SU1542420A3 - Electrolyzer for electrolytic production of aluminium from cryolite-silica melt - Google Patents

Abstract

In an electrolytic cell for the production of aluminum from alumina, having an anode-to-cathode gap of from 1 to 5 cm, the flow of electrolyte to the inter-electrode gap is induced by positioning the cathode at an inclination of from about 2 to about 15 degrees from the horizontal, and operating at an anode current density of from about 0.5 to about 3.0 A/cm<2>. The cathode surface is a Refractory Hard Material which is wetted by aluminum.

Description

WITH

with

The invention relates to non-ferrous metallurgy, namely, electrolytic cells for the production of aluminum.

The aim of the invention is to reduce energy consumption by optimizing the flow of electrolyte.

Figure 1 shows a cell having a cathode in the shape of an inverted V, side view; figure 2 - the cell, where the cathode is made with a single slope, side view; on fig.Z - the electrolyzer, where the electrolyzer is flow-through, and the cathode - with one slope, side view; 4 shows an electrolysis cell with a V-shaped cathode having a central metal discharge, side view; Fig. 5 shows a cell with one inclined cathode, having a system for continuously discharging aluminum and a separate zone for replenishing and mixing, horizontal projection; Fig. 6 illustrates the placement of a series of electrolyzers with cathodes having a single slope, a horizontal projection; Fig. 7 shows a cell with a cathode having a single slope, in which partitions are made to limit the flow rate in the bath, a horizontal projection; on - electrolyzer, helcododes have opposite slope, horizontal projection; figure 9 is an experimental electrolyzer with an inclined cathode, the section; Fig. 10 is an experimental electrolyzer, vertical projection from the side.

The electrolyzer contains anodes 1, an opening 2 for the outlet of anode gases, a system 3 for collecting gases, cathode rods 4, a collector 5 for aluminum, coating the surface of the cathode 6,

space 7 between the cathode and the anodes, a hopper 8 for feeding alumina, an outlet 9 from the bath, partitions 10, bypass channels 11, a system 12 for continuous discharge of aluminum, gas bubbles 13, a mechanical cover 14 a magnetic pump 15. Arrows in the drawings indicate the flow of metal and gas bubbles.

The essence of the invention lies in the fact that the return bypass channels of the electrolyzer for the production of aluminum are made with dimensions determined by the formula

(О «« Г Д2Ь ± Н)

im - z i p.w-b)

where h is the depth, cm;

W - width, cm;

L is the length of the corresponding bypass channels, cm; n is the number of bypass channels.

The cathode is located at an angle of 2-15 ° to the horizontal plane, and the distance between the anodes and the cathode is 1-5 cm.

The length of the bypass channels is 15-300 cm, and the surface of the cathode is made of titanium diboride.

This dependence is characteristic of a cell with a different arrangement of anodes and a cathode (Fig. 1-10),

The location of the cathode at an angle of 2-15 due to the following. The slope of the cathode 2-15 provides the required flow of metal in the bath and avoids turbulence between the cathode and the anode.

The angle of inclination affects the configuration and movement of the gas bubbles. When the cathode surface is inclined from the horizontal, the bubbles have an oblong oval shape, the long axis of which runs perpendicularly to the direction of movement of the puffs on the cathode inclination. Large sized bubbles on the cathode surface undergo significant deformation and resistance when the cathode is inclined 15 ° from the horizontal.

The preferred slope of the cathode is 6-8 °. The best results were obtained when the cathode was tilted at an angle of 8 °. When the angle of inclination increases more than 15, an obstacle to the discharge of aluminum is found.

The cathode surface is made with a titanium diboride coating. That is.

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the coating ensures good wetting of the cathode with aluminum. Aluminum easily flows from the inclined surface of the cathode. This increases the current output of the metal, accelerates the release of the metal. The thin film of the flowed aluminum is not sensitive to the created magnetic fields m.,

Example. Figure 10 shows the relationship of parameters such as the angle of inclination of the cathode (F) predominantly. 2-15, the size of the surface of the anode in the direction of the flow of bubbles (designated as BFL and equal in many tests 122 cm), the size of the surface of the anode perpendicular to the direction of flow of bubbles (equal in many tests 61 cm);

the distance between the inclined surfaces of the anode and the cathode (labeled ACD and equal to 1-5 cm)} immersion depth of the vertical anode h (varies depending on the size of the BFL in accordance with the cathode angle), the minimum anode immersion depth at the high end of the cathode B0) equal to 10 cm in most tests; the width of the channels of the upper W in and lower

Wh

The bypass channels transfer the metal flow in the bath from the upper channel to the corresponding lower channel, and are located along the edge of the anodes, where there is a gap in the bath between the anode and the cathode.

Tests have shown that inclined cathode electrolyzers are more stable in operation.

At reduced distances between the anodes and the cathode, the voltage decreases and more localization removes the anode gases.

Claims (3)

1. Electrolyzer for electrolytic production of aluminum from a cryolite-alumina melt containing a bath, anodes, an inclined cathode with an aluminum-wetted surface, a working compartment between the cathode and each anode characterized in that, in order to reduce energy consumption, by optimizing the flow of electrolyte the bypass channels are made with dimensions determined by the formula - «- r (2b + w) -i, r1 / 2 where h is the depth, cm; W - width, cm; (0,4) ± (Ig-) L is the length of the corresponding bypass channels, cm; p - the number of bypass channels, eight // S / S 7777Y / T FA4.W4HH / 14 five the cathode is inclined at an angle of 2 to 15 degrees to the horizontal plane, and the distance between the anodes and the cathode is 1 to 5 cm. 2. Electrolyzer according to claim 2, characterized in that the length of the bypass channel is 15-300 cm. 3. The electrolyzer according to claim 1, wherein the surface is The cathode is made of titanium diboride. TGGG / 2 f {t 77777t CHHHU u 1  I / g / J eight 2 about um Jg-j r LO I ten, fl 512 i & 1Z n SEE five s . FIG. at -n FIG. 7 7 W TO Schi To ACD UCffl Ј0.fOcmL FIG. 9 10