01. Corrosion resistance is divided into alkaline and acidic.
Corrosion resistance is divided into alkaline and acidic, which is also corrosion caused by both acid and alkali. Therefore, it is necessary to understand the performance of refractory bricks of different materials in order to make better choices.
Refractory bricks are divided into silicon-aluminum series, magnesium series, chromium series, silicon series, calcium aluminate series, composite material series, corundum series, and aluminum-carbon series.
02. Refractory brick types series
High-aluminum bricks contain mullite components, which have good thermal shock resistance but poor corrosion resistance. Corundum bricks have good resistance to alkali metals and small volume changes. If it is at high temperature and alkali metal concentration, high-aluminum bricks cannot be used as linings.
Magnesium-chromium and chrome-corundum refractory bricks have high refractoriness and high temperature strength. Good resistance to alkali and high temperature, magnesium-chromium refractory bricks have good material density and hot bonding strength, low porosity, and good resistance to slag erosion. Although chromium refractory bricks have strong resistance to alkali corrosion and even good resistance to acid corrosion, chromium is a toxic substance and has been put on the agenda of public pollution. Chromium products should be used with caution.
The calcium aluminate series has excellent compatibility with aluminum products, good stability in high-temperature reducing atmospheres, and good corrosion resistance in alkaline environments.
The crystal structure of corundum refractory bricks can absorb alkali metal ions between layers, and the volume of the refractory bricks does not change significantly; when resistant to alkali corrosion, its volume stability is higher than that of other refractory materials.
Magnesium aluminum spinel refractory bricks have a stable structure. High temperature resistance, especially when used in alkaline atmosphere, has very good resistance to alkali corrosion. Magnesium aluminum spinel refractory bricks have low thermal conductivity, small thermal expansion coefficient, high strength, high hardness, strong impact resistance and alkali corrosion resistance.
Composite refractory bricks have good alkali corrosion resistance. Composite refractory bricks have good thermal shock stability, corrosion resistance, wear resistance and good slag corrosion resistance. Moreover, zirconium corundum composite bricks have strong acid corrosion resistance.
03. Aluminum-carbon series avoids lining embrittlement and damage
Aluminum-carbon series refractory bricks are more commonly used in high-temperature furnace bottoms. In a reducing atmosphere, the alkali metal corrosion rate is low, which can not only slow down the alkali corrosion process, but also adhere to the refractory ash and avoid lining embrittlement and damage.
The above series of refractory bricks have different properties. After understanding, you can choose the appropriate refractory bricks according to the conditions of different furnace linings.
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