NO20210630A1 - Na removal from pot-room Al metal with under-pressure and forced convection - Google Patents
Na removal from pot-room Al metal with under-pressure and forced convection Download PDFInfo
- Publication number
- NO20210630A1 NO20210630A1 NO20210630A NO20210630A NO20210630A1 NO 20210630 A1 NO20210630 A1 NO 20210630A1 NO 20210630 A NO20210630 A NO 20210630A NO 20210630 A NO20210630 A NO 20210630A NO 20210630 A1 NO20210630 A1 NO 20210630A1
- Authority
- NO
- Norway
- Prior art keywords
- crucible
- metal
- tapping
- lid
- ems
- Prior art date
Links
- 229910052751 metal Inorganic materials 0.000 title claims description 73
- 239000002184 metal Substances 0.000 title claims description 73
- 238000011282 treatment Methods 0.000 claims description 33
- 238000010079 rubber tapping Methods 0.000 claims description 32
- 238000003756 stirring Methods 0.000 claims description 26
- 239000000155 melt Substances 0.000 claims description 21
- 239000004411 aluminium Substances 0.000 claims description 16
- 229910052782 aluminium Inorganic materials 0.000 claims description 16
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 15
- 239000003795 chemical substances by application Substances 0.000 claims description 6
- 230000005672 electromagnetic field Effects 0.000 claims description 4
- 239000012080 ambient air Substances 0.000 claims description 3
- 239000003570 air Substances 0.000 claims description 2
- 239000003302 ferromagnetic material Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 claims 2
- 229910000963 austenitic stainless steel Inorganic materials 0.000 claims 1
- 239000011734 sodium Substances 0.000 description 47
- 239000007789 gas Substances 0.000 description 18
- 239000000376 reactant Substances 0.000 description 9
- 229910052708 sodium Inorganic materials 0.000 description 9
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 8
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 8
- 238000005266 casting Methods 0.000 description 8
- 238000001704 evaporation Methods 0.000 description 8
- 230000008020 evaporation Effects 0.000 description 8
- 229910052731 fluorine Inorganic materials 0.000 description 8
- 239000011737 fluorine Substances 0.000 description 8
- 238000005868 electrolysis reaction Methods 0.000 description 6
- 229910001338 liquidmetal Inorganic materials 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 238000000746 purification Methods 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000005275 alloying Methods 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- 239000000274 aluminium melt Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000011403 purification operation Methods 0.000 description 2
- 238000009489 vacuum treatment Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- -1 AlF3 Substances 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000003760 magnetic stirring Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000010907 mechanical stirring Methods 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 239000013528 metallic particle Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
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
- C22B21/068—Obtaining aluminium refining handling in vacuum
-
- 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
-
- 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
- C22B21/066—Treatment of circulating aluminium, e.g. by filtration
-
- 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
- C22B9/003—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals by induction
-
- 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
- C22B9/006—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals with use of an inert protective material including the use of an inert gas
-
- 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
- C22B9/04—Refining by applying a vacuum
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Processing Of Solid Wastes (AREA)
Description
Method and equipment for treatment of molten aluminium metal
The present invention relates to a method and an equipment for treatment of molten aluminium metal, in particular purification of the metal with respect to Na.
Commonly, aluminium metal is produced in electrolysis cells of Hall-Héroult type. Liquid metal that is produced by the cell is regularly tapped in batches via a drain tube that is dipped below the level of molten metal in the cell. The drain tube is at its opposite end connected to a tapping/transport crucible that is underpressurised for suction of metal.
The liquid metal is transported in the tapping/transport crucible to a casting furnace, or as an intermediate step to a holding furnace.
The invention is in the field of sodium (Na) removal from pot-room Al metal transported in crucibles.
There are several ways of removing Na in Al pot-room metal, e.g. treatment with addition of AlF3 and argon in crucible, and casthouse furnace treatment with the addition of salt.
These treatments typically involve the addition of active fluxing agents, e.g. AlF3. Transfer of fluorine from crucible to casthouse furnace is an environmental issue and should be reduced as much as possible.
Depending on requirements of the final product produced by the casthouses, there are limits for the contents of impurities. For instance, the molten metal in the electrolysis cells may contain 80 - 200 ppm of sodium (Na), while the threshold for instance for some cast products can be typically 1 - 15 ppm Na. This requires that sodium is removed in advance of the casting operation in a separate purification operation.
Previously, sodium has been removed from a casting furnace after the furnace being filled up with molten aluminium. As large furnaces, that may contain typically 50-60 tons of metal, are basically not efficient reactors, it is more efficient to remove sodium from the melt while it is still residing in the tapping/transport crucible, which typically contains 4-9 tons of metal.
Removal of alkali metals from an aluminium melt can be done by bringing the tapping/transport crucible to a fluxing station before its content is filled into a furnace. In the fluxing station there is added a reactant the can either be a gas (Cl2) or a powder (Cl based salt or fluoride (AlF3)). Often such fluxing stations are placed in the casthouse and the tapping/transport crucible needs to be taken away from the tapping/transport vehicle and handled into the fluxing station by separate handling equipment.
By applying a pulverulent reactant, it can either be introduced in the melt via a hollow axle or with a lance, or by being spread at the surface of the melt. Common for these solutions is that a strong stirring of the melt must be created to be able to distribute the powder thoroughly in the melt. It is also crucial that the stirring action is performed over a certain time lapse to take full benefit of the reactant and thereby achieving a good purification effect.
Further, in the prior art there are known patent publications that describe treatment of molten metal with gas, based on the principle of supplying the gas to and dispersing the gas in the molten metal using a rotor. An example of such a rotor is shown and described in the applicant’s own EP 0151434 B1, in which the gas is supplied via a drilled hole in the rotor shaft of the rotor, which consists of a hollow, cylindrical rotating body, and in which the gas is supplied to and dispersed in the liquid (molten metal) via holes in the rotating body.
Further, in US 8,128,726 B2 there is disclosed a method and a device for the treatment of molten aluminium metal by admixture of powder in a liquid metal flowing through a drain tube connected with and influenced by sub pressure in a crucible to which the liquid metal is to be transferred.
US 3,895,937 relates to a method and apparatus for producing light metal alloys, in particular aluminium alloys, in which the desired alloying elements are first introduced into a vacuum furnace which is then evacuated, whereafter light metal melt is introduced into the furnace chamber by suction in the form of a free-falling metal jet which is thereby subjected to a vacuum treatment for reducing the contents of impurities, such as hydrogen, sodium, oxides and other non-metallic particles, therein. The free-falling metal jet is given such a configuration with respect to composition and flow pattern, such an average length as well as such velocity and direction that the alloying elements are readily dissolved and mixed into the melt in the vacuum furnace, whereby an alloy of desired quality is ready for casting immediately after termination of the vacuum treatment and alloying process.
RU 2337980C discloses refining of aluminium in a transport ladle before pouring of metal into casting metal mixers. Blending is implemented by a travelling electromagnetic field created by an electromagnetic field source which is installed against an external wall of the ladle in a fluxing station.
According to one aspect of the present invention molten metal can be purified in an apparatus or purifying station while still being in the tapping/transport crucible, that will say after the tapping/transport has finished but before the molten metal is filled into a furnace. In one other aspect the metal can be purified in the furnace.
According to one aspect of the invention, the purifying station comprises means for stirring the metal in the crucible without involving submerged rotating parts.
According to one aspect of the invention, the purifying of the metal is done without active or passive reactants. An active reactant reacts chemically with Na, whereas a passive reactant is inert.
According to one aspect of the invention it is based upon exposing the molten aluminium to under-pressure (vacuum) in the atmosphere above the molten metal in the crucible to enhance evaporation of Na from the melt in the crucible. More specifically, the under-pressure could be created with a vacuum pump. With the use of a compressor coupled to an ejector the evaporated atmosphere over the metal surface is removed continuously.
The crucible can be exposed to under-pressure just after tapping from the cells, to the electro-magnetic stirring (EMS) station for treatment and finally to the casthouse furnace. This exposes the metal to under-pressure a longer time, reducing the effective treatment time in the EMS station.
According to one additional aspect of the invention, equipment comprising means for generating forced convection, e.g. through EMS is arranged in close vicinity of the crucible to stir the melt preferably in a vertical or horizontal direction, or a combination.
According to one aspect of the invention the equipment will ensure that the complete metal volume in the crucible is exposed to the under-pressure as long as the melt treatment lasts.
The under-pressure (sub-atmospheric pressure) ensures a high evaporation rate and the forced convection ensures that the total metal volume in the crucible is treated.
It has been found that exposing the melt in the crucible to a sufficiently low underpressure in combination with sufficient stirring can remove alkali metals as Na to a high extent.
The equipment according to the present invention will demand little maintenance due to no moving parts needed to generate a stirring action of the molten metal. Further it will demand less space compared to commonly available fluxing stations, due to its relatively slim design. It can be arranged in or close to the electrolysis hall and thus space in the casthouse can be available for other purposes.
The crucibles can be provided with a lid for the sub pressurisation or the equipment can have a special lid to be placed on top of the crucible for sub pressurisation during metal treatment.
The invention is in particular favourable for the removal of sodium (Na) from aluminium melts.
According to the invention it is provided a method and equipment for treatment of molten aluminium metal. More specific it relates to Na removal in a crucible with molten aluminium metal where an electromagnetic coil (EMS) generates a stirring action of the molten aluminium metal inside the crucible and where the crucible can be provided with a lid and the atmosphere below the lid is continuously evacuated during stirring of the metal where Na is removed effectively without use of active or passive reactants.
These and further advantages can be obtained by the invention as defined in the accompanying claims.
The present invention will be described further by examples and Figures where:
Fig. 1 discloses Na removal by FactSage™ Modelling,
Fig. 2 discloses from one side a tapping/transport crucible with a lid provided with equipment for evacuating atmosphere inside the crucible and connected with an EMS,
Fig. 3 discloses the crucible of Fig.2, seen at a left side view,
Fig. 4 discloses a tapping/transport vehicle with a crucible at an electromagnetic stirring station including an electromagnetic spool (EMS), the crucible having a lid for sub pressurisation.
The invention is in the field of sodium (Na) removal from pot-room Al metal in crucibles, in particular transport crucibles. The crucible may be of a stationary type receiving molten metal from electrolysis and further arranged for Na removal according to the invention, before the metal is transferred to a casting furnace. In an alternative, a casting furnace may be provided with Na removing equipment, according to the invention.
As previously stated, there are several methods used to removing Na in Al pot-room metal, e.g. treatment with addition of AlF3 and argon in crucible, and casthouse furnace treatment with the addition of salt.
Commonly such treatments involve the addition of an active reactant, such as AlF3. Transfer of fluorine in the melt from crucible to casthouse furnace is an environmental issue and should be reduced as much as possible.
The current idea is based upon eliminating the use of reactants e.g. AlF3, gas (chlorine) or salts to remove Na from pot-room metal, by applying under-pressure (vacuum) in combination with removing the atmosphere above the melt surface in the crucible to enhance evaporation of Na from the melt in the crucible. In addition, forced convection, e.g. through EMS (electromagnetic stirring) mounted on the crucible to stir the melt will be used so that the complete metal volume in the crucible is circulated and exposed to the under-pressure as long as the melt treatment lasts.
The under-pressure (vacuum) and the continuous removal of the atmosphere above the melt surface ensure a high evaporation rate and the forced convection ensures that the total metal volume in the crucible is treated.
The pot-room metal temperature is generally high during crucible treatment, typically above 900 °C, resulting in relatively high Na vapour pressure over the melt. Using under-pressure (vacuum) in combination with removing the atmosphere over the melt surface will further increase the Na evaporation rate. The removal of the atmosphere ensures that there is no back diffusion of Na into the melt. Typically, an under-pressure of 100 mbar is sufficient to allow for a high Na removal rate within a normal treatment time of 10 minutes. The lower the under-pressure, the higher the Na removal rate for a certain treatment time, the shorter the treatment time will be to achieve a certain Na removal rate.
The efficiency of the process has been verified by modelling of Na removal with evaporation from Al with a modelling tool named FactSage.
According to Fig. 1, FactSage modelling has shown a strong Na removal rate with increased under-pressure. As an example, at metal temperature of 940 °C and underpressure of 100 mbar, FactSage predicts acceptably high Na removal efficiency. However, FactSage does not predict kinetics, i.e. how long time the reduction will take. In the FactSage diagram of Figure 1, -1 on log scale corresponds to 100 mbar, -2 on log scale corresponds to 10 mbar.
Based upon these modelling results, full scale trials have shown 80 % Na removal rate after 10 minutes treatment time.
Follow-up full-scale trials showed Na removal rates of 67 % after 5 minutes treatment time (two crucibles), 76 % after 10 minutes treatment time (two crucibles), and 80 % after 15 minutes treatment time (two crucibles), all with EMS with 85 Amperage current intensity and 180 mbar under-pressure. The metal temperature during the trial was approximately 900 °C.
Further, full-scale trial filling a furnace with vacuum treated pot-room metal shows that the Na level during casting from the furnace ended at 7 ppm. Typical customer specification in Al extrusion ingots is maximum 15 ppm Na, however stricter requirements are seen, e.g. for rolled products.
The sub-pressurized atmosphere in combination with removal of the atmosphere in the crucible and the use of EMS increase kinetics of Na evaporation and can ensure that all metal in crucible is treated in short amount of time.
High pot-room metal temperature ensures high evaporation, typically > 900 °C. At temperatures > 883 °C Na is a gas (boiling point: 882.9 °C).
The environmental advantages are very important when eliminating or reducing the consume of AlF3 to a very little amount. AlF3 is assumed to be one source of fluorine emissions in the casthouse.
By the use of the invention, strongly reduced fugitive fluorine emissions are expected, both from casthouse furnaces and from dross processor. The elimination of the use of AlF3 in order to remove Na from pot-room metal gives an important contribution in reduction of fluorine emissions and reduces the need for gas treatment. In addition, there are financial gains due to the relatively high cost for the fluxing agents.
According to the invention as shown in Figs. 2 and 3, the stirring of the molten metal in the tapping/transport crucible 1 is done by application of an electromagnetic coil (EMS) that due to the electromagnetic fields can generate a stirring or formation of vortexes of the molten metal. The EMS equipment can simply be a vertically arranged structure such as a column or a similar structure that carries the electromagnetic coil (EMS).
In general, the steel quality of the crucible should preferably be a non-ferromagnetic material, preferably austenitic steel.
The wall or mantle of the tapping/transport crucible can in general be of a steel quality as mentioned, and can also be provided with an inner liner of refractory material.
Further, during treatment and for the purpose of removal of Na, the system must be able to evacuate at least partly the atmosphere that is present in the crucible. That will say the space below its lid 6 and above the metal melt.
This evacuation can be done by exposing the atmosphere to a sub-pressure and allowing ambient air to replace the gas containing Na that is evacuated. That will say the evacuation is done in a continuous manner for continuous removal of Na.
As shown in Figs.2 and 3 the evacuating system can basically comprise an ejector 8 having a suction tube 7 communicating with the inside of the crucible 1 below the lid 6 thereof. Further, referring to Fig. 3, the ejector 8 is provided with an inlet CA for compressed air and one outlet for evacuated gas, EG. An arrow inside the suction tube 7 indicates flow/removal of gas from the crucible’s inside, which basically is separated in a lower metal part M, and an upper gas part, G.
To replace evacuated gas, the lid is provided with an inlet tube 10 that allows ambient air to flow into the inside of the lid 6. The inflow can be controlled by a valve 11, which also will influence the level of the sub-pressure that will be achieved as well as the removal rate of the atmosphere.
The evacuated gas EG can be captured and removed by a suction system arranged above the lid of the crucible.
As shown in Fig. 4, the evacuating system of the tapping/transport crucible can be arranged onboard a tapping/transport vehicle 5 provided with a compressor for operating the ejector 8. The vehicle 5 may also have provisions for handling a lid to be placed upon the crucible, and in general comprise similar equipment as described above.
As the stirring action is to be performed, the tapping/transport crucible 1 is placed towards the electromagnetic coil (EMS). By energizing the coil with electrical current, a strong stirring action of the molten metal in the tapping/transport crucible 1 is generated. The tapping/transport crucible 1 can rest in the tapping/transport vehicle 5 during this operation. The EMS can be arranged in a column or a similar structure and further in a manner where it can be moved horizontally towards the tapping/transport crucible 1.
The columns with electromagnetic coils EMS will demand very little space. As the treatment or purification now can be done in the electrolysis hall where the electrolysis cells are placed or at least in close vicinity to the hall, the off suction of gas from the tapping/transport crucibles, can be handled by a much simpler duct system.
The time necessary to perform the purification operation can be reduced as there will be no time-consuming dosing action of fluxing agents needed.
The sub-pressure can extract gas components such as Na during purification through a hole 7 in a lid 6 of the tapping/transport crucible 1.
Regarding the stirring pattern of the liquid metal, it can be changed by changing the electrical input, such as current intensity and polarity, to the EMS. A pre-requisite is that as much as possible of the melt is exposed to the under-pressure in the crucible atmosphere during treatment, and the EMS can be controlled according to this.
The EMS is utilized to create a powerful stirring of the metal while the crucible is attached to the transport vehicle without removing the crucible lid. The transport vehicle will position the crucible close to the EMS for stirring.
In an alternative, the EMS is utilized to create a powerful stirring of the metal when the crucible is removed away from the transport vehicle and positioned close to the EMS.
Forced convection (e.g. EMS) in crucible with pot-room metal is used to obtain forced movement of metal. Stirs metal so that all crucible pot-room metal is exposed to subpressurized atmosphere.
Advantages of the present invention:
• No addition in crucible of active or passive agents:
• No consumption of AlF3 which can be estimated to 0.5-1.0 kg AlF3 per ton aluminium.
• No or reduced fluorine in off-gas from casthouse.
• Lower fluorine in casthouse dross.
• Reduced fluorine problem for dross processor.
• No use of injection carrier gas or other passive agents in crucible
• Reduced cost for removing Na
• No use of mechanical stirring in crucible
• The overall cost with vacuum and EMS treatment to remove Na versus today’s standard equipment is assumed to be considerably lower.
Claims (13)
1. A method for the treatment of molten aluminium metal in particular Na removal in a tapping/transport crucible (1) by generating a stirring action of the molten aluminium metal, the tapping/transport crucible (1) has a mantle wall of a material that allows an electromagnetic field generated by an electromagnetic coil (EMS) brought in vicinity of said material to generate a stirring action of the molten aluminium metal inside the tapping/transport crucible (1) when energizing the electromagnetic coil (EMS)
c h a r a c t e r i s e d i n t h a t
the tapping/transport crucible (1) is adapted to fit a lid (6) or cover in a substantial air tight manner where the lid is provided with means for continuously evacuating the atmosphere below the lid during stirring of the metal, where Na is removed from said space.
2. A method according to claim 1,
c h a r a c t e r i s e d i n t h a t
the atmosphere is evacuated to a sub pressure between 300 – 10 mbar.
3. A method according to claim 1,
c h a r a c t e r i s e d i n t h a t
the atmosphere is evacuated to a sub pressure between 200 – 10 mbar.
4. A method according to claim 1,
c h a r a c t e r i s e d i n t h a t
the atmosphere is evacuated to a sub pressure between 100 – 10 mbar.
5. A method according to claim 1,
c h a r a c t e r i s e d i n t h a t
EMS coil is operated to generate forced convection in the upper part of the melt in the tapping/transport crucible (1) to maximize the exposure of volatile components to the sub pressurized space.
6. A method according to claim 1,
c h a r a c t e r i s e d i n t h a t
the EMS coil is operated to create highest metal velocity in the bottom part of the crucible to lift metal to the surface region.
7. A method according to claim 1,
c h a r a c t e r i s e d i n t h a t
the temperature in the metal during treatment is approximately 900 °C.
8. Equipment for the treatment of molten aluminium metal in particular Na removal in a tapping/transport crucible (1) and generating a stirring action, the crucible comprises an outer mantle wall (4), arranged adjacent an electromagnetic coil (EMS) in the metal treatment equipment and that a stirring action of the molten aluminium metal takes place by energizing the electromagnetic coil
c h a r a c t e r i s e d i n t h a t
the tapping/transport crucible (1) is provided with a lid (6) or cover having means for tightly adapt to it and further having means for continuously evacuating the atmosphere below the lid during the stirring of the metal for removal of Na without application of fluxing agents.
9. Equipment according to claim 8,
c h a r a c t e r i s e d i n t h a t
the tapping/transport crucible is made by a mantle wall (4) made out of a non-ferromagnetic material, such as austenitic stainless steel.
10. Equipment according to claim 8,
c h a r a c t e r i s e d i n t h a t
the lid (6) of the tapping/transport crucible is provided with a seal and locking mechanism that secures gas tight connection to the crucible.
11. Equipment according to claim 8,
c h a r a c t e r i s e d i n t h a t
the lid (6) of the tapping/transport crucible is provided with a gas connection for connecting to a vacuum pump controlled by a control station.
12. Equipment according to claim 8,
c h a r a c t e r i s e d i n t h a t
the lid (6) is provided with an ejector that allows the continuous removal of the atmosphere in the crucible.
13. Equipment according to claim 8,
c h a r a c t e r i s e d i n t h a t
the lid (6) is provided with a controllable inlet (10) for ambient air to enter the inside of the crucible below the lid (6).
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20210630A NO20210630A1 (en) | 2021-05-21 | 2021-05-21 | Na removal from pot-room Al metal with under-pressure and forced convection |
| CA3219210A CA3219210A1 (en) | 2021-05-21 | 2022-04-27 | Method and equipment for treatment of molten aluminium metal |
| NO20231167A NO20231167A1 (en) | 2021-05-21 | 2022-04-27 | Method and equipment for treatment of molten aluminium metal |
| PCT/EP2022/061130 WO2022242992A1 (en) | 2021-05-21 | 2022-04-27 | Method and equipment for treatment of molten aluminium metal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20210630A NO20210630A1 (en) | 2021-05-21 | 2021-05-21 | Na removal from pot-room Al metal with under-pressure and forced convection |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NO20210630A1 true NO20210630A1 (en) | 2022-11-22 |
Family
ID=81850423
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NO20210630A NO20210630A1 (en) | 2021-05-21 | 2021-05-21 | Na removal from pot-room Al metal with under-pressure and forced convection |
| NO20231167A NO20231167A1 (en) | 2021-05-21 | 2022-04-27 | Method and equipment for treatment of molten aluminium metal |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NO20231167A NO20231167A1 (en) | 2021-05-21 | 2022-04-27 | Method and equipment for treatment of molten aluminium metal |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA3219210A1 (en) |
| NO (2) | NO20210630A1 (en) |
| WO (1) | WO2022242992A1 (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0065854A2 (en) * | 1981-05-19 | 1982-12-01 | Alcan International Limited | Removal of alkali metals and alkaline earth metals from molten aluminium |
| EP1081240A1 (en) * | 1999-09-03 | 2001-03-07 | Norsk Hydro Asa | Stirrer equipment for the continuous treatment of liquid metals |
| WO2003106908A1 (en) * | 2002-06-15 | 2003-12-24 | Solios Thermal Limited | Electromagnetic induction apparatus and method of treatment of molten materials |
| RU2337980C2 (en) * | 2006-07-25 | 2008-11-10 | Общество с ограниченной ответственностью "Русская инжиниринговая компания" | Refining practice of aluminium and aluminium alloys in shipping ladle |
| WO2011021940A1 (en) * | 2009-08-21 | 2011-02-24 | Sør Norge Aluminium As | Method and apparatus for adding powder and gas in a melt |
| WO2016195507A1 (en) * | 2015-06-01 | 2016-12-08 | Hmr Hydeq As | A molten metal and powder adding and mixing system and a metal production system |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1508112B2 (en) * | 1965-10-07 | 1973-04-12 | Allmanna Svenska Elektnska AB, Vasteraas (Schweden) | PROCESS AND ARRANGEMENT FOR TREATMENT OF METAL MELT |
| US3895937A (en) | 1971-07-16 | 1975-07-22 | Ardal Og Sunndal Verk | Dynamic vacuum treatment to produce aluminum alloys |
| NO155447C (en) | 1984-01-25 | 1987-04-01 | Ardal Og Sunndal Verk | DEVICE FOR PLANT FOR TREATMENT OF A FLUID, E.g. AN ALUMINUM MELT. |
| RU2379114C2 (en) * | 2005-08-10 | 2010-01-20 | Сентрал Рисерч Инститьют Оф Электрик Пауэр Индастри | Cleaning plant and method of cleaning |
| NO325978B1 (en) | 2006-07-04 | 2008-08-25 | Heggset Teknologi As | Method and apparatus for adding powder to liquid |
| WO2010094337A1 (en) * | 2009-02-20 | 2010-08-26 | Abb Ab | Aluminium melting process and device |
| WO2019157589A1 (en) * | 2018-02-14 | 2019-08-22 | Entrepac Inc. | Methods and apparatuses for aluminum and zinc recovery from dross and metal-rich residues using induction melting |
-
2021
- 2021-05-21 NO NO20210630A patent/NO20210630A1/en unknown
-
2022
- 2022-04-27 WO PCT/EP2022/061130 patent/WO2022242992A1/en active Application Filing
- 2022-04-27 NO NO20231167A patent/NO20231167A1/en unknown
- 2022-04-27 CA CA3219210A patent/CA3219210A1/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0065854A2 (en) * | 1981-05-19 | 1982-12-01 | Alcan International Limited | Removal of alkali metals and alkaline earth metals from molten aluminium |
| EP1081240A1 (en) * | 1999-09-03 | 2001-03-07 | Norsk Hydro Asa | Stirrer equipment for the continuous treatment of liquid metals |
| WO2003106908A1 (en) * | 2002-06-15 | 2003-12-24 | Solios Thermal Limited | Electromagnetic induction apparatus and method of treatment of molten materials |
| RU2337980C2 (en) * | 2006-07-25 | 2008-11-10 | Общество с ограниченной ответственностью "Русская инжиниринговая компания" | Refining practice of aluminium and aluminium alloys in shipping ladle |
| WO2011021940A1 (en) * | 2009-08-21 | 2011-02-24 | Sør Norge Aluminium As | Method and apparatus for adding powder and gas in a melt |
| WO2016195507A1 (en) * | 2015-06-01 | 2016-12-08 | Hmr Hydeq As | A molten metal and powder adding and mixing system and a metal production system |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2022242992A1 (en) | 2022-11-24 |
| CA3219210A1 (en) | 2022-11-24 |
| NO20231167A1 (en) | 2023-11-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4169584A (en) | Gas injection apparatus | |
| JPS5844730B2 (en) | Gustiyuuniyuuhouhououoyobisouchi | |
| EP4190927A1 (en) | Method for autonomously producing aluminum-based composite material in situ with melt control under electromagnetic stirring | |
| AU635434B2 (en) | A method for operating electron beam furnace and intermediate pressure electron beam furnace | |
| CN112795804A (en) | Method for controlling in-situ authigenic aluminum-based composite material by melt with continuous treatment | |
| CN112808991A (en) | In-situ autogenous aluminum matrix composite material system with permanent magnet stirring function | |
| CN112813279A (en) | System for controlling in-situ authigenic aluminum-based composite material through melt with continuous treatment | |
| CN113857461A (en) | Pressure-regulating casting method and system for melt-controlled in-situ autogenous aluminum-based composite material | |
| NO20210630A1 (en) | Na removal from pot-room Al metal with under-pressure and forced convection | |
| CN112779433B (en) | Argon gas rotary blowing and raw material synchronous conveying method for in-situ autogenous aluminum-based composite material preparation | |
| EP1944383A1 (en) | PROCESS FOR PRODUCING Ti AND APPARATUS THEREFOR | |
| JP2001335854A (en) | Apparatus and method for refining high purity metal | |
| CN112795803B (en) | In-situ self-growing aluminum-based composite material system with powder injection | |
| CN112795805B (en) | Preparation method of in-situ autogenous aluminum-based composite material with powder injection | |
| US4584015A (en) | Process and system for the production of very pure alloys | |
| CN112760505B (en) | In-situ autogenous aluminum matrix composite material system with vacuum degassing | |
| CN112760518B (en) | Method for in-situ self-growing aluminum-based composite material with vacuum degassing | |
| CN112760517B (en) | Graphite rotor for in-situ self-generated aluminum-based composite material | |
| CN112760506A (en) | System with electromagnetic stirring for controlling in-situ authigenic aluminum-based composite material through melt | |
| CN112779434A (en) | Method for in-situ self-growing aluminum-based composite material with permanent magnet stirring | |
| JPH11315315A (en) | Metallurgical reaction apparatus for treating molten metal under reduced pressure | |
| EP0425525A1 (en) | Method for grain refining of metals | |
| JP2009299098A (en) | Metal production method | |
| WO1995017528A1 (en) | A method of processing ferrous materials | |
| RU2810410C1 (en) | Method for producing corrosion-resistant steel |