Method and apparatus for dividing a conductive liquid

Abstract

The present invention relates to a method for breaking up a conductive liquid, particularly a molten jet, comprising the steps of providing a conductive liquid in the form of a liquid jet (10) moving in a first direction (12) and generating a high frequency traveling electromagnetic field surrounding the liquid jet (10), the high frequency traveling electromagnetic field moving in the first direction (12) to accelerate the liquid jet (10) in the first direction (12), thereby atomizing the liquid jet (10).

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for dividing, i.e., atomizing or spraying, a conductive liquid. Atomization of the conductive liquid helps to divide the conductive liquid into micro-droplets. Specifically, the method and apparatus according to the present invention can be used for the production of high-purity spherical metal powders by atomization or spraying of a molten jet.

Background Art

[0002] Methods and apparatuses known from the prior art for generating atomized micro-droplets are often based on the atomization of a liquid or liquefied material by an inert gas. In fact, these methods are known, in particular, from the field of metal powder production. Here, a molten jet of a metal or metal alloy melt is provided and atomized using an inert gas nozzle.

[0003] The disadvantage of such a metal powder production method is the high consumption of inert gas and the associated high operating costs.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Accordingly, an object of the present invention is to overcome the disadvantages of the state of the prior art. Specifically, one of the problems of the present invention is to provide a method and an apparatus that enable reduction of operating costs for dividing a conductive liquid, particularly a molten jet.

[0005] This object is solved by a method and an apparatus for dividing a conductive liquid according to the scope of the independent patent claims. Options and embodiments of this method and apparatus are the subject matter of the dependent claims and the following description.

Means for Solving the Problems

[0006] A method for dividing a conductive liquid, particularly a molten jet, includes providing a conductive liquid moving in a first direction in the form of a liquid jet.

[0007] In the present invention, "atomization" means atomizing or spraying the conductive liquid. Here, the "liquid jet" refers to a continuous liquid jet or at least a series of closely continuous droplets. The liquid jet moves in the first direction substantially along the central axis of the flow path of the liquid jet. Specifically, the conductive liquid can be a melt of a metal or a metal alloy provided in the form of a molten jet. However, the method and apparatus according to the present invention are not limited to atomization of a metal melt and can be used for atomization of any conductive liquid that can be affected by a traveling electromagnetic field.

[0008] A further step of the method according to the present invention is to generate a high-frequency traveling electromagnetic field surrounding the liquid jet, which travels in the first direction to accelerate the liquid jet in the first direction, thereby atomizing the liquid jet.

[0009] More specifically, since the high-frequency traveling electromagnetic field traveling in the first direction is arranged circumferentially around the liquid jet, the outer layer of the liquid jet can be accelerated more than the inner layer. The high-frequency traveling electromagnetic field generates a strong tangential component in the outer layer of the liquid jet, especially substantially accelerating the outer layer. As a result, a critical velocity profile with a large velocity gradient in the liquid jet is obtained, which may appear as a U-shaped velocity profile of the liquid jet in the longitudinal cross-section. Specifically, the velocity profile of the laminar pipe flow can be substantially inverted into a U-shaped velocity profile. Since the pressure in the liquid jet suddenly or rapidly rises compared to the pressure around the liquid jet, the liquid jet is decomposed or atomized by the pressure difference. By atomization or nozzle formation, the liquid jet is split into ligaments, thereby generating the desired fine particles. In addition to the pressure rise in the liquid jet, the liquid jet may also overheat.

[0010] In contrast to conventional atomization methods, according to the method of the present invention, a homogeneous liquid jet, such as a molten jet, can be atomized using a high-frequency traveling electromagnetic field. It is not necessary to introduce an inert gas for this purpose, which means that the operating cost of the method of the present invention can be reduced.

[0011] In one embodiment, the high-frequency traveling electromagnetic field can have an alternating frequency of at least 0.1 MHz, preferably at least 1 MHz, more preferably at least 10 MHz, and even more preferably at least 100 MHz. For example, the traveling electromagnetic field can have an alternating frequency of 0.1 MHz to 100 MHz. The alternating frequency can be adjusted according to further method parameters, in particular according to the material of the liquid jet to be atomized and / or the dimensions of the particles or micro-droplets to be generated.

[0012] According to one embodiment, the high-frequency traveling electromagnetic field can be generated by a coil assembly having at least one pole pair, preferably a plurality of pole pairs. For example, the coil assembly can include at least two pole pairs, more preferably at least three pole pairs, and even more preferably at least four or more pole pairs. In the case of a coil assembly having a plurality of pole pairs, the pole pairs can each be arranged parallel to adjacent pole pairs along the central axis of the flow path. The coil assembly can be controlled such that the high-frequency traveling electromagnetic field moves in the first direction, that is, moves substantially in the first direction.

[0013] In one embodiment, a further step of the method of the present invention may be to generate a gas flow surrounding the liquid jet. The gas flow moves substantially in the first direction to further accelerate the liquid jet in the first direction. The gas used is preferably an inert gas, such as argon. The gas may be at a high pressure, for example, 0 Pa to 10 MPa, preferably 0.1 MPa to 5 MPa. The gas flow may be generated using an inert gas nozzle. The gas flow may impact the liquid jet. This impact is a form of superimposed acceleration in addition to and in cooperation with the high-frequency traveling electromagnetic field. The gas flow can accelerate the liquid jet simultaneously in the time and / or space directions, both in front of and behind the coil assembly. The gas flow acts on the liquid jet via shear stress. Thus, the critical velocity profile (U-shaped velocity profile) in the liquid jet, and thus the high internal pressure, are set by the high-frequency traveling electromagnetic field and the gas flow, thereby efficiently atomizing the liquid jet. Even if an additional gas flow is used, the gas consumption can be reduced compared to conventional atomization methods. This is because the atomization is performed not only by the gas flow but also together with the traveling electromagnetic field.

[0014] The inert gas nozzle may be a Laval nozzle.

[0015] In one embodiment, the high-frequency traveling electromagnetic field may be generated by a coil assembly incorporated in the inert gas nozzle. In this case, the liquid jet can be accelerated substantially simultaneously by the gas flow and the high-frequency traveling electromagnetic field.

[0016] In one embodiment, the high-frequency traveling electromagnetic field may be generated using a coil assembly attached upstream or downstream along the central axis of the flow path of the inert gas nozzle. In this case, the acceleration of the liquid jet by the high-frequency traveling electromagnetic field and the gas flow acts at least partially successively on the liquid jet, or at least partially on the already atomized liquid jet.

[0017] In one embodiment, the liquid jet can be atomized by an additional gas flow introduced through an annular nozzle. This additional gas flow can have an impulsive or impinging effect on the liquid jet or the at least partially atomized liquid jet. As a gas for this purpose, an inert gas such as argon can also be used. The annular nozzle can be arranged downstream of the coil assembly when viewed along the central axis of the flow path. When viewed along the central axis of the flow path, the annular nozzle can be attached downstream of the inert gas nozzle.

[0018] Specifically, the method may be, or may be used in, the EIGA method (Electrode Induction Melting (Inert) Gas Atomization), or the method may be the VIGA method (Vacuum Induction Melting combined with Inert Gas Atomization), the PIGA method (Plasma Melting Induction Guiding Gas Atomization), the CCIM method (Cold Crucible Induction Melting), or any other method for powder production.

[0019] Specifically, the liquid jet can be generated by melting a vertically suspended rotating electrode using a conical induction coil. For this purpose, the electrode can be continuously moved in the direction of the induction coil and melted without contact. By rotating the electrode about its longitudinal axis, uniform melting of the electrode can be ensured. Melting of the electrode and atomization of the generated molten jet can be carried out in a vacuum or an inert gas atmosphere. This is to prevent, for example, an adverse reaction of the melted material with oxygen. Using the EIGA method, it is possible to produce ceramic-free high-purity metal or precious metal powders (for example, powders of titanium, zirconium, niobium, tantalum alloys).

[0020] In one embodiment, the method of the present invention may further include the step of cooling the atomized liquid jet in order to produce solidified, particularly spherical particles. This cooling can be carried out under local cooling conditions. Also, the cooling can be actively influenced, in particular, by a cooling device incorporated in the collection container.

[0021] A further aspect of the present invention relates to an apparatus for dividing a conductive liquid, particularly a molten jet. The apparatus comprises a liquid source for providing a liquid jet of a conductive liquid moving in a first direction, and a coil assembly having at least one pair of poles arranged coaxially with the liquid jet with respect to the central axis of the flow path and downstream of the liquid source with respect to the moving direction of the liquid jet. The coil assembly is adapted to generate a high-frequency traveling electromagnetic field that surrounds the liquid jet and travels in the first direction, and accelerates the liquid jet in the first direction by the high-frequency traveling electromagnetic field, thereby atomizing the liquid jet.

[0022] The apparatus can be adapted to carry out the above-described method for dividing the conductive liquid.

[0023] According to one embodiment, the coil assembly for generating a traveling high-frequency electromagnetic field may include a plurality of pole pairs. For example, the coil assembly may include at least two pole pairs, more preferably at least three pole pairs, and even more preferably at least four or more pole pairs. Each of the pole pairs of the plurality of pole pairs may be arranged parallel to adjacent pole pairs along the central axis of the flow path of the liquid jet. The coil assembly may be driven such that the traveling high-frequency electromagnetic field travels at a predetermined speed in the first direction, that is, such that the traveling high-frequency electromagnetic field travels in substantially the first direction at the predetermined speed.

[0024] In one embodiment, the traveling high-frequency electromagnetic field can have an alternating frequency of at least 0.1 MHz, preferably at least 1 MHz, more preferably at least 10 MHz, and even more preferably at least 100 MHz. For example, the traveling electromagnetic field can have an alternating frequency of 0.1 MHz to 100 MHz. The alternating frequency can be adjusted according to further method parameters, in particular according to the material of the liquid jet to be atomized and / or the dimensions of the particles or micro-droplets to be generated.

[0025] According to one embodiment, the device may include an inert gas nozzle designed to generate a gas flow surrounding the liquid jet. The gas flow moves in substantially the first direction, thereby further accelerating the liquid jet in the first direction by the gas flow. The gas flow may be an inert gas flow. For example, argon gas can be used as the inert gas.

[0026] The gas flow can be generated by an inert gas nozzle in the form of a Laval nozzle.

[0027] In one embodiment, the coil assembly can be disposed or incorporated within the inert gas nozzle. The coil assembly and the inert gas nozzle can be coaxially arranged with respect to each other. In this case, the liquid jet can be accelerated substantially simultaneously by the gas flow and the high-frequency traveling electromagnetic field.

[0028] In one embodiment, the coil assembly can be disposed upstream or downstream of the inert gas nozzle when viewed along the central axis of the flow path. In this case, the acceleration of the liquid jet by the high-frequency traveling electromagnetic field and the gas flow acts at least partially successively on the liquid jet or the at least partially already atomized liquid jet.

[0029] Due to the arrangement of the inert gas nozzle, the gas flow can impact the liquid jet. This impact is a form of superimposed acceleration in addition to and in cooperation with the high-frequency traveling electromagnetic field. Thus, the critical velocity profile in the liquid jet can be adjusted using the high-frequency traveling electromagnetic field and the gas flow, thereby enabling efficient atomization of the liquid jet. Also, despite adding a gas flow, the gas consumption can be reduced compared to conventional atomization devices. This is because the atomization is not only by the gas flow but also by the combined use with the traveling electromagnetic field.

[0030] In one embodiment, the device may include an annular nozzle, and the annular nozzle is designed to additionally atomize the liquid jet using an additional gas flow introduced through the annular nozzle. The annular nozzle may be set to further atomize the liquid jet or the at least partially already atomized liquid jet by using an impact on the liquid jet or the at least partially already atomized liquid jet. For this purpose, an inert gas, for example argon, may also be used. The annular nozzle may be arranged downstream of the coil assembly when viewed along the central axis of the flow path. The annular nozzle may be arranged downstream of the inert gas nozzle when viewed along the central axis of the flow path.

[0031] In an embodiment comprising one inert gas nozzle and one annular nozzle, these two nozzles can be designed as one nozzle device. This nozzle device can be of an integral type.

[0032] In an embodiment comprising an inert gas nozzle and an annular nozzle, the quality and / or particle size of the powder produced will be affected by the interaction and adjustment of the coil assembly, the inert gas nozzle and the annular nozzle.

[0033] In one embodiment, the liquid source may specifically be a molten jet source in the form of an electrode. In one embodiment, the liquid jet may be a molten jet of the molten electrode material. The electrode may be a vertically suspended rotatable electrode. For example, the electrode may include or consist of titanium, titanium alloy, zirconium-based, niobium-based, nickel or tantalum-based alloy, noble metal or noble metal alloy, copper or aluminum alloy, special metal or special metal alloy. The electrode may have a diameter greater than 50 mm and a maximum of 150 mm, and a length greater than 500 mm and a maximum of 1000 mm.

[0034] Furthermore, the device may include a conical induction coil coaxial with the electrode and disposed in the region of the lower end of the electrode. This induction coil is adapted to melt the electrode to generate a molten jet. For this purpose, the electrode may be continuously displaceable in the direction of the induction coil. The electrode and the induction coil may be disposed in a housing provided with a vacuum or inert gas atmosphere.

[0035] In one embodiment, the device may include an atomization tower for cooling and solidifying the atomized liquid jet. This atomization tower may be connected to the housing and may also be supplied with a vacuum or inert gas atmosphere. The coil assembly and the inert gas nozzle (when attached) may also be disposed in the housing in the connection region with the atomization tower. The atomization tower may be provided with a cooling device for actively cooling the atomized liquid jet, whereby it is possible to act on particle formation with a defined target.

[0036] The device may be an EIGA system or may be mounted on an EIGA system.

[0037] Some aspects and features have been described only in the context of the method of the present invention, but these can be appropriately applied to the device and the embodiments, and vice versa.

[0038] Embodiments of the present invention will be described in more detail below with reference to the accompanying schematic diagrams.

Brief Description of the Drawings

[0039]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0040] FIG. 1 is a longitudinal sectional view of a part of a liquid jet 10 of a conductive liquid. In this example, the liquid jet 10 is substantially a continuous molten jet of a metal melt. Starting from a liquid source (not shown), the liquid jet 10 moves in a first direction 12 along its flow path central axis A. In the view of FIG. 1 shown, the liquid jet 10 falls downward from above by gravity.

[0041] The liquid jet 10 passes through a device 20 for atomizing the liquid jet 10. In the illustrated design example, the device 20 includes a coil assembly 22 having three pole pairs 24A, 24B, 24C. In an alternative design example, it will be understood that the coil assembly may have more or fewer pole pairs than three. The coil assembly 22 is downstream of a liquid source (not shown) in the moving direction, and the windings are arranged parallel to each other and coaxial with the liquid jet 10.

[0042] Each of the pole pairs 24A, 24B, 24C can be controlled in sequence such that the phase changes by φ i and thereby a high-frequency traveling electromagnetic field is generated. The order of the phase change φ i is illustrated by the numbers φ1, φ2, φ3 as an example. The high-frequency traveling electromagnetic field may have an alternating frequency, for example, from 0.1 MHz to 100 MHz.

[0043] Also, the high-frequency traveling electromagnetic field moves in the first direction 12 due to the phase change φ i . Since the windings of the coil sequence 22 are arranged around the liquid jet 10, the Lorentz force 26 generated by the high-frequency traveling electromagnetic field having a strong tangential component mainly impinges on the outer layer of the liquid jet 10 and further accelerates the outer layer in the first direction 12. Thus, the outer layer of the liquid jet 10 is accelerated more strongly than the inner layer of the liquid jet 10, and as a result, a critical velocity profile having a large velocity gradient in the liquid jet is formed. The dominant velocity (indicating the velocity profile in the liquid jet) in the course of the liquid jet is indicated by the arrow V mis illustrated, with the long arrows indicating higher speeds and the short arrows indicating lower speeds (for clarity, only one arrow is labeled with the reference symbol Vm). In the longitudinal cross-section, the critical velocity profile at the exit of the liquid jet 10 from the coil assembly 22 is shown as a U-shaped velocity profile 28. The large velocity gradient within the liquid jet 10 increases the pressure within the liquid jet 10. As a result, a large pressure difference occurs between the high pressure within the liquid jet 10 and the much lower pressure surrounding the liquid jet. This pressure difference causes the liquid jet 10 to break up into ligaments, i.e., the liquid jet 10 is atomized into fine particles. The fine particles can have, for example, an average particle size or average particle diameter d in the range of 20 μm to 100 μm 50 and may have.

[0044] FIG. 2 is a longitudinal cross-sectional view of a part of the molten jet 110 of the molten metal. The liquid jet 110 is atomized by an inert gas nozzle method or a Laval nozzle. The molten jet 110 passes through the opening of the inert gas nozzle 120 and enters an atomization tower (not shown).

[0045] Different from the method shown in FIG. 1, the critical velocity profile in the molten jet 110 in the method shown in FIG. 2 is generated by the inert gas flow 122. The inert gas flow 122 flows at a high speed V g through the inert gas nozzle 120 and enters the atomization tower. Since the molten jet 110 passes through the center of the inert gas nozzle 120, the inert gas flow 122 surrounds the molten jet 110 and acts on the outer layer of the molten jet 110 through shear stress. Thus, the outer layer of the molten jet 110 is accelerated more strongly in the first direction 12 than the inner layer of the molten jet 110. Thereby, a critical velocity profile 128 is generated within the molten jet 110, and the molten jet 110 is atomized after exiting the inert gas nozzle 120 or after entering the connected atomization tower.

[0046] FIG. 3 schematically shows a part of a cross-sectional view of the apparatus 20 according to the present invention in the EIGA method or in the EIGA system 200. The same reference numerals are given to the same components and features as in FIG. 1.

[0047] As can be seen in FIG. 3, the coil assembly 22 in the illustrated design example is incorporated into an inert gas nozzle 30 designed in the form of a Laue nozzle. Thus, FIG. 3 shows an embodiment of the present invention including the combination of the methods shown in FIGS. 1 and 2. As a result, a surprising synergistic effect can be obtained, leading to a further improvement in atomization.

[0048] The coil assembly 22 and the inert gas nozzle 30 are coaxially arranged, and the coil assembly 22 surrounds the inert gas nozzle 30 and the inside of the inert gas nozzle 30, respectively. An inert gas flow 32 flows through the inert gas nozzle 30, whereby a liquid jet 10 composed of a plurality of continuous droplets is accelerated in a layered manner (similar to FIG. 2). This layered acceleration (similar to FIG. 2) through the inert gas nozzle 30 or through the inert gas flow 32 is superimposed on the electromagnetic acceleration (similar to FIG. 1) of the conductive liquid jet 10 through the coil assembly 22.

[0049] Both accelerations cooperate to impart an impact to the liquid jet 10 so that the liquid jet 10 is accelerated in the first direction 12. Due to these superimposed accelerations, a U-shaped critical velocity profile corresponding to the velocity profiles of FIGS. 1 and 2 is formed in the liquid jet 10. The large velocity gradient in the liquid jet 10 generated in this way raises the pressure in the liquid jet 10, resulting in a large pressure difference between the high pressure in the liquid jet 10 and the much lower pressure around the liquid jet. This pressure difference causes the liquid jet 10 to break up into ligaments, that is, the liquid jet 10 is atomized into fine particles.

[0050] As also shown in FIG. 3, the liquid jet 10 is generated by the so-called EIGA method. For this purpose, an EIGA coil 40 or an induction coil 40 is attached in front of the coil assembly 22 and the inert gas nozzle 30. The induction coil 40 is arranged coaxially with the coil assembly 22 and the inert gas nozzle 30. The induction coil 40 is tapered when viewed in the first direction 12, i.e., it has a diameter that decreases when viewed in the first direction 12.

[0051] An electrode 42 is provided coaxially with the induction coil 40 and at least partially in front of the induction coil 40 and is melted by the induction coil 40 to generate the liquid jet 10. The illustrated electrode can be made of, for example, titanium, a titanium alloy, or an alloy based on zirconium, niobium, nickel, or tantalum, a noble metal or a noble metal alloy, an alloy of copper or aluminum, a special metal or a special metal alloy. The electrode 42 is suspended at its upper end (not shown) and is axially displaceable in the first direction (i.e., the arrangement direction of the coil device 22 and the inert gas nozzle 30). Thereby, the electrode 42 can continuously follow during the melting of the electrode 42.

[0052] There is an annular nozzle 50 downstream of the coil assembly 22 and the inert gas nozzle 30, through which a further inert gas flow 52 can be introduced into the entire assembly. The further inert gas flow 52 in the illustrated design impinges impulsively or shockingly on the liquid jet 10 emerging from the coil assembly 22 and the inert gas nozzle 30. The emerging liquid jet 10 will already be at least partially atomized when the further inert gas flow 52 from the annular nozzle 50 impinges on the liquid jet 10. The further inert gas flow 52 impinging on the liquid jet 10 or the at least partially atomized liquid jet 10 will cause the liquid jet 10 to be further atomized.

[0053] As shown in FIG. 3, the coil assembly 22, the inert gas nozzle (Laval nozzle) 30, and the annular nozzle 50 can be designed as a common device 20. The device 20 can be, for example, an integrated type.

[0054] As follows the entire device shown in FIG. 3, an atomization tower can be provided for cooling and solidifying the atomized liquid jet, but is only suggested here and not fully shown. The atomization tower may include a collection tank for collecting the solidified powder.

[0055] It will be understood that instead of the EIGA method for generating the liquid jet, an alternative method without using a crucible or a method using a crucible, for example, the VIGA method, the PIGA method, the CCIM method, or other methods can be provided. Therefore, in the system shown in FIG. 3, instead of the induction coil, one or more devices required for the above-described method may be provided upstream of the coil assembly.

[0056] It will be understood that the method according to the present invention and the device according to the present invention may, in one embodiment, include a combination of a device having a coil assembly and not including an inert gas nozzle and an annular nozzle.

[0057] By the method according to the present invention or the device according to the present invention, in particular, by saving the consumption of the inert gas, the operating cost can be reduced as compared with the conventional inert gas nozzle method.

Explanation of reference numerals

[0058] 10 Liquid jet A Central axis of the flow 12 First direction 20 Device for atomizing the liquid jet 22 Coil device 24A, 24B, 24C Pole pair / winding 26 Lorentz force 28 U-shaped velocity profile Vm Velocity in the liquid jet φ i , φ1, φ2, φ3 Phase change 30 Inert gas nozzle (Laval nozzle) 32 Inert gas flow 40 Induction coil 42 Electrode 50 Annular nozzle 52 Further inert gas flow 110 Melt jet (prior art) 120 Inert gas nozzle (prior art) 122 Inert gas flow (prior art) 128 Velocity profile (prior art) 200 EIGA system

Claims

1. A method for dividing a conductive liquid, comprising: providing a conductive liquid moving in a first direction (12) in the form of a liquid jet (10); generating a high-frequency traveling electromagnetic field surrounding the liquid jet (10), the high-frequency traveling electromagnetic field moving in the first direction (12) to accelerate the liquid jet (10) in the first direction (12), thereby atomizing the liquid jet (10).

2. The method according to claim 1, wherein the high-frequency traveling electromagnetic field has an alternating frequency of at least 0.1 MHz.

3. The method according to claim 1 or 2, wherein the high-frequency traveling electromagnetic field is generated by a coil assembly (22) having at least one pair of poles (24A, 24B, 24C).

4. The method according to any one of claims 1 to 3, further comprising generating a gas flow surrounding the liquid jet (10), the gas flow moving substantially in the first direction (12) to further accelerate the liquid jet (10) in the first direction (12).

5. The method according to any one of claims 1 to 4, further comprising generating a further gas flow impinging on the liquid jet (10) using an annular nozzle (50).

6. The method according to any one of claims 1 to 5, wherein the liquid jet (10) is generated by melting an electrode (42) using an induction coil (40).

7. The method according to any one of claims 1 to 6, further comprising cooling the atomized liquid jet (10) to produce solidified particles.

8. An apparatus (20) for dividing a conductive liquid, comprising: a liquid source for providing a liquid jet (10) of a conductive liquid moving in a first direction (12); a coil assembly (22) having at least one pair of poles (24A, 24B, 24C), disposed downstream of the liquid source and coaxially with the liquid jet (10); wherein the coil assembly (22) is adapted to generate a high-frequency traveling electromagnetic field surrounding the liquid jet (10) and traveling in the first direction (12), the high-frequency traveling electromagnetic field accelerating the liquid jet (10) in the first direction (12), thereby atomizing the liquid jet (10).

9. The apparatus (20) according to claim 8, wherein the high-frequency traveling electromagnetic field has an alternating frequency of at least 0.1 MHz.

10. The apparatus (20) according to claim 8 or 9, further comprising an inert gas nozzle (30) adapted to generate a gas flow surrounding the liquid jet (10), the gas flow moving substantially in the first direction (12) and further accelerating the liquid jet (10) in the first direction (12) by the gas flow.

11. The apparatus (20) according to claim 10, wherein the coil assembly (22) is disposed within the inert gas nozzle (30) and / or upstream and / or downstream of the inert gas nozzle (30) when viewed along the flow path central axis (A).

12. The apparatus (20) according to any one of claims 8 to 11, further comprising an annular nozzle (50) for generating a further gas flow adapted to impinge on the liquid jet (10).

13. The apparatus (20) according to any one of claims 8 to 12, wherein the liquid source is an electrode (42) and the liquid jet (10) is a molten jet.

14. The apparatus (20) according to claim 13, comprising an induction coil (40) disposed coaxially with the electrode (42) and in a region at one end of the electrode (42), the induction coil (40) being adapted to melt the electrode (42) to generate the molten jet.

15. The apparatus (20) according to any one of claims 8 to 11, comprising an atomization tower for cooling and solidifying the atomized liquid jet (10).

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