Research On The Erosion Of The Refractory In Rotary-Kiln By Powder Meterial And Their Bonding Mechanism

Abstract:As the grade-rotary kiln process in pellets production takes a more and more important positon, therefore, how to prevent and reduce the ring problem to improve the yield and quality of pellets is of great significance.To solve this prominent problem, this paper researches the erosion and bonding mechanism between erosion materials and refractory on two aspects:the adhesive of erosion materials on refractory lining; the erosion of the bonded materials to refractory. Though the research, it reveals the erosion mechanism of erosive temperature, erosive time, the content of erosive materials and the ways of making refractories. And it has certain directive significance on improving refractories from chemical composition, grain composition and physical and chemical performances.The test done in the muffle furnace simulates the erosive materials composition, fire time, temperature, etc to study the laws of refractory erosion.The test mainly studies the erosion law of refractories eroded by iron ore concentrate and iron ore concentrate added bentonite, coal ash and alkali metals at1200℃～1350℃for12h,24h,72h and120h.The results are that:the erosive depth increases by1.2mm,and the biggest Fe content eroded into refractories increases by2.7%as the SiO2content increases from4.2%to8.5%when the temperature and time is1350℃and12h respectively; the erosive depth increases by3.2mm, and the biggest Fe content eroded into refractories increases by2.2%after adding alkali metals into the erosive materials when the temperature and time is1350℃and120h; the erosive depth increases by2.9mm, and the biggest Fe content eroded into refractories increases by7.0%as the time increases from72h to120h when eroded by iron ore concentrate at1350℃; the erosive depth increases by1.95mm, and the biggest Fe content eroded into refractories increases by2.8%as the erosive temperature increases from1250℃to1400℃when eroded by erosive materials added2%bentonite for12h. Erosion materials are more aggressive to castable refractories than to precast refractories. It is hard for erosion materials to bond to precast refractories which eroded by erosion materials added alkali metals at1350℃for12h、72h and120h, however, the erosive materials bond to castable refractories when eroded just for24h under the same conditions.This article totally has45charts,22tables and79referencies.