摘要
攀钢西昌带式焙烧机生产线是国内第一条钒钛矿带式焙烧机球团生产线,投产后成品球平均抗压强度偏低,单个成品球团矿平均抗压强度≥1 950 N.本文从原料结构、造球工序、带式焙烧机工艺操作等方面分析原因,采取的优化措施包括:控制原料中TiO2质量分数≤12％、V2O5质量分数≤1％、Al2O3质量分数＜2.0％、MgO质量分数＜1.8％,精矿粒度-200目占比75％～80％,碱度应控制0.6倍左右,膨润土配比应适当降低至1.2％～1.4％,生球粒度10～12.5 mm占比≥60％;重力除尘灰配比＞1.5％,或者烧结机头除尘灰配比＞1.5％;焙烧机工艺操作制度为鼓干段温度300～330 ℃、抽干段温度370～390 ℃、预热温度梯度500℃→1 200 ℃、焙烧段温度1 230～1 240 ℃、大烟罩内氧质量分数17.3％～18.0％.工艺优化后,单个球团平均抗压强度约2 348 N,达到了考核指标;排放烟气中烟尘含量2.54 mg/Nm3、SO2含量3.13 mg/Nm3、NOx含量41.42 mg/Nm3、基准氧含量17.54％,均满足国家排放标准.
Abstract
Panzhihua iron and Steel Group's Xichang strip roaster production line is the first production line of vanadium-titanium ore strip roaster pellets in China,the average compressive strength of the finished pellets was lower than that of the original pellets,per pellet only ≥1 950 N.This paper analyzes the reasons from the aspects of raw material structure,pelletizing process,technological operation of belt roaster,etc.,the optimization measures adopted include:controlling the mass fraction of TiO2≤12％,V2O5 ≤ 1％,Al2O3＜2.0％,MgO＜1.8％,and the concentrate particle size of 200 mesh 75％～80％,the alkalinity should be controlled about 0.6 times,the proportion of bentonite should be reduced to 1.2％～1.4％,the proportion of green ball particle size 10～12.5 mm ≥60％,the proportion of gravity dust＞1.5％,or the proportion of Sintering Machine Head dust＞1.5％,The operating regulations of the roaster is as follows:the temperature of the drum drying section is 300～330 ℃,the temperature of the drying section is 370～390 ℃,the preheating temperature gradient is 500→1 200 ℃,the temperature of the roaster section is 1 230～1 240 ℃,and the oxygen content in the hood is 17.3％～18.0％.After optimization,the average compressive strength of single pellet was about 2 348 N,and the smoke dust content was 2.54 mg/Nm3,SO2 content was 3.13 mg/Nm3,NOx content was 41.42 mg/Nm3,and the reference oxygen content was 17.54％,all meet national emission standards.
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