SU1717584A1 - Raw materials mixture for manufacturing clay brick for cathode lining of aluminium electrolyzer - Google Patents

Abstract

The invention relates to the manufacture of refractories used for lining cathode devices of an aluminum electrolysis cell. In order to improve the performance properties of bricks by reducing the temperature of the beginning of softening, reducing the energy consumption for raw burning, improving the quality of electrolytic aluminum and increasing the service life of the electrolyzer, the raw material mixture includes the following components. The invention relates to the production of refractories, refractory masses and raw materials for producing ceramic materials. products, in particular, clay brick for coating the cathode devices of an aluminum electrolysis cell. Lime raw material mixture for the manufacture of clay bricks, including low-melting clay, emaciated and burnable additives in the following ratio of components, wt.%: Wt.%: Burnable additive 1-5, the powder of the upper layer cathode socle of the aluminum electrolyzer 44-78 and fusible clay the rest, moreover, the vybyka powder of the upper layer of the cathode socle has the following composition, wt.%: sodium fluoride 30-55, silicon oxide 25-40, aluminum oxide 10-15, iron oxides 2-3 and cryolite 8-12. The temperature of the onset of softening of clay bricks made from raw mix is reduced to 730-770 ° C, which allows you to create a plastic layer with protective properties directly during the firing of the bottom of the electrolyzer with the working temperature in the basement - brick 750-790 ° C, thereby preserving the integrity of the hearth in the early, most crucial period of the operation of the electrolyzer. By lowering the temperature of the onset of softening, the temperature of burning the raw material is reduced, which makes it possible to reduce the energy consumption for the manufacture of bricks. From the rational use of production waste, the cost of clay bricks used in the lining of aluminum electrolysis cells decreases. 2 tab. Depleting additives Burnable additives Fusible clay 5-20 1-3 The rest 1 VI CL 00-Ь The disadvantage of this raw mix is that the brick made from it has a high softening point, i.e. above the operating temperature of the cathode base, which prevents the plastic layer from being obtained from such a brick in the firing process of the bottom of the electrolyzer.

Description

Closest to the invention is a raw material mixture for the manufacture of clay bricks, comprising the following components, mill%:

Clay73-85

Burnout Supplement3-S

Fluorine-containing aluminum production wastes 12-22

The spent lining of electrolyzers 2 can be used as fluorine-containing waste.

A disadvantage of the known raw material mixture is that the brick made from it has a high softening onset (1300 ° C) due to the presence in its composition of fluorine-containing aluminum production waste - spent lining of electrolyzers with high refractoriness. Such a brick does not form a plastic layer during firing of the bottom of the aluminum electrolytic cell, which is able to compensate for vertical movements in the lining. Opening the central interblock seams leads to the penetration of molten aluminum to the cathode rods and to the heat insulating layers of the base. When the rods are dissolved, the grade of electrolytic aluminum deteriorates, and the violation of the integrity of the bottom with a decrease in the thermal resistance of the base leads to a reduction in the turnaround time of the operation of the electrolyzer. In addition, for firing raw material, a high temperature is required (950-980 ° C), which is associated with significant energy costs,

The aim of the invention is to improve the performance properties of bricks by lowering the temperature of the beginning of softening, reducing the energy consumption for firing raw material, improving the quality of electrolytic aluminum and extending the service life of the cell,

The goal is achieved by offering

the raw mix for making clay bricks for the cathode lining of an aluminum electrolysis cell, including low-melting clay, a burnable additive. aluminum production wastes containing sodium fluoride, silicon oxide, iron oxide, aluminum oxide, and contains the quality of aluminum production as waste powder: extraction of the upper layer of the aluminum electrolysis cell composition, wt.%: sodium fluoride 30-55g silicon oxide 25-40 , iron ohms 2-3, alumina 10-15 and cryolite 8-12 at

the following ratio of components, wt.%:

Burnout Supplement1-5

Vibration powder of the upper layer of the cathode base of the aluminum electrolysis cell of the specified composition 44-78

Fusible clayErest

The presence in the composition of the raw mix for the manufacture of clay brick of gray-white powder of the upper layer of the cathode socle (instead of fluorine-containing waste from aluminum production — spent lining of electrolyzers) at a given ratio of components reduces the temperature of the initial softening of brick from 1300 to 730-770 ° C, which makes it possible to create a plastic layer from it in the cathode base directly in the process of burning the bottom of the electrolyzer when the working temperature reaches 0 from 750-790 to 930 ° C. The plastic layer takes up the vertical forces arising in the cathode lining, thereby preventing the rise of the coal hearth and the opening of the central interblock stitches. 5 The penetration of molten aluminum to the cathode rods and into the underlying heat insulating layers of the basement is prevented in the early, most crucial period of the cell operation, which leads to an improvement in the grade of the electrolytic aluminum 0 and an increase in the service life of the cell,

By reducing the temperature of the onset of softening, the temperature of raw roasting significantly decreases, which leads to a reduction in energy consumption for the manufacture of bricks. In the raw mix, a fusible clay is used, the composition, wt.%:

Silicon oxide 70

Aluminum oxide .15

5 Oxides of iron

Calcium Oxide 5

Magnesia 1

Alkali Metal Oxides

 (NazO, K20) 2

0 As a burnable additives using coal material - coal or anthracite. A powder of gray-white substance is used - vybiku the upper layer of the cathode base with the content of components, wt.%:

Sodium fluoride30 - 55

Silicon oxide 25 - 40

Aluminum oxide 10-15

Iron oxides2-3

0 Cryolite8-12

The composition of the raw materials for the production of clay bricks is given in Table 1.

Of these mixtures, brick is prepared according to the usual technology, with the exception of roasting raw material carried out at a lower temperature. A brick made from the proposed raw material mixture is used to make the lining of the cathode base of the aluminum electrolysis cell. Samples are prepared that are tested for determining the temperature of the onset of softening.

The test results are shown in table 2.

As can be seen from the data of Table 2, the proposed composition of the raw mix ensures the production of clay bricks with a low softening onset temperature (730–770 ° C), which makes it possible to create a protective plastic layer in the cathode pedestal of the aluminum electrolyzer directly in the burning period of the hearth when reaching temperatures of 750–790 ° С, which leads to preservation of the integrity of the bottom in the early, most crucial period of the operation of the electrolyzer, as evidenced by the absence of molten aluminum proteins in the thermally insulated cathode basement and enny metal at high yield grade. The quality of electrolytic aluminum increases and the life of the cell increases. Due to a decrease in the temperature of the onset of softening, the tendease of the burner is reduced: oio: 1 o leads: d: more energy consumption for the manufacture of clay bricks.

FORUMA P 6 OUT 6. .

Raw mix for ready-made clay bricks for cathode fta; aluminum aluminum cell rozk, incl .;:

low-melting glyca, burnable additive, aluminum production wastes containing sodium fluoride, silica, iron oxide, aluminum oxide and cryolite, so that, in order to improve the performance properties of the ker-

by reducing the temperature of the beginning of softening, reducing the energy consumption from pressing raw material, improving the quality of electrolytic aluminum and increasing the service life of the electrolyzer, it contains as slots of aluminum production

cathode top coat

the base of the aluminum electrolysis cell composition, wt.%: fluoride nstri 30 - 55, oxide

silicon 25 - 40, iron oxide 2-3, oxide

aluminum 10 - 15 and cryolite 3 - 12 in the following ratio of components, wt.%:

Burnout Supplement1-5

Vibration powder of the upper layer of the cathode socket of the aluminum electrolysis cell of the specified composition 4 - 73

Rest

55

 ngCTOTWTJ J

G a b and c s 2

Claims (1)

The raw mix is the length of e-yugp ·· .. '··· -.i. clay bricks for the cathode flux of the aluminum electrolyzer, incl !? giving light-clay, a burnable additive, aluminum production wastes containing sodium fluoride, silicon oxide, iron oxide, aluminum oxide and cryolite, with the exception that in order to increase the operational properties of the brick due to lowering the temperature of the onset of softening, reducing energy consumption for roasting raw materials, improving the quality of electrolytic aluminum and increasing the life of the electrolyzer, it contains waste powder of the top layer of the cathode base aluminum as waste 40 to aluminum production electrolyzer composition, wt.%: sodium fluoride 30 - 55, silicon oxide 25 - 40, iron oxide 2-3, alumina 10 - 15 and cryolite 8 - 12 in the following ratio of components, wt.%: