CMA cement bonded MgO-MA unfired bricks and preparation method thereof

Abstract

The invention discloses CMA cement bonded MgO-MA unfired bricks and a preparation method thereof. The unfired bricks are prepared by taking 2-5wt% of silicon oxynitride fine powder, 5-20wt% of fused magnesite fine powder, 8-20wt% of magnesium aluminum spinel fine powder, 1-5wt% of aluminum powder, 1-5wt% of silicon powder and 1-10wt% of CMA cement as substrate materials, and using 50-65wt% of fused magnesite particles as aggregate. The preparation method comprises the steps of putting all the substrate materials into a roller ball mill, and mixing for 3-5 minutes to obtain substrate fine powder; putting the aggregate into a mixer, then adding the substrate fine powder, and dry-blending for 3-5 minutes; after that, adding water for wet mixing to obtain mixed pug, wherein the adding amount of the water is 1-10wt% of the total mass of the aggregate and the substrate fine powder; finally, mechanically pressing the mixed pug for molding under the condition of 100-250MPa to obtain the CMA cement bonded MgO-MA unfired bricks. The preparation method provided by the invention is simple, energy-saving, environmentally friendly and low in production cost; the unfired bricks are low in apparent porosity, high in breaking strength at the room temperature, high in compressive strength at the room temperature, high in breaking strength at the high temperature, and good in slag resistance andthermal shock resistance.

Description

technical field [0001] The invention relates to the technical field of refractory materials, in particular to a CMA cement-bonded MgO-MA unfired brick and a preparation method thereof. Background technique [0002] RH refining furnace is a kind of refining equipment outside the furnace, which has been widely used and promoted because of the good cost performance of the smelted steel. At present, the main refractory materials commonly used in RH refining furnaces and RH refining furnace dip tube linings are magnesium chromium refractory materials. [0003] Chinese patent CN201210239826.4 discloses a high-performance magnesium-aluminum-chromium composite spinel brick and its manufacturing method, which relates to high-performance magnesium-aluminum-chromium composite spinel bricks for RH refining furnace dip tubes and non-ferrous smelting furnaces. However, the magnesia-aluminum-chromium composite spinel brick contains heavy metal chromium, which will produce Cr during use, w...

AI Technical Summary

Problems solved by technology

However, the magnesia-aluminum-chromium composite spinel brick contains heavy metal chromium, which will produce Cr during use, which is harmful to the human body and the environment. Broad concern of those skilled in the art

[0004] Chinese patent CN201610163524.1 discloses a preparation method of magnesia-alumina spinel bricks. Magnesia-alumina spinel bricks are obtained by using magnesia and corundum fine powder of different particle sizes and mixing them uniformly with a binder; After sintering, the normal temperature compressive strength is greater than 75MPa, and the thermal shock resistance is water-cooled at 1100°C for more than 12 times. Although most of the properties are better, the process is complicated, and it needs to be sintered many times and the normal temperature compressive strength is low.

[0005] Chinese patent CN201210261919.7 discloses a non-fired magnesia-alumina spinel brick, which uses 80-90wt% of fused magnesia, 5-10wt% of magnesium-rich magnesia-alumina spinel, and 1 ~3wt%, aluminum-silicon alloy powder is 1~3wt%, and boron carbide is 0.2~0.6wt%, although many properties are better, but adding boron nitride as an antioxidant makes the cost too high, and the high temperature flexural strength is not good enough

[0006] Chinese patent CN201510363696.9 discloses a high thermal shock magnesia spinel refractory material and its preparation method. The product has been kept at 1740°C for more than 6 hours. Although it has good thermal shock performance, it can be cooled by water at 1100°C for more than 16 times. , but the apparent porosity is high and the compressive strength at room temperature is low