RU2231506C2 - Light-weight refractory material - Google Patents

Abstract

FIELD: refractory materials.

SUBSTANCE: invention relates to refractory materials and can be used in different technique fields for felting and heat-insulating the heat units working under high temperature. The light-weight refractory material comprises the following components, wt.-%: corundum modified with phosphate ions, 85.5-88.1; flour, 3.1-5.9, and technical lignosulfate, 8.6-8.8. Invention provides the significant enhancing the strength and to reduce heat conductivity and the apparent density value of heat-insulating refractory material. The additional advantage of the proposed material is it's the reduced abrasion capacity.

EFFECT: valuable properties of refractory material.

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Description

The invention relates to heat-insulating refractory materials and can be used in various fields of technology for thermal insulation and lining of thermal units operating at high temperatures.

State of the art

Based on corundum, it is possible to obtain high-quality heat-insulating refractory materials [Refractories for industrial units and furnaces. Handbook / Ed. I.D. Kashcheeva. - M .: Intermet Engineering, 2000, p. 548, 555].

Known material for porous products, including, wt.%: Monofraction electrocorundum 80-90, low-melting component magnesium montmorillonite 10-20, phosphoric acid 6 (over 100), water 2 (over 100) [A.S. USSR 1175924. A method of manufacturing porous products for refining molten metal. A.I. Snegirev et al. 03/21/1984. Publ. 08/30/1985. B.I. No. 32]. However, due to the introduction of the low-melting component, the refractoriness of the material sharply decreases, which narrows the scope of its application. In addition, products from this material have a very low strength.

Closest to the proposed invention in terms of material composition, i.e. the prototype is a heat-insulating refractory material for two-layer plates having a composition, wt.%: aluminum oxide 60-90, flour up to 5, sodium silicate as a binder 4-10 [British Patent No. 1115435. Production of Slabs for use in the Lining of Hot Tops and the Heads of Ingot Molds. Publ. 05/29/1968.] The disadvantage of the prototype is the use of sodium silicate as an astringent, which is a flume that greatly reduces the fire resistance of the material. The material is not fired, which means that a strong structure is not formed in it; the introduced flour burns out not during the manufacturing process of the products, but during their operation, which leads to the complete destruction of the thermal insulation coating. In addition, the material of the prototype has a higher apparent density and low thermal insulation ability due to high thermal conductivity.

SUMMARY OF THE INVENTION

The inventive task was to develop a heat-insulating refractory material based on corundum with higher strength and reduced thermal conductivity and apparent density.

The problem is solved by creating a heat-insulating refractory material of the following composition, wt.%:

Mechanical Activated Corundum

in aqueous phosphate medium 85.5-88.1

Flour 3.1-5.9

Technical lignosulfonate (LST) 8.6-8.8

Thus, the claimed heat-insulating refractory material differs from the prototype in that it contains alumina modified by mechanical activation in an aqueous phosphate medium as an alumina filler. Previously, corundum modified by mechanical activation in the presence of phosphate ions was not used in the compositions of heat-insulating refractories.

Corundum used in the composition of the material complies with GOST 30559-98; phosphoric acid - GOST 10678-76; wheat flour - GOST 26574-85; Technical lignosulfonate (LST) - TU 13-0281036-05-89.

Information confirming the possibility of carrying out the invention

Example 1. In a vibration mill for 40 min, a mechanochemical treatment of corundum (specific surface 600 m ² / kg) with phosphoric acid (density 1190 kg / m ³ ) is carried out. The ratio by weight of material: balls: phosphoric acid corresponded to 1: 5: 1. Then the suspension is washed until complete separation of unreacted acid and filtered on a Buchner funnel; the filter cake is dried.

To 200 g (87.0 wt.%) Of phosphate-ion modified corundum, 10 g (4.3 wt.%) Of flour and 20 g (8.7 wt.%) Of a 50% solution of years are added.

Samples of 60 x 40 mm in size are made from the mass obtained by the method of semi-dry vibrocompression at a specific pressure of 0.05 MPa (0.5 kgf / cm ² ). After drying, the samples are fired with the following extracts: at 100 ° C for 30 minutes; at 200 ° C-60 min; at 300 ° C for 30 minutes; at 500 and 1400 ° C - for 60 minutes

Determination of strength is carried out according to a known method [Workshop on the technology of ceramics and refractories / Ed. D.N. Poluboyarinova and R.Ya. Popilsky. - M .: Stroyizdat, 1972, p.191], apparent density - according to GOST 24468-80, thermal conductivity - according to GOST 12170-85.

Examples with other ratios of ingredients and test results are presented in the table.

As follows from the experimental data presented in the table, the use of ingredients in the stated ratios can significantly increase strength, as well as reduce thermal conductivity and the apparent density of the heat-insulating refractory material in comparison with the prototype. An additional advantage of the proposed material is its reduced abrasion (1.8 times).

Claims (1)

Lightweight refractory material, including an alumina-based filler, flour and a binder, characterized in that it contains corundum modified by phosphate ions as a refractory filler as a result of mechanochemical treatment with phosphoric acid in a vibration mill, with a ratio by weight of material: balls: orthophosphoric acid 1: 5: 1, and as a binder technical lignosulfonate, in the following ratio of components, wt.%: Specified Corundum 85.5-88.1 Flour 3.1-5.9 Technical lignosulfonate 8.6-8.8