1、Higher strength and wear resistance;
2、Erosion and penetration resistance of acid slag: The main crystal phase of various types of corundum is a-Al2O3, which has good corrosion resistance and penetration resistance of acid slag. The slag produced in the ironmaking process is generally acidic slag with high SiO2 content and low CaO content. The ironmaking industry generally uses Al2O3-based refractories as linings, such as high-alumina bricks for blast furnace bodies, Al2O3-SiC-C refractories (castables and ramming materials) for tapping trenches, and taphole clay (Al2O3-SiO2-SiC). -C quality), Al2O3-SiC-C quality refractories (castables and refractory bricks) for ladle and torpedo tanks, etc.
3、Diversity of materials and properties: The main crystal phase of corundum is a-Al2O3, which can be compounded with many oxides and non-oxide phases, improving some of its own properties, such as thermal shock resistance, slag (acidic or alkaline) corrosion resistance sex, etc. It is compounded with SiO2 to form corundum mullite refractory material, compounded with MgO to form corundum-spinel quality refractory material, compounded with zircon sand (ZrO2 and SiO2) to form Al2O3-SiO2-ZrO2 quality refractory material, and silicon carbide and Carbon composite forms Al2O3-SiC-C refractories, etc.;
4、Due to the diversity of bonding methods, corundum has good compatibility with various binders, and various bonding methods can be used, such as high-temperature sintering, low-temperature bonding, etc., which can impart different characteristics to the material.
Corundum is mainly divided into two categories in refractory materials: shaped products and unshaped products.
The main products are:
1、Corundum refractory products: Al2O398% or more, self-bonding solid-phase sintered high-purity corundum products, the bonding phase is mainly corundum, and a small amount of mullite, etc., mainly used in petrochemical industrial gasifiers, carbon black reaction furnaces, gas production Furnace, ammonia decomposition furnace, two-stage reformer, high temperature and ultra-high temperature kiln in refractory ceramics industry, blast furnace in metallurgical industry, etc.
2、Modified high-alumina bricks: ①Low-creep high-alumina bricks: For high-alumina bricks with a creep temperature of 1500℃-1550℃, high-alumina bricks with low creep rate can be obtained by adding some fused corundum and silica raw materials. ② Phosphate-bonded high alumina bricks: use super or first-grade high alumina bauxite clinker as the main raw material, phosphoric acid solution or aluminum phosphate solution as the binder, add a small amount of fused corundum, mullite, etc. to strengthen the matrix, at 400- Chemically bonded refractory products made by heat treatment at 600°C. Mainly used in iron-making hot blast stove, cement kiln, electric furnace roof, ladle, etc.
3、Corundum-mullite products: made of fused white corundum, tabular corundum, fused mullite and other raw materials, through batching, mixing, high-pressure molding, and firing in a high-temperature kiln. The main crystal phase of the product is corundum, and the combined phase is mullite. It is mainly used in high-temperature firing kilns in the ceramic industry and its kiln furniture such as push plates and setter plates.
Unshaped products:
Various corundum raw materials can be used as aggregates and powders for the preparation of amorphous refractory products. According to different binders and construction methods, they can be divided into the following categories:
Refractory castables: corundum, corundum-spinel, corundum-SiC-C
Refractory plastic: corundum, aggregate: all kinds of corundum; binder: water glass, phosphate, organic binder.
Refractory ramming material: corundum, aggregate: all kinds of corundum; binder: phosphoric acid, phosphate, etc.
Refractory mortar: for joints in corundum refractory masonry
