EP0395138A1 - Device for the purification of molten metal, in particular aluminium - Google Patents

Device for the purification of molten metal, in particular aluminium Download PDF

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Publication number
EP0395138A1
EP0395138A1 EP90200932A EP90200932A EP0395138A1 EP 0395138 A1 EP0395138 A1 EP 0395138A1 EP 90200932 A EP90200932 A EP 90200932A EP 90200932 A EP90200932 A EP 90200932A EP 0395138 A1 EP0395138 A1 EP 0395138A1
Authority
EP
European Patent Office
Prior art keywords
molten metal
purification
chemical compound
rotor
alkaline
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.)
Withdrawn
Application number
EP90200932A
Other languages
German (de)
French (fr)
Inventor
Nazario Ghislandi
Maurizio Sala
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PROTECME Srl
Original Assignee
PROTECME Srl
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by PROTECME Srl filed Critical PROTECME Srl
Publication of EP0395138A1 publication Critical patent/EP0395138A1/en
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B21/00—Obtaining aluminium
    • C22B21/06—Obtaining aluminium refining
    • C22B21/064—Obtaining aluminium refining using inert or reactive gases
    • 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
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/42—Constructional features of converters
    • C21C5/46—Details or accessories
    • C21C5/4606—Lances or injectors
    • C21C5/4613—Refractory coated lances; Immersion lances
    • 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
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/0037—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by injecting powdered material
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/05—Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ

Definitions

  • the present invention relates to a device for the purification of molten metal, in particular aluminium.
  • a fundamental prerogative of the metal to be used is purity which, in the industrial practice of aluminium foundries, allows the fulfilment of the primary requirements of quality and reliability of production processes.
  • the proper processing of the molten metal represents a fundamental step in maintaining the high standards of quality required.
  • Molten aluminium contains undesired impurities, such as dissolved gases (particularly hydrogen) and heterogeneous compounds (aluminium oxides in various forms, refractory parts, etc.).
  • impurities such as dissolved gases (particularly hydrogen) and heterogeneous compounds (aluminium oxides in various forms, refractory parts, etc.).
  • said solution provides for the use of a device based on a rotor supplied with gas.
  • Said rotor is made to rotate in the bath so as to disperse the supplied gas substantially increasing the yield of the operation, both in terms of the contact surface of the inert gas (H2 bubble to be removed), and in terms of the staying time of the inert gas inside the molten bath.
  • the gas thus centrifuged creates small bubbles which, while rising to the surface, capture the impurities present and carry them away.
  • the object of the present invention is now that of improving the yield of the known devices.
  • such object is attained by means of a device comprising a rotor which can be immersed in the molten metal, means for causing the rotation of said rotor and means associated with the rotor for supplying an inert gas into one of its internal passages, characterized in that it comprises means for introducing into said internal passage at least one chemical compound which can be mixed with said gas.
  • the purfication device shown in the drawing comprises a rotor 6 mechanically supported by a rotor-holding rod 3 loosely connected to a chuck 1 by means of a coupling 4.
  • Chuck 1 is rotatably supported by a pair of bearings 8 inside a support 9, which is adjustable in height with respect to a base structure 10 by means of an adjustment system consisting of a motor 11, a threaded rod 12, a nut screw 13 and a slide guide 14.
  • a unit for supplying gases and chemical compounds comprising a mixing chamber 15 into which run a conduit 16 for supplying an inert gas and a conduit 19 for supplying suitably selected chemical compounds.
  • a hopper 17 contains chemical compound 18 and it intermittently communicates with conduit 19 through a system which controls the frequency of supply of the chemical compound as well as the quantity supplied.
  • Said control device consists in the example considered of a stem valve 21 with operating piston 22.
  • Two conduits 35 allow the introduction and the discharge of operating air for piston 22.
  • a limit device for piston 22 which is constituted by a threaded rod 23 with a corresponding operating handwheel 24.
  • the above cover is provided with a vent opening 28.
  • an operating device 29 of rotor 6 which comprises a motor 30 held by support 31, a toothed pulley 32 keyed on the output shaft of motor 30, another toothed pulley 33 keyed on chuck 1 and a toothed connecting belt 34.
  • the device for the purification of molten metal illustrated in the drawing is in a position of operating as follows.
  • An inert gas is supplied under pressure to internal passage 5 of rod 3 and of rotor 6 in combination with chemical compound 18, added intermittently to the gaseous vehicle due to the effect of the alternating movements of stem valve 21.
  • the gaseous vehicle and the chemical compound are forcefully introduced into the molten metal through terminal mouth 7.
  • the divergent shape of the above mouth 7 has the advantage of avoiding problems of obstruction which may otherwise be caused by the chemical compound added, simplifying cleaning operations.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

The device comprises a rotor (6) which can be immersed in the molten metal (27). Said rotor is rotated by a motor (30) through a mechanism (29). There is provided above said rotor (6) a supply unit for gases and chemical compounds comprising a mixing chamber (15) into which lead a supply conduit (16) for inert gases and a supply conduit (19) for a suitably selected chemical compound (18). There is moreover provided a control system (20) of the frequency and of the quantity of chemical compound supplied on each occasion.

Description

  • The present invention relates to a device for the purification of molten metal, in particular aluminium.
  • The use is known, in fields such as foundryworks, of molten metal to be introduced in appropriate die cavities.
  • A fundamental prerogative of the metal to be used is purity which, in the industrial practice of aluminium foundries, allows the fulfilment of the primary requirements of quality and reliability of production processes.
  • The proper processing of the molten metal represents a fundamental step in maintaining the high standards of quality required.
  • Molten aluminium contains undesired impurities, such as dissolved gases (particularly hydrogen) and heterogeneous compounds (aluminium oxides in various forms, refractory parts, etc.).
  • These factors worsen the quality of alloys, impair the quality of castings in hydraulic seal tests, increase the risks of crackability and greatly damage both static and dynamic mechanical resistances (resistance in fatigue tests, etc.), as well as the yield of mechanical processes and of anodization treatments and the resistance to corrosive environments.
  • Various devices have been accomplished in the past to carry out operations of degassing/elimination of impurities.
  • Among the different technologies adopted in the past to remove dissolved gases and impurities contained in molten metal baths one solution has been based on the introduction of gases or of mixtures of inert gases (N₂, Ar, halogen derivatives) inside the molten metal baths.
  • In particular said solution provides for the use of a device based on a rotor supplied with gas. Said rotor is made to rotate in the bath so as to disperse the supplied gas substantially increasing the yield of the operation, both in terms of the contact surface of the inert gas (H₂ bubble to be removed), and in terms of the staying time of the inert gas inside the molten bath. The gas thus centrifuged creates small bubbles which, while rising to the surface, capture the impurities present and carry them away.
  • The object of the present invention is now that of improving the yield of the known devices.
  • According to the invention such object is attained by means of a device comprising a rotor which can be immersed in the molten metal, means for causing the rotation of said rotor and means associated with the rotor for supplying an inert gas into one of its internal passages, characterized in that it comprises means for introducing into said internal passage at least one chemical compound which can be mixed with said gas.
  • It has been possible to verify that with the addition of said chemical compound, or possibly of a mixture of compounds of such a nature, the purification action of the inert gas is notably improved and strengthened.
  • The mechanical action of a finely dispersed inert rinsing gas, together with the homogeneous diffusion of chemically active salt mixtures on the impurities contained in molten aluminium baths, allows the fulfilment of high production standards in terms of quality and financial yield.
  • It has been possible to observe that especially suitable chemical compounds are:
    - products having a degassing effect (hexachloroethane)
    - products having a deoxidiser effect (20-25% alkaline fluorides, 75-80% mixture of alkaline chlorides)
    - products having a slagging effect (alkaline/alkaline earth chlorides (70-80%), alkaline/alkaline earth fluoro silicates 20-30%.
  • These and other features of the present invention shall be made evident by the following detailed description of one of its embodiments illustrated as a non-limiting example in the single figure in the enclosed drawing.
  • The purfication device shown in the drawing comprises a rotor 6 mechanically supported by a rotor-holding rod 3 loosely connected to a chuck 1 by means of a coupling 4.
  • Inside said rotor 6 and said rod 3 there is obtained a channel 5 which terminates at its lower end in a divergent mouth 7 in the shape of an inverted V.
  • Chuck 1 is rotatably supported by a pair of bearings 8 inside a support 9, which is adjustable in height with respect to a base structure 10 by means of an adjustment system consisting of a motor 11, a threaded rod 12, a nut screw 13 and a slide guide 14.
  • Above the chuck 1 there is fastened to support 9 a unit for supplying gases and chemical compounds comprising a mixing chamber 15 into which run a conduit 16 for supplying an inert gas and a conduit 19 for supplying suitably selected chemical compounds.
  • A hopper 17 contains chemical compound 18 and it intermittently communicates with conduit 19 through a system which controls the frequency of supply of the chemical compound as well as the quantity supplied.
  • Said control device, indicated in its entirety with 20, consists in the example considered of a stem valve 21 with operating piston 22. Two conduits 35 allow the introduction and the discharge of operating air for piston 22. There is also present a limit device for piston 22 which is constituted by a threaded rod 23 with a corresponding operating handwheel 24.
  • Below said support 9 there is constrained a closing cover 25 for a vessel 26 suitable for containing the molten metal to be purified, indicated with 27.
  • The above cover is provided with a vent opening 28.
  • There is lastly provided an operating device 29 of rotor 6, which comprises a motor 30 held by support 31, a toothed pulley 32 keyed on the output shaft of motor 30, another toothed pulley 33 keyed on chuck 1 and a toothed connecting belt 34.
  • Due to the effect of the described structure the device for the purification of molten metal illustrated in the drawing is in a position of operating as follows.
  • Once the rotor 6 has been introduced into the bath of molten metal 27 and the corresponding vessel has been closed with closing cover 25, chuck 1 is rotated by motor 30 and mechanism 29.
  • An inert gas is supplied under pressure to internal passage 5 of rod 3 and of rotor 6 in combination with chemical compound 18, added intermittently to the gaseous vehicle due to the effect of the alternating movements of stem valve 21.
  • The gaseous vehicle and the chemical compound are forcefully introduced into the molten metal through terminal mouth 7.
  • It should be noted in this respect that the divergent shape of the above mouth 7 has the advantage of avoiding problems of obstruction which may otherwise be caused by the chemical compound added, simplifying cleaning operations.

Claims (7)

1. Device for the purification of molten metal, in particular aluminium, comprising a rotor (6) which can be immersed in the molten metal, means (29, 30) for causing the rotation of said rotor and means (16) associated with the rotor for supplying an inert gas into one of its internal passages (5), characterized in that it comprises means (17, 19, 20) for introducing into said internal passage (5) at least one chemical compound which can be mixed with said gas.
2. Device for the purification of molten metal according to claim 1 characterized in that said internal passage (5) terminates at its lower end in a divergent mouth (7) in the shape of an inverted V.
3. Device for the purification of molten metal according to claim 1 characterized in that there is provided a mixing chamber (15), in which converge said means (16; 17, 19, 20) for supplying the inert gas and the chemical compound.
4. Device for the purification of molten metal according to claim 1 characterized in that said means (17, 19, 20) for introducing the chemical compound include means for controlling the frequency and the quantity of supply.
5. Device for the purification of molten metal according to claim 1 characterized in that said chemical compound is constituted by one or more products having a degassing effect, such as hexachloroethane.
6. Device for the purification of molten metal according to claim 1 characterized in that said chemical compound is constituted by one or more products having a deoxidiser effect, such as alkaline fluorides (20-25%), mixture of alkaline chlorides (75-80)%.
7. Device for the purification of molten metal according to claim 1 characterized in that said chemical compound is constituted by one or more products having a slagging effect such as alkaline/alkaline earth chlorides (70-80%), alkaline/­alkaline earth fluoro silicate (20-30%).
EP90200932A 1989-04-20 1990-04-17 Device for the purification of molten metal, in particular aluminium Withdrawn EP0395138A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT8920274A IT1229673B (en) 1989-04-20 1989-04-20 Molten metal, in particular aluminium purificn. device
IT2027489 1989-04-26

Publications (1)

Publication Number Publication Date
EP0395138A1 true EP0395138A1 (en) 1990-10-31

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ID=11165344

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EP90200932A Withdrawn EP0395138A1 (en) 1989-04-20 1990-04-17 Device for the purification of molten metal, in particular aluminium

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EP (1) EP0395138A1 (en)
IT (1) IT1229673B (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0620285A1 (en) * 1993-04-14 1994-10-19 Norsk Hydro A/S Injection equipment
EP0753589A1 (en) * 1995-07-12 1997-01-15 Steven Stride Melt treatment head, apparatus and method
ES2121542A1 (en) * 1996-09-19 1998-11-16 Lin Yeun Junn Device for removing gases and impurities from molten aluminium
US6589313B2 (en) 2000-09-12 2003-07-08 Alcan International Limited Process and apparatus for adding particulate solid material to molten metal
EP1462530A1 (en) * 2003-03-28 2004-09-29 Nippon Light Metal Company Ltd. Apparatus for refining molten metal and method for refining molten metal using the same
CN1322154C (en) * 2005-05-31 2007-06-20 山东大学 Purification equipment for liquid aluminium alloy
WO2007048240A3 (en) * 2005-10-25 2007-11-08 Alcan Int Ltd In-line salt refining of molten aluminium alloys
US7785394B2 (en) 2007-02-23 2010-08-31 Alcoa Inc. System and method for in-line molten metal processing using salt reactant in a deep box degasser
CN105992638A (en) * 2013-05-29 2016-10-05 力拓艾尔坎国际有限公司 Rotary injector and process of adding fluxing solids in molten aluminum
CN108149028A (en) * 2017-12-26 2018-06-12 江苏凯特汽车部件有限公司 A kind of automobile aluminum wheel hub melt composite purification device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2614585A (en) * 1948-01-22 1952-10-21 Hydrocarbon Research Inc Composite pipe
US2804339A (en) * 1955-03-30 1957-08-27 Union Carbide Corp Injection nozzle
US2807508A (en) * 1954-05-03 1957-09-24 Union Carbide Corp Powder dispenser
FR2185570A1 (en) * 1972-05-25 1974-01-04 Arbed
US3891196A (en) * 1974-01-21 1975-06-24 Thyssen Niederrhein Ag Apparatus for treating a melt
GB2041982A (en) * 1979-02-08 1980-09-17 Magyar Aluminium Process for decreasing the contaminant content of aluminium melts and aluminium alloy melts
US4286774A (en) * 1980-04-22 1981-09-01 Victor Benatar System for automatically injecting a measured quantity of powdered reagent into a pool of molten metal

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2614585A (en) * 1948-01-22 1952-10-21 Hydrocarbon Research Inc Composite pipe
US2807508A (en) * 1954-05-03 1957-09-24 Union Carbide Corp Powder dispenser
US2804339A (en) * 1955-03-30 1957-08-27 Union Carbide Corp Injection nozzle
FR2185570A1 (en) * 1972-05-25 1974-01-04 Arbed
US3891196A (en) * 1974-01-21 1975-06-24 Thyssen Niederrhein Ag Apparatus for treating a melt
GB2041982A (en) * 1979-02-08 1980-09-17 Magyar Aluminium Process for decreasing the contaminant content of aluminium melts and aluminium alloy melts
US4286774A (en) * 1980-04-22 1981-09-01 Victor Benatar System for automatically injecting a measured quantity of powdered reagent into a pool of molten metal

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0620285A1 (en) * 1993-04-14 1994-10-19 Norsk Hydro A/S Injection equipment
US5413315A (en) * 1993-04-14 1995-05-09 Norsk Hydro A.S. Injection equipment
AU671351B2 (en) * 1993-04-14 1996-08-22 Norsk Hydro A.S Injection equipment
EP0753589A1 (en) * 1995-07-12 1997-01-15 Steven Stride Melt treatment head, apparatus and method
ES2121542A1 (en) * 1996-09-19 1998-11-16 Lin Yeun Junn Device for removing gases and impurities from molten aluminium
US6589313B2 (en) 2000-09-12 2003-07-08 Alcan International Limited Process and apparatus for adding particulate solid material to molten metal
US6960239B2 (en) 2000-09-12 2005-11-01 Alcan International Limited Process and apparatus for adding particulate solid material to molten metal
EP1462530A1 (en) * 2003-03-28 2004-09-29 Nippon Light Metal Company Ltd. Apparatus for refining molten metal and method for refining molten metal using the same
CN1322154C (en) * 2005-05-31 2007-06-20 山东大学 Purification equipment for liquid aluminium alloy
WO2007048240A3 (en) * 2005-10-25 2007-11-08 Alcan Int Ltd In-line salt refining of molten aluminium alloys
JP2009512782A (en) * 2005-10-25 2009-03-26 アルカン・インターナショナル・リミテッド In-line salt refining of molten aluminum alloy
AU2006308469B2 (en) * 2005-10-25 2011-09-08 Stas Inc. In-line salt refining of molten aluminium alloys
US8025712B2 (en) 2005-10-25 2011-09-27 Rio Tinto Alcan International Limited In-line salt refining of molten aluminium alloys
CN101297052B (en) * 2005-10-25 2012-03-21 力拓加铝国际有限公司 In-line salt refining of molten aluminium alloys
US7785394B2 (en) 2007-02-23 2010-08-31 Alcoa Inc. System and method for in-line molten metal processing using salt reactant in a deep box degasser
CN105992638A (en) * 2013-05-29 2016-10-05 力拓艾尔坎国际有限公司 Rotary injector and process of adding fluxing solids in molten aluminum
US9840754B2 (en) 2013-05-29 2017-12-12 Rio Tinto Alcan International Limited Rotary injector and process of adding fluxing solids in molten aluminum
CN105992638B (en) * 2013-05-29 2018-12-11 力拓艾尔坎国际有限公司 Rotary syringe and the method that fluxing solid is added in melting aluminum
CN108149028A (en) * 2017-12-26 2018-06-12 江苏凯特汽车部件有限公司 A kind of automobile aluminum wheel hub melt composite purification device

Also Published As

Publication number Publication date
IT8920274A0 (en) 1989-04-20
IT1229673B (en) 1991-09-06

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