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通过实验研究,纠正或澄清了以前存在的有关浸钒后钠化球团还原膨胀的某些观点,阐明了若干规律。证明导致钠化球团还原粉化的原因与Fe_2O_3转变为Fe_3O_4过程中的体积变化无关,它是由内应力积累引起Fe_3O_4开裂造成的;粗晶粒Fe_2O_3还原时,易于积累应力,故较之细晶粒Fe_2O_3更易引起球团的异常膨胀;控制Fe_2O_3晶粒长大的主要因素是钠化剂添加量、焙烧温度以及钠化剂类型;提高球团开始还原的温度一般可以降低还原膨胀率。基于对机理的研究结果,主张应适当控制球团的氧化焙烧温度。在回转窑直接还原工艺中,应采用高温还原。若使用该类球团作高炉原料,则必须采取细磨降硅降钠方法以及对浸钒后球团施以其它辅助措施,否则无法从物理和化学性能上满足高炉对球团的要求。
Some experimental observations have corrected or clarified some of the existing preconceptions about the reduction and swelling of sodium-containing pellets after vanadium precipitation, and clarified several rules. The reason that sodium carbonate pellets are reduced and pulverized is proved to be independent of the volume change of Fe 2 O 3 to Fe 3 O 4. It is caused by the crack of Fe 3 O 4 caused by the accumulation of internal stress. The reduction of coarse grain Fe 2 O 3 is easy to accumulate stress, The main factors that control the grain growth of Fe 2 O 3 are the amount of sodium addition, the calcination temperature and the type of sodium alcoholate. Increasing the temperature at which the pellets begin to reduce usually reduces the reduction and expansion rate. Based on the results of research on mechanism, it is argued that the temperature of the pellets should be properly controlled. In the rotary kiln direct reduction process, should be used high temperature reduction. If such pellets are to be used as blast furnace raw materials, the fine grinding method of lowering the silicon content and other auxiliary measures must be taken to ensure that the pellets can not meet the requirements of the blast furnace on the physical and chemical properties.