WO2012037611A1

WO2012037611A1 - Anode jacking system

Info

Publication number: WO2012037611A1
Application number: PCT/AU2011/001224
Authority: WO
Inventors: Christopher Peter Jones; Steven John Appleby
Original assignee: Aluminium Smelter Developments Pty Ltd
Priority date: 2010-09-23
Filing date: 2011-09-22
Publication date: 2012-03-29

Abstract

A system for jacking anodes through a cassette means (1, 3A) for supporting the anodes in an electrolytic cell (32), the cassette means (1, 3A) having anode contact means associated with the cassette (1, 3A) for engaging contact surfaces of the anodes, the jacking system comprising a frame (41) for supporting jacking means (46, 47) for engagement with the anodes (1A, 2A) or (2, 3) the frame (41) including means for releasably attaching the frame (41) to a superstructure of the cell and further means to support at least some of the contact means as the jacking rheans (46, 47) operates to push the anodes (1A, 2A) or (2, 3) through the cassette.

Description

ANODE JACKING SYSTEM

This invention relates to anode jacking systems for use with rodless anodes mounted in one or more cassettes in an electrolytic aluminium reduction cell.

In our recent International Patent Application No. PCT/AU201 1 /001043 filed 16 August, 201 1 the disclosure of which is hereby incorporated by reference we have described an improved anode cassette for supporting rodless anodes in an aluminium reduction cell. The improved cassette support superstructure resulting from this development also allows further innovation to be adopted in relation to the means for moving the anodes through the cassette as the anodes are consumed during the smelting process.

It is an object of the present invention to provide an improved jacking system for this purpose.

The invention provides a system for jacking anodes through a rodless anode cassette means for supporting the anodes in an electrolytic cell, the cassette means having anode contact means associated with the cassette for engaging contact surfaces of the anodes, the jacking system comprising a frame for supporting jacking means for engagement with the anodes, the frame including means for releasably attaching the frame to the superstructure of the cell and further means to support at least some of the contact means as the jacking means operates to push the anodes through the cassette.

The system defined above allows the jacking mechanism to be shared among a number of reduction cells, since each cell only requires the anodes to be advanced once per tapping cycle. Furthermore, the removal of the anode jacking system once the anodes have been advanced leaves the top of the superstructure free of obstructions when introducing replacement anodes. An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a schematic plan view of anodes in a cassette;

Figure 2 is a schematic plan view of an alternative two anode cassette;

Figure 3 schematically illustrates the anodes of Figure 2 in a reduction cell without the jacking system embodying the invention in place; and

Figures 4 and 5 schematically illustrate the jacking system embodying the invention being positioned on the reduction cell and operating to push the anodes through the cassette, respectively.

Referring to Fig. 1 , the cassette 1 comprises a multiplicity of pairs of half-width or standard width anodes 2 sufficient to cover a full cell. The anodes 2 are surrounded by a force containment member 4 comprising end beams 5, 6 interconnected by tensile straps 7, 8 having associated adjustment means (not shown) which pull the end beams 5, 6 together to support the entire anode pack. At each end of the cell, a set of fixed contacts 9, 10 and 1 1 are attached to one of the end beams 5, 6 as illustrated in Fig. 1. These contacts have angular faces which engage chamfered corners of the end pairs of anodes to provide the necessary electrical contact.

The cassette 1 includes two sub-assemblies of anode contacts; a fixed contacts subassembly 12 and a clamping contacts sub-assembly 13. Theses sub-assemblies alternate down the length of the cell, as illustrated in Fig. l . Each fixed contact sub-assembly 12 includes outer fixed contacts 14, 15 and a central fixed contact 16 each having angular faces which contact the chamfered corners of the anodes 2, 3 as illustrated and the outer contacts 14, 15 are joined by a central tensile member 17 which also engages the central fixed contact 16. The outer fixed contacts 14, 15 are thereby fixed against lateral movement and semi-restrained in the longitudinal direction and are thermally insulated by insulating pads 18 engaging the cassette 1 to prevent excessive heat loss from the cell.

The clamping contacts sub-assembly 13 comprise inner and outer contact members 20, 21 interconnected by tensile members 22, the outer ends of which are connected to tensioning jacks 23 which operate to pull the inner contacts 20 towards the outer contacts 21 and push the outer contacts 21 towards the chamfered edges of the anodes 2, 3. Referring to Figure 2, an alternative cassette 3 A having pairs of anodes 1 A, 2A are supported in an electrolytic cell by means of a series of cassettes 3A having external and internal wedge-like contact members 4A and 5A, which are arranged to apply forces to the anodes to ensure good electrical contact between the wedge-like contacts 4A and 5A and the angular contact faces of the anodes by means of the jacking arrangement, as illustrated in Figure 1 , and as described in the PCT application referred to above.

As illustrated in the schematic diagram of Figure 3, current is supplied to the wedge-like contact members 4A and 5A by flexible current straps 30 extending from the bus work 31 of the cell 32, and control jacks 33 are provided for regulating the cell voltage in the usual way. As the anodes 1A, 2 A are consumed during the electrolytic process, they need to be advanced through the cassette towards the molten bath and cathode, at least once during each tapping cycle.

In the embodiment, this advancement is achieved by means of a removable jacking system 40 which is brought to the cell by means of a crane engaging the illustrated lifting points as required. In this way, the jacking system may be shared among a number of reduction cells, thereby saving infrastucture costs.

Referring to Figures 4 and 5, an embodiment of a suitable jacking system is schematically illustrated. The jacking system 40 includes a jacking frame 41 , adapted to be rigidly connected to the superstructure S of the cell 32, which carries a pair of jacking devices 42 and 43, of any suitable form, for each anode in the cassette 3A, and locking lugs 44, 45 which are adapted to engage complementary fittings at the ends of masts 46, 47, .which protrude through the top cover C of the cell for connection to the internal wedges 5 A. In use, the operative stems of the jacks push through "cat-flaps" F in the top cover C of the cell to contact the top surfaces of the anodes 1 A, 2A to push the anodes through the cassette 3A. The inner wedges 5A are held in position by the engagement between the mast 46, 47 and the locking lugs 44, 45. The outer wedges 4A are held in place by the cassette 3A, and/or by the flexible current straps connected to the bus work 31 . The connection of the masts 46, 47 to the inner wedges 5A may be via the flexible straps 30 as shown, which are relatively inextensible in tension, or by some other suitable form of direct attachment to the inner wedges 5A.

It will be appreciated that the anode arrangement of Figure 1 may be used in place of the arrangement of Figure 2 with no loss of advantage.

The jacking frame 41 may straddle the whole cell and advance all anodes in all cassettes of the cell, simultaneously. As the anodes advance, the distance between the anode and the cathode decreases, but this is automatically compensated for by the control jacking system 33 which regulates this distance in the usual way. In this way, the control jacking system 33 does not run out of travel as the anodes are consumed. Generally, the anodes would be advanced immediately after tapping of the molten metal. At the end of the anode jacking operation, the jacking frame 41 is moved to the next cell.

As previously mentioned, a removable anode jacking system 41 is preferred because the equipment can be shared among a number of reduction cells, and the removal of the anode jacking equipment leaves the top of the superstructure free of obstructions when introducing replacement anodes.

When the anodes have been consumed and a new one is required, the top cover C of the superstructure is opened, the top surface of the anodes is prepared for gluing of the new anode, and the new anode is brought to the cell by an overhead crane and lowered in position. Guides fitted to the wedge-like contact members align the new anode in the correct position on top of the existing anode.

The invention, and the embodiment described above may be modified by persons skilled in the art for use with the cassette arrangements described in PCT/AU2010/000414, the disclosure of which application is hereby incorporated by reference. The invention has been described by way of non-limiting example only and many modifications and variations may be made thereto without departing from the spirit and scope of the invention.

Claims

1 . A system for jacking anodes through a cassette means for supporting the anodes in an electrolytic cell, the cassette means having anode contact means associated with the cassette for engaging contact surfaces of the anodes, the jacking system comprising a frame for supporting jacking means for engagement with the anodes, the frame including means for releasably attaching the frame to a superstructure of the cell and further means to support at least some of the contact means as the jacking means operates to push the anodes through the cassette.

2. The system of claim 1 , wherein the frame includes at least one lifting point by means of which the frame is able to be transported to an electrolytic cell when it is required.

3. The system of claim 2, wherein the means to support at least some of the contact means includes masts attached to the contact means and engaging locking means associated with the frame.

4. The system of claim 3, wherein each mast is connected to its contact means by a flexible strap which is relatively inextensible in tension.

5. The system of any preceding claim, wherein operative stems of the jacks extend through closures in a top cover of the cell to contact the anode.

6. The system of any preceding claim wherein the cassette means includes pairs of anodes spaced along the length of the cell.

7. The system of claim 6, wherein the anodes are arranged as claimed in International Patent Application No. PCT/AU201 1/001043.