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Use and function of refractory raw materials
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Author:佚名
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Published time: 2021-04-13
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1. Nano-ceramic fiberboard with acidic raw materials
Mainly siliceous raw materials, such as quartz, scaly quartz, quartzite, chalcedony, chert, opal, quartzite, white silica sand, diatomite, these siliceous raw materials contain at least more than 90% SiO2, pure raw materials have more than 99% SiO2. Silicate raw materials are acidic in high temperature chemical dynamics, when the presence of metal oxides, or contact with the chemical action, and combine to form fusible silicate. Therefore, if the silicon material contains a small amount of metal oxides, its heat resistance will be seriously affected.
The use and function of five kinds of natural refractory raw materials
2. Semi-acid raw materials (mainly refractory clay)
In previous classifications, clay has been listed as an acidic material, which is actually inappropriate. The acidity of refractory raw materials is based on free silica (SiO2) as the main body, because according to the chemical composition of refractory clay and siliceous raw materials, the free silica in refractory clay is much less than siliceous raw materials. Because there is 30%~45% alumina in the general refractory clay, and alumina is rarely free state, must be combined with silica into kaolinite (Al2O3·2SiO2·2H2O), even if there is little amount of excess silica, the role is also very small. As a result, refractory clay is much less acidic than siliceous materials. Some people believe that refractory clay at high temperature decomposition into free silicate, free alumina, but is not the same, in the continued heat free silicate and free alumina will combine to become illite (3Al2O3·2SiO2). The lai stone of alkaline slag can have very good resistance to acid, increased at the same time, due to the alumina refractory clay composition and its acid become weak gradually, when alumina reached 50%, and alkaline or neutral nature, especially in clay brick made of ultra-high pressure, density, meticulous close, low porosity, under the condition of high temperature resistance of alkaline slag than in silica. In terms of its erodibility, dillite is also very slow, so we consider it more appropriate to classify refractory clay as a semi-acidic material. Refractory clay is one of the most basic and widely used raw materials in the refractory industry.
3, neutral raw materials
Neutral raw materials are mainly chromite, graphite, silicon carbide (artificial), in any temperature conditions do not react with acid or alkaline slag. There are currently two such materials found in nature, chromite and graphite. In addition to natural graphite, there are man-made graphite, these neutral raw materials, have significant resistance to slag, the most suitable for use as an alkaline refractory and acid refractory layer.
4, alkaline refractory materials
They are mainly magnesite, dolomite, lime, olivine, serpentine and high alumina oxygen raw materials (sometimes neutral). These raw materials have strong resistance to alkaline slag and are mostly used in laying alkaline furnaces, but they are especially easy to react with acidic slag and become salts.
5, special refractory materials
Mainly zirconia, titanium oxide, beryllium oxide, cerium oxide, thorium oxide, yttrium oxide and so on. These raw materials have different degrees of resistance to a variety of slag, but due to the raw material source is not much, can not be used in a large number of refractories in the industry, can only be used in special circumstances, so known as special refractory raw materials.
Mainly siliceous raw materials, such as quartz, scaly quartz, quartzite, chalcedony, chert, opal, quartzite, white silica sand, diatomite, these siliceous raw materials contain at least more than 90% SiO2, pure raw materials have more than 99% SiO2. Silicate raw materials are acidic in high temperature chemical dynamics, when the presence of metal oxides, or contact with the chemical action, and combine to form fusible silicate. Therefore, if the silicon material contains a small amount of metal oxides, its heat resistance will be seriously affected.
The use and function of five kinds of natural refractory raw materials
2. Semi-acid raw materials (mainly refractory clay)
In previous classifications, clay has been listed as an acidic material, which is actually inappropriate. The acidity of refractory raw materials is based on free silica (SiO2) as the main body, because according to the chemical composition of refractory clay and siliceous raw materials, the free silica in refractory clay is much less than siliceous raw materials. Because there is 30%~45% alumina in the general refractory clay, and alumina is rarely free state, must be combined with silica into kaolinite (Al2O3·2SiO2·2H2O), even if there is little amount of excess silica, the role is also very small. As a result, refractory clay is much less acidic than siliceous materials. Some people believe that refractory clay at high temperature decomposition into free silicate, free alumina, but is not the same, in the continued heat free silicate and free alumina will combine to become illite (3Al2O3·2SiO2). The lai stone of alkaline slag can have very good resistance to acid, increased at the same time, due to the alumina refractory clay composition and its acid become weak gradually, when alumina reached 50%, and alkaline or neutral nature, especially in clay brick made of ultra-high pressure, density, meticulous close, low porosity, under the condition of high temperature resistance of alkaline slag than in silica. In terms of its erodibility, dillite is also very slow, so we consider it more appropriate to classify refractory clay as a semi-acidic material. Refractory clay is one of the most basic and widely used raw materials in the refractory industry.
3, neutral raw materials
Neutral raw materials are mainly chromite, graphite, silicon carbide (artificial), in any temperature conditions do not react with acid or alkaline slag. There are currently two such materials found in nature, chromite and graphite. In addition to natural graphite, there are man-made graphite, these neutral raw materials, have significant resistance to slag, the most suitable for use as an alkaline refractory and acid refractory layer.
4, alkaline refractory materials
They are mainly magnesite, dolomite, lime, olivine, serpentine and high alumina oxygen raw materials (sometimes neutral). These raw materials have strong resistance to alkaline slag and are mostly used in laying alkaline furnaces, but they are especially easy to react with acidic slag and become salts.
5, special refractory materials
Mainly zirconia, titanium oxide, beryllium oxide, cerium oxide, thorium oxide, yttrium oxide and so on. These raw materials have different degrees of resistance to a variety of slag, but due to the raw material source is not much, can not be used in a large number of refractories in the industry, can only be used in special circumstances, so known as special refractory raw materials.
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