SU1081149A1 - Refractory composition for lining induction furnaces - Google Patents

Abstract

REFRACTORY WEIGHT FOR INDUCTION FUTE- Rovkov PECHEP comprising vysokokremnezemisty material slag aluminothermic producing metallic chromium, silicon carbide and boron-containing material of m and n sistent with the fact that, in order to increase the smelting metalloustoychivosti grained tin bronzes, it contains boron as component octoborate of sodium and additionally - aluminosilicate material in the following ratio of components, May.%: Slag of aluminothermic production of metal chromium 5-15 Karborund 5-15 (L Oktoborat on When 0.5-2.5 aluminosilicate ma35-55 Therians Vysokokremnezemisty Other material

Description

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About the invention relates to compositions of refractory masses used to make linings for induction furnaces, melted copper-based alloys. Currently, the smelting of tin bronze from recycled materials is predominantly carried out in reflective furnaces. The remelting of secondary raw materials (scrap, chips, etc. in such melting units is characterized by high waste of alloy components, insufficient precision of the chemical composition, sanitary conditions and hygienic working conditions, prospective melting units for melting secondary raw materials including tin bronze , large-capacity induction furnaces that have significant advantages compared to reflective furnaces are counted. However, the existing and widespread ramming mass compositions for smelting alloys based on copper, do not meet the operational requirements for smelting tin bronzes, which is one of the main reasons hindering their widespread adoption in industry. The known refractory padding mass for lining induction furnaces that produce copper-based alloys, including quartzite and 23 wt.% Borax or boric acid. The mass is widely used in induction furnaces, as it has a low cost and is characterized by high reliability in the work as a result of the absence of shrinkage effects that lead to the passage of metal The inductor during the ClJ service. However, it has been established by tests that the lining of induction furnaces made of the specified mass during melting of tin bronzes is characterized by low chemical stability and high melt permeability as a result of cracking, which is not related to polymorphic transformations of quartz, and low thermal stability. Closest to the offer is a refractory mass for the fusion of induction furnaces, including a high-silica material (37.0-84.5 wt.%), Slag of aluminothermic production of chromium metal (10.0-30.0 wt.%), Carborundum (5.0-30.0 wt.%) And boron boric anhydride or boric acid (0 3.0 wt.%) As a boron-containing material. The lining, manufactured and of a known mass, is distinguished by increased strength, heat resistance and wound metal permeability when melting on the basis of copper C2. However, when smelting tin Ronz lining, made of an assa of known composition, it is characterized by low metal resistance and, as a result, by deep impregnation of the lining with melt components. The aim of the invention is to improve the metal resistance in the smelting of tin bronze. This goal is achieved by the fact that the refractory mass for lining induction furnaces, including high-silica material, slag of aluminothermic production of metallic chromium, carborundum and boron-containing material, contains sodium oktoborate as a boron-containing component and additionally aluminosilicate material with the following ratio of components, May,%,%,%, and%: Aluminum thermal production of metallic chromium 5-15 Carborundum 5-15 Oktoborat sodium 0.5-2.5 Aluminosilicate material 35-55 High-silica material Wasps cial As vyuokokremnezemistogo material may be applied .kristallichesky skvartsit, quartz or mixtures thereof. The most effective use of high-silica material fraction 7-1 mm, sodium oktoborat should be used in the form of a fraction of less than 0.5 mm. By chemical composition, slag contains 75-85% alumina, 10-16% calcium oxide, 7-10% chromium oxide, 0.5-1.5% magnesium oxide and 0.2-0.5% silicon oxide. The highest performance indicators of the composition are characterized when using slag granular less than 1 mm. It is advisable to use a carborundum black or green fraction less than 0.3 mm. Chamotte, predominantly mullite or mullite-corundum compositions, a distensillimanite concentrate or their mixtures can be used as an aluminosilicic material. If it is necessary to obtain plastic mass, one fifth of the aluminosilicate material can be in the form of ground refractory clay (fraction less than 0.5 mm) . It is advisable to use aluminosilicate material of a fraction of 3-0 mm. The manufacture of the lining can be done using pneumatic tamping, vibro-compaction or other conventional methods.

The compositions of the mixture are given in Table 1, and the results of testing samples containing various types of high-silica and aluminosilicate materials are given in Table. 2

Table 1

High-silica 22.5 33.5 i 44.5 material Crystal-Kristalli-Quartz

quartzite

Slag alumothermic production of metallic chromium

Carborundum Oktoborate Sodium Lumosilicate Material

The main advantage of the lining of the proposed composition is its high metal resistance when smelting tin bronze. At the same time, other lining performance indicators are maintained — increased accuracy, heat resistance, moderate growth during service.

The positive properties of the stuffed lining are achieved as a result of the partial replacement of high-silica material, which contributes to the additional growth of the lining and is characterized by insufficient

38.3 A mixture of crystalline quartzite and quartz 1: 1

0

10.0

5.0

10.0-30.0 0

15.0

10.0 5.0-30.0

Oh 5

1.5

0.5-3.0 Boric acid, boric anhydride

chemical resistance to tin bronze, aluminosilicate materials, predominantly mullite composition, showing high chemical resistance to tin alloys. Reducing the aluminosilicate material; 35 wt.% Helps to increase the degree of impregnation and eaten refractories. An increase in the content of aluminosilicate material to 55 wt.% Contributes to a decrease in the growth of the lining, the formation of shrinkage cracks during operation and the passage of metal to the inductor. 55.0, 45.0 35.0 40.0 Shamot Mule Shamot. Distensili- A mixture of shamolitocomuli-manitol and mullithoreundum concentrate concentrate and mullis composition of alumina composition

The use of sodium oktoborate as a boron-containing material as a result of the presence of sodium oxide contributes to reducing the loosening of the slag from the thermal-thermal production, increasing strength, reducing the porosity and metal permeability of the lining. Together with silicon, calcium and aluminum oxides, sodium oxide contributes to the formation of a dense glaze-like surface on contact with the melt, which prevents the lining from being impregnated with the components of the melts,

The aluminum oxide of the aluminosilicate material increases the melting point of the glass phase, thereby increasing its viscosity and erosion resistance.

Increasing the content of sodium oktoborat 2.5 weight%, contributes to

deep sintering, the formation of shrinkage cracks, the increase in metallot permeability of the lining.

Reducing the content of sodium oktoborate to 0.5 wt.% Helps to reduce strength, increase porosity and impregnate the lining with melt components.

The use of the refractory composition of the proposed composition for lining induction furnaces, tin-smelting bronze, contributes to the reliable operation of large-capacity high-performance melting unit, which can significantly (by 5-8%) reduce the waste of melted alloys, increase the output of tin bronze, improve sanitary and hygienic conditions smelters, reduce environmental pollution.

Claims (1)

FIRE-RESISTANT MASS FOR FUTE-1 INDUCTION FURNACES FABRIC, including high-siliceous material, alumothermal slag of metallic chromium, carborundum and boron-containing material, which consists in that, in order to increase the metal resistance during melting of the tin-like boron boron, it contains sodium and optionally aluminosilicate material in the following ratio of components, May.%: Aluminothermic slag metal production - whom chrome 5-15 £ Carborundum 5-15 (L Sodium octoborate 0.5-2.5 Aluminosilicate terial 35-55 Cz High siliceous material Rest eo