高铝砖的性能High alumina brick performance

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河南高铝砖厂家有什么品牌

    高铝耐火砖又称高铝砖,其生产与粘士砖生产工艺类似,不同点是配粉掺高铝熟料较多,耐火度高于粘土砖,抗酸碱侵烛性能较好,适于各种窑炉烧成带等处使用。
    Al2O3含量大于48%的硅酸铝质耐火砖统称为高铝耐火砖。按Al2O3含量的多少划分为三个等级:I等(Al2O3>75%);II等(Al2O3为60%~75%);Ⅲ等(Al2O3为48%~60%)。根据矿物组成可分为:低莫来石质(包括硅线石质)及莫来石质(Al2O3为48%~71.8%),莫来石-刚玉质及刚玉-莫来石质(Al2O3为71.8%~95%),刚玉质(Al2O3为95%~100%)等耐火砖。
    随着高铝耐火砖中Al2O3含量的增加,莫来石和刚玉成分的数量也增加,玻璃相相应减少,高铝耐火砖的耐火性及密度也随之提高。当高铝砖中Al2O3含量小于71.8%时,高铝耐火砖中高温稳定晶相是莫来石,且随Al2O3含量加而增多。对Al2O3含量在71.8%以上的高铝耐火砖,高温稳定晶相是莫来石和刚玉,随71.8%含量增加,刚玉量增多,莫来石减少,相应地提高高铝耐火砖的高温性能。
    高铝耐火砖的烧成温度取决于矾土原料的烧结性。用特级及I级矾土熟料(体积密度≥2.80g/cm3)时,原料的组织结构均匀,杂质含量偏高,使坯体易烧结,但烧成温度范围较窄,易引起过烧或欠烧。采用II级矾土熟料(体积密度≥2.55g/cm3)时,由于二次莫来石化造成的膨胀和松散效应,使坯体不易烧结,故烧成温度略高。采用III级矾土熟料(体积密度≥2.45g/cm3)时,组织致密,Al2O3含量低,烧成温度较低,一般略高于熟料粘土砖的烧成温度的30~50℃。高铝耐火砖在氧化焰中烧成。
    由于高铝耐火砖荷重软化温度是一项重要性质。实验结果表明它随高铝耐火砖中Al2O3含量的变化而变化:Al2O3含量低于莫来石理论组成时,高铝耐火砖中平衡相为莫来石-玻璃相。莫来石含量随Al2O3含量的增加而增加,荷重软化温度也相应提高。
    高铝耐火砖抗热震性比粘土砖差,850℃水冷循环3~5次。主要是由于刚玉的热膨胀性较莫来石高,而无晶形转化之故。而且Ⅰ等、Ⅱ等高铝砖耐热震性比Ⅲ等高铝耐火砖差些。
    在生产上,通常采取凋整泥料颗粒组成的办法,以改善高铝耐火砖的颗粒结构特性,从而改善其耐热震性。近年釆,在高铝耐火砖的配料中加入一定数量的合成堇青石制造高耐热震性的高铝耐火砖,取得明显的效果。
    高铝耐火砖的抗渣性也随Al2O3含较的增加而提高。降低杂质含量,有利于提高抗侵蚀性。
    高铝耐火砖与粘土砖的区别在于高铝耐火砖具有良好的使用性能,因此比粘土砖具有较长的使用寿命,成为目前建材工业应用较广泛的耐火砖之一。

High alumina refractory brick is also known as high alumina brick, its production and viscose brick production process is similar, the difference is with powder mixed with high alumina clinker more, higher fire resistance than clay brick, acid and alkali resistance candle better performance, suitable for a variety of kiln firing belt, etc.

Al2O3 containing more than 48% aluminum silicate refractory bricks are collectively referred to as high aluminum refractory bricks.According to the content of Al2O3, it is divided into three levels: I grade (Al2O3>75%);II grade (Al2O3:60%~75%);Ⅲ (Al2O3 48% ~ 60%), etc.According to the mineral composition, it can be divided into: low mullite (including siliconite) and mullite (Al2O3 is 48%~71.8%), mullite-corundum and corundum -mullite (Al2O3 is 71.8%~95%), diamond (Al2O3 is 95%~100%) and other refractory bricks.

With the increase of Al2O3 content in high-alumina refractory brick, the amount of mullite and corundum components also increases, while the amount of glass decreases correspondingly, and the fire-resistance and density of high-alumina refractory brick also increase accordingly.When Al2O3 content in high-alumina brick is less than 71.8%, the high-temperature stable crystal phase in high-alumina refractory brick is mullite, which increases with the content of Al2O3.For Al2O3 containing more than 71.8% of high-alumina refractory brick, the high-temperature stable crystal phase is mullite and corundum. With the increase of 71.8% of Al2O3 content, the quantity of corundum increases and the quantity of mullite decreases, and the high-temperature performance of high-alumina refractory brick is improved correspondingly.

The firing temperature of high alumina refractory bricks depends on the sintering properties of bauxite raw materials.When using super and I grade bauxite clinker (volume density 2.80g/cm3), the structure of the raw material is uniform, the impurity content is high, which makes the body easy to sintering, but the firing temperature range is narrow, easy to cause over or under burning.When grade II bauxite clinker (volume density 2.55g/cm3) is used, the expansion and loose effect caused by secondary mullite makes the body not easy to be sintered, so the sintering temperature is slightly higher.The level III bauxite clinker (bulk density 2.45 g/cm3) or higher, compact structure, low content of Al2O3, firing temperature is low, usually slightly higher than the firing temperature of the clinker clay brick of 30 ~ 50 ℃.High alumina refractory bricks are fired in an oxidizing flame.

The softening temperature of high alumina refractory bricks under load is an important property.The experimental results show that it varies with the content of Al2O3 in high-alumina refractory bricks: when the content of Al2O3 is lower than the theoretical composition of mullite, the equilibrium phase of high-alumina refractory bricks is mullite-glass phase.The content of mullite increased with the content of Al2O3, and the softening temperature under load increased accordingly.

High aluminum refractory clay brick worse than thermal shock resistance, 850 ℃ water cycle 3 ~ 5 times.The main reason is that the thermal expansion of corundum is higher than mullite.And Ⅰ, Ⅱ high alumina brick thermal shock resistance than Ⅲ high aluminum refractory brick.

In production, the composition of clay particles is usually adjusted to improve the particle structure characteristics of high alumina refractory brick, so as to improve its heat shock resistance.In recent years, a certain amount of synthetic cordierite was added into the ingredients of high-alumina refractory bricks to produce high-alumina refractory bricks with high heat shock resistance, and obvious results were obtained.

The slag resistance of high alumina refractory brick also increases with the increase of Al2O3 content.Reducing the impurity content is beneficial to improve the corrosion resistance.

The difference between high alumina refractory brick and clay brick is that high alumina refractory brick has good service performance, so it has a longer service life than clay brick.

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------以上为辉煌耐火砖厂家为大家简述的常见问题解答的一些基本详情!本文章为辉煌耐材原创文章如需转载请注明版权------

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