Air brick for magnesia carbon ladle and method for producing the same

Abstract

The invention discloses an air brick used for a magnesium and carbon ladle, and a producing method thereof, aiming at producing high-quality air bricks used for the ladles. The mass percentage of the chemical compositions of the air brick is: 55 to 99 percent of MgO, 0 to 20 percent of C, 0 to 20 percent of AI2O3, 0 to 5 percent of ZrO2, 0 to 5 percent of AI, 0 to 5 percent of AI-Mg alloy, 0 to 5 percent of CaB6, and 0 to 2 percent of B4; the physical property indexes are: volume density (g/cm<3>): 3.00 to 3.15, apparent porosity (%): 1.5 to 5.0, cold compressive strength (MPa): 40 to 65, and distortion resistance at high temperature (MPa): 14.0 to 25.0. Raw materials adopted by the invention comprise fused magnesite, magnesite clinker, crystalline flake graphite, corundum, zirconia and oxidation inhibitor. The raw materials are added into a pug mill and externally added with a bonding agent for mulling. Mulled pug is added into a mould, and molded by utilizing isopressing equipment or a friction brick press or a hydraulic press. The invention obviously reduces the apparent porosity of the air brick, not only can improve the basic slag corrosion resistant capability of the air brick, but also can reduce the cost of the raw materials by more than two thirds.

Description

technical field [0001] The invention relates to a carbon-containing refractory material for iron and steel metallurgy, in particular to an air-permeable brick for a magnesia-carbon ladle and a production method thereof. Background technique [0002] Breathable brick is a functional refractory material widely used in the iron and steel metallurgical industry. It is mainly installed in metallurgical industrial equipment such as converters, electric furnaces or ladles. Its main function is to blow argon, nitrogen, helium and other gases into the molten steel through the breathable brick. , can greatly improve the smelting efficiency. At present, the main materials of air-permeable bricks for ladles are corundum, chrome corundum, corundum-spinel, and high-temperature fired chrome-corundum-mullite. The content disclosed in the patent document with the patent number ZL94118264.9 represents Breathable bricks made of this material; β-Sialon combined with SiC, patent literature intr...

AI Technical Summary

Problems solved by technology

Since the above materials are all neutral refractory materials, they are easy to mix with CaO and SiO in alkaline slag. 2 , Fe 2 o 3 etc. chemical reactions occur to form low-melting point compounds, and the ability to resist alkaline slag erosion is worse than that of alkaline refractory materials. Disadvantages such as low service life, workers have to replace the ventilation bricks many times, etc.

[0003] The air bricks for ladles of the above materials are all formed by vibration casting or pressure molding, which has the problem of high apparent porosity. The apparent porosity of the corundum air bricks formed by vibration casting is 20%, and the pressure-formed β-Sialon combined with SiC air bricks The apparent porosity is 14%

At the same time, there are also problems such as poor corrosion resistance, poor resistance to molten steel and slag penetration, easy blockage of air passages, easy sticking of slag, and low service life.