SU1740499A1 - Method of roasting and starting electrolyzer for obtaining aluminium - Google Patents

Abstract

Usage: electrolytic production of aluminum from molten salts. SUBSTANCE: method of burning and starting an electrolyzer for producing aluminum includes mounting anode cells with electrically insulated side walls and an electrically conductive bottom on the bottom, mounting electric heating elements, loading anode mass, heating and forming a self-burning anode in a series, melt pouring, installation voltage on the cell. As the anode burns out, the self-burning anode cells are replaced with burnt anodes. The method of calcining and starting the electrolyzer to produce aluminum allows for a smooth, uniform heating of the bottom and an increase in the service life of the electrolyzer. 2 Il.

Description

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The invention relates to an electrolytic method for producing aluminum from molten salts and is aimed at improving the firing and start-up of the electrolyzer.

There is a known method of burning and starting an electrolytic cell to produce aluminum, including heating the bottom and firing seams using grit carbon materials, as well as fusing electrolyte from salts by electrolytic current. In this method, coal grains separated from dust and having a uniform grain composition are used as electrical resistance, which serves to generate heat in the electrolyzer. A layer of this grit is placed between the anode and the hearth.

The disadvantage of this method is that the electrolyzer is put into operation only after disconnecting it from the electrical network of the series for cleaning

hearth from coal grains. During the bottom cleaning process, the carbon-graphite lining is cooled, shrinkage cracks are formed in the bottom, through which the cathode aluminum penetrates to the cathode rods during the start of the electrolyzer, dissolves them, reducing the service life of the electrolyzer.

Closest to the invention is a method comprising laying a metal sheet on a hearth, installing shell plates and heating elements, loading the anode paste, heating the bottom, forming a self-burning anode with a series current, pouring the melt and connecting the operating voltage.

The disadvantage of this method and the start-up of an electrolytic cell to produce aluminum is that when the anode paste is fired, an anode array is formed with through cracks through which the liquid anodic mass flows out during the start-electrolyzer.

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interelectrode space, closure anode with cathode aluminum. In the region of the sub-electrolyte, it overheats. Uneven current distribution in the anode and hearth ultimately leads to premature shutdown of the electrolyzer for overhaul.

The purpose of the invention is to increase the service life of the aluminum electrolysis cell due to the uniform heating of the bottom.

The goal is achieved by the fact that according to the known method of burning and starting the electrolyzer to produce aluminum, including laying a metal sheet on the hearth, mounting the anodic cells of the shell and heating elements, loading the anode mass, heating the bottom, forming a self-burning anode in the series, melt casting and the connection of the working voltage, pre-set wooden partitions separating the anode cells in the hearth, and after burning the anrd install the burned anode block .

It is known that electrolyzers with a self-burning anode and the upper current supply of a new series have a service life of 10-15 months more than electrolyzers with burnt anodes of a new series of the same power. One of the main reasons for the decrease in the service life of electrolyzers with burnt anodes of the new series is the imperfection of the technology of burning and starting electrolyzers. The proposed technical solution allows to provide the same firing conditions and the start-up of electrolyzers with baked anodes as are the case when firing and starting electrolyzers with a self-burning anode and upper current supply, i.e. the formation of a new anode and uniform heating of the hearth with a slow rise of the current series. Distinctive features of the claimed technical solution from the known ones are that before forming the anode of the anode, the anode array is divided by partitions into rectangular cells, the dimensions of which are equal to the dimensions of the annealed anode. In the anode cells, the anode blocks are burned; as the anode burns, the anode blocks are replaced by burned anodes.

Figure 1 shows the electrolyzer, a cross-section; fig 2 is the same, top view. Cathode casing 1, lined from the inside insulating and carbon-graphite

lining 2, installed on concrete supports. Aluminum sheets 4 are placed on a carbon-gravel bottom 3 and wooden partitions 5 are installed. An aluminum shell 6 is mounted in each cell. The heating elements 7 are made of steel strip. The anode holders 8 are welded with heating elements, installed on the bottom of the aluminum shell and connected to the anode busbar. I am loading the small briquette anode mass 9 into the anode cells of the self-burning anode. The shaft of the electrolyzer is closed with steel covers 10. The electrolyzer is connected through a shunt-rheostat, and the current rate of rise is maintained. The carbonaceous anode mass is melted and coked. The uniformity of sintering cone growth is achieved by differentiating the electrical resistance of the heating elements, disconnecting and connecting the anode cell, and the rate of current rise. The firing of the bottom and the anode is completed when the height of the sintering cone is equal to 2/3 of the height of the anode pillar. The anode is torn from

the bottom surfaces, pour the cathode metal and the electrolyte, raise the voltage on the electrolyzer to the anode effect, weld the melt, and set the operating voltage on the electrolyzer. As

the anode burns a burned anode block.

Claims (1)

Claim Method A method for burning and starting an electrolytic cell to produce aluminum, including laying a metal sheet on a bottom, installing anode cells by installing a shell and heating elements, loading the anode paste, heating the bottom, forming a series self-burning anode, pouring the melt and connecting the operating voltage, characterized in that, in order to increase the service life of the electrolyzer, wooden partitions are pre-installed on the hearth, separating the anode cells, and after the combustion of the anode set the burned anode block. ft / g 1 fig 2