AU2005244546B2

AU2005244546B2 - Device and method for careful separation of anode blocks from their anode rods

Info

Publication number: AU2005244546B2
Application number: AU2005244546A
Authority: AU
Inventors: Roland Anklam; Hardy Nagel
Original assignee: Outotec Oyj
Current assignee: Reel GmbH
Priority date: 2004-12-17
Filing date: 2005-12-15
Publication date: 2010-10-28
Anticipated expiration: 2025-12-15
Also published as: EP1672099A2; EP1672099A3; DE102004060823B4; DE102004060823A1; EP1672099B1; AU2005244546A1; AU2005244546B8

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant (s): Outokumpu Technology Oy Invention Title: DEVICE AND METHOD FOR CAREFUL SEPARATION OF ANODE BLOCKS FROM THEIR ANODE RODS The following statement is a full description of this invention, including the best method for performing it know to me/us: -2 Device for separation of anode blocks from their anode rods Description: 5 The invention is directed to a device for the separation of anode blocks from their anode rods in the line of molten phase electrolysis for the production of aluminium. During that operation the anode blocks are 10 suspended with their fastening holes formed in the upper side by means of annular gap filling metal bushes to their bottom stub-like anode rod ends that have been formed to a yoke. To prepare anode blocks for their use in molten 15 phase electrolysis for the production of aluminium the anode blocks have to be firmly joined to power supply rods and/or the so-called anode rods. To that end the bottom ends of the anode rods which mostly have the form of a yoke with two, three or four adjacently arranged rod ends 20 are introduced from above into correspondingly pre-shaped recesses of the anode block and the remaining gaps and/or cavities in the recesses are then filled with molten iron. During that operation bushes are formed around the anode rod ends - also known as stubs - which ensure not only 25 mechanical stability of the connection between anode rod/anode block but also a good electric conductivity from the anode rod to the anode block. After solidification of the cast metal a firm bonding is established between the bush and the anode rod end as well as between the bush and 30 the anode block. These anode blocks which are produced in so called anode plants from calcined petroleum coke and normally pitch as binder in vibrating compactors by compaction of grainy raw materials and which are then 35 baked feature very large dimensions and a correspondingly high weight. Reference is made in this respect to e.g. the catalogue 10-715e published by KHD Humboldt Wedag AG H:\Linda\Keep\spec\P59227.doc 15/12/05 - 3 showing photographs of new and not yet consumed anode blocks on pages 2 and 3. After anode consumption anode butts and the bushes remain at the anode rods which have to be removed 5 from the bottom anode rod ends normally by cracking off or withdrawing before a new anode block is fastened to the anode rod. In case imperfections occur when moulding the iron bushes it may become necessary to separate the 10 properly speaking serviceable anode block from its anode rod. If withdrawal presses known so far were used for that separation process, i.e. for withdrawing anode butts and bushes from the anode rods by the application of high withdrawing forces, the actually usable anode block would 15 in an unwanted manner be damaged or broken completely and its reuse at any rate become impossible. The problem to be solved by the invention is to create a device by which not yet consumed anode blocks can be mechanically separated from the yoke ends of their 20 anode rods after the occurrence of imperfect bushes, i.e. so that both the anode block and the anode rod each remain undamaged and can be used again. The separation of anode blocks from their anode rod yoke end is achieved according to the invention by 25 means of a device with an impact fork featuring fork prongs which can be introduced into the gaps between the anode rod yoke and the upper side of the anode block suspended from the yoke. The fork prongs are arranged at the bottom side of at least one impact fork mass body 30 which can be moved vertically upward and downward with a certain stroke above the anode rod yoke. This impact stroke of the impact fork corresponds to the distance between the fork prongs and the yoke bottom side (bottom position of the impact fork) and/or the distance between 35 the upper side of the yoke and the bottom side of the impact fork mass body (top position of the impact fork). The impact stroke length is preferably adjusted such that H:\Linda\Keep\spec\P59227.doc 15/12/05 - 4 upon the downward stroke the fork prongs just do not touch the upper side of the anode block suspended from the anode rod yoke. In an embodiment the impact fork is periodically 5 lifted by the impact stroke length mentioned above with the aid of a lifting cylinder of the device according to the invention and dropped by the effect of gravity. During the upward movement the impact fork strikes the anode rod yoke from below and during the downward movement 10 from above while the anode block remains positioned on the base formed as support of the device according to the invention. Following a specified number of impact strokes and/or load changes the stubs of the anode rod yoke are loosened in the fastening holes of the anode block. 15 During this loosening procedure they project more and more from the fastening holes of the anode block until the anode rod with its yoke which was no more than loosely retained during that operation has been completely separated from the anode block so that both the anode rod 20 and, in particular, the anode block that remain undamaged can be used again after removal of the metal bushes. In a further embodiment, there is provided a method for the separation of anode blocks from their anode rods in the line of molten phase electrolysis for the 25 production of aluminium with a device according to any of the preceding claims, wherein the anode blocks are suspended with their fastening holes formed on the upper side by means of annual gap filling metal bushes from bottom stub-like anode-rod ends that have been formed to a 30 yoke, the method comprising: an impact fork engaging with its bottom prongs in gaps between the anode rod yoke and the upper side of anode block, wherein the fork prongs are arranged at a 23393131 (GHMatters) 19A08/10 - 4a bottom side of at least one impact fork mass body which can be moved upward and downward above the anode rod yoke; and the impact fork periodically moving up and down 5 to strike the anode rod yoke during an upward stroke from below and during a downward stroke from above. The invention and its further features and advantages are explained in more detail by the typical embodiment shown schematically in the figures. The 10 figures show the following: Fig. 1 the vertical section of the device according to the invention along line B-B in Fig. 2, Fig. 2 a vertical section along line A-A in Fig. 1 and is Fig. 3 the section of Fig. 2 in a position of the anode rod yoke which has already been separated from the anode block suspended from it. Fig. 1 shows an anode block 10 with three fastening holes formed in its upper side in which 20 correspondingly three stubs 11, 12, 13 of the bottom end of an anode rod 15 formed to a yoke 14 have been introduced. The annular-shaped gaps between the stubs and 23393131 (GHMatters) 19/08/10 - 5 the fastening holes have been filled with molten iron to obtain metal bushes 16. In case the metal bushes 16 are imperfect the device according to the invention offers the possibility to have the anode block 10 carefully separated 5 from the anode rod yoke 14. The device according to the invention features a frame 17 with a lower base 18 and an upper cross beam 19. Anode 10 with its anode rod 15 is placed on base 18. An impact fork that can be moved upward and downward in the 10 device engages with its two bottom prongs 20, 21 shown in the typical configuration in the gaps between yoke 14 and the upper side of anode block 10. The fork prongs 20, 21 have been arranged at the bottom side of an impact fork mass body 22 which can be moved upward and downward above 15 the anode rod yoke 14 by a lifting cylinder 23 engaging the upper side of the impact fork mass body 22 which cylinder has been linked with its upper end to the top cross beam 19 of the machine frame 17. This means that the impact fork can be periodically lifted by means of the 20 lifting cylinder and the impact fork dropped simply by gravity after every lifting cycle. During that operation impact stroke 24 of the impact fork corresponds to the distance between fork prongs 20, 21 and the underside of yoke 14 (bottom 25 position of the impact fork) and/or the distance between the upper side of the yoke 14 and the bottom side of the impact fork mass body 22 (top position of the impact fork as shown in Figs. 1 to 3). In other words, the impact fork strikes anode rod yoke 14 during the upward stroke 30 from below and during the downward stroke from above. The impact intensity of lifting cylinder 23 can even be adjusted such that the impact intensity of the impact fork is greater during the upward stroke than during the downward stroke. 35 At any rate stubs 11, 12, 13 are loosened in their fastening holes after a specific number of load changes, yoke 14 projects more and more from anode block H:\Linda\Keep\spec\P59227.doc 15/12/05 -6 10 until as shown in Fig. 3 anode rod 15 with yoke 14 and bushes 16 have been completely separated from the anode block that remained undamaged. The anode block 10 placed on base 18 is not lifted during that operation. 5 Fig. 1 shows in addition that the impact fork mass body 22 is vertically guided in machine frame 17, e.g. along roller guides 25, 26. The impact fork mass body 22 features a central passage by which it encompasses anode rod 15. Furthermore, swivelling clamps 27 for 10 loosely enclosing, i.e. for loosely retaining anode rod 15, have been linked to upper cross-beam 19 of machine frame 17. In the claims which follow and in the preceding description of the invention, except where the context 15 requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further 20 features in various embodiments of the invention. It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia 25 or any other country. H:\Linda\Keep\spec\P59227.doc 15/12/05

Claims

1. A device for the separation of anode blocks from anode rods, the anode blocks being suspended from an anode 5 rod yoke, the device comprising: an impact fork comprising fork prongs for engaging gaps between the anode rod yoke and an upper side of the anode block, the fork prongs being arranged at a bottom side 10 of at least one impact fork mass body which can be moved upward and downward above the anode rod yoke, and wherein an impact stroke of the impact fork corresponds to a distance between the fork prongs and an underside of the yoke and/or a distance between an upper side of the 15 yoke and the bottom side of the impact fork mass body.

2. A device according to claim 1, wherein the device comprises a base on which the anode block including the anode rod can be placed. 20

3. A device according to claim 1 or 2, wherein at least one impact fork mass body is guided along vertical guide units of a machine frame. 25

4. A device according to any one of the preceding claims, wherein a lifting cylinder acts at the upper side of the impact fork mass body which has been linked with its top end to an upper cross beam of machine frame and by which the impact fork can be periodically lifted, whereby 30 following lifting cycles, the impact fork is dropped by the effect of gravity.

5. A device according to any one of the preceding claims, wherein swivelling clamps for loosely retaining 35 anode rod are linked to the upper cross beam of machine frame. 23393131 (GHMatters) 19/08110 -8

6. A device according to any one of the preceding claims wherein the impact fork mass body arranged above the anode rod yoke comprises a passage by which it encompasses the anode rod. 5

7. A method for the separation of anode blocks from their anode rods in the line of molten phase electrolysis for the production of aluminium with a device according to any of the preceding claims, wherein the anode blocks are 10 suspended with their fastening holes formed on the upper side by means of annual gap filling metal bushes from bottom stub-like anode-rod ends that have been formed to the yoke, the method comprising: an impact fork engaging with its bottom prongs in 15 gaps between the anode rod yoke and the upper side of anode block, wherein the fork prongs are arranged at a bottom side of at least one impact fork mass body which can be moved upward and downward above the anode rod yoke; and 20 the impact fork periodically moving up and down to strike the anode rod yoke during an upward stroke from below and during a downward stroke from above.

8. A method according to claim 7, wherein the impact 25 stroke of the impact fork corresponds to the distance between the fork prongs and the underside of the yoke and/or the distance between the upper side of the yoke and the bottom side of the impact fork mass body. 30

9. A method according to claim 7 or 8, wherein a lifting cylinder acts at the upper side of the impact fork mass body which has been linked with its top end to an upper cross beam of machine frame and by which the impact fork is periodically lifted, such that following the 35 lifting cycles, the impact fork is dropped by effect of gravity. 23393131 (GHMatters) 19/08/10 -9

10. A method according to claim 9, wherein the impact intensity of the lifting cylinder and, consequently, of the impact fork is greater during the upward stroke than during the downward stroke. 5

11. A device as claimed in claim 1 substantially as herein described with reference to the accompanying drawings. 10

12. A method as claimed in claim 7 substantially as herein described with reference to the accompanying drawings. 23393131 (GHMatters) 19/08/10