SU1079640A1 - Method for making porous magnesite refractories - Google Patents

Abstract

METHOD OF MAKING POROUS MAGNESITE FLARES, including obtaining dense highly baked magnesite powder, fine grinding it, mixing it with porosity powder, moistening, pressing and burning products, characterized in that, in order to increase the strength of the product, you will need to find an accountant for an accountant for an application. t in the form of a granular fraction by roasting piperunos or a mixture of raw magnesite with П№Луносом in the ratio of not more than 1.5 at 1650-1700 C for 30 -50 minutes, i and the burning product at a temperature of 5 ° -150 ° C below the firing temperature (L of dusting or its mixture with raw magnesite for 1.5-4 hours).

Description

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The invention of fire retardant to fire retardant cutting equipment and can be used for the manufacture of Lagnesite gov refractories.

A method of making magnesite refractories, including burning raw magnesite to mine magnesite powder in shaft furnaces and pipe magnesite tube powder in rotary kilns, crushing, fractioning, dosing, and preparing the mass containing 75-8% of granular magnetite powder; and 2O-25% of the gonkodisperse fraction of pipe-magnet magnesite powder, curing, pressing raw, drying and roasting jtj.

As a result, products with an apparent porosity of 22.4-24.7% are obtained.

The disadvantages of the products received

the porosity and the high thermal conductivity are relatively low, and the fact that the production of products does not use psceunos from vraschayushchih furnaces.

The closest to the invention is a method of making porous magnesite refractories, which includes preparing densely strongly magnesite powder by burning magnesite or magnesium hydroxide by finely grinding it, preparing an unbaked powder of magnesium oxide hydrate, porous, having the same size of the skin as the size of the article, the skin, the skin of the magnesite or magnesium hydroxide, having the same size of the article, has the size of the article, masses for forming articles by mixing a dense highly-sintered powder and unfired magnesia hydrate in a ratio of 20-9 O: 10-8 O with bp mennoy communication viscous, molding and calcining at 1400-2000 ° C to the sintering

The disadvantage of these products is the low mechanical strength due to the large pore structure. This is due to the fact that the pores in the fragments are formed during their firing due to physicochemical processes associated with the decomposition of magnesium hydroxide and the difference in shrinkage of the magnesium hydroxide powder and strongly baked magnesite powder.

The purpose of the invention is to improve the strength of porous magnesite products by creating a finely porous structure.

This object is achieved in that according to the method of manufacturing porous magnesite refractories comprising providing dense silnospechennogo magnesite powder, subtle igmelchenie it smshtenie with magniysoderzhashim poroobrazkotsim powder hydration, molding and firing the product, blowing the powder prepared as a granular fraction firing dust discharge or mixture of raw magnesite with dusting in a ratio of not more than 1.5 at 1650-17OO ° C for 30 -30 O min, and the products are fired at this temperature of 5O-150 C firing temperature of pshcheunos or esi with raw magnesite for 1.5-4 hours.

The manufacture of a pore-forming powder under the specified regime of roasting of the pteunos or its mixture with raw magnesite provides for obtaining durable grains with small, evenly distributed pores. The structure of such grains, obtained by roasting at 165О-1750 0, does not undergo significant changes and results in a finely porous structure of the products when they are roasted at a temperature of 5О-15О ° С below the temperature of roasting of pshcheunos or its mixture with raw magnesite for powder. The fine porous structure in the articles is also created between the filler grains and the finely dispersed bond due to their almost equal shrinkage in the specified firing mode. When firing dust extracts or its mixture with raw magnesite at temperatures above 17OO Siv for more than 50 minutes, the porosity of the products decreases without increasing their strength, and a decrease in temperature below 1650 C and firing time less than 30 min leads to a decrease in the strength of the products. If the difference in the temperatures of burning psheunos and products is more than 50 ° C, then this leads to the appearance of treshin in ideli x and marriage, but if this difference is greater than 150, then the pore size of the products increases and their strength decreases. The duration of roasting products less than 1.5 hours also reduces their strength. Roasting products for more than 4 hours does not provide an improvement in their properties and leads to excessive fuel consumption.

Example. Intractable piecheunos, captured and flue gas exhaust, or a mixture of raw magnesite with pulverizer in a ratio of not more than 1.5 lay on a weakly treated pore-forming powder in a vrashuy furnace at 1680 ° C for 40 minutes, after it was sieved, a fraction of 3-0 was extracted, 01 mm.

Highly sintered dense gonkodisperse magnesite powder obtained by conventional technology in rotary kilns actively sintering raw magnesite and subsequent grinding in pipe mills to a particle size of less than 0.063 mm.

Weakly porous porous granular powder from the 3-0.01 mm pyepunos fraction is mixed with a highly strongly baked dense fine magnetic powder in a 2: 1 ratio, moistened with a sut-grade yeast mash with a density of 1.22 g / cm. The products are pressed on 10OO-ton hydra & presses P-9O7, the specific pressing pressure of products of grades M-3 and M-1 is 1O6 and 120 MPa, respectively, then they are dried in a kiln in a tunnel kiln at a temperature of 1OO ° below the firing temperature mixtures of dust with raw magnesite for 2 hours, ready iaaepi are tested for strength and porosity. Refractory materials were manufactured and tested ana-bargainly, the technological modes of production and the properties of which are summarized in a table.

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In addition, the coefficient of those lopro-: wires of ordinary ispepium. Temperature

The water content of porous products at 100The beginning of deformation of porous products of the dog. is 3-6 W / m "hail, which in average 0.2 MPa is 162 O-17OO C,

it is 1.5 times less heat-additional shrinkage at 165CfC 0.3%.

Claims (1)

METHOD FOR PRODUCING POROUS MAGNESITE FIRE-PACKAGES, including obtaining dense strongly sintered magnesite powder, fine grinding it, mixing it with magnesium-containing pore-forming powder, moistening, pressing and firing products, characterized in that, in order to increase the strength of the products, the powder is poured into a fine structure to create finely porous in the form of a granular fraction by roasting Psheunos or a mixture of crude magnesite with dust extractor in a ratio of not more than 1.5 at 1650-17СУ ° С for 30-50 minutes, and the products are burned at that at a temperature of 50-150 ° C below the firing temperature of the dust extractor or a mixture of it with crude magnesite for 1.5-4 hours I The invention relates to a gay refractory industry and can be used for the manufacture of magnesite refractories.