The different components of high-alumina brick determine which functions

Posted by adela li on December 19th, 2016

High-alumina refractory bricks, also known as high-alumina brick, clay brick production and similar process, the difference is more ingredients in the high-alumina clinker, refractoriness higher than the clay brick, anti-acid alkali invasion candle performance is good for a variety of kiln Furnace firing zone, etc. used.

      As the content of A1203 in high alumina brick increases, the amount of refractories mullite and corundum components increases, and the glass decreases accordingly. The fire resistance and density of high alumina refractory bricks also increase. When the content of A1203 in high alumina brick is less than 71.8%, the high temperature stable crystalline phase of high alumina refractory brick is mullite, and increases with the content of A1203. For high alumina refractory bricks with A1203 content of 71.8% or more, the high temperature stable crystalline phase is mullite and corundum. With the content of 71.8%, the amount of corundum increases and the amount of mullite decreases. High temperature performance.

      A1203 content of more than 48% of the aluminum silicate refractory bricks collectively referred to as high alumina bricks. According to the content of A1203, there are three grades: I (A1203> 75%), Ⅱ (60% ~ 75% for A1203) and 48% ~ 60% for A1203. According to the composition of minerals, there are three types of minerals: low mullite (including silicate) and mullite (A1203: 48% ~ 71.8%), mullite-corundum and corundum-mullite 71.8% to 95%), corundum (A1203 95% to 100%) and other refractory bricks.

      The firing temperature of the Refractory company alumina bricks depends on the sintering properties of the alumina raw material. With the special grade I bauxite clinker (bulk density ≥ 2.80g / cm3), the raw material structure uniformity, high content of impurities, so that the body easy to sintering, but the firing temperature range is narrow, easy to cause over-burning Or less burning. With the grade Ⅱ bauxite clinker cake (bulk density ≥ 2.55g / cm3), due to the secondary mullitization caused by the expansion and loosening effect, so that the body is not easy to sintering, the firing temperature is slightly higher. When the grade Ⅲ bauxite clinker (volume density ≥2.45g / cm3) is used, the microstructure is dense and the content of A1203 is low. The firing temperature is lower than that of clinker clay brick, which is 30 ~ 50 ℃. High alumina refractory bricks in the oxidation flame burning.

      As the high-alumina refractory brick load softening temperature is an important property. The results show that it changes with the content of A1203 in high alumina refractory bricks. When the content of A1203 is lower than that of mullite, the equilibrium phase is mullite-glass phase. The content of mullite increases with the content of A1203, and the softening temperature is also increased accordingly.

High alumina refractory brick thermal shock resistance than poor, 850 ℃ water-cooled cycle 3 to 5 times. Mainly due to the thermal expansion of corundum than mullite high, and no crystalline transformation of it. And I, etc., Ⅱ and other high-alumina brick thermal shock resistance than Ⅲ and other high-alumina refractory brick worse.

      In production, usually adjust the composition of the composition of particles of mud to improve the high-alumina refractory bricks of the particle structure characteristics, thereby improving its thermal shock resistance. In recent years, in the high alumina refractory brick ingredients - adding a certain amount of synthetic cordierite to produce high thermal shock resistance of high alumina refractory bricks, and achieved remarkable results.

      The slag resistance of high alumina brick also increases with the content of A1203. Reduce the impurity content, help to improve corrosion resistance.

The difference between high-alumina refractory brick and clay brick is that the high-alumina refractory brick has good performance, so it has a longer service life than the clay brick and becomes one of the refractory bricks of the building material industry.

      Special high-alumina brick is a new type of chemical combination of high-alumina refractory bricks, which overcome the high-alumina refractory brick thermal shock performance, low temperature strength at room temperature with the weakness, with the phosphate refractory chemical resistance and high strength A variety of advantages, but also easy to hang kiln skin, is a new type of firing with refractory bricks. High alumina brick refractory mud, blending method and clay brick is basically the same, can also use high-strength refractory mud.