CS240459B1 - A method of producing high-density basic refractory building materials - Google Patents

Abstract

The invention falls into the field of production of refractory materials and solves the issues of obtaining high-density basic refractory building materials. The procedure is that the cold-pressed magnesite, magnesite-chromite, and chrome-magnesite pressing is heated to a temperature of 1700 to 2,200 °C at a heating rate of 30 to 300 °C. h_1 for a maximum of 8 hours, then it is pressed at this temperature with a pressure of 10 to 200 MPa and the pressing is further tempered at the dipping temperature for 4 hours and then cooled at a rate of 20 to 300 °C. h_1 and the cooled pressing is dimensionally adjusted to the required size by mechanical processing.

Description

The invention is in the field of producing refractory materials and addresses the issue of obtaining high-density basic refractory materials.

The process is carried out by heating the cold-pressed compact magnesite, magnesite-chromium, and chromomagnesite to a temperature of 1700-2200 ° C at a heating rate of 30-300 ° C. For a maximum of 8 hours, at this temperature, the pressure is 10 to 200 MPa and the molding is further tempered at a soaking temperature of 4 hours and then cooled at a rate of 20 to 300 ° C. h_1 and the cooled molded part are dimensionally adjusted to the desired dimension by mechanical processing. 240459 240459

BACKGROUND OF THE INVENTION The present invention relates to a process for producing high density basic refractory builders of magnesite, magnesia, chromium magnesium, or other building materials, the basic component of which is magnesium oxide. Basic refractory builders, the basic component of which is magnesium oxide, are produced by pressing granulometrically treated mixtures of magnesia clinkers with or without the addition of granulometrically treated refractory chrome ore, containing small amounts of usually organic binders. The moldings are then dried and fired at temperatures from 1,600 to 1,850 °. Basic refractory building materials for particularly demanding high-temperature conditions, pressure changes, corrosion effects of molten metals and slags are produced or carved out of casts of remelted magnesia clinkers, to which chrome ore may be added or extruded by molding from refractory granulometrically treated material and firing molding at high temperatures. Refractory basic carvings carved from molten cast blocks show a very good service life, but their production is very energy intensive, around 80 GJ. . t_1. The lifespan of these building materials reduces the occurrence of a large number of macropores, which is difficult to limit by melt chemistry and melting and casting technology.

Also of high quality are refractory basic building materials made from molten grain. However, the energy consumption during their production is also high and is given mainly by the energy consumption of remelting the magnesia stink or its mixture with chromium ore, the lifespan of the so-called building materials depends on the quality of the molten grain and the achievement of suitable parameters of porosity and bulk density in the firing of moldings.

The aforementioned drawbacks of the technology of producing the highest qualities of basic refractory building materials, namely high energy consumption in their manufacture and limited service life due to the relatively high porosity of these structures, eliminate the invention, which is based on that the chemical composition of fever. the molding heats up to 1700 to 2 200 ° C at a heating rate of 30 to 300 ° C. . h '1 for a maximum of 8 hours and at a temperature of 100 to 150 ° C higher than the starting temperature, the hot mold is pressurized with a pressure of 10 to 200 MPa. The pressed compact is then maintained at a soaking temperature of 4 hours to remove internal strains and subjected to cooling at 20 to 300 ° C. tr1, corresponding to the chemistry of the material being processed. The cooled moldings are dimensioned by milling and grinding.

The high-magnesia magnesite chromium magnesium stearite refractory material produced by the process of the present invention is characterized in that it exhibits 0.5 to 6% lower apparent porosity than that of the same chemical composition produced by the conventional process, ie cold pressing and compacting at temperatures up to 1800 ° C without hot pressing. Example:

The cold pressed unburned maghezitch chrome brick was heated to 1800 ° C at a heating rate of 150 ° C. h1, then pressed at a pressure of 83 MPa and cooled down at 60 ° C after compression. h “1. The cooled compact had a density of 3.21 g / cm < 3 > and an apparent porosity of 13.8%. Example 1 and 2:

The cold pressed, unburned magnesite-chrome brick was heated to 950 ° C at a heating rate of 150 ° C and then compressed to 166 MPa, after pressing it was cooled at 60 ° C. The resulting molding had a density of 3.28g. cm -1 and 12.6% apparent porosity.

Claims (1)

SUBJECT A method of producing high-density, magnesite, magnesite-chromium, chromium-magnesite, or other building materials, the basic component of which is magnesium oxide, characterized in that the cold-pressed compact is heated to 1700 to 2200 ° C at a heating rate of 30 to 300 ° C C. after at least 8 hours, then at this temperature the pressure is 10 to 200 MPa and the molding is further tempered at the soaking temperature for 4 hours and then cooled at a rate of 20 to 300 ° C. required dimension by mechanical processing.