RU2116274C1 - Refractory binding material for lining of high-temperature assemblies - Google Patents

Abstract

FIELD: refractory materials. SUBSTANCE: material includes magnesia refractory filler (base), 7.5-11.5% of aluminum powder, 18.5-28.5% of ferrophosphorus powder, and 3-9% (above 100%) of liquid binder. Material is designed for use as refractory mortar for laying linings in steel-smelting assemblies and rotary furnaces serving to bake refractory and cement clinkers. EFFECT: increased strength of mortar-to-lining adhesion, reduced porosity and mass hardening time. 2 tbl

Description

 The invention relates to magnesite refractory materials and can be used as a refractory mortar for laying refractory linings of steelmaking units and rotary kilns for refractory and cement clinkers.

Known composition for the filler of the seams of brickwork, including, by weight. %:
Magnesite powder - 52-60
Aluminum Powder - 8-12
Rolling Scale - 32-38
The mixture is poured into the gaps between the bricks when laying the lining, and when the lining is heated, sintering of the mixture occurs [1].

 The disadvantage of the composition is the lack of a fluid bond, flowability, the lack of ductility and adhesion and, as a result, the impossibility of laying steeply inclined and vertical sections of the lining.

The closest analogue to the claimed invention is a refractory mortar for masonry lining of thermal aggregates of the composition, wt.%:
Magnesite-containing component of the fraction 3-1 mm - 40-50
Magnesium-containing component of the fraction 0.09 mm - 30-40
Aluminum powder - 3-8
Liquid glass - 10-15
where fused or sintered periclase, as well as ground battle of magnesite, magnesite chromite and chromomagnesite products, is used as a magnesium-containing component [2].

 The disadvantages of the solution are insufficient cold strength and slow setting of the mass, as well as a slow increase in strength during heating due to the oxidation of aluminum and spinel formation, and in addition, insufficiently high adhesion strength to the lining, as well as high porosity due to the uneven grain composition.

 The technical problem solved by the invention is to increase the adhesion strength of the solution to the lining, reduce porosity, increase cold strength and the setting time of the mass, as well as increase the sintering speed.

To solve the technical problem, a refractory binder for lining high-temperature thermal units, including magnesia refractory aggregate, aluminum powder and a liquid binder, additionally contains fused ferrophosphorus powder in the following ratio, wt.%:
Magnesia aggregate - base
Aluminum Powder - 7.5-11.5
The specified fused ferrophosphorus powder is 18.5-28.5
Fluid ligament (in excess of 100%) - 9-13.

 As a magnesian aggregate, it contains scrap of refractory periclase-containing products, periclase powder, or a mixture thereof. As a liquid binder, a chemical binder is used, for example, solutions of magnesium salts.

In the proposed binder material, the setting process in comparison with the known composition is enhanced by the binder - magnesium salts and finely ground components. The ferrophosphorus component, having a low melting point (960 ^o C), sinter the masonry mortar in the weld at lower temperatures, compacts the structure and increases strength. When the lining is heated, sintering occurs in the form of an exothermic reaction between oxidizing agents - iron oxide, which is partially formed by grinding ferrophosphorus and magnesium sulfate on the one hand and reducing agents - metal aluminum and iron on the other hand. In addition, ferrophosphorus powder is oxidized to form iron phosphates and iron oxides, spinel formation. Iron oxides interact with periclase and form high-temperature compounds - magnesiouustite with a melting point of 2100 ^o C and magnesioferrite with a melting point of 1750 ^o C. All these reactions are accompanied by an increase in volume, which also increases the strength and density of the weld.

Example
Refractory scrap of periclase-chromite products and finely ground periclase powder were used as magnesia aggregate. As fused ferrophosphoric silicate, finely ground material was used, which, according to the chemical analysis, contains: Fe ₂ O ₃ - 74.1%, P ₂ O ₅ - 14.1%, MnO - 0.5%, SiO ₂ - 7.5% . These components, taken in the required ratio, were mixed in a mortar mixer, adding aluminum powder and a magnesium sulfate solution with a density of 1.20 g / cm ³ The resulting solution was used in the lining of a rotary kiln of magnesite in the hot head area. In addition, laboratory tests of the solution between magnesian dies were carried out and cubic samples were made to determine the properties. For comparison, solutions of known composition were made and tested, and, in addition, a composition containing iron oxide instead of fused ferrophosphorus material. The composition according to the invention gives a smooth, dense joint without cracks in the masonry. This composition is not tinted from the joints of the masonry, but in the form of cake remains until the end of the campaign of the furnace.

 As can be seen from the tab. 1 and 2, the invention achieves an increase in the adhesion strength to the lining, a decrease in porosity, an increase in cold strength and mass setting time.

Claims (1)

Refractory binder material for lining high-temperature thermal aggregates, including magnesian refractory aggregate, aluminum powder, liquid binder, characterized in that it further comprises fused ferrophosphoric powder in the following ratio of components, wt. %:
Magnesia Aggregate - Base
Aluminum Powder - 7.5 - 11.5
Ferrophosphoric powder - 18.5 - 28.5
Liquid bond (over 100%) - 9 - 3o

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