Plant for producing metal anodes

Abstract

A plant for producing metal anodes, in particular for use in an electrolytic tinplate production line, the plant comprising - a melting furnace (1 ) adapted to be loaded with scrap of said metal and provided with at least one pouring duct (4) for pouring molten metal; - a carousel (2), arranged below said melting furnace (1 ) and provided with a plurality of shell molds (3) arranged radially with respect to an axis of rotation (X) of said carousel (2); wherein said carousel (2) is configured to intermittently rotate so that at each radial rotation step at least one shell mold (3) of said plurality of shell molds stops in a respective casting position (9) at the corresponding pouring duct (4), and at least one other shell mold (3) stops in an extraction position (10) for the extraction of a solidified anode; wherein, in the casting position (9), the shell molds (3) are in an inclined position, at an angle other than zero, with respect to the horizontal so that a first end (5) of the shell mold (3), proximal to the corresponding pouring duct (4), is higher than a second end (6) thereof, opposite the first end (5) and distal from said pouring duct (4); and wherein there is provided an adjustment system (7, 8) for adjusting the inclination of each shell mold (3) along at least one part of the carousel (2), said adjustment system being configured to bring each shell mold (3) from said inclined position at the respective casting position (9) to a horizontal position at the respective extraction position (10), and then back to said inclined position.

Description

[0001] PLANT FOR PRODUCING METAL ANODES

[0002] ************

[0003] Field of the invention

[0004] The present invention relates to a plant for producing metal anodes, in particular tin anodes for use in an electrolytic tinplate production line.

[0005] Background art

[0006] The refining of metals is carried out in an electrolytic cell whose anode consists of the metal to be refined, while the cathode consists of a sheet, for example made of the same metal, in its pure state.

[0007] The electrolytic bath, on the other hand, consists of a solution containing a dissolved salt of the metal to be refined.

[0008] Generally, the anode consists of a plate or ingot of the metal to be refined, preferably in the form of a parallelepiped that is cast and shaped according to the needs of the downstream electrolytic process.

[0009] After being cast into the respective shell mold, or simply casting mold, the anode is subjected to a cooling treatment until complete solidification.

[0010] Metal anode production plants are known.

[0011] In the electrolytic recovery of the high purity metal, it is known in the state of the art to introduce groups of metal anodes into electrolytic baths to be dissolved therein. Deposits are formed on the cathode as metal, obtained practically with a purity of even 99%. While impurities present in the anode material in quantities of about 20% do not constitute a particular problem, it has been found that towards the end of the electrolysis process the difference in thickness between the individual anode plates is a serious drawback. Known anode production plants are of the linear or rotary type and are provided with a plurality of shell molds arranged horizontally, which are filled one at a time with molten metal coming from a melting furnace, which in turn is fed with metal scrap even obtained from worn anodes.

[0012] Once solidified, each anode must be extracted from the respective shell mold. Disadvantageously, the arrangement of the shell molds, which are essentially flat, along a horizontal plane does not guarantee efficient filling of the casting cavity from above, particularly if the anode is to be given particular shape characteristics. An example of this arrangement is disclosed in document US1966596A. A further disadvantage is that, once the anode has solidified, the operator must manually dismantle the shell mold and extract the anode cast in it on off-line tables before said anode is put back in line for subsequent processing operations.

[0013] An attempt to overcome the aforesaid drawbacks is disclosed in document US2861303A. In this rotary anode production plant, the shell molds are always in a vertical position. Only in the casting or pouring station for casting or pouring the molten metal into the shell, said shell is tilted from the vertical position before starting to pour the molten metal into said shell from above, and then returns to the vertical position once filling is complete. During rotation of the carousel the shell molds remain in the vertical position. In the extraction station, the solidified anode is extracted from the vertical shell and pushed into a channel housing, also arranged vertically. Subsequently, this channel housing is rotated into a horizontal position and the anode is finally pushed outwards from said channel housing until it reaches a horizontal roller path.

[0014] Disadvantageously, the extraction of the solidified anode from the vertical shell mold occurs by means of a very complex mechanical system fixed to the support columns of the operators' fixed platform, about which the annular carousel provided with the shell molds rotates. Furthermore, even after extracting the shell mold, the movement of the anode until reaching the horizontal roller path is just as complex.

[0015] A further disadvantage of known solutions is represented by the fact that, during the casting of molten metal into the shell mold, the operator managing the melting furnace tries to fill the shell mold based on a marking present on the wall of the shell mold. However, also because the casting is managed manually by the operator, it is dangerous to stop the mass of molten metal while it is moving, which is also inconstant. Manual casting control can result in metal shortages in the finished anode or malformations, as the manually cast metal may not have a constant flow, as well as directly affecting the productivity of the system.

[0016] Finally, manually managing the casting by operators is also exhausting, and productivity is lower and less repeatable.

[0017] There is thus a need to create a plant for the production of anode ingots capable of overcoming the aforementioned drawbacks.

[0018] Summary of the invention An object of the present invention is to provide a plant for the production of metal anodes which is significantly simplified and which allows for greater productivity to be obtained.

[0019] A further object of the present invention is to provide a plant that allows the operator, either in a fully automated or semi-automatic manner, to easily open the shell mold and quickly extract the solidified anode directly in-line, avoiding the movement of the shell mold off-line.

[0020] Another object of the present invention is to provide a plant that allows, in an automated manner, to precisely regulate the pouring of the molten metal into the shell mold, ensuring complete filling of the casting volume, minimizing waste (sprues), avoiding spills of molten metal outside the casting machine and ensuring complete formation of the anode inside the shell.

[0021] Another object of the present invention is to provide a plant for the production of metal anodes which guarantees efficient filling of the casting cavity, even when it is desired to give the anode particular shape characteristics.

[0022] A further object of the present invention is to provide a process for the production of metal anodes that is more efficient than known processes.

[0023] The present invention achieves at least one of these objects, and other objects which will be apparent in light of the present description, by means of a plant for the production of metal anodes, in particular for a subsequent use of the anodes in an electrolytic tinplate production line, the plant comprising

[0024] - a melting furnace adapted to be loaded with scrap of said metal and provided with at least one pouring duct for pouring molten metal;

[0025] - a carousel, arranged below said melting furnace and provided with a plurality of shell molds arranged radially with respect to an axis of rotation X of said carousel; wherein said carousel is configured to intermittently rotate so that at each radial rotation step at least one shell mold of said plurality of shell molds stops in a respective casting position or station at the corresponding pouring duct, and at least one other shell mold stops in a respective extraction position or station for the extraction of a solidified anode; wherein, in the casting position, the shell molds are in an inclined position, at an angle other than zero, with respect to the horizontal so that a first end of the shell mold, proximal to the corresponding pouring duct and provided with an opening for the inlet of the molten metal, is higher than a second end thereof, opposite the first end and distal from said pouring duct; and wherein there is provided an adjustment system for adjusting the inclination of each shell mold along at least one part of the carousel during its rotation about the axis of rotation X, said adjustment system comprising a cam mechanism to bring each shell mold from said inclined position at the respective casting position to a horizontal position at said respective extraction position, and then back to said inclined position; wherein each shell mold is provided, on its structure, with actuators for opening the shell mold and extracting the solidified anode in the extraction position; and wherein, below the extraction position, in which the shell mold is in the horizontal position, there is provided a roller path, adapted to directly receive the solidified anode just extracted from the shell mold.

[0026] The invention also relates to a process for producing metal anodes, by means of the aforesaid plant, in particular for producing tin anodes for use in an electrolytic tinplate production line, the process comprising the following steps:

[0027] - loading metal scrap into the melting furnace to obtain the molten metal;

[0028] - rotating the carousel intermittently so that at each radial rotation step at least one shell mold of said plurality of shell molds stops in the respective casting position and the molten metal is cast into it by means of the corresponding pouring duct, and at least one other shell mold stops in the respective extraction position and a solidified anode is extracted; wherein there is provided an adjustment of the inclination of each shell mold along at least part of the carousel during its rotation about the axis of rotation X, by means of the adjustment system comprising said cam mechanism, bringing each shell mold from the inclined position at the respective casting position to the horizontal position at the respective extraction position, and then back to said inclined position; wherein, when each shell mold reaches the horizontal position in the respective extraction position, there are provided an opening of the shell mold, by means of the actuators provided on the structure of said shell mold, and an extraction of the respective solidified anode, which is received directly by the roller path, placed below the extraction position.

[0029] Advantageously, the combination of the horizontal position of the shell mold in the extraction station with the presence of both the actuators on the same structure of the shell and the underlying roller path, to directly receive the solidified product, allows to significantly simplify the plant and increase its productivity.

[0030] Furthermore, the automated adjustment of the inclination of each shell mold during the rotation of the carousel allows for efficient filling of the casting cavity thanks to the inclined position of the shell mold in the casting station, which is different from both the horizontal position and the vertical position.

[0031] The automatic movement of the shell mold from the inclined position to the horizontal position at the extraction position of the solidified anode allows for an easier extraction of the anode, at a horizontal roller path located below the shell mold which occupies said extraction position.

[0032] The solution of the invention can also allow for an automatic extraction of the anode, avoiding the need for operators to manually move the shell mold and the solidified anode extracted from said shell mold, dragging it along the roller path. Said solution can also possibly avoid the use of overhead cranes for lifting the shell mold and / or anode.

[0033] Further features and advantages of the invention will become more apparent in light of the detailed description of exemplary but non-exclusive embodiments.

[0034] The dependent claims describe particular embodiments of the invention.

[0035] Brief description of the drawings

[0036] The description of the invention refers to the accompanying drawings, which are provided by way of non-limiting example, in which:

[0037] Figure 1 shows a perspective view of a layout of a plant according to the invention; Figure 2 shows an enlargement of the layout of Figure 1 ;

[0038] Figure 3 shows a plan view of the carousel of said plant;

[0039] Figure 4 shows a side view of said carousel;

[0040] Figure 5 shows a first perspective view of a shell mold of said plant in a first operating position;

[0041] Figure 6 shows a second perspective view of said shell mold in said first operating position;

[0042] Figure 7 shows a perspective view of said shell mold in a second operating position; Figures 8 and 9 show perspective views of said shell mold in a third operating position;

[0043] Figures 10, 11 and 12 show perspective views of said shell mold in a fourth operating position.

[0044] The same elements or components have the same reference numerals.

[0045] Description of exemplary embodiments of the invention

[0046] With reference to the Figures, exemplary embodiments of a plant for the production of metal anodes are described, in particular tin anodes for use in a process line for producing electrolytic tinplate.

[0047] Electrolytic tinplate is a product (in the form of a strip or coil of strip) made of carbon steel coated on both faces with tin applied by electrolytic deposition.

[0048] The plant of the present invention can be used for the production of anodes made of metals other than tin, such as brass, cadmium, chromium, copper, gold, iron, nickel, silver, titanium, zinc.

[0049] In all the embodiments, the plant comprises:

[0050] - a melting furnace 1 adapted to be loaded, in a known way, with scrap, e.g., in the form of worn anodes and / or residual sprues of the same metal recovered from the downstream production process, said melting furnace being provided with at least one pouring duct 4 for pouring molten metal;

[0051] - a carousel 2, arranged below said melting furnace 1 and provided with a plurality of longitudinal shell molds 3 arranged radially with respect to an axis of rotation X of the carousel 2.

[0052] The carousel 2 is configured to intermittently rotate so that at each radial rotation step, one shell mold 3 of said plurality of shell molds stops in a respective casting position or station 9 at the at least one pouring duct 4, and another shell mold 3 stops in a respective extraction position or station 10 for the extraction of a solidified anode.

[0053] In the example of Figures 1 -4, the melting furnace 1 is provided with only one pouring duct 4, and only one casting position 9 and only one extraction position 10 are provided, whereby the carousel 2 is configured to intermittently rotate so that at each radial rotation step only one shell mold 3 stops in the casting position 9 at the pouring duct 4, and only one other shell mold 3 stops in the extraction position 10 for the extraction of a solidified anode.

[0054] The remaining shell molds are instead located between the casting position and the extraction position, as illustrated for example in Figure 2.

[0055] By way of example only, the carousel 2 can be provided with shell molds 3 in a number comprised from 6 to at least 12, preferably positioned at a same angular distance from one another, corresponding to the radial rotation pitch from one position to another.

[0056] In the example of Figure 2, ten shell molds 3 are provided.

[0057] Advantageously, in the casting position 9, the shell molds 3 are in an inclined position, at an angle other than zero, with respect to the horizontal so that a first end 5 of the shell mold 3, proximal to the pouring duct 4 and provided with an opening 11 for the inlet of the molten metal, is higher than a second end 6 of said shell mold, opposite the first end 5 and distal from said pouring duct 4.

[0058] The vertical position of the shell mold 3 is excluded.

[0059] In particular, the inclination angle of the shell molds 3 in the casting position 9 is comprised within a range from 10 to 40°, preferably 10 to 35° or 10 to 30°.

[0060] This inclination allows an efficient filling of the entire casting cavity, even if the anode is to be given particular shape characteristics.

[0061] In the casting position 9 and also in the intermediate positions between the casting position 9 and the extraction position 10, the shell molds 3 are in a closed configuration thereof. The shell molds 3 pass from the closed configuration to an open configuration exclusively in the extraction position 10, to allow the extraction of the solidified anode.

[0062] Furthermore, there is advantageously provided an adjustment system 7, 8 for automatically adjusting the inclination of each shell mold 3 along at least one part of the carousel 2 during the rotation thereof about the axis X, said adjustment system being configured to bring each shell mold 3 from the inclined position taken at the respective casting position 9 to a horizontal position at the respective extraction position 10, and then back to said inclined position for filling of the shell mold in the casting position 9 again. Advantageously, said adjustment system comprises, or consists of a cam mechanism for bringing each shell mold 3 from said inclined position to said horizontal position, and vice versa.

[0063] The horizontal position of the shell mold in the extraction position 10 allows an easier extraction of the solidified anode.

[0064] The solidification of the anode is achieved by means of a cooling of the shell molds 3 during their movement from the casting position 9 to the extraction position 10.

[0065] In the plant of the invention, the shell molds 3 can be connected, in a known manner, to a water cooling circuit, or, in an innovative manner, a forced ventilation system 50 can be provided, arranged in proximity to the shell molds 3, for example underneath or alongside, in a carousel stretch that goes from a casting position 9 to an extraction position 10, as for example illustrated in Figure 2.

[0066] In a further example, not shown, the melting furnace 1 is provided with at least two pouring ducts and there are provided at least two casting positions and at least two extraction positions; whereby the carousel 2 is configured to intermittently rotate so that at each radial rotation step at least one shell mold stops in a respective casting position at the corresponding pouring duct, and at least one other shell mold stops in a respective extraction position for the extraction of a solidified anode. Preferably, the carousel is configured to intermittently rotate so that at each radial rotation step two shell molds stop in a respective casting position at a corresponding pouring duct, and other two shell molds stop in a respective extraction position for the extraction of a solidified anode.

[0067] Advantageously, in all embodiments of the invention, each shell mold 3 is provided with actuators 15, 16, 17, arranged on the same structure of the shell mold, to open, preferably automatically, the shell mold and extract the solidified anode in said extraction position 10.

[0068] Advantageously, below the extraction position or station 10 in which the shell mold 3 is in the horizontal position, there is provided a roller path 20 adapted to receive the solidified anode, just extracted, directly from the shell mold in the open configuration thereof.

[0069] Said roller path 20 can transfer the solidified anode just extracted from the shell mold 3 to a corresponding processing station 21 of the solidified anode. This processing station 21 can be a cutting station for cutting any burrs. Preferably, said rollers are at least partially motorized.

[0070] For example, as illustrated in Figures 3 and 11 , the shell mold 3 in the extraction position 10 is arranged parallel to and above the roller path 20, but laterally to the latter so that the longitudinal anode which is extracted can be positioned substantially at the center of said roller path 20, preferably supported by a lever system 40 (Figure 11 ) accompanying the anode from the height of the open shell mold to the lower height of the roller path 20.

[0071] In particular, said lever system 40 comprises levers interposed between, and protruding from, the rollers of said roller path 20 to accompany the solidified anode from the height of the shell mold 3 in its horizontal position to the height of the underlying roller path 20.

[0072] Preferably, the longitudinal shell molds 3 are arranged radially with respect to the axis X defining a circular crown that defines an inner circular periphery and an outer circular periphery of the carousel 2 (Figure 3).

[0073] In a first variant of the plant, shown in Figures 1 -2, the outlet section of the pouring duct 4 is arranged in proximity to the axis of rotation X of the carousel 2, along the inner circular periphery of said carousel 2.

[0074] Therefore, the first ends 5 of the shell molds 3 are arranged at said inner circular periphery of the carousel 2, while the second ends 6 of the shell molds 3 are arranged at said outer circular periphery of said carousel 2 (Figure 3).

[0075] Preferably, in this variant the melting furnace 1 is arranged above the carousel 2 in proximity to its axis of rotation X.

[0076] In a second variant of the plant, not shown, the outlet section of the pouring duct 4 is arranged distal from the axis of rotation X of the carousel 2, along the outer periphery of said carousel 2.

[0077] Therefore, in this variant, the first ends 5 of the shell molds 3 are arranged at the outer circular periphery of the carousel 2, whereas the second ends 6 of the shell molds 3 are arranged at the inner circular periphery of said carousel 2.

[0078] Preferably, in this variant, the melting furnace 1 is arranged above the carousel 2 in proximity to the outer periphery thereof.

[0079] In a variant, shown in Figures 1 -4, the aforesaid cam mechanism comprises

[0080] - at least one roller or skid 7, provided at the second end 6 of each shell mold 3, and - at least one track 8 arranged along said at least one part of the carousel 2, so as to define a shape contact by engaging at least some wheels or skids 7 of some shell molds 3 with the track 8, whereby the transition from an inclined position to a horizontal position takes place by lifting the second end 6 of the respective shell mold 3.

[0081] As shown in Figures 2-4, the single track 8 only extends along a portion of the outer circular periphery of the carousel 2, preferably for about 150-200°, for example about 180° (Figure 3), passing from a minimum height to a maximum height in proximity to the extraction position 10, and from said maximum height back to said minimum height (Figure 4).

[0082] In this case, the first ends 5 of the shell molds 3 are arranged at the inner circular periphery of the carousel 2, whereas the second ends 6 of the shell molds 3 are arranged at the outer circular periphery of said carousel 2.

[0083] Preferably, in this variant the melting furnace 1 is arranged above the carousel 2 in proximity to the axis of rotation X thereof.

[0084] In an alternative not shown, the first ends 5 of the shell molds 3 are arranged at the outer circular periphery of the carousel 2, whereas the second ends 6 of the shell molds 3 are arranged at the inner circular periphery of said carousel 2. The track 8 only extends along a portion of the inner circular periphery of the carousel 2, preferably for about 150-200°, for example about 180°, passing from a minimum height to a maximum height in proximity to the extraction position 10, and from said maximum height back to said minimum height.

[0085] Preferably, in this variant the melting furnace 1 is arranged above the carousel 2 in proximity to the outer circular periphery thereof.

[0086] In a further variant, not shown, the cam mechanism comprises

[0087] - at least one wheel or skid 7, provided at the first end 5 of each shell mold 3, i.e. , the end provided with the opening 11 for the entry of the molten metal, and at least one track 8 arranged along said at least one part of the carousel 2, so as to define a shape contact by engaging at least some wheels or skids 7 of some shell molds 3 with said track, whereby the transition from the inclined position to the horizontal position takes place by lowering the first end 5 of the respective shell mold 3. The track 8 can extend only along a portion of the inner circular periphery of the carousel 2, preferably for about 150-200°, for example about 180°, passing from a minimum height to a maximum height in proximity to the casting position 9, and from said maximum height back to said minimum height.

[0088] In this case, the first ends 5 of the shell molds 3 are arranged at the inner circular periphery of the carousel 2, whereas the second ends 6 of the shell molds 3 are arranged at the outer circular periphery of said carousel 2.

[0089] Preferably, in this variant the melting furnace 1 is arranged above the carousel 2 in proximity to the axis of rotation X thereof.

[0090] In an alternative not shown, the first ends 5 of the shell molds 3 are arranged at the outer circular periphery of the carousel 2, whereas the second ends 6 of the shell molds 3 are arranged at the inner circular periphery of said carousel 2. The track 8 only extends along a portion of the outer circular periphery of the carousel 2, preferably for about 150-200°, for example about 180°, passing from a minimum height to a maximum height in proximity to the casting position 9, and from said maximum height back to said minimum height.

[0091] Preferably, in this variant the melting furnace 1 is arranged above the carousel 2 in proximity to the outer circular periphery thereof.

[0092] In case of only one pouring duct 4, only one casting position 9 and only one extraction position 10, only one track 8 is provided which can only extend along a part of a circular periphery of the carousel 2, or can extend along the entire carousel, thus forming a closed loop.

[0093] In case of at least two pouring ducts, at least two casting positions and at least two extraction positions, at least two tracks can be provided which can extend along a respective portion of a circular periphery of the carousel, or a single track can be provided which can extend along the entire carousel, thus forming a closed loop. Preferably, each shell mold 3 is shaped, in a closed configuration thereof, substantially like a hollow rectangular parallelepiped, preferably having a longitudinal extension arranged radially with respect to the axis of rotation X of the carousel 2 (Figures 5-6).

[0094] This longitudinal extension is preferably much greater than the other two dimensions (width and depth). In an embodiment, this hollow rectangular parallelepiped can comprise:

[0095] - a first base provided with the opening 11 , at the first end 5 of the shell mold, for casting the molten metal into the shell mold 3;

[0096] - a second base, opposite the first base, defined by a bottom 12 of the shell mold 3 at the second end 6 of the shell mold;

[0097] - and a side surface defined by a first fixed, L-shaped, longitudinal plate 13 and a second movable, L-shaped, longitudinal plate 14 hinged to said first fixed longitudinal plate 13 such that, in said closed configuration, said second movable longitudinal plate 14 is closed onto said first fixed longitudinal plate 13 defining, together with the bottom 12, a pouring or casting cavity for an anode.

[0098] In particular, if the anode is to be given particular shape characteristics, it is possible to provide, on at least one inner surface of said first fixed longitudinal plate 13 and / or of said second movable longitudinal plate 14, some protrusions with complementary shape to the desired shape of some portions of the anode.

[0099] For example, as can be seen in Figures 11 and 12 where the shell mold 3 is in an open configuration, the following can be provided:

[0100] - a first protrusion 22 on an inner surface of the movable longitudinal plate 14, at the second end 6 of the shell mold, to produce a thinning 25 of a first end of the anode 31 ;

[0101] - a second protrusion 23 on said inner surface of the movable longitudinal plate 14, at the first end 5 of the shell mold, to produce a thinning 26 of a second end of the anode 31 , on the same side as the thinning 25;

[0102] - a third protrusion 24 on an inner surface of the fixed longitudinal plate 13, at the second end 6 of the shell mold, to produce a recess 27 in the first end of the anode 31 , on the opposite side of the thinning 25.

[0103] At the second end 6 of the shell mold, the movable longitudinal plate 14 and the first protrusion 22 are provided with a respective hole 28 for the insertion of a pin 29 (Figure 12) which, when the shell is closed during casting, produces a corresponding through hole 30 in said first end of the anode (Figure 11 ).

[0104] By way of example, the first thinning 25 serves as a stop to estimate the residual thickness of the anode in the electrolytic process tank or cell to know when to replace it, the portion of the anode with said first thinning 25 remaining not immersed in the electrolytic bath, thus not entering the process; the second thinning 26 serves to insert the anode upright into a recess in the anodizing position inside the electrolytic cell; the recess 27 serves to hang the anode in a rack or in the electrolytic process tank; the through hole 30 serves to lock the moving part of the shell mold with respect to the fixed part and to create a hole for a lifting of the anode useful for its transport and insertion into the process tanks.

[0105] To allow the operator to easily open the shell mold manually or in a completely or partially automated manner and quickly extract the solidified anode directly in line in the extraction position 10 of the carousel 2, each shell mold 3 is provided with the aforesaid actuators 15, 16, 17 to move the second movable longitudinal plate 14 with respect to the first fixed longitudinal plate 13, opening the shell mold, and to extract the solidified anode.

[0106] In a particular configuration, said actuators can comprise (Figures 5-12):

[0107] - a first actuator 15, preferably connected to the second movable longitudinal plate 14, even more preferably in the form of a first lever attached to the movable longitudinal plate 14, to open the shell mold 3;

[0108] - a second actuator 16, preferably connected to the first fixed longitudinal plate 13, even more preferably in the form of a second lever, actuating at least one pusher 18 adapted to cross a wall of said first fixed longitudinal plate 13, to push the solidified anode out of the shell mold 3;

[0109] - preferably a third actuator 17, preferably connected to the first fixed longitudinal plate 13, for example in the form of a third lever, for activating or deactivating a safety lock 32 for the shell mold in its closed configuration.

[0110] Preferably, the first actuator 15 is fixed directly to the movable longitudinal plate 14. Some of the variants of the actuators 16 and 17 are illustrated in Figures 5-12.

[0111] For example, the second actuator 16 is in the form of a lever connected to a rotating axis 33, arranged parallel to a wall of the fixed longitudinal plate 13 and connected at its two ends to respective actuation mechanisms 34 of two pushers 18 which can pass through said wall to push the anode 31 out of the shell mold (Figures 9-11 ). These actuation mechanisms 34 can comprise, for example, a rack and pinion system or pneumatic or hydraulic mechanisms. Preferably, but not necessarily, the second actuator 16 is indirectly connected to the fixed longitudinal plate 13.

[0112] The third actuator 17, on the other hand, can be in the form of a lever actuating the safety lock 32, for example in the form of a lever system comprising two parallel pairs of levers 35, 35’ that move synchronously from a locking position of the movable longitudinal plate 14 on the fixed longitudinal plate 13 to an unlocking position, or vice versa.

[0113] In particular, each pair of levers 35, 35’ can be arranged at a respective end 5, 6 of the shell mold 3.

[0114] The levers 35, 35’ of each pair are arranged parallel to each other and connected to each other at their respective first end by a synchronization pin 41 perpendicular thereto, defining a U-shaped structure.

[0115] The second ends of the levers are provided with a respective locking element 42. The upper levers 35 of the two pairs of levers, or the lower levers 35’, are connected to each other by a synchronization rod 43.

[0116] Therefore, when the movable longitudinal plate 14 is closed on the fixed longitudinal plate 13, thus with the shell mold closed, the pairs of levers 35, 35’ are in the locking position, with the respective locking elements 42 locking the movable longitudinal plate 14 in the closed position, being in direct or indirect contact with both walls of the L-shape of said plate 14 (Figure 6).

[0117] When the shell mold 3 needs to be opened, the third actuator 17 is manually or automatically operated, causing the two pairs of levers 35, 35’ to rotate synchronously about the respective synchronization pin 41 , moving the locking elements 42 into a non-interference position which allows the movable longitudinal plate 14 to rotate, by means of the first actuator 15, with respect to the fixed longitudinal plate 13.

[0118] The third actuator 17 and related safety block 32 provide, in the variant described above, a very simple system, based exclusively on a lever mechanism. Alternatively, third actuator 17 and safety block 32 can comprise actuators of various types, for example hydraulic, electromechanical, pneumatic, etc.

[0119] Preferably, but not necessarily, the third actuator 17 is indirectly connected to the fixed longitudinal plate 13. Preferably, to precisely regulate the pouring of the molten metal into the shell mold in an automated manner, the following are provided (Figure 2):

[0120] - at least one sensor 19 arranged at the outlet of the melting furnace to detect the filling level of the shell mold in the casting position,

[0121] - at least one opening / closing valve (not shown) of the pouring duct 4,

[0122] - and a control device 20 adapted to receive data from said at least one sensor 19 and consequently control said at least one opening / closing valve.

[0123] For example, at least one sensor, e.g., a laser sensor, can be provided on a ladle or at the base of the melting furnace 1 or externally on the pouring duct 4, to detect the filling level of the shell mold 3 at the casting position 9 and transmit it to the control device 20. Preferably, the melting furnace is equipped with an emergency pin, which can terminate the casting process in an emergency.

[0124] In all variants, when the level of the molten metal reaches a preset height inside the shell mold which is in the inclined position, the flow of molten metal is interrupted by the valve controlled by the control device.

[0125] Preferably, in the casting position, an overflow sensor is also provided below the shell mold so that any spillage of molten metal from the opening 11 of the first end 5 of the shell mold can be detected and transmitted to the control device which promptly blocks the casting flow.

[0126] Below, a process is described for producing metal anodes by means of the plant described above, in particular for producing tin anodes for use in an electrolytic tinplate production line. The process of the invention comprises the following steps:

[0127] - loading tin scrap into the melting furnace 1 to obtain molten tin;

[0128] - intermittently rotating the carousel 2 so that at each radial rotation step at least one shell mold 3 of a plurality of shell molds stops in a respective casting position 9 and the molten tin is poured by means of the corresponding pouring duct 4 into said shell mold, and at least one other shell mold 3 stops in a respective extraction position 10 and a solidified anode is extracted.

[0129] Advantageously, there is provided an adjustment of the inclination of each shell mold 3 along at least one part of the carousel 2 during its rotation about the axis of rotation X, by means of the adjustment system 7, 8 described above, bringing each shell mold 3 from the inclined position at the respective casting position 9 to the horizontal position at a respective extraction position 10, and then back to said inclined position.

[0130] The transition from said inclined position to said horizontal position can take place by lifting the second end 6, or lowering the first end 5, of the respective shell mold 3 by means of the cam mechanism described above.

[0131] An advantage of the process of the invention is represented by the fact that, when each shell mold 3 reaches the horizontal position in the extraction position 10, there are provided, preferably automatically, an opening of the shell mold 3 by means of the actuators 15, 16, 17 provided on the structure of the shell mold itself, and an extraction of the respective solidified anode, which is received directly by the underlying roller path 20, with rollers preferably at least partially motorized, which transfers the solidified anode downstream, for example to a processing station 21 . A further advantage of the process of the invention is represented by the fact that the following steps can also be provided:

[0132] - detecting the filling level of the shell mold 3 in said casting position 9 by means of at least one sensor 19;

[0133] - controlling at least one opening / closing valve for the pouring duct 4, by means of a control device 20 that receives data of said filling level, which are detected by said at least one sensor 19.

Claims

CLAIMS1. A plant for producing metal anodes, in particular tin anodes for use in an electrolytic tinplate production line, the plant comprising- a melting furnace (1 ) adapted to be loaded with scrap of said metal and provided with at least one pouring duct (4) for pouring molten metal;- a carousel (2), arranged below said melting furnace (1 ) and provided with a plurality of shell molds (3) arranged radially with respect to an axis of rotation (X) of said carousel (2); wherein said carousel (2) is configured to intermittently rotate so that at each radial rotation step at least one shell mold (3) of said plurality of shell molds stops in a respective casting position (9) at the corresponding pouring duct (4), and at least one other shell mold (3) stops in a respective extraction position (10) for the extraction of a solidified anode; wherein, in the casting position (9), the shell molds (3) are in an inclined position, at an angle other than zero, with respect to the horizontal so that a first end (5) of the shell mold (3), proximal to the corresponding pouring duct (4) and provided with an opening (11 ) for the inlet of the molten metal, is higher than a second end (6) thereof, opposite the first end (5) and distal from said pouring duct (4); wherein there is provided an adjustment system (7, 8) for adjusting the inclination of each shell mold (3) along at least one part of the carousel (2) during the rotation thereof about an axis of rotation (X), said adjustment system comprising a cam mechanism to bring each shell mold (3) from said inclined position at the respective casting position (9) to a horizontal position at said respective extraction position (10), and then back to said inclined position; wherein each shell mold (3) is provided, on the structure thereof, with actuators (15, 16, 17) for opening the shell mold and extracting the solidified anode in the extraction position (10); and wherein, below the extraction position (10), in which the shell mold (3) is in a horizontal position, there is provided a roller path (20), adapted to directly receive the solidified anode just extracted from the shell mold (3).

2. A plant according to claim 1 , wherein the outlet section of the at least one pouring duct (4) is arranged in proximity to the axis of rotation (X) of the carousel (2), alongan inner periphery of the carousel (2); or wherein the outlet section of the at least one pouring duct (4) is arranged distal from the axis of rotation (X) of the carousel (2), along an outer periphery of the carousel (2).

3. A plant according to claim 1 or 2, wherein, in the casting position (9), the shell molds (3) are in a closed configuration thereof; preferably wherein, in said casting position (9), the shell molds (3) are inclined at an angle in the range of 10 to 40° with respect to the horizontal.

4. A plant according to claim 3, wherein said cam mechanism comprises at least one wheel or skid (7), provided at the second end (6) of each shell mold (3), and at least one track (8) arranged along said at least one part of the carousel (2), so as to define a shape contact by engaging at least some wheels or skids (7) with said at least one track (8), whereby the transition from said inclined position to said horizontal position takes place by lifting the respective second end (6); preferably wherein the track (8) passes from a minimum height to a maximum height in proximity to an extraction position (10), and from said maximum height back to said minimum height.

5. A plant according to claim 3, wherein said cam mechanism comprises at least one wheel or skid (7), provided at the first end (5) of each shell mold (3), and at least one track arranged along said at least one part of the carousel (2), so as to define a shape contact by engaging at least some wheels or skids (7) with said at least one track, whereby the transition from said inclined position to said horizontal position takes place by lowering the respective first end (5); preferably wherein the track passes from a minimum height to a maximum height in proximity to a casting position (9), and from said maximum height back to said minimum height.

6. A plant according to any one of the preceding claims, wherein said roller path (20) is adapted to transfer the solidified anode just extracted from the shell mold (3) to a corresponding processing station (21 ) of the solidified anode; preferably wherein said rollers are at least partially motorized.

7. A plant according to any one of the preceding claims, wherein each shell mold (3) is shaped, in a closed configuration thereof, substantially like a hollow rectangularparallelepiped, preferably having a longitudinal extension arranged radially with respect to the axis of rotation (X) of the carousel (2).

8. A plant according to claim 7, wherein said hollow rectangular parallelepiped has a first base provided with said opening (11 ), at said first end (5), for casting the molten metal into the shell mold (3); a second base defined by a bottom (12) of the shell mold (3) at said second end (6); and a side surface defined by a first fixed, L- shaped, longitudinal plate (13) and a second movable, L-shaped, longitudinal plate(14) hinged to said first fixed longitudinal plate (13) such that, in said closed configuration, said second movable longitudinal plate (14) is closed onto said first fixed longitudinal plate (13) defining together with the bottom (12) a casting cavity for an anode.

9. A plant according to claim 8, wherein the actuators (15, 16, 17) of each shell mold (3) are adapted both to move said second movable longitudinal plate (14) with respect to said first fixed longitudinal plate (13), opening or closing the shell mold, and to extract the solidified anode in the extraction position (10).

10. A plant according to claim 9, wherein said actuators comprise a first actuator(15), preferably connected to said second movable longitudinal plate (14) and preferably in the form of a first lever, for opening the shell mold (3); a second actuator (16), preferably connected to said first fixed longitudinal plate (13) and preferably in the form of a second lever, for actuating at least one pusher (18) adapted to cross a wall of said first fixed longitudinal plate (13), for bringing the solidified anode out of the shell mold (3); preferably wherein there is provided a third actuator (17), preferably connected to said first fixed longitudinal plate (13) and preferably in the form of a third lever, for activating or deactivating a safety lock for the shell mold in the closed configuration.11 . A plant according to any one of the preceding claims, wherein there are provided at least one sensor (19) for detecting the filling level of a shell mold (3) in the casting position (9), at least one opening / closing valve of the at least one pouring duct (4), and a control device (20) adapted to receive data from said at least one sensor (19) and to control, accordingly, said at least one opening / closing valve; preferably wherein said at least one sensor (19) is arranged either on a ladle or at the base of the melting furnace (1 ) or externally on the at least one pouring duct (4).

12. A plant according to any one of the preceding claims, wherein the melting furnace (1 ) is provided with only one pouring duct (4); and wherein only one casting position (9) and only one extraction position (10) are provided; whereby said carousel (2) is configured to intermittently rotate so that at each radial rotation step only one shell mold (3) of said plurality of shell molds stops in the casting position (9) at the pouring duct (4), and only one other shell mold (3) stops in the extraction position (10) for the extraction of a solidified anode; or wherein the melting furnace (1 ) is provided with at least two pouring ducts; and wherein at least two casting positions and at least two extraction positions are provided; whereby said carousel (2) is configured to intermittently rotate so that at each radial rotation step at least one shell mold of said plurality of shell molds stops in a respective casting position at the corresponding pouring duct, and at least one other shell mold stops in a respective extraction position for the extraction of a solidified anode; preferably wherein said carousel (2) is configured to intermittently rotate so that at each radial rotation step two shell molds of said plurality of shell molds stop in the respective casting position at the corresponding pouring duct, and two other shell molds stop in the respective extraction position for the extraction of a solidified anode.

13. A plant according to any one of the preceding claims, wherein in said extraction position (10) there is provided a lever system (40), said levers being interposed between, and protruding from, the rollers of said roller path (20) for accompanying the solidified anode from the height of the shell mold (3) in the horizontal position thereof to the height of the underlying roller path (20).

14. A plant according to any one of the preceding claims, wherein there is provided a forced ventilation system (50), arranged in proximity to the shell molds (3) in a carousel (2) stretch from said casting position (9) to said extraction position (10).

15. A process for producing metal anodes, by means of the plant according to any one of the preceding claims, in particular for producing tin anodes for use in an electrolytic tinplate production line, the process comprising the following steps:- loading metal scrap into the melting furnace (1 ) to obtain the molten metal;- rotating the carousel (2) intermittently so that at each radial rotation step at least one shell mold (3) of said plurality of shell molds stops in the respective castingposition (9) and the molten metal is cast into said at least one shell mold by means of the corresponding pouring duct (4), and at least one other shell mold (3) stops in the respective extraction position (10) and a solidified anode is extracted; wherein there is provided an adjustment of the inclination of each shell mold (3) along at least one part of the carousel (2) during the rotation thereof about the axis of rotation (X), by means of the adjustment system (7, 8) comprising a cam mechanism, bringing each shell mold (3) from the inclined position at the respective casting position (9) to the horizontal position at the respective extraction position (10), and then back to said inclined position; wherein, when each shell mold (3) reaches the horizontal position in the respective extraction position (10), there are provided an opening of the shell mold (3), by means of the actuators (15, 16, 17) provided on the structure of said shell mold, and an extraction of the respective solidified anode, which is received directly by the roller path (20) placed below the extraction position (10).

16. A process according to claim 15, wherein the transition from said inclined position to said horizontal position takes place by lifting the second end (6), or lowering the first end (5), of the respective shell mold (3) by means of said cam mechanism.

17. A process according to claim 15 or 16, wherein said roller path (20) transfers said solidified anode to a corresponding processing station (21 ).

18. A process according to any one of claims 15 to 17, wherein there are further provided the steps of- detecting the filling level of the shell mold (3) in the casting position (9) by means of at least one sensor (19);- controlling at least one opening / closing valve for opening / closing the at least one pouring duct (4), by means of a control device (20) that receives data of said filling level, which are detected by said at least one sensor (19).

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