The characteristics of corundum in refractory materials mainly have the following characteristics:
1. High strength and wear resistance;
2. Resistance to erosion and penetration of acid slag: The main crystal phase of various types of it is a-Al2O3, which has good resistance to erosion and penetration of acid slag. The slag produced in the iron making process is generally acidic slag with high SiO2 content and low CaO content. The iron making industry generally uses Al2O3-based refractories as linings, such as high-alumina bricks for blast furnace bodies, Al2O3-SiC-C-based 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 it 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 resistance (acidic or alkaline) ) aggressiveness, etc. It is compounded with SiO2 to form corundum-mullite refractory, compounded with MgO to form corundum-spinel refractory, compounded with zircon sand (ZrO2 and SiO2) to form Al2O3-SiO2-ZrO2 refractory, and silicon carbide and Carbon composite forms Al2O3-SiC-C refractories, etc.;
4. Diversity of bonding methods, it has good compatibility with various binders, and various bonding methods can be used, such as high-temperature sintering, low-temperature bonding, etc., which can endow materials with different characteristics.
It is mainly divided into two categories in refractory materials: shaped products and unshaped products.
The main products are:
1. Refractory products: Al2O398% or more, self-bonding solid-phase sintered high-purity products, the bonding phase is mainly corundum, and a small amount of mullite, etc., mainly used in petrochemical industrial gasifiers, carbon black reactors, Gas making furnace, ammonia decomposition furnace, two-stage reformer, high temperature and ultra-high temperature furnace 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℃, adding some fused it and silica raw materials can make low-creep rate high-alumina bricks. 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 it, 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 or tabular corundum, fused mullite and other raw materials, through batching, mixing, high-pressure molding, and firing in a high-temperature kiln. 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 its 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, refractory plastic, refractory ramming material , refractory mortar: for joints in its refractory masonry
