SU1694541A1 - Raw mixture for making bricks - Google Patents

Description

one

(21) 4720516/33 (22) 07.20.89 (46) 30.11.91. Bul №44

(71) Bratsk aluminum plant

(72) A.N. Little, FK Teplov and A.P. Panin

(53) 666.713 (088.8)

(56) Kashkaev I.S. and others. Production of clay bricks. M .: Higher School, 1974, p. 19-36.

USSR Author's Certificate No. 617435, cl. From 04 To 33/00, 1976. (54) RAW MATERIAL MIXTURES FOR MANUFACTURING A BRICK

(57) The invention relates to the production of refractories for the lining of cathode devices of an aluminum electrolysis cell. The purpose of the invention is to reduce the firing temperature and to obtain a brick for the cathode lining of an aluminum electrolyzer with improved performance properties by lowering the temperature of the softening and forming a ductile protective layer during the firing period of the aluminum electrolysis cell. For this, the raw mix includes the following components, wt.%: Burn out additive 1-5; sodium fluoride 20-35; fusible clay - the rest. The firing temperature of raw 700-750 ° C, is completely absent aluminum flowed to the base during firing hearth. 2 tab.

The invention relates to the manufacture of refractories and relates to refractory masses and raw materials for the production of ceramic products, in particular clay bricks for lining cathode devices of an aluminum electrolysis cell.

The purpose of the invention is to reduce the firing temperature and to obtain a brick for the cathode lining of an aluminum electrolysis cell with improved performance properties by lowering the softening start temperature and forming a ductile protective layer during the firing period of the bottom of the aluminum electrolysis cell.

The presence in the composition of the raw material mixture for the manufacture of clay brick sodium fluoride and the absence of otoshchitel and replacements (/ С

at specified ratios of the components, they reduce the temperature of the onset of softening to 720-770 ° C, which makes it possible to create from it a plastic layer between the carbonic bottom and the heat insulating base directly in the process of burning and starting the electrolyzer when the operating temperature in the location zone brick 740-790 ° C, i.e. in a short time. With the formation of a ductile protective layer in the baking process of the hearth, its density is maintained in the early most critical period of the operation of the electrolyzer, which is associated with intensive heating and impregnation with lining salts, as a result of which melt penetration is prevented.

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aluminum to the cathode rods and into the underlying thermal insulation layers of the base, which leads to an improvement in the grade of electrolytic aluminum and an increase in the service life of the electrolyzer.

In addition, due to the low temperature of the beginning of softening, the temperature for burning the raw material from the proposed mixture is reduced.

A decrease in the temperature of the beginning of the g-I phase to 720-770 ° С allows placing clay bricks with obtaining a plastic layer (pillow) in the zones of the socle with a working temperature from 930 to 740-790 ° С. Due to such a wide range, the efficiency of application of clay bricks made from the proposed raw mix in the lining of an aluminum electrolyzer is improved.

The fusible clay has a composition, wt.%: SI02 70; 15; iron oxides b; CaO 5; MDO 1; alkali metal oxides (NaaO and KAO) 2.

As a burnable additives using coal material, coal or anthracite. Use technical sodium according to GOST 2871-75 with the change No. 1 corresponding 1,

The compositions of the raw materials for the production of clay bricks are presented in Table. 1, Of these mixtures, the clay brick is used in a well-known technology, with the exception of the process 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 device of an aluminum electrolysis cell, located between the thermal insulation layer and the carbon hearth.

In tab. 2 shows the test performance of clay bricks in the electrolyzer.

Claims (1)

Invention Formula Raw material for making bricks, including low-melting clay, burnable additive and metal fluoride, characterized in that, in order to reduce the firing temperature and to obtain bricks for the cathode lining of the aluminum electrolyzer with improved performance properties by reducing the temperature of the beginning of softening and forming a ductile protective layer during the firing of the bottom of the aluminum electrolysis cell, it contains sodium fluoride as a metal fluoride in the following ratio of components. wt.%: Burnout additive1-5 Sodium fluoride 20-35 Fusible clay Remaining table Table 2