SU1397543A1 - Method and electrolyzer for producing aluminium - Google Patents

Abstract

1. A method of producing aluminum by the electrolysis of chloride melts at a temperature of 670-750 ° C and an aluminum chloride concentration of 5-40 wt.%, About the fact that, in order to increase productivity and reduce power consumption, before the introduction of aluminum chloride, a melt of chlorides Hold in the electrolyzer at an electrolysis temperature of 3-5 minutes, and electrolysis is carried out at an anodic current density of 2-20 A / cm and a cathode current density of 0.8-3.0 A / cm. 2. An electrolyzer for producing aluminum, containing a caisson metal case with a bottom, flat anodes and cathodes and a crush, which also, in order to increase productivity and reduce energy consumption, the anodes and the cathodes are made with vertical hollow cavities filled with low-melting metal, the lower edge of the cathodes is located at a distance of 0.3–1.0 of their thickness from the bottom, and the anodes are at a distance of 1.8–3.0 of their thickness from the bottom . i (L

Description

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The invention relates to the electrolytic production of aluminum, to a method for producing aluminum by the electrolysis of chlorides, and to a cell structure.

The purpose of the invention is to increase productivity and reduce power consumption.

Figure 1 shows the cell, longitudinal section ;, figure 2 is the same, the cross-section.

The electrolyzer contains a caisson water-cooled metal body 1 with a water-cooled cap 2. In the side walls of the body 1 there are electrically insulated holes 3 for introducing the current leads 4 to the graphite electrodes — the anodes 5 and the cathodes 6.

The anodes 5 and cathodes 6 are made flat with deaf cavities 7 filled with a low-melting metal, for example, aluminum.

The lower edge of the anodes 5 is located on

The distance 1.8-3.0 of the anode thickness 5 from 25 liters has the following composition, wt.%:

thirty

35

40

cathode 6 - at a distance of 0.3-1.0 cathode 6 thickness from the bottom.

The cell operates as follows.

A melt of chlorides, for example, sodium and potassium chlorides at a molar ratio of (2-3): 1 is poured into the electrolyzer and held at an electrolysis temperature of 670-750 C for 3-5 minutes. At this time, a skull is formed in the walls of the housing 1, which serves as a lining.

Then in the melt load aluminum chloride in the amount of 5-40 wt.% From the mass of the melt. Through the anodes 5 and the cathodes 6, a constant current is passed with an anode density of 2-20 A / cm and a cathode density of 0.8-3 A / cm,

During electrolysis, aluminum is formed at cathode 6, and chlorine is formed at anode 5. Aluminum accumulates on the bottom and the chlorine is removed from the electrolytic cell through the opening in lid 2. Aluminum chloride is continuously fed to the electrolytic cell to maintain a concentration of 5-40 wt.%, 50 and the aluminum is periodically downloaded,

for example, using a vacuum ladle, t

The metal accumulating on the bottom of the electrolytic cell gradually closes the lower part of the cathodes 6, forming a single cathode with a developed surface, exceeding 3-12 times the area of the anodes 5.

45

55

NaCl 80, NaF 11, AlF, 9, to which up to 15% aluminum chloride is added.

Example 2. The electrolyzer described in example 1 is characterized in that the electrodes do not have cavities 7.

Example 3. An electrolyzer, as described in Example 1, characterized in that it has areas of immersed electrodes of 84.5 cm, which do not have a cavity. The electrolyte consists of NaCl-KCI in a molecular ratio of 2: 1. The concentration of aluminum chloride was maintained within 5.1–5.3 wt.%.

EXAMPLE 4. An electrolyzer, op Sanny in Example 1, is characterized in that it has areas of immersed anode 5 equal to 42.5 cm, cathode 6 is 84.5 cm, electrodes are made of flat graphite plates 1.5 thick cm with two cavities 7 in each with a diameter of 6-8 mm and not reaching the bottom plane of the electrodes. The strips 7 are filled with aluminum. The electrolyte is from NaCl: KCl in a molecular ratio of 2: 1, the concentration of aluminum chloride is maintained within 5 5.6 wt.%.

Example s5i6. The electrolysis described in example 4, characterized in that it has an electrolyte, in which the content of aluminum chloride is maintained in the range of 6-7 wt.%.

The vertical dummy cavities 7 contribute to the reduction of the ohmic resistance of the electrodes, which makes it possible to maintain elevated current densities without additional heat. This reduces power consumption and improves performance.

Example 1. A large-scale, water-cooled, skull-type cell, open at the top, is a rectangular case 1 with internal dimensions of 160 x 120 x X 150 mm.

A cathode 6 is installed in the electrolyzer, the immersion area of which is 167 cm in the electrolyte, and the anode 5, the submerged area of which is 420 cm. The electrodes are flat, 13 5 cm thick, with cavities 7 5-6 mm in diameter and 50 mm lower electrolyte level, but not reaching the bottom of the electrode; Electro

NaCl 80, NaF 11, AlF, 9, to which up to 15% aluminum chloride is added.

Example 2. The electrolyzer described in Example 1 differs only in that the electrodes do not have cavities 7.

Example 3. The electrolyzer described in example 1, characterized in that it has immersed electrode areas of 84.5 cm, which do not have cavities. The electrolyte consists of NaClrKCI in a 2: 1 molecular ratio. The concentration of aluminum chloride was maintained in the range of 5.1-5.3 wt.%.

EXAMPLE 4. The cell described in example 1 differs only in that it has areas of immersed anode 5 equal to 42.5 cm, cathode 6 to 84.5 cm, the electrodes are made of flat graphite plates 1 , 5 cm with two cavities 7 in each 6–8 mm in diameter and not reaching the lower plane of the electrodes. Cavity 7 is filled with aluminum. The electrolyte consists of NaCl: KCl in a molecular ratio of 2: 1, the concentration of aluminum chloride is maintained in the range of 5.1–5.6 wt.%.

Example s5i6. The electrolyzer described in example 4, characterized in that it has an electrolyte in which the content of aluminum chloride is maintained within 6-7 wt.%.

31397543

Example 7-7. Electrolyzer, indicators with indicators of others

described in example 4, different ways produced comparative

the fact that it has areas of immersed calculation of the performance of the electrolyte 5 12.5-13 cm and the cathode 84 cm Zera with internal dimensions 1 1 1000 x

there are cavities in the electrodes 7, zapol-x 1000 x 1000 mm,

liquid aluminum, and the content of the test results by

aluminum chloride in the electrolysis of sub-: examples 1-8 are shown in the table, kept in the range of 10-25 wt.%. As can be seen from the table, carrying

Since in studies using the proposed modes (the large-laboratory electrolysis cells 4, 6, and 7 are encouraged),

and its operation time from 8-10 hours to non-improve performance and reduce

how many days, then for the sake of its consumption of electricity.

Note. In example 1, use the known electrolyzer

and in Examples 3-8, proposed.

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Claims (2)

A method of producing aluminum and an electrolysis cell for producing aluminum 1. A method for producing aluminum by electrolysis of chloride melts at a temperature of 670-750 ° C of aluminum chloride 5-40, which involves a concentration of wt.%, About 1 liter, in order to increase productivity and reduce energy consumption , before the introduction of aluminum chloride, the chloride melt is maintained in the electrolyzer at an electrolysis temperature of 3-5 minutes, and the electrolysis is carried out at an anode current density of 2-20 A / cm ² and a cathodic current density of 0.8-3.0 A / cm ² . 2. An electrolytic cell for producing aluminum, comprising a coffered metal case with a bottom, flat anodes and cathodes and a cover, characterized in that, in order to increase; To improve performance and reduce energy consumption, the anodes and cathodes are made with vertical blank cavities filled with fusible metal, the lower edge of the cathodes is located at a distance of 0.3-1.0 of their thickness from the bottom, and the anodes are at a distance 1.8-3.0 of their thickness from the bottom.