Title of Invention

A METHOD FOR REBUILDING SELF-BAKING ANODE INTO PREBAKING ANODE FOR ALUMINUM ELECTROLYSIS TANK

Abstract

A method for rebuilding self baking anode into prebaking anode for aluminum electrolysis tank is disclosed in the invention. In the method, an upper assembly of an aluminum electrolsis tank with self-baking anode is firstly rebuilt by means of prebaking, without rebuilding a series of cathode buses, cathode liner and tank housing of conventional tank. Firstly, an upper assembly with prebaking anode is made and assemble, and then the upper assembly with self baking anode is slung out. Next, the assembled upper assembly with prebaking anode is slung to the rebuilding tank so as to be installed. Contacts of reiser buses and cathode buses are welded together and then the tank is energized. In addition, electrolyte is poured and the anode is lifted so as to renew normal production. The invention has many advantages, for example, the tank may be rebuilt without stop production of all series of devices, the rebuilding period os substantially reduced, and the loss due to stop production is reduced.

Full Text

THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See Section 10; rule 13) TITLE A METHOD FOR REBUILDING SELF-BAKING ANODE INTO PREBAKING ANODE FOR ALUMINUM ELECTROLYSIS TANK APPLICANT CHINA ALUMINUM INTERNATIONAL ENGINEERING CORPORATION LIMITED B-15/F., Tongtai Mansion, 33 Jinrong Street Xicheng District Beijing 100032 China Nationality : a Chinese corporation The following specification particularly describes the nature of this invention and the manner in which it is to be performed FPME051400581IN A METHOD FOR REBUILDING SELF-BAKING ANODE INTO PREBAKING ANODE FOR ALUMINUM ELECTROLYSIS TANK Field of the Invention The invention refers to a method for rebuilding aluminum electrolysis tank. Background of the Invention Recently, all the aluminum electrolysis tank with self-baking anode need to be rebuilt by means of prebaking due to the requirements of environmental protection and economic and technical guideline of the aluminum electrolysis factory. During a process of rebuilding, two solutions are used generally on the stage. One solution is to rebuild by means of power off of all series of devices. And the other solution is to seriatim rebuild those self-baking tanks to be stopped during heavy repair. If the preceding solution is used, power off of all series of devices will bring great economic loss, although the engineering construction of rebuilding may be accomplished quickly. If the latter solution is used, the progress of the rebuilding engineering will be slow, even the rebuilding engineering might not be finished until it took a period of several years for the heavy repair. Thereby, it is not allowable due to the requirements of environmental protection and self-development. Thus, an economic and reasonable method should be found in prebaking rebuilding of the aluminum electrolysis tank with self-baking anode, so that it can promote the process of rebuilding and give attention to the economic benefit of the manufactories. Summary of Invention An object of the invention is to provide a method for rebuilding aluminum electrolysis tank with self-baking anode by means of prebaking on the spot, on the condition of maintaining normal -1- production of tanks which have not been rebuilt and without the power off of all series of devices. The invention is realized by following steps, comprising firstly rebuilding an upper assembly of an aluminum electrolysis tank with self-baking anode by means of prebaking, without rebuilding a series of cathode buses, cathode liner and tank housing of conventional tank; making and assembling an upper assembly with prebaking anode; and then pumping the electrolyte in the rebuilding tank out and descending its anode into aluminum liquid; next, slinging the upper assembly with self-baking anode out and slinging the assembled upper assembly with prebaking anode to the rebuilding tank so as to be installed; hooking said prebaking anode and declining a bottom surface of the anode into the reserved aluminum liquid in tank; welding contacts of riser buses and cathode buses and then energizing the tank; pouring electrolyte and lifting the anode so as to renew normal production. The invention have many advantages when compared with the prior art, for example, the tank may be rebuilt without stop production of all series of devices, the rebuilding period is substantially reduced, and the loss due to stop production is reduced, etc. Detailed Description Embodiment of the Invention In an embodiment of the invention, an upper assembly of an aluminum electrolysis tank with self-baking anode is firstly rebuilt by means of prebaking, while a series of cathode buses need not to be rebuilt and cathode liner and tank housing of conventional tank are also used temporarily. Then, rebuilt electrolysis tank performs production under a low current density. After upper assemblies of all series of electrolysis tanks have been rebuilt, a current value of the series of devices may be adjusted into a rebuilt design value so as to -2- enter into normal production completely. Cathode liner and tank housing of conventional tank may be rebuilt according to the design requirements during heavy repair of the tanks. Firstly, an upper assembly with prebaking anode (comprising a baiting case, a blanking machine with constant volume, a cylinder for crustbreaking and blanking and air supply pipes for pressurized air) is made and assembled. And then electrolyte in the rebuilding tank is pumped out. The anode is descending while electrolyte is pumping out and the anode may not be descended into aluminum liquid until electrolyte is pumped out entirely (and aluminum liquid is not pumped out). A short circuit opening of the rebuilding tank buses is constructed and then the tank is powered off. Contacts of riser buses and cathode buses are cut off. Next, the upper assembly with self-baking anode is slung out by a crown block and welded to four axial seats of risers at the periphery of the tank. The assembled upper assembly with prebaking anode is slung to the rebuilding tank so as to be installed. Said prebaking anode is hooked and a bottom surface of the anode is descended into the reserved aluminum liquid in tank. Then the contacts of the riser bus and the cathode bus are welded together and an insulated sheet for the short circuit opening of the rebuilding tank is removed. The tank is then energized and poured with electrolyte. The anode is lifted and the tank renews normal production. It usually takes 8-10 hours for the reconstruction of each tank. For example, if there are 200 tanks in a single series, the upper assemblies of at least two tanks may be rebuilt by this means everyday. Thus it only takes more than three months to finish the reconstruction of the upper assemblies of all series of tanks. It is considered to implement the reconstruction of all series of devices in the form of power off if 200 tanks of the original series are aluminum electrolysis tanks with 65KA self-baking anodes. Currently, it takes about one year for the reconstruction project at a similar scale, -3- so that a loss of production resulted from stop production for the series of devices is about 33 thousands ton. The direct loss due to stop production is up to 5 hundreds million Yuan if the price of the aluminum ingot is about 15 thousands Yuan per ton. If all series of devices do not stop production, only those tanks to be heavily repaired are rebuilt on the spot. It is difficult to bear a long process of reconstruction due to the requirements of environmental protection, survival and self-development, although it does not directly effect the yield. If the method of the invention is used, it takes 10 hours for per tank and a loss of production of each tank is about 193Kg, then, a loss of production resulted from reconstruction of the series of devices is only about 38.6 ton. -4-

Documents:

0456-che-2006 abstract-duplicate.pdf

0456-che-2006 claims-duplicate.pdf

0456-che-2006 description (complete)-duplicate.pdf

456-CHE-2006 CORRESPONDENCE OTHERS.pdf

456-CHE-2006 CORRESPONDENCE PO.pdf

456-CHE-2006 FORM 18.pdf

456-CHE-2006 POWER OF ATTORNEY.pdf

456-che-2006-abstract.pdf

456-che-2006-claim.pdf

456-che-2006-correspondence-others.pdf

456-che-2006-description(complete).pdf

456-che-2006-form 1.pdf

456-che-2006-form 3.pdf

456-che-2006-form 5.pdf