| Lime is an important flux in the iron and smelting process,and plays a very important role in the process of iron and steel smelting.The quality of the lime not only influences the smelting process directly,but also has an important influence on the quality of steel and economic benefits.Using the active lime in the process of metallurgical production,on the one hand,it can improve the desulfurization and dephosphorization ability of lime;on the other hand,also effectively reduces lime consumption and improves the service life of the refractories.Therefore,with the fierce competition in the iron and steel market,a lot of more stringent requirements have been made for the metallurgical industry,and the quality of lime is one of the important factors.By comparing and analyzing the lime production process at home and abroad,especially the process of calcining lime in rotary kiln,the process characteristics and its advantages in the production of metallurgical lime were pointed out,and then taking the lime production process at Baosteel as the object of this study,analyzing the main raw materials used for the Baosteel rotary kiln roasting,roasting process and equipment used in the process of production,and finally the existing problems and improvement measures of rotary kiln roasting technology in Baosteel were put forward.By analyzing the mechanism of the lime roasting and based on the relevant theory,the factors of influencing the lime quality were summed up.The thermal cracking test for the ordinary limestone and high magnesium limestone were carried out at 850 C,900 C and 950 C,respectively in the muffle furnace,and the amount of burning loss and the rate of preheating decomposition at different temperatures were investigated.The decomposed lime was further heated from 950℃ to 1000℃,1050℃and 1100℃ for calcination,and the chemical composition,activity degree and change rate of fall damage rate of the lime were analyzed and the optimum process for calcining the two kinds of limestone was determined.On the basis of laboratory research,the industrial test of the lime calcination was carried out,and the factors of influencing lime activation were investigated.The results showed that the degree of the lime activity was mainly affected by the raw materials,equipment,process and other factors,by improving the lime production process of Baosteel,the quality of the lime in rotary kiln had been remarkably improved.The effective CaO content in the lime reached 93.10%,the average activity degree was above 385ml,and the product quality reached the national level lime standard,and it was in the advanced level in china. |
