EP1150085A1 - Rotary drum furnace for the melting of metals - Google Patents

Abstract

Rotating drum oven comprises a rotating drum (1) with a casing (2) having an opening (8) formed as a radial opening which can be closed using a lid (9). Preferred Features: The radial opening is circular and has a diameter of more than 0.1 D (where D = the diameter of the drum casing). The lid is formed as a pivoting lid. A mechanical/hydraulic adjusting device is used to close the lid. The lid has an outer lining made from steel and an inner lining made from a refractory masonry.

Description

The invention relates to a rotary drum furnace for Melting and / or remelting of metals, especially aluminum, with a rotatably mounted furnace drum with drum casing, and with at least one opening in the drum jacket.

Such a rotary drum furnace is used in the German Patent 892 382. With those there Openings in the drum jacket are on the one hand a viewing opening, on the other hand a pouring opening, which by a stopper during the melting process is closed. - Both openings in the drum casing can be found in the respective end walls.

Metal and especially aluminum scrap or Aluminum dross is often used in flame-heated Rotary drum furnaces of the construction described above melted. To reduce burn loss and non-metallic Separate impurities from the metal or aluminum can, the respective batch is usually a molten salt based on, for example, table salt (NaCl), Potassium chloride (KCL) or calcium fluoride (CaF2) added.

After the batch has melted, it accumulates Salt slag due to metal oxides and goes into one more or less viscous consistency over. That is so far disadvantageous, as a salt slag rack advantageous (only) then succeeds if the associated salt slag if possible is thin.

As a result, salt has been added in the past dosed accordingly so that the required Flowability was achieved. So are weight additions from approx. 25 to 30% by weight of salt per metal batch to be melted quite common, the amount added of course from Degree of contamination of the metal scrap to be melted depends. In any case, one makes the phenomenon here take advantage that with an increased amount of salt the percentage of metal oxides in the generated Salt slag is reduced, which leads to the fact that the Salt slag changes into a thinner consistency.

However, the salt consumption is such The procedure is enormous and drives the melting costs into the Height. This is also ensured by the fact that the tapped salt slag mostly represents hazardous waste and thus to a further increase in price per melted Batch leads.

For this reason, you have in practice in parallel tried metal scrap, dross or non-ferrous metals to melt with as little salt as possible. Then forms inevitably a crumbly or lumpy salt slag, only removed from the rotary drum furnace can be, if this is tilted. That is, it is one additional tilting device for the rotary drum furnace required, which ensures that after the Melting and draining of the liquid metal through strong Tilting the longitudinal axis and rotating the oven at the same time the lumpy salt slag through the mandatory Charge opening can be carried out.

As part of this development, the salt consumption be significantly reduced, but the handling is for that. d. H. the batching, the metal tapping and slag discharge much more cumbersome than with non-tilting Rotary drum furnaces. Also not to be neglected are those for Partly exorbitant costs for the required tipping device. - The invention as a whole wants to remedy this create.

The invention is based on the technical problem, one Generic rotary drum furnace so that the salt slag produced with low salt consumption removed easily and with structurally simple means can be.

To achieve this object, the invention proposes Generic rotary drum furnace that the opening as optionally lockable with the help of a lid Radial opening is formed. Of course you can also several, over the longitudinal extent of the drum shell distributed, radial openings can be realized.

In particular, the corresponding opening or Radial opening essentially circular, oval or even be elliptical. So that the emerging highly viscous to crumbly or even lumpy salt slag can be easily removed from the rotary kiln, recommends the invention at this point with openings a diameter of more than 0.1 D with D the diameter of the drum casing. This usually poses Openings with a diameter of more than approx. 0.5 m, preferably more than about 1 m. In the case of an oval or elliptical design, the above applies Design rule then of course for the largest diameter. Usually, however, with radial openings in the diameter range worked from approx. 1 m to approx. 2 m. To the Closing this opening in the melting shop is already addressed cover provided.

This lid is usually one Swing lid, which is essentially one horizontal rest position in a largely vertical Operating position is transferable. In other words the lid is closed and opened in one Position of the drum shell, which leads to a more or corresponds to the less vertical position of the opening.

To adjust the cover is a mechanical / hydraulic Actuating device provided that runs semi-automatically can be. That is, usually becomes an operator initiate appropriate opening and closing movements, which then to the desired adjustment or pivoting of the lid leads.

So that the cover in the operating position in the drum jacket rotation of the rotary drum furnace can remain releasably connected to the actuating device. To this The cover can be in the operating position in the drum jacket anchored and from the actuator for rotating the Drum jacket or the rotary drum oven separated as a whole become.

It is usually necessary to have the cover exactly insert centrally into the corresponding opening. To this The adjusting device can be used to compensate heat-induced displacements of the opening in horizontal and / or vertical direction (preferably over one common foundation of the furnace or actuator) be moved. Basically, of course it is too conceivable, only the lid in the corresponding sense adjust.

To the exact position of the rotary drum furnace or One or more to be able to detect opening (Distance) sensors are provided, which a heat-related Change in length and / or diameter of the rotary kiln determine and of course also a heat-related Hike the radial opening can register. This transmit at least one sensor or the plurality of sensors corresponding measurement signals to a control device. The control device in turn now acts on the Actuator depending on the measurement signals, and in such a way that the actuating device or the cover is ultimately brought into alignment with the opening or become, d. H. Opening and lid are centered on each other.

The actuating device gives the opening and / or Closing process before a swing curve of the lid, namely in such a way that it fits into the associated Radial opening is used. This is special Meaning because the lid is usually a External cladding made of steel and a Inner lining from z. B. has fireproof masonry. If the swivel movement is not coordinated, there is a risk that that the lid touches the opening and the Inner lining is partially damaged. Also one Mostly used seal made of a glass fiber mat between cover and opening is due to the damage-free Movement of the lid along the (programmed) Function of the swivel curve is not impaired.

Fig. 1

einen erfindungsgemäßen Drehtrommelofen im Längsschnitt,

Fig. 2

einen Querschnitt durch Fig. 1 entlang der Linie A-A,

Fig. 3

die Radialöffnung mit dem Deckel im Detail und

Fig. 4

eine Frontansicht des Gegenstandes nach Fig. 3.

The invention is explained in more detail below on the basis of a drawing illustrating only one exemplary embodiment; show it:

Fig. 1

a rotary drum furnace according to the invention in longitudinal section,

Fig. 2

2 shows a cross section through FIG. 1 along the line AA,

Fig. 3

the radial opening with the lid in detail and

Fig. 4

3 shows a front view of the object according to FIG. 3.

In the figures is a rotary drum furnace for opening and / or Remelting of metals, especially aluminum scrap, shown. This consists in its basic Structure from an oven drum 1 with a drum jacket 2. The Drum casing 2 has in the area of its end faces a plurality of axially extending openings, one Oven opening 3 with oven door 4 and associated burner an end wall. The opposite end wall is also equipped with an opening 5, which in connection with an exhaust pipe 6 for removing any that may arise Exhaust serves. Another tap opening 7 on the end face ensures the desired drainage of the melted Metal.

In addition, an opening or Radial opening 8 provided in the drum jacket, which with the help a lid 9 can be optionally closed or opened can. That is, this radial opening 8 is - in contrast to which are axially compared to the longitudinal axis in the drum shell extending openings 3, 5, 7 - arranged radially. The Salt slag discharged via this leaves the furnace drum 1 in the radial direction.

Motor-driven ones drive the furnace drum 1 Rollers 10, the associated drum shell 2 Apply to the surrounding, radial races 11 in a rotating manner (see in particular Fig. 2).

The radial opening 8 is within the scope of the exemplary embodiment circular in shape, has a diameter of more than 0.1 D or more than about half a meter and leaves can also be easily retrofitted (D = diameter of the drum shell) Diameter in the range between approx. 1 m and approx. 2 m located. Through this radial opening 8 is - how said - the salt slag that forms from the furnace drum 1 discharged after the molten liquid metal through the tap opening 7 has been tapped. The size of the Radial opening 8 ensures that even extreme viscous salt slag and even large crumbs and Chunks of salt are removed from the drum casing 2 without any problems can be.

In order to facilitate this process, the radial opening 8 at the end of a largely conical funnel 12 arranged within the drum shell 2, which in Supervision has an oval to circular design. Of course, several, e.g. B. two, Radial openings 8 are provided with associated funnels 12 are, as indicated by Fig. 1.

During operation of the rotary drum furnace, i.e. H. at filled aluminum scrap and added salt as well increasing melting of the metal with the help of the burner in the axial opening 3, of course, the drum shell 2 be closed in the region of the radial opening 8. Therefor provides the already mentioned cover 9, which as Swivel cover 9 is executed. Based on the representations in 3 and 4 it can be seen that the cover or Swing lid 9 from a substantially horizontal Rest position (dash-dotted line) in a mostly vertical operating position (solid drawn) can be transferred. This is ensured by mechanical / hydraulic actuating device 13. The cover 9 is detachably connected to this actuating device 13, so that it is anchored in the drum casing 2 in the operating position and from the actuator 13 for rotating the Drum casing 2 can be removed.

The cover 9 consists in detail of an outer cladding 14 made of, for example, steel and an inner lining 15, which is fireproof masonry from z. B. Firebricks can act.

The actuating device 13 has a cylinder 16 equipped, in which a plunger 17 is immersed a pivot bearing 18 on a bracket 19 with the Outer lining 14 of the lid 9 is connected. The Cylinder 16 is arranged essentially vertically, so that the piston moving in the same direction here 17 in the transition from his retired to his extended position the cover 9 by about 90 ° associated pivot bearing 20 is pivoted, as shown in FIG. 3 is indicated. It can act on the cylinder 16 at the push of a button, d. H. manual or semi-automatic, or also controlled using a control device 21 done.

When the lid 9 is shown in its solid line Operating position is in the left part of Fig. 3 can he on the drum shell 2 by connected to it, tensionable pressure pieces 22 are anchored (see FIG. 2). The cover 9 can be removed from the cover by means of rotary locks 28 Remove actuator 13 so that in the operating position the drum shell 2 freely around its longitudinal axis L can rotate.

It is particularly important that the cover 9 is accurate centrically in the radial opening 8 at its transition from the horizontal rest position to the vertical Operating position is introduced. For this purpose, the Invention motor drives in X and / or Y and / or Z direction in front of which the associated actuating device 13 according to FIGS. 3 and 4 influence accordingly. Consequently, the actuator 13 moves to compensate heat-related displacements of the drum shell 2 or Radial opening 8 at least in horizontal and / or Vertical direction, and that against a common Foundation 23 for the furnace drum 1 and the actuating device 13. - Of course, instead of the actuator 13 also the lid or swivel lid 9 in the aforementioned Directions will experience an adjustment as long as this it is ensured that the lid 9 is exactly centered in the Radial opening 8 at the transition to the operating position immersed.

The aforementioned adjustment is necessary because the Oven drum 1 as a whole or the drum shell 2 through the prevailing temperatures (up to 1000 ° C and more) expands, both in terms of its diameter D as well as in the longitudinal direction L.

Diameter changes regularly lead to the fact that the radial opening 8 moves more or less in the Z direction and, if necessary, slightly increased their diameter (cf. Fig. 3). That is relatively unproblematic because the Radial opening 8 has a conical outer ring 24, in which also has a conical outer surface 25 of the cover 9 or the inner lining 15 engages sealingly. in the The rest is provided between the two aforementioned areas 24, 25 inserted seal or sealing mat DM from one Glass fiber and / or rock wool insulation mixture for one tight closure. This is indicated in Fig. 3.

Heat-related elongations of the Drum shell 2 in the longitudinal direction (X direction) L. This definitely need to be balanced because they are too Walks of the radial opening 8 in this Longitudinal direction L correspond. About these opening shifts to be able to master it as a whole the actuating device 13 or the cover 9 in X and / or Move the Z direction (horizontal or vertical direction). All control signals for the corresponding actuators provides the control device 21 already mentioned. For this purpose, it processes signals from (distance) Sensors 26, 27. With the help of these sensors 26, 27 the control device 21 predicts the exact one heat-related (new) position of the radial opening 8 and provides for the associated displacement of the actuating device 13.

In detail, the sensor 26 is one Distance sensor, which relative movements of the opposite End face (s) of drum shell 2 detected, which are basically approved because of the drum shell 2 via the roller guide 10, 11 or the rollers 10 and the races 11 can migrate. Besides this (Distance) sensor 26 on one end face can of course also another (distance) sensor 26 on the other Be arranged as dash-dotted the front Fig. 1 shows. In any case, the one or the two allows (Distance) sensors 26 draw a conclusion about the result Elongation of the drum shell 2 in the X direction.

If you assume that the drum casing 2, starting from an average symmetry plane M, increasingly and uniformly due to the heat in both X-directions expands, so can be from the registered Distance changes in the end face of the drum shell 2 in Compared to the (distance) sensors 26 one movement of a central axis S due to heat Derive radial opening 8 in exactly this X direction. The Central axis T of the cover or swivel cover 9 can now aligned with the aforementioned axis S (again) be by the actuator 13 accordingly in X direction is shifted (see. Fig. 4).

In a comparable sense, the (distance) sensor 27 determines Circumferential expansions of the drum shell 2, which in corresponding Control movements in the Z and / or Y direction transformed become. This sensor 27 is also able to make changes of the distance or displacements of the central axis S of the Detect radial opening 8 opposite the foundation 23 to adjust the adjusting device 13 in Z and / or Initiate Y direction with the help of the control device 21 (see Fig. 3).

Since the rollers 10 are also controlled by the control device 21 can be loaded, the furnace drum 1 or Drum jacket 2 sensitive using if necessary Frequency converter and a gear can be rotated, namely in terms of control and / or regulation (see FIG. 2). This rotary movement can be shown by not shown Limit switches and / or further distance sensors such stop that the radial opening 8 is vertical, like this is indicated in Fig. 3. Now the drum casing 2 or the radial opening 8 with the aid of the cover or Swing lid 9 are closed. Before that, however Actuating device 13 after querying sensors 26 and / or 27 moved accordingly, so in the operating position of the Cover 9, the two central axes S and T are in cover. This due to thermal expansion of the drum shell 2 caused movements can be made using recourse to the control device 21 in the sense of a control and / or arrange regulation. In any case, this will ensures that the lid 9 is exactly centered in the Radial opening 8 is inserted.

During the pivoting-in movement indicated in FIG Cover 9, the pivoting curve can be changed in such a way that a tapping of the lid 9 and damage to the Seal DM and / or the inner lining 15 avoided becomes. This is largely ensured by the cylinder 16 with the Piston 17 in connection with the servomotor in the Z direction, which is the distance between the pivot bearing 20 and the axis of rotation 20 compared to the foundation 23 in the course of this pivoting movement changed. In this way, the lid 9 does not describe simple circular arc (quarter circle), but can be from it Cover deviating swivel curves. Possibly. let yourself the curve movement described by a program-controlled tracking rotation of the drum jacket 2 support as a whole.

Finally, the cover 9 on the drum casing 2 secured and the pivoting device 13 detached from the cover 9 and retracted, with the help of the drive for the Y direction. So the drum jacket 2 (again) ready for operation after the open radial opening 8 crumbly salt slag removed from the drum jacket 2 has been.

The control device 21 is a programmable logic controller (PLC). So this is in able to record the measured values after entering and stored algorithms in corresponding control signals convert.

Claims (10)

Rotary drum furnace for melting and / or remelting metals, in particular aluminum, with a rotatably mounted furnace drum (1) with drum shell (2), and with at least one opening (8) in the drum shell (2), characterized in that the opening ( 8) is designed as a radial opening (8) which can optionally be closed with the aid of a cover (9). Rotary drum furnace according to claim 1, characterized in that the radial opening (8) is essentially circular and has a diameter of more than 0.1 D (with D = diameter of the drum shell (2)). Rotary drum furnace according to claim 1 or 2, characterized in that the cover (9) is designed as a swivel cover (9). Rotary drum furnace according to one of claims 1 to 3, characterized in that the cover (9) can be transferred from an essentially horizontal rest position to a largely vertical operating position (cf. FIG. 3). Rotary drum furnace according to one of claims 1 to 4, characterized in that a mechanical / hydraulic adjusting device (13) for adjusting the cover (9) is realized. Rotary drum furnace according to one of claims 1 to 5, characterized in that the cover (9) is detachably connected to the actuating device (13) so that it is anchored in the drum casing (2) in the operating position and from the actuating device (13) for rotating the drum casing ( 2) can be separated. Rotary drum furnace according to one of claims 1 to 6, characterized in that the cover (9) has an outer cladding (14) made of steel, for example, and an inner lining (15) made of fireproof masonry, for example. Rotary drum furnace according to one of claims 1 to 7, characterized in that the adjusting device (13) for compensating for heat-induced displacements of the radial opening (8) can be moved in the horizontal and / or vertical direction. Rotary drum furnace according to one of claims 1 to 8, characterized in that sensors (26, 27) are provided for detecting a heat-induced migration of the radial opening (8), which transmit corresponding measurement signals to a control device (21), which in turn transmit the adjusting device (13) depending on the measurement signals applied accordingly. Rotary drum furnace according to one of claims 1 to 9, characterized in that the adjusting device (13) specifies a preferably variable pivoting curve of the cover (9) for its damage-free movement.

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