as reductant and wood shavings (in order to decline the bulk density of the charge to prevent the sintering and to obtain a macro porous carbon skeleton.) which is fed into the arc furnace laddle (A). Slag formation doesn't occur due to low amount of carbon in ferroboron being produced thus, boron yield arises to 98%.
Description
DESCRIPTION
PRODUCTION OF FERROBORON IN DIRECT CURRENT ELECTRICAL ARC
FURNACE
Technical Field
This invention is related with the production process of ferroboron in direct current electrical arc furnace. Ferroboron is used in several areas of the industry.
Prior Art
In production of ferroboron several methods can be used. Production process is determined by the usage area of ferroboron. Ferroboron, added to steel in order to improve its mechanical properties, is being usually produced with the aluminothermic method. In this method, iron oxide, boron oxide and aluminium powder are put in a laddie, specific for aluminothermy, to interact with each other. Ferroboron produced with this method usually contains 16-20% boron and 1 ,5-6% aluminium, and the boron recovery is 40-60%. In this process ferroboron can be produced to blocks of 1 ton weight. If the aluminothermic reaction is supported with an electrical arc, the boron concentration in ferroboron increases to 20%, aluminium concentration remains at 2-4% and the boron recovery is 50-68%. The usage of ferroboron produced by this process is limited because of the impurities it contains.
If the ferroboron is planned to be used as an electrical or magnetic material, the production method is carbothermic process. In experiments carried out in shaft furnace the raw material feed, consisting of boron oxide or boric acid, pre-reduced or sintered iron and coke, yields some ferroboron suitable for metallic glass. However the boron recoveries are low (38,5-73%), and the high percentage of carbon makes a decarburization necessary. During decarburization, boron shows similar thermodynamic behaviour as carbon and gets lost increasing the cost of the process. In the published patent application US 4486226, it has been reported that boric acid, iron or iron oxide, coke and sugar were mixed with different ratios, and the mixture was pre-reduced in a rotary furnace and melted in an arc furnace. Ferroboron which contains 13,6-15,4% B and 0,3% C was produced with 68-86% boron recovery. The usage of carbon lined electric arc
furnace resulted in 70% boron recovery. The mixture was melted in a furnace powered with 1000 kVA and an alloy containing 5,35% B, 37,2% Si, 0,21% C has been produced.
The published patent application JP1177334 describes a ferroboron production method using a direct current girod furnace with a ladle of 100-500 mm height. As boron raw material boron oxide or boric acid has been used.
As an alternative to these methods the ferroboron production in direct current arc furnace can be used. The ladle of the furnace is being charged with the feed material (4) consisting of boron carrying raw materials (such as boron oxide, boric acid, borax and borax anhydrite), iron and iron oxide carrying raw materials (such as low silica hematite ores, iron oxide containing minimill wastes and metallic iron as lubricant free lathe shavings), charcoal as reductant and wood shavings (in order to decline the bulk density of the charge, to prevent sintering and to obtain a macro-porous carbon skeleton.) Because of the low amount of carbon, slag formation doesn't occur. Thus, the boron yield increases to 98% and the energy consumption decreases.
Aim of the Invention
The aim of the invention is to decrease the consumption of electrode and energy and also the abrasion of refractory lining by using DC arc furnace in ferroboron production. Another purpose of the invention is to provide an homogeneous product by means of homogeneously heat distribution in the charge and owing to the mobility of the molten phase. Furthermore a slag-free production is aimed.
Description of the Figures
Subject of the invention, DC arc furnace and its main parts are shown in attached figure.
Figure 1 is a side view of the DC arc furnace ladle.
The parts in the figure are individually numbered and explained below as:
DC arc furnace ladle (A) Steel envelope (1) Lining (2)
Movable upper electrode (3) Charge (4)
Bottom electrode (5) Tapping hole (7) Furnace base (8) Side edge (9)
Disclosure of the Invention
While the outer body of the DC arc furnace, shown in figure 1 , is coated with steel cover (1), its inner body is lined with carbon refractory (2). Moreover, the DC arc furnace comprises the furnace ladle (A), the tapping hole (7) which is opened to the bottom part of the side edge (9) of the furnace ladle (A), the moveable upper electrode (3) and the stationary bottom electrode (5).
The ladle (A) of the furnace is being filled with the charge (4) comprising boron carrying raw materials selected from the group which comprises boron oxide, boric acid, borax and borax anhydrite; low silica hematite ores; iron oxide containing minimill wastes; iron and iron oxide carrying raw materials selected from the group which comprises metallic iron, charcoal as reductant and wood shavings in order to decline the bulk density of the charge, to prevent sintering and to obtain a macro- porous carbon skeleton. In the charge (4), the ratio of boric acid (H3BO3) to iron oxide (Fe2O3) is to be kept between 0,3-2; H3BO3 to iron oxide (FeO) between 0,3- 2,1 and H3BO3 to iron (Fe) between 0,3-2,4. The charcoal amount in the charge (4) is about 5-25% of total charge weight and the amount of wood shavings is about 10- 20% of total charge weight. The moving upper electrode (3) is submerged, vertically to the furnace base (8), into the charge (4) fed into the DC arc furnace ladle (A). Using electrical arc, created between the movable upper electrode (3) and stationary bottom electrode (5), which is fixed to furnace base (8) and placed as keeping movable upper electrode (3) at a distance, by feeding them with direct current, a part of the charge (4) is melted down to ferroboron (FeB) and the liquid ferroboron is accumulated at the furnace base. This liquid metal, formed at the furnace heart is
taken out at certain time intervals through the tapping hole (7) by opening the hole (7). After desired amount of ferroboron is tapped, the upper electrode (3) is lifted up in order to cut off the electrical arc and the furnace is left for cooling. Thus, slag-free ferroboron alloy containing 1 ,5-22% boron is produced. Moreover, after reduction and smelting processes have started, due to the decrease in level of the charge (4) new charge (4) is fed continuously into the furnace ladle (A).
Changing the amount of boron carrying raw materials (boric acid, boron oxide, borax and borax anhydrite), iron and iron oxide carrying raw materials (low silica-hematite ores, iron oxide containing minimill wastes and metallic iron), charcoal and wood shavings in determined intervals, the boron concentration in ferroboron can be increased. With increasing boron concentration, the percentage of carbon in ferroboron can be reduced to 0,2%. Calcium compounds in the charge lead to slag formation so a slag-free production is made by the decrease of calcium compounds in ferroboron. Even more, in the case of slag formation, as a remarkable amount of boron can be dissolved in the slag and as it is almost impossible to regain the dissolved boron from the slag, boron is lost in the slag and this leads to decrease in boron efficiency.
Because of its high vapour pressure at high temperatures the not yet reduced boron oxide rises upwards in the furnace. By choosing the height/diameter ratio of the DC arc furnace ladle (A) between 1 ,5-2,5 and by cooling the upper region of the furnace by continuously fed of the charge (4) , the condensed boron oxide flows back to the heart of the furnace. Thus, the boron recovery rises to 98%. Boron yield of the process is calculated as below:
Boron yield (%B) = Boron in the product (FeB) / Boron in the charge * 100
The preferred production method in direct current arc furnace mentioned above does not restrict the protection scope of this invention. Changes which will be realized on the preferred ferroboron production method in DC electrical arc furnace in regard of the information declared with this invention, should be evaluated within the protection scope of the invention.
Claims
1. Ferroboron production method in direct current electrical arc furnace comprising a movable upper electrode (3), a stationary bottom electrode (5) and a furnace ladle (A) which is surrounded with a steel cover (1) at the outer body and lined with a carbon refractory (2) at the inner side; including the tapping hole (7) positioned at the bottom part of the side edge (9), characterized in that it has following steps:
• the charge (4) comprising boron carrying raw materials selected from the group which comprises boron oxide, boric acid, borax and borax anhydrite; low silica hematite ores; iron oxide containing minimill wastes; iron and iron oxide carrying raw materials selected from the group which comprises metallic iron, charcoal as reductant and wood shavings in order to decline the bulk density of the charge, to prevent sintering and to obtain a macro-porous carbon skeleton is filled in to the ladle (A) of the furnace,
• charge (4) is melted down by creating electrical arc between the movable upper electrode (3) and stationary bottom electrode (5) by feeding them with direct current, • The liquid ferroboron resulting from melted charge (4) is accumulated at the furnace base (8),
• Accumulated ferroboron is taken out at certain time intervals through the tapping hole (7) by opening the hole (7).
2. Ferroboron production method in direct current electrical arc furnace according to claim 1 , wherein the ratio of boric acid (H3BO3) to iron oxide (Fe2O3) in the charge (4) is chosen between 0,3 and 2 in order to increase the boron concentration in ferroboron aiming to decrease the carbon concentration and to avoid slag formation.
3. Ferroboron production method in direct current electrical arc furnace according to claim 1 , wherein the ratio of boric acid (H3BO3) to iron oxide (FeO) in the charge (4) is chosen between 0,3 and 2,1 in order to increase the boron concentration in ferroboron aiming to decrease the carbon concentration and to avoid slag formation.
4. Ferroboron production method in direct current electrical arc furnace according to claim 1 , wherein the ratio of boric acid (H3BO3) to iron (Fe) in the charge (4) is chosen between 0,3 and 2,4 in order to increase the boron concentration in ferroboron aiming to decrease the carbon concentration and to avoid slag formation.
5. Ferroboron production method in direct current electrical arc furnace according to claim 1 , wherein the weight percentage of the charcoal in the charge (4) is between 5% and 25% in order to increase the boron concentration in ferroboron aiming to decrease the carbon concentration and to avoid slag formation.
6. Ferroboron production method in direct current electrical arc furnace according to claim 1 , wherein the weight percentage of wood shavings in the charge (4) is between 10% and 20% in order to decrease the charge density, to obtain a macro-porous skeleton, to avoid sintering, to increase the boron concentration in ferroboron aiming to decrease the carbon concentration and to avoid slag formation.
7. Ferroboron production method in direct current electrical arc furnace according to claim 1 , wherein the height/diameter ratio of arc furnace ladle (A) is 1 ,5-2,5 in order to increase the boron yield to 98%, and that the boron oxide is condensed at the upper region of the ladle (A) and returned into the reduction zone by cooling of the region by the new cold charge (4) mixture.
8. Ferroboron production method in direct current electrical arc furnace according to claim 1 , wherein the charge (4) doesn't contain any calcium compounds to achieve slag-free ferroboron production.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TR2005/03469 | 2005-08-31 | ||
| TR2005/03469A TR200503469A2 (en) | 2005-08-31 | 2005-08-31 | Ferroboron production in direct current electric arc furnace @ |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2007026192A1 true WO2007026192A1 (en) | 2007-03-08 |
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ID=35735267
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IB2005/053499 WO2007026192A1 (en) | 2005-08-31 | 2005-10-26 | Production of ferroboron in direct current electrical arc furnace |
Country Status (2)
| Country | Link |
|---|---|
| TR (1) | TR200503469A2 (en) |
| WO (1) | WO2007026192A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105509485A (en) * | 2015-06-04 | 2016-04-20 | 新疆天业（集团）有限公司 | Blow-in method of calcium carbide furnace |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4569691A (en) * | 1984-03-14 | 1986-02-11 | Gfe Gesellschaft Fur Elektrometallurgie Mbh | Method of making ferroboron and ferroborosilicon alloys and the alloys made by this method |
| JPH01177334A (en) * | 1987-12-29 | 1989-07-13 | Nkk Corp | Manufacture of ferroboron |
| RU2063462C1 (en) * | 1992-03-11 | 1996-07-10 | Савостьянов Игорь Андреевич | Method of boron alloys production mainly in electrical furnace |
-
2005
- 2005-08-31 TR TR2005/03469A patent/TR200503469A2/en unknown
- 2005-10-26 WO PCT/IB2005/053499 patent/WO2007026192A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4569691A (en) * | 1984-03-14 | 1986-02-11 | Gfe Gesellschaft Fur Elektrometallurgie Mbh | Method of making ferroboron and ferroborosilicon alloys and the alloys made by this method |
| JPH01177334A (en) * | 1987-12-29 | 1989-07-13 | Nkk Corp | Manufacture of ferroboron |
| RU2063462C1 (en) * | 1992-03-11 | 1996-07-10 | Савостьянов Игорь Андреевич | Method of boron alloys production mainly in electrical furnace |
Non-Patent Citations (2)
| Title |
|---|
| DATABASE WPI Section Ch Week 199711, Derwent World Patents Index; Class M26, AN 1997-117458, XP002367756 * |
| PATENT ABSTRACTS OF JAPAN vol. 013, no. 457 (C - 644) 16 October 1989 (1989-10-16) * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105509485A (en) * | 2015-06-04 | 2016-04-20 | 新疆天业（集团）有限公司 | Blow-in method of calcium carbide furnace |
Also Published As
| Publication number | Publication date |
|---|---|
| TR200503469A2 (en) | 2007-03-21 |
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