CS215520B1 - Refractory cement - Google Patents

Abstract

The purpose of the refractory putty is to achieve high bond strength when removing stains Properties; The refractory putty contains alumina and a phosphorous component introduced into the sealant as phosphoric acid and / or aluminum phosphate in an amount of 10 to 70% by weight, recalculated phosphorus pentoxide, the remainder being amorphous alumina and / or gamma , having a specific surface area greater than 2 m 2 / g. The sealant may further comprise coarse-grained inorganic 10 / tm to 2 mm, for example sand, corundum, zirconium, crushed glass. It is designed primarily for joining materials high temperatures from 100 ° C up to 1800 ° C, especially ceramics and building silicate materials.

Description

The purpose of the refractory sealant is to achieve high bond strength while eliminating coloring properties;

The refractory mastic comprises alumina and a phosphorous component introduced into the mastic such as phosphoric acid and / or phosphate, aluminum in an amount of 10 to 70% by weight, calculated as phosphorus pentoxide, the remainder being amorphous alumina and / or gamma, with specific surface area greater than 2 m ² / g.

The sealant may further comprise a coarse inorganic additive having a grain size of 10 µm to 2 mm, for example sand, corundum, zirconium, crushed glass.

It is designed primarily for joining materials exposed to high temperatures from 100 to 1800 ° C, especially ceramics and construction silicate materials.

The invention relates to a refractory sealant containing alumina and a phosphorus component suitable for high temperatures.

As a sealant for use temperatures above 100 to 150 ° C, water glass with a variety of fillers such as finely ground fireclay, corundum, limestone, quartz sand and the like is generally used. Their use is given by the amount of water glass and type of additives, and is possible above 1000 ° C. Furthermore, various organic silicon compounds such as silicone-type substances and the like can be applied. However, their use is limited by temperatures of 200 to 600 ° C. Phosphate based sealants are most commonly used, and also contain various inorganic oxides.

The highest strengths are achieved with the use of chromium-aluminum phosphates, as is known from the US. They can be used for a variety of purposes, for example in metallurgy and the like. However, the sealant is not entirely suitable where it interferes with the coloring ability of chromium oxide, for example in the glass industry.

According to the invention, the above-mentioned drawbacks are overcome by a refractory mastic containing alumina and a phosphorus component. It consists in that the amount of phosphorus component introduced preferably into the sealant, such as phosphoric acid and ammonium phosphate or phosphoric acid and / or aluminum phosphate, is 10 to 70% by weight, calculated as phosphorus pentoxide, the remainder being amorphous alumina and / or in the form of gamma having a specific surface area greater than 2 mc / g.

The effect of the sealant according to the invention is primarily to achieve a high bond strength and further to have no coloring properties.

• The phosphorous component contained in the sealant in excess reacts with the surfaces of the sealed parts, eventually penetrating into the pores, creating a very strong bond. It is understandable that the sealant must be thermally fixed. Finally, it can be diluted with water if necessary.

The sealant according to the invention is further described in several exemplary embodiments.

Example 1

100 g of alumina in the form of gamma ground to a specific surface area below 2 m ² / g, 50 ml

85% HaPO4. It was used to bond refractory fibers to iron sheet. After the firing at 300 ° C, the bonding strength was considerably higher than the intrinsic cohesion of the fibers.

Example 2

100 g of amorphous aluminum phosphate, 5 ml of 85% H3PO4. It was used for joining corundum materials. A bending strength of 3 MPa was achieved after firing at 400 ° C.

Example 3,

100 g alumina · in the form of gamma, ground to a specific surface below 2 m ² / g, 50 ml 85% H 3 PO 4, 85 g corundum 0.06 to 0.1 mm ·. It was used to bond silicium carbide materials. A bending strength of 2.5 MPa was achieved after firing at 400 ° C.

Example 4

100 g of amorphous aluminum phosphate, 40 g of corundum with a grain size of 0.01 and 0.1 mm, dispersed in water. It was used for cementing highly resistant refractory materials. After firing at 400 ° C, the joint strength in fracture was 2 MPa.

Example 1 and d 5

100 g of gamma alumina ground to a specific surface area below 2 m ² / g, 10 g of primary ammonium phosphate, 40 ml of 85% H3PO4. It was used for sealing highly resistant refractory materials. The fracture strength of the joint · after firing at 400 ° C was 2 MPa.

The composition according to the invention is suitable for joining materials where the joint is subjected to high temperature, i.e. 100 to 1800 ° C, in particular ceramics, refractory material, building silicate materials, glass, to each other, but very good results have also been achieved in bonding certain metals to each other and metals to said types of materials.

Claims (2)

Subject CLAIMS 1. A refractory mastic containing alumina and a phosphorous component, characterized in that the amount of phosphorous component introduced preferably into the mastic such as phosphoric acid and / or aluminum phosphate is 10 to 70% by weight, calculated as phosphorus pentoxide, the remainder being amorphous oxide aluminum and / or OF THE INVENTION a gamma form having a specific surface area greater than 2 m ² / g. 2. Refractory mastic according to claim 1, characterized in that it contains a coarse-grained inorganic additive with a particle size of 10 μΐΏ, up to 2 millimeters, such as sand, corundum, zirconium, crushed glass.