Method for roasting aluminum electrolytic tank with special-shaped cathode structure

Abstract

The invention relates to an aluminum electrolytic technology, more specifically relates to a preheating and roasting method for an aluminum electrolytic tank, especially provides a method for roasting the aluminum electrolytic tank with a special-shaped cathode structure. The invention solves the technical problem that the aluminum electrolytic tank with special-shaped cathode structure can be roasted by reducing the amount of a carbon material. The roasting method comprises the following steps: A, filling a basic material in a special-shaped cathode groove, wherein the basic material can not contact with anode; B, laying the carbon material on a convex plate of the special-shaped cathode, wherein the carbon material is contact with anode; C, electrifying and roasting; wherein the basic material is an electrolyte block or / and cryolite. One of the electrolyte block and cryolite can be selected, or a mixture of the electrolyte block and cryolite can be used; any proportion can be employed for mixing. The roasting method of the invention can reduce the carbon material amount, the workload for fishing, and the phenomena of overburn and chipping. The method of the invention provides an effective method for roasting the aluminum electrolytic tank.

Description

technical field [0001] The invention relates to an aluminum electrolysis process, in particular to a preheating roasting method for an aluminum electrolytic cell, in particular to a roasting method for an aluminum electrolytic cell with a special-shaped cathode structure. Background technique [0002] Roasting the aluminum electrolytic cell is the process of preheating the inner lining of the aluminum electrolytic cell, which generally needs to be heated to above 900°C. This process is directly related to the start-up quality of the aluminum electrolytic cell, and affects the later production and service life of the aluminum electrolytic cell, especially the life of the lining of the aluminum electrolytic cell. The purpose and function of roasting the aluminum electrolytic cell are: (1) coking: by roasting the solid paste between the cathode carbon block and the side carbon block to make it coke, so that the cathode carbon block and the side carbon block become a whole; (2 ...

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Problems solved by technology

However, the use of grooves increases the difficulty of roasting coke particles. Taking the 300KA large-scale prebaked aluminum electrolytic cell as an example, the aluminum electrolytic cell with a planar cathode structure needs about 800kg of coke particles and about 200kg of graphite powder. The amount of coke particles after the tank will reach 2.5 tons, and the amount of graphite powder will exceed 1 ton. Carbon materials such as coke particles and graphite powder must be salvaged after the aluminum electrolytic cell is started. At the same time, affected by the high temperature factors of the aluminum electrolytic cell, more than 1 ton of carbon slag will remain in the aluminum electrolytic cell, which will have an adverse effect on the normal production of the aluminum electrolytic cell, resulting in the voltage and temperature of the aluminum electrolytic cell If it is too high, the stability of the aluminum electrolytic cell will deteriorate, which will eventually increase the unit energy consumption of primary aluminum

Although the problem of salvage can be overcome if fuel roasting is used to treat aluminum electrolytic cells with special-shaped cathode structures, fuel roasting will cause early damage to aluminum electrolytic cells (data show that an electrolytic aluminum factory uses this method, and electrolytic cells occur within 3 months after start-up) Leakage phenomenon), affecting the economic benefits of production enterprises

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