Study On Mechanism Of SiO₂Content On Sinter Strength

At present, burden structure in BF is most of the high basicity sinter plus a smallamount of acid pellets or natural lump ore. The import prices of pellets and lump ore ishigh, so it is very important to improve quality of sinter and further increase the amountof sinter. This led to a range of magnification of the sinter basicity trend. Most ofproduction of sinter used the mode of ore of import and domestic mixed. Therefore, thescope of silicon content of sinter increased significantly. How in the silicon content andalkalinity conditions to ensure the expansion range of sinter strength, The focus of thestudy subject is how to ensure the strength under the conditions of rang of content ofsilicon and basicity expansion.Based on small sintering cup as the main line in laboratorystudies The results showed that: when the production of flux sinter, accordance with thesilicon content and basicity of sinter take the different cooling methods. Only use thecorrect cooling system can ensure the qualified sinter strength. When the silicon contentis high, cooling intensity should be increased. When the silicon content is low, should bereduced the cooling intensity. This treatment process will make a higher sinter strength.Two main factors affect the sinter strength: crystal change of2CaO·SiO₂and contentof vitreous.2CaO·SiO₂is the main binding phase of flux sinter. The higher silicon contentand basicity the higher is the content of2CaO·SiO₂In the cooling process crystaltransformation of2CaO·SiO₂can occur, a significant volume expansion.2CaO·SiO₂content reaches a certain level can lead to serious degradation of sinter strength. Theslower of cooling rate, the more thorough transformation crystals of2CaO·SiO₂, and thegreater effects for sinter strength. Under the condition of high basicity and high SiO₂content, this effect dominates. If the silicon content is low, content of2CaO·SiO₂isdecreased, the crystal changes are no longer the dominant factor on sinter strength. If thecooling rate is too fast, it will lead to an increase in the vitreous, however the sinterstrength is decreased. Therefore, in contrast with the above, the cooling intensity shouldbe appropriately reduced.