Lining structure of large-scale pre-baking aluminium electrolysis trough

Abstract

The invention relates to an improvement of apparatus in aluminium electrolytic industry, specially relate to a large-sized lining structure for prebaking aluminium electrolysis. The inventive lining structure has, on the bottom of electrolytic cell housing, from the bottom up, in order, asbestos plate layer, heat-insulating layer made of calcium silicate plate with heat-resisting, heat-insulating layer made of both layers light-weight bricks, impermeable layer made of one layer alumina, impermeable layer made of both layers firebricks, half-graphite-rod-cathode complex TiB2 coating, with the leteral of allotypic lateral mass. The advantages of the invention are that: (1) the structure has higher heat conductivity, lower electrical resistivity and low dilatability of electrolytic sodium, and current distribution in cathodic charcoal is more uniform; (2) impermeable layer is especially advantageous for prolonging the life of electrolytic cell; (3) allotypic lateral mass has higher thermal conductivity and lower electrical resistivity, in particular, prolonging the the life of electrolytic cell. The large-sized lining structure for prebaking aluminium electrolysis of more than 200kA is used in the invention.

Description

technical field [0001] The invention relates to an improvement of equipment in the aluminum electrolysis industry, in particular to a lining structure of a large prebaked aluminum electrolysis tank. Background technique [0002] The design of the electrolytic cell lining is related to the production index and cell life of the electrolytic cell. It is generally believed that a good lining design should be able to meet the special requirements of the heat balance of the electrolytic cell, and a good heat dissipation should be formed on the upper part of the cell side to ensure a regular furnace side in the cell. The lower part of the tank sides and the bottom need to be well insulated to save energy and prevent excessive leg extension. In addition, special attention should be paid to the selection and combination of bottom insulation materials to ensure that the 900°C temperature line falls below the cathode carbon block, and the 800°C isotherm line ...

AI Technical Summary

Problems solved by technology

This kind of lining structure has the following disadvantages: (1) the bottom adopts semi-graphite cathode carbon block containing 6-10%, due to the low thermal conductivity, low resistivity and high sodium expansion rate, in Electrolytic production cannot effectively prevent the sodium expansion caused by the penetration of sodium in the electrolyte. (2) dry anti-seepage material, because the light anti-seepage material cannot be compared with NaF-Na 3 AlF 6 The eutectic temperature (888°C) is high, even 30°C lower, and it cannot effectively prevent the penetration of sodium in the electrolyte and produce a large amount of gray-white layer at the bottom of the cathode carbon block; (3) The side is a semi-graphitic carbon block , due to the high electrical conductivity and low thermal conductivity, it is easy to generate leakage on the side during electrolytic production and cannot form a regular furnace on the side

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