WO2024115645A1

WO2024115645A1 - Distillation device

Info

Publication number: WO2024115645A1
Application number: PCT/EP2023/083706
Authority: WO
Inventors: Leopold BERGER; Sandro Reto MATTER
Original assignee: Kairos Medical Ag
Priority date: 2022-12-01
Filing date: 2023-11-30
Publication date: 2024-06-06

Abstract

A distillation device (10.1) for producing purified metal(M2), preferably purified magnesium, by vacuum distillation, is described, comprising a vacuum chamber (2) and a retort (1) elongated along a horizontal axis (L) and arranged within the vacuum chamber, the retort comprising a separation wall (11) arranged in the retort, an evaporation chamber (12) adjacent to a first side of the separation wall and a condensation chamber (13) adjacent to a second side of the separation wall, wherein the separation wall is arranged such that a communication aperture (14) fluidically connecting the evaporation chamber and the condensation chamber is formed at an upper portion of the retort.

Description

DISTILLATION DEVICE

Field of the invention

The present invention relates to a distillation device and a method for producing puri fied metal , preferably magnesium, by vacuum distillation .

Background of the invention

Recently, high-purity metals have increasingly been used for example in medical technology or various other high-tech applications . High-purity magnesium for example , is considered as an alternative material to titanium for the fabrication of medical implants due to its biocompatibility and biodegradability . Thereby, vacuum distillation is used as an ef ficient and reliable refining method for the puri fication of metals .

Vacuum distillation is particularly suited for puri fying magnesium due to its low boiling point . In a typical setup, condensation and solidi fication of puri fied magnesium vapor takes place on baf fles , which are basically cooled or not cooled plates , resulting in either dendritically shaped final material or powder . Although high purity can be achieved in this fashion, the so-obtained material may not be suitable for some applications due to the high surface area of the dendritic structure or the powder, which may lead to undesirable high oxidation . For example , high content of metal oxides can be

A23704WO detrimental to certain materials properties such as ductility or the ability to perform wire drawing .

A process for the production of largely oxide- free ultrahigh- purity magnesium is known in the art on the basis of liquid- phase-collection distillation . In this process , both the impure primary material and the puri fied target material are present in liquid state during the performance of the distillation process . Material trans fer occurs due to di f ferent temperature levels and thus di f ferent equilibrium vapor pressures . The collected target material is ultimately solidi fied as a block, thereby achieving a homogenous bulk material with comparatively small surface to volume ratio .

Such a process i s for example described in WO 2013/ 107644 Al by a device to puri fy magnesium by distillation and collect the puri fied material in liquid state based on a liquid-phase- collection . After the distillation process has been finished, the puri fied magnesium melt can be solidi fied by cool-down and subsequently extracted from the device .

WO 2018 / 189175 Al describes a device for producing puri fied, especially high-purity, magnesium, having a reactor for vacuum distillation that is extended along a longitudinal axis , wherein the reactor forms a reactor inner chamber having a heating region for heating magnesium made available in the heating region, a crucible that forms a crucible inner chamber for receiving puri fied magnesium vapori zed by means of the device and then condensed . The reactor has on the heating region a radial proj ection, wherein a contact surface of the proj ection, which contact surface extends essentially transverse to the longitudinal axis , is embodied such that , with an edge of the crucible adj acent to the crucible inner chamber, it forms an essentially sealing connection .

Summary of the invention

When performing vacuum distillation for the puri fication of a material , in particular a metal , such as magnesium, it is desired that measures such as evacuation, heating, cooling, cleaning etc . for reaching and maintaining the required process parameters can be taken in an ef ficient and simple fashion . Further, it is desired that complexity in supply of primary material to be puri fied and extraction of puri fied material may be reduced or minimi zed . The high temperatures involved in the puri fication process usually pose further challenges to the vacuum distillation device , for example to the material used to build the vacuum distillation device or the sealing used between di f ferent components .

It is therefore an obj ect of the invention to provide a distillation device and a method for producing puri fied material , preferably puri fied metal , particularly preferably puri fied magnesium, by vacuum distillation, which at least partially improve the prior art and avoid at least part of the disadvantages of the prior art .

According to the present invention, this obj ect is achieved by the features of the independent claims . In addition, further advantageous embodiments follow from the dependent claims and the description as well as the figures .

According to an aspect of the invention, the obj ect is particularly achieved by a distillation device for producing puri fied material , preferably puri fied metal , particularly preferably puri fied magnesium, by vacuum distillation, comprising a vacuum chamber and a retort elongated along a hori zontal axis and arranged within the vacuum chamber, the retort comprising a separation wall arranged in the retort , an evaporation chamber adj acent to a first side of the separation wall and a condensation chamber adj acent to a second side of the separation wall , wherein the separation wall is arranged such that a communication aperture fluidically connecting the evaporation chamber and the condensation chamber is formed at an upper portion of the retort .

By providing a vacuum chamber, the retort can be arranged in an environment of reduced pressure . This has the advantage that susceptibility of the retort to oxidation at elevated temperatures can be reduced, which broadens the range of possible materials for manufacturing the retort . Due to the hori zontal orientation of the retort , the relative reduction of condensation surface area due to a raising level of collected puri fied material in the condensation chamber can be lowered compared to vertically oriented devices known from the prior art , such that the puri fication ef ficiency can be improved . By providing the separation wall , a constructively simple separation between the evaporation and condensation chamber can be enabled . Preferably, the separation wall is vertical . Further, communication between the evaporation chamber and the condensation chamber can be provided in a simple fashion by the communication aperture , and thus , by the separation wall . The hori zontal orientation of the retort with the separation wall therefore advantageously allows to provide a distillation device with reduced complexity, especially with respect to device geometry, compared to devices known in the prior art. At the same time, efficiency and reliability for the purification may be maintained or improved.

The horizontal orientation may further provide the advantage that the working height for the user for feeding of the distillation device with raw material to be purified or raw metal or raw magnesium to be purified, respectively, and removal of purified material from the distillation device may be improved compared to vertically oriented distillation devices known from the prior art.

In this respect, the person skilled in the art understands that for the purposes the present disclosure, terms like e.g. "upper", "lower" etc. shall be understood with respect to the direction of evaporation or gravity, i.e. according to the orientation as shown in the figures.

Preferably, the separation wall covers half or more than half of the transverse cross-section of the retort. In particular, the separation wall may cover at least the lower half of the transverse cross-section of the retort.

In some embodiments, the communication aperture is transversely bordered at a lower portion by an edge of the separation wall and at an upper portion by a lateral side wall of the retort.

In some embodiments, the side wall and the retort may be configured that the communication aperture has a shape of a circular segment. In some embodiments , the separation wall comprises a bore within the separation wall which forms the communication aperture . The bore may have a circular shape .

Preferably, the separation wall is arranged under a rectangular angle with respect to a lateral side wall of the retort . The transverse area of the side wal l may be smaller than the transverse cross-section of the retort .

While manufacturing the distillation device , the separation wall may be introduced into the retort and welded onto a lateral side wall of the retort .

In some embodiments , the separation wall may be integrally formed with a lateral side wall of the retort . In particular, the separation wall and a lateral side wall of the retort may be formed from a monolithic piece of material .

In some embodiments , the retort comprises a refill opening arranged at an axial side wall of the condensation chamber opposite to the separation wall and/or at an axial side wall of the evaporation chamber opposite to the separation wall and/or at an upper portion of a lateral wall of the evaporation chamber .

The refill opening allows to feed the retort or the evaporation chamber, respectively, with raw material , such as magnesium which is to be puri fied .

For an embodiment where the refi ll opening is arranged at an axial side wall of the condensation chamber opposite to the separation wall , feeding of the evaporation chamber may be executed by inserting a guiding tube through the refill opening in order to bridge the condensation chamber and the separation wall . The guiding tube may again be removed after completing the feeding . Arranging the refill opening at an axial side wall of the condensation chamber opposite to the separation wall may be advantageous for the reliability of one or more sealing elements for a lid closing the refill opening, due to the lower temperatures prevailing at the condensation chamber compared to the evaporation chamber .

A refill opening arranged at an axial side wall of the evaporation chamber opposite to the separation wall or at an upper portion of a lateral wall of the evaporation chamber provides the advantage that the raw material can directly be fed into the evaporation chamber without having to bridge the condensation chamber and the separation wall . Furthermore , a continuous feeding into the evaporation chamber may be enabled while distillation may be ongoing . This may particularly be advantageous for an embodiment where the puri fied magnesium is extracted in the liquid phase by an outlet arranged at the condensation chamber .

In particular, the refill opening may be flush with the communication aperture .

This may particularly be advantageous for an embodiment where the refill opening is arranged at an axial side wall of the condensation chamber opposite to the separation wall , as insertion of a guiding tube and bridging of the condensation chamber and the separation wall can be facilitated .

In some embodiments , the retort comprises a lid configured to sealingly close the refill opening . The refill opening can thus be closed and sealed by the lid to prevent material vapor, such as magnesium vapor, to escape during the distillation process . Sealing closure by the lid may be facilitated by a sealing element , e . g . a gasket , arranged between the lid and the refill opening . The lid may be made of molybdenum or a molybdenum alloy, niobium or a niobium alloy, tantalum or a tantalum alloy, or graphite . The sealing element may be made of graphite .

In some embodiments , the lid is configured to close the refill opening by a screw connection or a press- fit connection .

A screw connection may be a s imple and reliable way to sealingly close the refill opening by the lid . A press- fit connection may be achieved by a pressure-exerting element , such as for example an axially movable piston . The pressureexerting element may advantageously be configured to exert a force onto the lid and/or the seal ing element between the lid and the refill opening, respectively . In particular, the pressure-exerting element may be configured to exert an essentially constant force onto the lid and/or the sealing element between the lid and the refill opening, respectively, independent of the operating status , temperature and thermal deformation of components of the distillation device . Closing of the refill opening by the lid through a press- fit connection may especially be advantageous i f the material from which the retort is made of is not favorable for making a screw connection . The pressure-exerting element , for example the axially movable piston, may be controllable from outside of the retort and/or the vacuum chamber . In some embodiments , a refill opening temperature sensor is arranged at the refill opening .

Using the refill opening temperature sensor, the temperature at the refill opening can be monitored in order to ensure that during cool-down of the retort , the temperature at the refill opening is in a range that magnesium vapor pre ferentially condensates and solidi fies at other parts of the retort than at the refill opening . By monitoring the refill opening temperature sensor and controlling one or more heaters of the distillation device , blocking of the refill opening by solidi fied magnesium may therefore be avoided .

The refill opening temperature sensor may be connected to a controller which is configured to control the one or more heaters of the distillation device .

In some embodiments , the retort comprises an extraction outlet arranged at a lower portion of the condensation chamber and configured to extract puri fied material , preferably magnesium, from the condensation chamber .

The extraction outlet provides the advantage that a continuous or periodic extraction of puri fied material from the condensation chamber, preferably in liquid form, can be achieved . In some embodiments , the puri fied material may be extracted in solid, for example granular form, or in gaseous form through the extraction outlet . By providing the extraction outlet , continuous or semi-continuous operation of the distillation device can therefore be achieved, depending on the feeding mechanism of raw material to the retort . For a continuous extraction of puri fied material through the extraction outlet , continuous operation of the distillation device may be achieved by a continuous feeding of raw material into the evaporation chamber . For a batchwise feeding of raw material , semi-continuous operation of the distillation device may be achieved by the continuous extraction of puri fied material through the extraction outlet . By arranging the extraction outlet at a lower portion of the condensation chamber, puri fied material can be extracted from the bottom portion of the melt of puri fied material in the condensation chamber while puri fied material condensates and accumulates from the upper portion of the melt . The extraction outlet may be arranged at an axial side wall of the retort or at a lateral side wall of the retort .

In some embodiments , the retort comprises an extraction outlet arranged at an axial face of the condensation chamber . The extraction outlet may extend over an axial face of the condensation chamber . The retort may comprise a lid configured to sealingly close the extraction outlet . Sealing closure by the lid may be facilitated by a sealing element , e . g . a gasket , arranged between the lid and the extraction outlet . The sealing element may be made of graphite . The lid may close the extraction outlet by a press- fit connection, in particular, by a pressure-exerting element , such as for example a pressureexerting piston . The lid may be moved away from the condensation chamber in order to open the extraction outlet and to collect puri fied material from the condensation chamber . This may particularly be advantageous for a solid-phase- collection distillation process where the puri fied material solidi fies in the condensation chamber .

In some embodiments , the retort may comprise a refi ll opening arranged at an axial face of the evaporation chamber and an extraction outlet arranged at an axial face of the condensation chamber . The refill opening and the extraction outlet may be configured symmetrically . For example , the refill opening may extend over an axial face of the evaporation chamber and the extraction outlet may extend over an axial face of the condensation chamber . Further, both the refill opening and the extraction outlet may be closable by a respective l id, e . g . a refill opening lid and an extraction outlet lid, respectively . Sealing closure of the extraction outlet by the extraction outlet lid may be facilitated by a first sealing element , e . g . a first gasket , arranged between the extraction outlet lid and the extraction outlet . Sealing closure of the refill opening by the refill opening lid may be facilitated by a second sealing element , e . g . a second gasket , arranged between the refill opening lid and the refill opening . The first and/or second sealing element may be made of graphite .

In some embodiments , the extraction outlet comprises a hori zontal extraction pipe protruding from an axial side wall of the condensation chamber, wherein the extraction pipe preferably compri ses an extraction aperture at a lower face of the extraction pipe .

In some embodiments , the extraction pipe protrudes from a lateral side wall of the retort .

An extraction pipe protruding from a side wall of the condensation chamber provides the advantage that one or more extraction parameters at the extraction outlet can better be controlled . For example , an improved control of the temperature at the extraction outlet may be provided by a heating element at least partially surrounding the extraction pipe . The extraction pipe protruding from an axial side wall of the condensation chamber provides the further advantage that the position where the puri fied material is to be received can be varied . For example , the extraction pipe may guide the puri fied material to a site where the puri fied material is received by a reservoir, such as a mold . The extraction pipe may also provide a guide such that the puri fied material is conveyed to an extraction chamber, as described further below .

By arranging the extraction pipe at an axial side wall of the condensation chamber, axial insertion of the retort into the vacuum chamber can be facilitated which may be bene ficial for assembling the distillation device .

In some embodiments , the extraction outlet comprises an extraction valve configured to regulate the fluid flow of material through the extraction outlet .

By using an extraction valve , periodic extraction of the puri fied material from the condensation chamber can be provided, as the extraction valve advantageously allows to interrupt the flow of puri fied material out of the condensation chamber . The extraction valve can controllably be opened to allow the puri fied material to flow out of the condensation chamber i f the puri fied material is supposed to be extracted from the condensation chamber .

The extraction valve may be a thermal valve with a valve heater configured to heat the extraction outlet to a temperature above the melting point of a material in the condensation chamber, preferably of magnesium . The thermal valve provides the advantage that the use of delicate parts such as for example a moving valve regulating element arranged in a seat of a valve body or sealing elements can be avoided, such that reliability and operability under the process conditions of the distillation device , in particular with respect to the prevailing high temperatures , can be improved .

A thermal valve usually operates by heat where the thermal valve can be heated to a temperature above the melting point of the material to be controlled, in order to allow the material to flow through the extraction valve . In order to interrupt the material flow, the temperature at the thermal valve can be lowered to a temperature below the melting point of the material to be controlled such that the material in the thermal valve solidi fies and interrupts further flow of material through the extraction valve .

Lowering the temperature at the thermal valve below the melting point of the material to be controlled can for example be achieved by interrupting the heating by the valve heater .

Alternatively or additionally, a valve cooler may be used to cool the thermal valve . In some embodiments , the thermal valve therefore comprises a valve cooler configured to cool the extraction outlet to a temperature below the melting point of a material in the condensation chamber, preferably of magnesium .

In some embodiments , a thermal valve temperature sensor is arranged at the thermal valve . Using the thermal valve temperature sensor, the temperature at the thermal valve can be monitored and the valve heater and/or valve cooler be controlled depending on the temperature determined by the thermal valve temperature sensor .

The thermal valve temperature sensor may therefore be connected to a controller which is configured to control the valve heater and/or the valve cooler .

In some embodiments , the extraction valve is a piston valve .

A piston valve provides the advantage that control of the material flow can be achieved by a linearly moving valve regulating element . Thus , a delicate rotating valve regulating element with e . g . clearances in the valve seat which may be detrimental for use at the high temperatures prevailing can be avoided . The piston may comprise a handle which may advantageously be accessible from outside of the retort and/or the vacuum chamber .

The retort may have a tubular shape , preferably with a circular or polygonal , in particular rectangular or triangular, crosssection .

Compared to distillation devices known in the prior art , the retort thus comprises a rather simple geometry . Such a geometry may particularly be advantageous considering the challenges related with the high temperatures prevailing during the distillation process , such as for example di f fering thermal expansion coef ficients of the materials of di f ferent components of the distillation device , reliability of sealing elements or welding seams arranged between di f ferent components of the distillation device etc . Furthermore , such geometries may reduce the complexity in manufacturing of the distillation device .

In some embodiments , the evaporation chamber is larger than the condensation chamber .

In particular, the evaporation chamber may be at least five times , ten times , or fi fteen times larger than the condensation chamber .

By making the evaporation chamber larger than the condensation chamber, the amount of raw material inserted into the evaporation chamber can be increased . Providing a large amount of raw material may be advantageous since the period of an operation cycle of the distillation device can be increased and the frequency of time-consuming cooldown and reheating and/or venting and evacuating of the distillation device can be decreased .

In some embodiments , the vacuum chamber comprises a retort chamber in which the retort is arranged .

In some embodiments , the vacuum chamber comprises an extraction chamber arranged below the retort chamber, and a conduit connecting the retort chamber and the extraction chamber, wherein the conduit is arranged below the extraction outlet .

The puri fied material extracted through the extraction outlet may fall into the extraction chamber through the conduit .

In embodiments with an extraction pipe , the conduit may be arranged below the extraction pipe and in particular, below the extraction aperture of the extraction pipe . With the retort chamber and the extraction chamber, separate chambers for housing the retort and for collecting the puri fied material can therefore be provided . Providing separate chambers may be advantageous since the temperature requirements for the distillation and condensation usually di f fer from the temperature requirements for collection .

For a liquid-phase-collection distillation process for example , the temperature at the retort chamber may be maintained at a temperature above the melting point of the raw material and/or the puri fied material . The temperature at the extraction chamber, on the other hand, may be lowered such that the extracted puri fied material conveyed into the extraction chamber may be cooled . In particular, the extraction chamber may be cooled to a temperature around or below the melting point of the puri fied material such that solidi fication of the puri fied material may occur in the extraction chamber . After solidi fication, a block of the solid puri fied material may be removed from the extraction chamber .

In some embodiments , the extraction chamber comprises one or more ports configured for connection with a vacuum pump .

Due to the lower temperatures that may prevail at the extraction chamber, as described above , connection to a vacuum pump may be more reliable i f the ports and associated sealing elements are arranged at the extraction chamber .

While evacuating the vacuum chamber through the one or more ports , the retort may be evacuated through the extraction outlet or extraction pipe , respectively . A valve at the extraction outlet may be switched to an open state such that the retort may be evacuated through the extraction outlet . In case of a thermal valve at the extraction outlet , the thermal valve may therefore be heated to a temperature where the thermal valve is open such that evacuation through the extraction outlet may be performed . Alternatively or additionally, the retort may be evacuated through the refill opening .

In some embodiments , the retort chamber and/or the conduit may comprise one or more ports configured for connection with a vacuum pump . One or more ports configured for connection with a vacuum pump may also be arranged at other positions of the vacuum chamber .

In some embodiments , a pressure-exerting element usable for the lid closing the refill opening, e . g . a pressure-exerting piston, is configured that the vacuum chamber can be evacuated through the pressure-exerting element . The pressure-exerting piston may comprise a conduit with a first conduit aperture arranged in the retort chamber and a second conduit aperture arranged outside of the vacuum chamber . The conduit may establish a communication between the interior and the exterior of the vacuum chamber such that the vacuum chamber may be evacuated by connecting a vacuum pump to the second conduit aperture .

In some embodiments , the retort chamber comprises a retort chamber access door arranged at an axial side wall of the retort chamber .

The retort chamber access door may be used to insert the retort into the vacuum chamber along the longitudinal axis . For maintenance purposes , the retort may again be removed from the vacuum chamber through the retort chamber access door . In some embodiments , the retort may be removed from the vacuum chamber through the retort chamber access door for collecting the puri fied material from the condensation chamber . This may particularly be advantageous for a solid-phase-collection distillation process where the puri fied material solidi fies in the condensation chamber .

In some embodiments , the retort chamber access door is arranged at an axial side wall of the retort chamber facing the refill opening of the retort .

By arranging the retort chamber access door at an axial side wall facing the refill opening of the retort , feeding of the retort with raw material can be facilitated .

In some embodiments , the retort chamber comprises a retort chamber refill door arranged at an upper portion of a lateral wall of the retort chamber and flush with the re fill opening of the retort . This may therefore be particularly suitable for a refill opening arranged at an upper portion o f a lateral wall of the evaporation chamber .

In some embodiments , an access door cooler is arranged at the retort chamber access door .

By providing an access door cooler, the temperature at the retort chamber access door can be maintained at a temperature where sealing elements and/or gaskets of the retort chamber access door remain reliable and durable .

In some embodiments , one or more heat shields are arranged between the retort and the retort chamber access door . In some embodiments , one or more heat shields are arranged at the retort chamber access door .

The one or more heat shields may have the ef fect of passively maintaining the temperature at the retort chamber access door at a temperature where sealing elements and/or gaskets of the retort chamber access door remain reliable and durable . Further, the one or more heat shields may advantageously contribute to thermally insulating the retort chamber .

In some embodiments , an insulation plate is arranged within the retort chamber and adj acent to an axial side wall of the condensation chamber .

By arranging the insulation plate adj acent to an axial side wall of the condensation chamber, thermal insulation of the retort may be improved . In particular, the insulation plate may provide a thermal insulation between the retort and the extraction chamber or the conduit connecting the retort chamber and the extraction chamber, respectively . In some embodiments , the insulation plate may be arranged between an axial side wall of the condensation chamber and the retort chamber access door .

The insulation plate may comprise a bore configured to receive the extraction pipe therethrough .

Thus , the insulation plate may provide a thermal insulation for an axial side wall of the condensation chamber where the extraction pipe protrudes from. The extraction pipe may protrude through the bore of the insulation plate such that the puri fied material may pass through the insulation plate when being extracted through the extraction pipe . In some embodiments, the extraction chamber comprises a mold arranged to receive purified material, preferably magnesium, extracted through the extraction outlet.

Purified material extracted through the extraction outlet may therefore be collected in the mold where it may solidify to form a solid block of purified target material. When the mold is filled, the solid block of purified target material may be seized by removing the mold from the extraction chamber. Using a mold in the extraction chamber provides the advantage that molds with different geometries can be used.

The mold may be made of graphite.

In some embodiments, the extraction chamber comprises a mold cooler arranged at a bottom portion of the mold and configured to cool a bottom portion of the mold.

The liquid purified material may solidify in the mold by cooling of the extraction chamber. Using a mold cooler provides the advantage that the efficiency of solidification of the purified material in the mold can be increased. By arranging the mold cooler at a bottom portion of the mold, a directional solidification of the purified material starting from the bottom portion of the mold towards the upper portion of the mold can be achieved. A directional solidification of the purified material in the mold may be advantageous as occurrence of cavities in the solidified, purified material can be reduced or minimized.

In some embodiments, the extraction chamber comprises a mold heater configured to heat the mold, preferably an upper portion of the mold. Using a mold heater may provide an additional control on the solidi fication conditions in the mold . Arranging the mold heater at an upper portion of the mold may be advantageous for directional solidi fication of the puri fied material .

A mold temperature sensor and/or the mold heater may each comprise a plug and/or a socket for cabling . Using a plug and/or a socket , the mold temperature sensor and/or the mold heater can be plugged of f when the mold is extracted from the extraction chamber and plugged in when the mold is moved into the extraction chamber . The mold heater and/or the mold temperature sensor may thereby be moved together with the mold .

In some embodiments , the mold cooler may comprise a stationary cooling element arranged in the extraction chamber . The cooling element may be arranged such that the mold may thermally couple to the cooling element when inserted into the extraction chamber .

In some embodiments , the distillation device comprises an air lock connected to the extraction chamber by a gate valve .

After solidi fication of the puri fied material in the mold, the solid block of puri fied target material may be removed from the extraction chamber together with the mold by the air lock without impairing the reduced pressure inside the vacuum chamber . With the gate valve , communication between the air lock and the extraction chamber can be opened and closed . Before removing the mold with the solid puri fied material , the air lock may be evacuated by a vacuum pump connected to an evacuation port arranged at the air lock . After evacuation, the gate valve may be opened and the mold with the solid puri fied material can be moved from the extraction chamber to the air lock . After closing the gate valve again, the air lock may be flushed with air and the mold with the solid puri fied material may be removed from the air lock through an air lock access door . The empty mold may then be moved back into the extraction chamber by evacuating the air lock, opening the gate valve after evacuation and moving the empty mold into the extraction chamber .

In some embodiments , the distillation device comprises one or more manipulators configured to move the mold between the extraction chamber and the air lock .

In particular, the manipulators may be configured to move the mold between the extraction chamber and the air lock under reduced pressure . The manipulators may advantageously be accessible from outside of the vacuum chamber .

In some embodiments , the vacuum chamber comprises a feedthrough for receiving cabling, preferably one or more of temperature sensor cabling, heater cabling, cooler cabling, therethrough .

The feedthrough may be arranged at the extraction chamber . This may be advantageous , in particular for the sealing of the feedthrough, due to the lower temperatures prevailing at the extraction chamber compared to the retort chamber . Cabling fed through the feedthrough may comprise one or more of cabling for a temperature sensor for the evaporation chamber, for a temperature sensor for the condensation chamber, for a temperature sensor for the extraction outlet , for a temperature sensor for the thermal valve , for a temperature sensor for the refill opening of the retort , for a temperature sensor for the mold, for a heater and/or cooler of the mold etc . In some embodiments , a first temperature sensor is arranged at an outer face of the evaporation chamber, preferably at a bottom portion of the evaporation chamber, and a second temperature sensor is arranged at an outer face of the condensation chamber, preferably at a bottom portion of the condensation chamber .

The first temperature sensor may be used to determine the temperature of the evaporation chamber in order to ensure that the raw material can be evaporated . The second temperature sensor may be used to determine the temperature in the condensation chamber in order to ensure that solidi fication of the puri fied material in the condensation chamber can be avoided during the distillation process running .

In some embodiments , the first temperature sensor and/or the second temperature sensor is arranged at an outer face of the vacuum chamber .

Arranging the first temperature sensor and/or the second temperature sensor at an outer face of the vacuum chamber provides the advantage that feedthrough of cabling of the first and/or second temperature sensor into the vacuum chamber can be avoided .

In some embodiments , the distillation device comprises one or more secondary separation walls sequentially arranged in the condensation chamber and spaced from the separation wall and/or from each other so as to form two or more secondary distillation chambers , wherein the one or more secondary separation walls are arranged such that one or more secondary communication apertures are formed at an upper portion of the retort . By providing one or more secondary separation walls , fractional distillation may be achieved by the distillation device , as multiple sequential evaporation and condensation of the material to be puri fied can occur by way of the two or more secondary distillation chambers . A temperature gradient may prevail across the two or more secondary distillation chambers , in particular, with the temperature decreasing from the evaporation chamber across the condensation chamber . The secondary separation walls may be shaped in a same or analogous fashion, respectively, as the separation wall . By providing fractional distillation, elements of higher equilibrium vapor pressure than magnesium, such as zinc or cadmium may be removed, and the purity of the puri fied magnesium may further be increased .

In some embodiments , the one or more secondary separation walls each comprise an interior space .

By providing an interior space in the one or more secondary separation walls , the thermal insulation by the one or more secondary separation walls may be improved .

In particular, the interior space of the one or more secondary separation walls may be hollow or filled with a thermally insulating material .

In some embodiments , the distillation device comprises one or more inverted separation walls arranged such that one or more inverted communication apertures are formed at a bottom portion of the retort , wherein the one or more inverted separation walls and the one or more secondary separation walls are arranged in an alternating fashion . By providing one or more inverted separation walls , vapor or liquid of the material to be puri fied may be allowed to pass at a lower portion of the retort through the inverted communication apertures , in addition to the passage at the upper portion of the retort through the one or more secondary communication apertures provided by the one or more secondary separation walls . Thereby, the path that the vapor or liquid of the material to be puri fied may be increased such that the multiple condensation and evaporation may be promoted .

In some embodiments , the separation wall comprises an interior space .

By providing an interior space in the separation wall , the thermal insulation by the separation wall may be improved .

In particular, the interior space of the separation wall may be hollow or filled with a thermally insulating material .

In some embodiments , the distillation device comprises a thermal insulation j acket covering at least partial ly a lateral outer face and an axial side wall of the retort chamber .

By providing the thermal insulation j acket , thermal insulation of the retort chamber and advantageously the retort , can be improved . In particular, ef ficiency of heating the evaporation chamber and/or the condensation chamber can be increased by providing the thermal insulation j acket .

In some embodiments , the thermal insulation j acket comprises one or more access doors . In particular, the thermal insulation j acket may comprise a j acket access door arranged at an upper portion of a lateral wall of the thermal insulation j acket . For an embodiment with a refill opening arranged at an upper portion of a lateral wall of the retort and a retort chamber refill door arranged at an upper portion of a lateral wall of the retort chamber, the j acket access door may be arranged flush with the retort chamber refill door and the refill opening .

In some embodiments , the distillation device comprises a first heater arranged at an outer face of the vacuum chamber and in the region of the evaporation chamber, and a second heater arranged at an outer face of the vacuum chamber and in the region of the condensation chamber .

Arranging the first heater and the second heater at an outer face of the vacuum chamber provides the advantage that feedthrough of cabling of the first heater and the second heater into the vacuum chamber can be avoided . In some embodiments , however, the first heater and/or the second heater may be arranged at an outer face of the retort , between the vacuum chamber and the retort .

By providing the first heater in the region of or at , respectively, the evaporation chamber, the evaporation chamber may be heated to or above a temperature at which the material to be puri fied transitions from the liquid phase to the gaseous phase . , thereby forming a first heat zone . By providing the second heater in the region of or at , respectively, the condensation chamber, the condensation chamber may be heated to or above a temperature at which the puri f ied material transitions from the solid phase to the liquid phase , thereby forming a second heat zone .

In particular, using the first heater and the second heater, the temperature of the first heat zone can be controlled to be higher than the temperature of the second heat zone , such that a temperature gradient can be created .

In some embodiments , the distillation device comprises an extraction chamber cooler arranged at the extraction chamber .

By providing the extraction chamber cooler, the extracted puri fied material conveyed into the extraction chamber may be cooled . In particular, the extraction chamber may be cooled to a temperature around or below the melting point of the puri fied material such that a solidi fication of the puri fied material may occur in the extraction chamber .

In some embodiments , the retort is made of at least one of : molybdenum or a molybdenum alloy, niobium or a niobium alloy, tantalum or a tantalum alloy, graphite . In particular, the retort may be made of a metallic material or composite which is not soluble in liquid magnesium .

In some embodiments , the retort has a length of between 150 cm and 300 cm and a height of between 20 cm and 40 cm .

According to a further aspect , the present invention is also directed to a method of producing puri fied material , preferably puri fied metal , particularly preferably puri fied magnesium, by vacuum distillation, comprising the steps of : Providing a distillation device according to the present disclosure ; feeding the evaporation chamber with raw material to be puri fied; evacuating the vacuum chamber containing the retort ; heating the evaporation chamber with a first heater to or above a temperature at which the material to be puri fied transitions from the liquid phase to the gaseous phase ; heating the condensation chamber with a second heater to or above a temperature at which the material transitions from the solid phase to the liquid phase ; extracting the puri fied material from the condensation chamber .

According to a further aspect , the present invention is also directed to a retort for producing puri fied material , preferably puri fied metal , particularly preferably puri fied magnesium, by vacuum distillation, the retort being elongated along a hori zontal axis and comprising a separation wall arranged in the retort , an evaporation chamber adj acent to a first side of the separation wall and a condensation chamber adj acent to a second side of the separation wall , wherein the separation wall is arranged such that a communication aperture fluidically connecting the evaporation chamber and the condensation chamber is formed at an upper portion of the retort .

Brief description of the drawings

The present invention will be explained in more detail , by way of exemplary embodiments , with reference to the schematic drawings , in which :

Fig . l shows a side cut view of an embodiment of a distillation device with the refill opening arranged at an axial side wall of the condensation chamber ;

Fig . 2 shows a side cut view of an embodiment of a distillation device with the refill opening arranged at an axial side wall of the evaporation chamber ; Fig . 3 shows a side cut view of an embodiment of a distillation device with the refill opening arranged at an upper portion of a lateral wall of the evaporation chamber ;

Fig . 4 shows a side cut view of an embodiment of a distillation device where the extraction valve of the extraction outlet is a piston valve ;

Fig . 5 shows a side cut view of an embodiment of a distillation device where the lid of the refill opening is configured to close the refill opening by a press- fit connection;

Fig . 6 shows a side cut view of an embodiment of a distillation device with a plurality of sequentially arranged secondary separation walls ;

Fig . 7 shows a side cut view of an embodiment of a distillation device where the separation wall comprises an interior space ;

Fig . 8 shows a side cut view of an embodiment of a distillation device with a pressure-exerting piston configured to exert a force onto the lid such that the refill opening is closed by a press- fit connection, wherein the pressure-exerting piston is configured that the vacuum chamber can be evacuated through the pressure-exerting piston . Detailed description of exemplary embodiments

Figure 1 shows an embodiment of a distillation device 10 . 1 comprising a retort 1 elongated along a hori zontal axis L . The retort 1 comprises a vertical separation wall 11 separating the retort 1 into an evaporation chamber 12 adj acent to a first side of the separation wall 11 and a condensation chamber 13 adj acent to a second side of the separation wall 12 . The retort 1 and the separation wall 11 are made of molybdenum or a molybdenum alloy, niobium or a niobium alloy, tantalum or a tantalum alloy, or graphite . The separation wall 11 is arranged in the retort 1 such that a communication aperture 14 is formed at an upper portion of the retort 1 fluidically connecting the evaporation chamber 12 and the condensation chamber 13 . The retort 1 has a tubular shape with a circular cross-section . In other embodiments , the retort may have a tubular shape with a polygonal , in particular rectangular or triangular, crosssection . The separation wall 11 covers more than hal f of the cross-section of the retort 1 . The communication aperture 14 is transversely bordered at the lower portion by an upper edge of the separation wall 11 and at the upper portion by the lateral side wall of the retort 1 and has a shape of a circular segment . The separation wall 11 is welded onto the lateral side wall of the retort 1 . Alternatively, the separation wall and the lateral side wall of the retort may be formed from a monolithic piece of material . The separation wall 11 is arranged under a rectangular angle with respect to the lateral side wall of the retort 1 .

The retort 1 comprises a refill opening 15 arranged at an axial side wall of the condensation chamber 13 opposite to the separation wall 11 . Raw material Ml , such as magnesium, is arranged in the evaporation chamber 12 after being fed into the retort 1 through the refill opening 15 . Feeding of the evaporation chamber 12 is executed by inserting a guiding tube (not shown in Figure 1 ) through the refill opening 15 in a fashion that the guiding tube bridges the condensation chamber 13 and the separation wall 11 . In order to facilitate feeding, the refill opening 15 is flush with the communication aperture 14 . The retort 1 further comprises a lid 151 configured to sealingly close the refill opening 15 . The lid 151 is configured to close the refill opening 15 by a screw connection . Although not visible in Figure 1 , a sealing element in the form of a gasket is arranged between the lid 151 and the refill opening 15 . Such a sealing element may also be arranged between the lid and the refill opening for the embodiments shown in Figures 2- 8 .

The retort 1 comprises an extraction outlet 16 arranged at the lower portion of the condensation chamber 13 . The extraction outlet 16 is configured to extract from the condensation chamber 13 puri fied material M2 which has condensed in the condensation chamber M2 . The extraction outlet 16 comprises an extraction pipe 161 protruding from the axial side wall of the condensation chamber 13 opposite to the separation wall 11 . The extraction pipe 161 comprises an extraction aperture 1611 at a lower face of the extraction pipe 161 . The extraction outlet 16 comprises an extraction valve configured as a thermal valve 162 with a valve heater 1621 wound around the extraction pipe 161 . The puri fied material M2 may therefore solidi fy or liqui fy within the extraction pipe 161 , depending on the temperature at the extraction pipe 161 as controlled by the valve heater 1621 . The extraction pipe 161 and the valve heater 1621 are thus ef fectively components of the thermal valve 162 .

The evaporation chamber 12 is larger than the condensation chamber 13 , such that a large amount of raw material Ml can be fed into the evaporation chamber 12 , increasing the period of an operation cycle of the distillation device 10 . 1 .

The distillation device 10 . 1 comprises a vacuum chamber 2 formed by a housing, with a retort chamber 21 in which the retort 1 is arranged, and an extraction chamber 22 arranged below the retort chamber 21 , and a conduit 23 which connects the retort chamber 21 and the extraction chamber 22 . The conduit 23 is arranged below the extraction aperture 1611 of the extraction pipe 161 such that the puri fied material M2 may fall into the extraction chamber 22 through the conduit 23 , when extracted from the condensation chamber 13 .

The retort chamber 21 comprises a retort chamber access door 211 arranged at an axial side wall of the retort chamber 21 facing the refill opening 15 of the retort 1 . Since the refill opening 15 of the retort 1 is arranged at the condensation chamber 13 , the retort chamber access door 211 is arranged at a side of the retort chamber 21 facing the condensation chamber 13 . The retort 1 may be inserted into the vacuum chamber 2 through the retort chamber access door 211 . A plurality of heat shields 212 are mounted at the retort chamber access door 211 . Further, an access door cooler 213 is arranged at the retort chamber access door 211 . The retort chamber access door 211 is configured to sealingly close the retort chamber 21 .

The extraction chamber 22 comprises a port 25 configured for connection with a vacuum pump such that the vacuum chamber 2 can be evacuated through the port 25 . When evacuating the vacuum chamber 2 , the retort 1 can be evacuated through the extraction outlet 16 . Therefor, the thermal valve 162 is opened, that is the thermal valve 162 is controlled such that the extraction pipe 161 is not blocked by solidi fied material .

An insulation plate 31 is arranged within the retort chamber

21 and adj acent to the axial side wall of the condensation chamber 13 opposite to the separation wall 11 , improving thermal insulation for the retort 1 . The insulation plate 31 comprises a bore through which the extraction pipe 161 protrudes . The insulation plate 31 may be inserted into the vacuum chamber 2 through the retort chamber access door 211 after the retort 1 has been inserted into the retort chamber 21 .

A first heater 121 is arranged at the outer face of the vacuum chamber 2 and in the region of the evaporation chamber 12 , thereby creating a first heat zone . A second heater 131 is arranged at the outer face of the vacuum chamber 2 and in the region of the condensation chamber 13 , thereby creating a second heat zone of lower temperature than the first heat zone . An extraction chamber cooler 221 is arranged at the extraction chamber 22 .

A mold 4 made of graphite is arranged in the extraction chamber

22 below the conduit 23 such that puri fied material M2 that has been extracted from the condensation chamber 13 may fall through the conduit 23 into the mold 4 . A mold cooler 41 is arranged at a bottom portion of the mold 4 and a mold heater 42 is arranged at an upper portion of the mold 4 . Using the mold cooler 41 and the mold heater 42 , a directional solidi fication of the puri fied material in the mold 4 from the bottom portion to the upper portion can be achieved .

An air lock 5 is connected to the extraction chamber by a gate valve 51 . By opening the gate valve 51 , the mold 4 can be moved from the extraction chamber 22 into the air lock 5 . The air lock 5 comprises a port 52 through which the air lock 5 can be evacuated and vented . A mold 4 in the air lock 5 can be removed through an air lock access door 53 . The mold 4 is positioned on a manipulator in the form of a movable tray 43 . By moving the tray 43 , the mold 4 may be trans ferred from the extraction chamber 22 to the air lock 5 and back .

The distillation device 10 . 1 comprises a first temperature sensor arranged at an outer face and a bottom portion of the evaporation chamber 12 and a second temperature sensor arranged at an outer face and a bottom portion of the condensation chamber 13 . The distillation device 10 . 1 further comprises a refill opening temperature sensor arranged at the refill opening 15 and a thermal valve temperature sensor arranged at the thermal valve 162 . A mold temperature sensor is arranged at the mold 4 . For better visibility, the temperature sensors shall be shown in the embodiment o f the distillation device in Figure 2 comprising a corresponding arrangement of the temperature sensors . The extraction chamber 22 comprises a feedthrough 24 configured to receive cabling for temperature sensors , in particular the first and second temperature sensors , refill opening temperature sensor, mold temperature sensor, mold heater and the thermal valve temperature sensor therethrough . The feedthrough 24 may further be configured to receive tubes or conduits for cooling medium used by the mold cooler . The distillation device 10.1 comprises a thermal insulation jacket 3 at least partially covering a lateral outer face of the retort chamber 21 and the axial side wall of the retort chamber 21 facing the evaporation chamber 12. The thermal insulation jacket 3 comprises a lateral opening where the conduit 23 passes through and an axial opening at the retort chamber access door 211 such that the retort chamber access door 211 can be opened and closed. Between the first heater 121 and the second heater 131, the thermal insulation jacket 3 comprises a circumferential protrusion 32 abutting the vacuum chamber 2. Next to both axial sides of the protrusion 32, the thermal insulation jacket 3 is undercut, thereby providing a space for receiving the first heater 121 and the second heater 131, respectively.

Figure 2 shows a side cut view of an embodiment of a distillation device 10.2 with the refill opening 15.2 and the lid 151.2 arranged at an axial side wall of the evaporation chamber 12.2 opposite to the separation wall 11.2. Further, the retort chamber access door 211.2 is arranged at an axial side wall of the retort chamber 21.2 facing the refill opening 15.2 of the retort 1.2. Compared to the embodiment of Figure 1, however, the retort chamber access door 211.2 is arranged on the side of the retort chamber 21.2 facing the evaporation chamber 12.2 since the refill opening 15.2 is arranged at the evaporation chamber 12.2. Due to the arrangement of the refill opening 15.2 at the evaporation chamber 12.2, the distillation device 10.2 is in principle suitable for continuous supply of raw material into the evaporation chamber 12.2 and thus a continuous purification. For a continuous operation of the distillation device 10.2, the retort chamber access door 211.2 may be modified to comprise a feedthrough for a supply tube for supplying raw material into the evaporation chamber 12.2.

The thermal insulation jacket 3 covers the axial side wall of the retort chamber 21.2 facing the condensation chamber 13.2 and has an axial opening at the side of the evaporation chamber

12.2. The retort 1.2 is inserted into the vacuum chamber 2.2 or the retort chamber 21.2, respectively, through the retort chamber access door 211.2. Before inserting the retort 1.2 into the retort chamber 21.2, the insulation plate 31.2 may be slid over the extraction pipe 161.2 and inserted together with the retort 1.2 into the retort chamber 21.2.

The distillation device 10.2 comprises a first temperature sensor 61.2 arranged at an outer face and a bottom portion of the evaporation chamber 12.2 and a second temperature sensor

62.2 arranged at an outer face and a bottom portion of the condensation chamber 13.2. The distillation device 10.2 further comprises a refill opening temperature sensor 63.2 arranged at the refill opening 15.2 and a thermal valve temperature sensor 64.2 arranged at the thermal valve 162.2. A mold temperature sensor 65.2 is arranged at the mold 4.2. As mentioned above, the temperature sensors 61.2, 62.2, 63.2,

64.2, 65.2 may correspondingly be arranged at the distillation device 10.1 shown in Figure 1. Accordingly, temperature sensors may be arranged in the embodiments described in connection with the further Figures, although not explicitly shown. The cabling for the temperature sensors 61.2, 62.2, 63.2, 64.2,

65.2 are fed through the feedthrough 24.2 of the extraction chamber 22.2. Figure 3 shows a side cut view of an embodiment of a distillation device 10.3 with the refill opening 15.3 arranged at an upper portion of the lateral wall of the evaporation chamber 12.3. A lid 151.3 is configured to sealingly close the refill opening 15.3 in a horizontal orientation. In addition to the retort chamber access door 211.3 arranged at an axial side wall of the retort chamber 21.3, the retort chamber 21.3 comprises a retort chamber refill door 214.3 arranged at an upper portion of a lateral wall of the retort chamber 21.3. The retort chamber refill door 214.3 is arranged flush with the refill opening 15.3. The thermal insulation jacket 3.3 comprises at an upper portion of a lateral wall a jacket access door 33.3 which is arranged flush with the retort chamber refill door 214.3. The raw material to be purified may therefore be fed from above into the evaporation chamber 12.3 by opening the jacket access door 33.3, the retort chamber refill door 214.3 and the lid 151.3.

Figure 3 further shows the thermal valve 162.3 being controlled by the valve heater 1621.3 to a temperature where the purified material in the extraction pipe 161.3 solidifies. In addition to the valve heater 1621.3, a valve cooler may be used in order to increase the efficiency of lowering the temperature of the thermal valve 162.3. Therefore, a solid block M2' of purified material is formed in the extraction pipe 161.3 which blocks the extraction outlet 16.3.

Figure 4 shows a side cut view of an embodiment of a distillation device 10.4 which largely corresponds to the distillation device 10.1. However, the extraction valve of the extraction outlet 16.4 is a piston valve 163.4. The piston valve 163.4 comprises a piston 1631.4 which is slidably movable in the extraction pipe 161.4. In particular, the piston 1631.4 may be moved in the extraction pipe 161.4 into a position where the piston 1631.4 closes the extraction aperture 1611.4 such that the extraction outlet 16.4 is blocked. The piston valve

163.4 comprises a control disk 1632.4 slidably arranged in a cylinder 1633.4 which is arranged outside of the retort chamber

21.4 next to the retort chamber access door 211.4. By moving the piston 1631.4, the extraction aperture 1611.4 may be opened and the extraction outlet 16.4 unblocked, such that the purified material may be extracted from the condensation chamber 13.4. The piston 1631.4 is for example moved pneumatically or by an electric motor. In Figure 4, a valve heater 1621.4 is shown at the extraction pipe 161.4 for controlling the temperature at the extraction pipe 161.4. However, the valve heater 1621.4 may also be omitted due to the piston valve 163.4 controlling the opening and closing of the extraction outlet 16.4.

Figure 5 a side cut view of an embodiment of a distillation device 10.5 where the lid 151.5 of the refill opening 15.5 is configured to close the refill opening 15.5 by a press-fit connection. The press-fit connection is achieved by a pressureexerting device 152.5. The pressure-exerting device 152.5 comprises an axially movable pressure-exerting piston 1521.5 exerting a force onto the lid 151.5 in order to close and seal the refill opening 15.5. The pressure-exerting device 152.5 comprises a control disk 1522.5 slidably arranged in a cylinder 1523.5. The cylinder 1523.5 is arranged outside of the retort chamber 21.5 next to the retort chamber access door 211.5. The insulation plate 31.5 comprises besides the bore for the extraction pipe 161.5 an additional bore configured to receive therethrough the pressure-exerting piston 1521.5.

Figure 6 shows a side cut view of an embodiment of a distillation device 10.6 with a plurality of sequentially arranged secondary separation walls 111.6. The plurality of secondary separation walls 111.6 are sequentially arranged in the condensation chamber 13.6 next to the separation wall 11.6. Due to the arrangement of the plurality of secondary separation walls 111.6, a plurality of secondary distillation chambers 1213.6 are formed between the separation wall 11.6 and one of the secondary separation walls 111.6 adjacent to the separation wall 11.6 and between neighboring secondary separation walls

111.6. Furthermore, the secondary separation walls 111.6 are arranged such that a plurality of secondary communication apertures 141.6 are formed at an upper portion of the retort

1.6.

The distillation device 10.6 further comprises a plurality of inverted separation walls 112.6 arranged in an alternating fashion with the secondary separation walls 111.6. The inverted separation walls 112.6 are arranged such that a plurality of inverted communication apertures 142.6 are formed at a bottom portion of the retort 1.6.

Due to the arrangement of the plurality of the secondary separation walls 111.6 and the plurality of inverted separation walls 112.6, the refill opening 15.6 of the retort 1.6 is arranged at an axial side wall of the evaporation chamber 12.6 opposite to the separation wall 11.6.

Figure 7 shows a side cut view of an embodiment of a distillation device 10.7 where the separation wall 11.7 comprises an interior space 113.7. The interior space 113.7 is hollow and communicates with the retort chamber 21.7. Thus, when the retort chamber 21.7 is evacuated, the interior space 113.7 is also evacuated, thereby improving thermal insulation of the separation wall 11.7.

Figure 8 shows a side cut view of an embodiment of a distillation device 10.8 with a pressure-exerting piston 1521.8 configured to exert a force onto the lid 151.8 such that the refill opening 15.8 is closed by a press-fit connection, similar to the distillation device 10.5 shown in Figure 5. However, the pressure-exerting piston 1521.8 comprises a conduit 1524.8 with a first conduit aperture 1525.8 arranged in the retort chamber 21.8 and a second conduit aperture 1526.8 arranged outside of the vacuum chamber 2.8. Thus, the conduit 1524.8 establishes a communication between the interior of the vacuum chamber 2.8 and the exterior of the vacuum chamber 2.8. Using the conduit 1524.8 and the first conduit aperture 1525.8 and the second conduit aperture 1526.8, the vacuum chamber 2.8 can be evacuated by connecting a vacuum pump to the second conduit aperture 1526.8. Therefore, evacuation ports at the extraction chamber 22.8 can be omitted.

Claims

1. A distillation device (10.1-10.8) for producing purified metal (M2) , preferably purified magnesium, by vacuum distillation, comprising a vacuum chamber (2, 2.2, 2.8) and a retort (1, 1.2, 1.6) elongated along a horizontal axis (L) and arranged within the vacuum chamber, the retort comprising a separation wall (11, 11.2, 11.6, 11.7) arranged in the retort, an evaporation chamber (12, 12.2, 12.3, 12.6) adjacent to a first side of the separation wall and a condensation chamber (13, 13.2, 13.4, 13.6) adjacent to a second side of the separation wall, wherein the separation wall is arranged such that a communication aperture (14, 14.6) fluidically connecting the evaporation chamber and the condensation chamber is formed at an upper portion of the retort.

2. The distillation device according to claim 1, wherein the separation wall covers half or more than half of the transverse cross-section of the retort.

3. The distillation device (10.1-10.8) according to claim 1 or 2, wherein the retort (1, 1.2, 1.6) comprises a refill opening (15, 15.2, 15.3, 15.5, 15.6, 15.8) arranged at an axial side wall of the condensation chamber (13, 13.4) opposite to the separation wall (11) and/or at an axial side wall of the evaporation chamber (12.2, 12.6) opposite to the separation wall (11.2, 11.6) and/or at an upper portion of a lateral wall of the evaporation chamber (12.3) . The distillation device according to claim 3, wherein the refill opening is flush with the communication aperture. The distillation device (1 0.1-10.8) according to claim 3 or 4, wherein the retort (1, 1.2, 1.6) comprises a lid (151, 151.2, 151.3, 151.5, 151.8) configured to sealingly close the refill opening (15, 15.2, 15.3, 15.5, 15.6, 15.8) . The distillation device (10.1-10.8) according to claim 5, wherein a sealing element is arranged between the lid (151, 151.2, 151.3, 151.5, 151.8) and the refill opening (15, 15.2, 15.3, 15.5, 15.6, 15.8) , wherein the sealing element is preferably made of graphite. The distillation device (10.1-10.8) according to claim 5 or 6, wherein the lid (151, 151.2, 151.3, 151.5, 151.8) is configured to close the refill opening (15, 15.2, 15.3, 15.5, 15.6, 15.8) by a screw connection or a press-fit connection . The distillation device (10.2) according to one of the claims 3 to 7, wherein a refill opening temperature sensor (63.2) is arranged at the refill opening (15.2) . The distillation device (10.1-10.8) according to one of the preceding claims, wherein the retort (1, 1.2, 1.6) comprises an extraction outlet (16, 16.3, 16.4) , arranged at a lower portion of the condensation chamber (13, 13.2, 13.4, 13.6) and configured to extract purified material (M2) , preferably purified magnesium, from the condensation chamber. The distillation device (10.1-10.8) according to claim 9, wherein the extraction outlet (16, 16.3, 16.4) comprises a horizontal extraction pipe (161, 161.2-161.5) protruding from an axial side wall of the condensation chamber (13, 13.2, 13.4, 13.6) , wherein the extraction pipe preferably comprises an extraction aperture (1611, 1611.4) at a lower face of the extraction pipe. The distillation device according to claim 10, wherein the extraction pipe comprises an extraction aperture at a lower face of the extraction pipe. The distillation device (10.1-10.8) according to one of the claims 9 to 11, wherein the extraction outlet (16,

16.3, 16.4) comprises an extraction valve (162, 162.2,

162.3, 163.4) configured to regulate the fluid flow of material through the extraction outlet. The distillation device (10.1-10.3, 10.5-10.8) according to claim 12, wherein the extraction valve is a thermal valve (162, 162.2, 162.3) with a valve heater (1621,

1621.3) configured to heat the extraction outlet (16,

16.3) to a temperature above the melting point of a material (M2) in the condensation chamber (13, 13.2) , preferably of magnesium. The distillation device according to claim 13, wherein the thermal valve comprises a valve cooler configured to cool the extraction outlet to a temperature below the melting point of a material in the condensation chamber, preferably of magnesium. The distillation device (10.2) according to claim 13 or

14, wherein a thermal valve temperature sensor (64.2) is arranged at the thermal valve (162.2) . The distillation device (10.4) according to claim 12, wherein the extraction valve is a piston valve (163.4) . The distillation device (10.1-10.8) according to one of the preceding claims, wherein the retort (1, 1.2, 1.6) has a tubular shape, preferably with a circular or polygonal, in particular rectangular or triangular, cross-section . The distillation device (10.1-10.8) according to one of the preceding claims, wherein the evaporation chamber (12, 12.2, 12.3, 12.6) is larger than the condensation chamber (13, 13.2, 13.4, 13.6) . The distillation device according to claim 18, wherein the evaporation chamber is at least five times, ten times, or fifteen times larger than the condensation chamber. The distillation device (10.1-10.8) according to one of the preceding claims, wherein the vacuum chamber (2, 2.2,

2.8) comprises a retort chamber (21, 21.2-21.5, 21.7,

21.8) in which the retort (1, 1.2, 1.6) is arranged, an extraction chamber (22, 22.2, 22.8) arranged below the retort chamber, and a conduit (23) connecting the retort chamber and the extraction chamber, wherein the conduit is arranged below the extraction outlet (16, 16.3, 16.4) . The distillation device (10.1-10.7) according to claim 20, wherein the extraction chamber (22, 22.2) comprises one or more ports (25) configured for connection with a vacuum pump . The distillation device (10.1-10.8) according to claim 20 or 21, wherein the retort chamber (21, 21.2-21.5, 21.7, 21.8) comprises a retort chamber access door (211, 211.2-

211.5) arranged at an axial side wall of the retort chamber . The distillation device (10.1, 10.2, 10.4-10.8) according to claim 22, wherein the retort chamber access door (211, 211.2, 211.4, 211.5) is arranged at an axial side wall of the retort chamber (21, 21.2, 21.4, 21.5, 21.7, 21.8) facing the refill opening (15, 15.2, 15.5, 15.6, 15.8) of the retort (1, 1.2, 1.6) . The distillation device (10.3) according to claim 22, wherein the retort chamber (21.3) comprises a retort chamber refill door (214.3) arranged at an upper portion of a lateral wall of the retort chamber and flush with the refill opening (15.3) of the retort. The distillation device (10.1-10.8) according to one of the claims 22 to 24, wherein an access door cooler (213) is arranged at the retort chamber access door (211, 211.2-

211.5) . The distillation device (10.1-10.8) according to claim 22 to 25, wherein one or more heat shields (212) are arranged between the retort (1, 1.2, 1.6) and the retort chamber access door (211, 211.2-211.5) . The distillation device (10.1-10.8) according to one of the claims 20 to 26, wherein an insulation plate (31,

31.2, 31.5) is arranged within the retort chamber (21, 21.2-21.5, 21.7, 21.8) and adjacent to an axial side wall of the condensation chamber (13, 13.2, 13.4, 13.6) . The distillation device according to claim 27 and 10, wherein the insulation plate comprises a bore configured to receive the extraction pipe therethrough. The distillation device (10.1-10.8) according to one of the claims 20 to 28, wherein the extraction chamber (22, 22.2, 22.8) comprises a mold (4, 4.2) arranged to receive purified material, preferably purified magnesium, extracted through the extraction outlet (16, 16.3, 16.4) . The distillation device (10.1-10.8) according to claim

29, wherein the extraction chamber (22, 22.2, 22.8) comprises a mold cooler (41) arranged at a bottom portion of the mold (4, 4.2) and configured to cool a bottom portion of the mold. The distillation device (10.1-10.8) according to claim 29 or 30, wherein the extraction chamber (22, 22.2, 22.8) comprises a mold heater (42) configured to heat the mold (4, 4.2) , preferably an upper portion of the mold. The distillation device (10.1-10.8) according to one of the claims 20 to 31, comprising an air lock (5) connected to the extraction chamber (22) by a gate valve (51) . The distillation device (10.1-10.8) according to claim 29 and claim 32, comprising one or more manipulators (43) configured to move the mold (4, 4.2) between the extraction chamber (22, 22.2, 22.8) and the air lock (5) . The distillation device (10.1-10.8) according to one of the preceding claims, wherein the vacuum chamber (2, 2.2, 2.8) comprises a feedthrough (24, 24.2) for receiving cabling, in particular temperature sensor cabling, therethrough . The distillation device (10.2) according to one of the preceding claims, wherein a first temperature sensor

(61.2) is arranged at an outer face of the evaporation chamber (12.2) , preferably at a bottom portion of the evaporation chamber, and a second temperature sensor

(62.2) is arranged at an outer face of the condensation chamber (13.2) , preferably at a bottom portion of the condensation chamber. The distillation device according to claim 35, wherein the first temperature sensor and/or the second temperature sensor is arranged at an outer face of the vacuum chamber. The distillation device (10.6) according to one of the preceding claims, comprising one or more secondary separation walls (111.6) sequentially arranged in the condensation chamber (13.6) and spaced from the separation wall (11.6) and/or from each other so as to form two or more secondary distillation chambers (1213.6) , wherein the one or more secondary separation walls are arranged such that one or more secondary communication apertures (141.6) are formed at an upper portion of the retort (1.6) . The distillation device according to claim 37, wherein the one or more secondary separation walls each comprise an interior space, wherein the interior space of the one or more secondary separation walls is preferably hollow or filled with a thermally insulating material. The distillation device (10.6) according to claim 37 or 38, comprising one or more inverted separation walls (112.6) arranged such that one or more inverted communication apertures (142.6) are formed at a bottom portion of the retort (1.6) , wherein the one or more inverted separation walls and the one or more secondary separation walls are arranged in an alternating fashion. The distillation device (10.7) according to one of the preceding claims, wherein the separation wall (11.7) comprises an interior space (113.7) , wherein the interior space is preferably hollow or filled with a thermally insulating material. The distillation device (10.1-10.8) according to one of the preceding claims and claim 20, comprising a thermal insulation jacket (3, 3.2, 3.3) covering at least partially a lateral outer face and an axial side wall of the retort chamber (21, 21.2-21.5, 21.7, 21.8) . The distillation device (10.1-10.8) according to one of the preceding claims, comprising a first heater (121) arranged at an outer face of the vacuum chamber (2, 2.2, 2.8) and in the region of the evaporation chamber (12, 12.2, 12.3, 12.6) , and a second heater (131) arranged at an outer face of the vacuum chamber and in the region of the condensation chamber (13, 13.2, 13.4, 13.6) . The distillation device (10.1-10.8) according to one of the preceding claims and claim 20, comprising an extraction chamber cooler (221) arranged at the extraction chamber. The distillation device (10.1-10.8) according to one of the preceding claims, wherein the retort (1, 1.2, 1.6) is made of at least one of: Molybdenum or a Molybdenum alloy, Niobium or a Niobium alloy, Tantalum or a Tantalum alloy, graphite . The distillation device according to one of the preceding claims, wherein the retort has a length of between 150 cm and 300 cm and a height of between 20 cm and 40 cm. A method of producing purified metal, preferably purified magnesium, by vacuum distillation, comprising the steps of :

- Providing a distillation device (10.1-10.8) according to one of the preceding claims;

- Feeding the evaporation chamber (12, 12.2, 12.3, 12.6) with raw material (Ml) to be purified;

- Evacuating the vacuum chamber (2, 2.2, 2.8) containing the retort (1, 1.2, 1.6) ;

- Heating the evaporation chamber with a first heater (121) to or above a temperature at which the material to be purified transitions from the liquid phase to the gaseous phase; - Heating the condensation chamber with a second heater (131) to or above a temperature at which the material transitions from the solid phase to the liquid phase;

- Extracting the purified material (M2) from the condensation chamber (13, 13.2, 13.4, 13.6) . retort (1, 1.2, 1.6) for producing purified metal, preferably purified magnesium, by vacuum distillation, the retort being elongated along a horizontal axis (L) and comprising a separation wall (11, 11.2, 11.6, 11.7) arranged in the retort, an evaporation chamber (12, 12.2,

12.3, 12.6) adjacent to a first side of the separation wall and a condensation chamber (13, 13.2, 13.4, 13.6) adjacent to a second side of the separation wall, wherein the separation wall is arranged such that a communication aperture (14, 14.6) fluidically connecting the evaporation chamber and the condensation chamber is formed at an upper portion of the retort.