Factors affecting the ash fusion point and slagging tendency of coal
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The acid-base ratio in coal ash affects the ash fusion point of coal, while the silica-alumina ratio influences slagging tendency. I’m not sure whether this theory is correct; I hope experts can provide more convincing reasons and conclusions, and it would be great if they could cite some relevant literature
Does the silicon-aluminum ratio affect slagging tendency? I don’t know. How great is the impact? I also hope to get an answer
The main components of ash are SiO2, Al2O3, CaO, Fe2O3, and MgO, among which SiO2 and Al2O3 are acidic components, while CaO, Fe2O3, and MgO are basic components. Generally, the higher the ratio of acidic to basic components in coal ash, the higher the ash fusion point of the coal; a ratio of around 0.8 is considered suitable for use. Since SiO2 can form a low-melting substance, CaSiO3, with CaO, the ash melting point of coal can be reduced within a certain range by adding CaCO3; however, if an excessive amount of CaCO3 is added, the formation of CaO will increase the ash melting point. In addition to adding CaCO3, coal blending technology can also be used to lower the ash fusion point of coal, and many manufacturers in the industry have conducted coal blending trials.
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pH level does indeed affect the ash fusion point of coal; this is why some facilities add limestone. Adding papermaking waste liquid can also lower the ash fusion point, but due to the presence of sodium ions, it affects the lifespan of refractory bricks. The remaining portion is collectively referred to as the mineral content of coal, and generally has no significant impact on production.