RU1796601C - Melted and cast fire-proof material having high aluminum content - Google Patents

Abstract

Purpose: the invention relates to the refractory industry, in particular. 2 to refractory materials for lining glass melting furnaces. The inventive fused-cast aluminous refractory material contains, wt.%: MdO 0.4-2.8; B20z 0.2-2.5; Si02 0.2-0.4; Na20 0.2-0.4; - the rest. The new ratio of components provides high corrosion properties (corrosion in the melt of the Co-115 aluminosilicate glass at 1500 ° C for 24 hours was 0.30-0.45 mm) and a minimum tendency to release defects in the molten glass. The use of the invention will extend the campaign of glass melting furnaces during the cooking of sintered aluminum silicate glass and expand its production. 1 tab, fe

Description

The invention relates to the refractory industry and can be used for the manufacture of molten alumina refractory refractory materials for the lining of glass melting furnaces.

Known fused cast refractory material based on alumina, containing, wt.%: MdO 5-10. N320 0.2-0.4, Si02p, 2-0.4i ABO3 - the rest.

The disadvantage of this refractory is the low corrosion resistance to melts of sintered aluminum silicate glass.

The closest technical solution to the proposed one is fused refractory material containing.

wt.%: MdO 3-12, 5X2 0.5-2.0. Zr02 0.5-2.0. Na20 0.5-1.0. B20z 3-12, - the rest. The said refractory is characterized by reduced corrosion resistance to the action of melts of sintallizing aluminosilicate glass at temperatures of 1500-1550 ° C. In addition, the presence of zirconium dioxide adversely affects the physical properties of the resulting ceramic. An object of the invention is to increase the corrosion resistance of a refractory material in melts of a sintered aluminosilicate glass. The goal is achieved in that the fused-cast aluminous refractory material, including A12Oz, MdO, B20z,

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Na20 and S102 containing these components in the following ratio, May. %: MdO0.4-2.8 V20z 0.2-2.5 S102 0.2-0.4 NaaO 0.2-0.4 A1aOz Else The ratio between, MdO and BaOz is determined empirically and provides a fluid melt, forms a dense texture of the refractory, characterized by a low corrosion rate in the melt of glass-forming aluminosilicate glass.

A decrease in the content of MgO and BrO3 oxides, respectively, less than 0.4% and 0.2% leads to a significant increase in the porosity of the material, an increase in the degree of melt impregnation, and, as a result, reduces the corrosion resistance of the refractory. In addition, an improvement in the casting properties of the melt is noted when the content of BrO3 and MgO exceeds 0.5% of each component.

The presence of MgO in the range of up to 2.8% and BrO3 in the range of up to 2.5% forms in the refractory, respectively, refractory crystalline phases: magnesian spinel in an amount of up to 10% and borosluminate QAIaOs 2B20z in an amount of up to 20%, which provide the required corrosion resistance refractory material in a melt of a sintered aluminosilicate glass. However, an increase in the content of MgO and B203 over 2.8 and 2.5%, respectively, leads to a decrease in the corrosion resistance of the refractory.

A limited content of SI02 and N32O oxides in the range of 0.2-0.4% allows the formation of a glass phase in the refractory, not exceeding 3% in volume, which ensures the manufacturability of the production of refractory products (minimum rejects for cracks and chips of the product corners).

In order to obtain refractory material, mixtures of alumina, magnesium oxide, boric anhydride, silica sand and soda were prepared. The charges were melted in an electric arc furnace at a voltage of 150-160 V on electrodes and a current of 600-1000 A. The melts were conducted under oxidizing conditions (on an open arc, with electrodes raised above the melt). The melt was poured into graphite casting molds, after which the resulting castings were annealed under natural conditions in thermocouples with diatomite filling for 3-4 days.

Specific compositions of the proposed refractory material are presented in the table.

Determination of the corrosion resistance of refractory materials was carried out under static conditions. Refractory samples of 10x10x100 mm in size were kept in a melt of a metallizing aluminosilicate glass of the СО-115 М grade at a temperature of 1500 ° С for 24 hours.

Corrosion resistance (corrosion rate) was evaluated by changing the thickness of the sample before and after the test at the level of glass melt.

It follows from the table that the refractory alumina material of the proposed composition (formulations 2-8) is characterized by increased corrosion resistance compared to the known refractory (formulations 10-11).

The use of the claimed invention allows:

- organize the production of fused alumina refractories for the needs of the optical industry.

- increase the duration of the campaign of glass melting furnaces due to the greater corrosion resistance of refractories with high quality glass production.

Formula a of the invention Fused-cast highly clayey refractory material, including. МДО, В20з, S102 и МазО, characterized in that, in order to increase the corrosion resistance to melts of sintallizing aluminosilicate glass, it contains

these components in the following ratio. wt.%:

MdO0.4-2.8 VDz 0.2-2.5 StO2 0.2-0.4 Na20 0.2-0.4 Alabs Else