【作者】 常宝龙；

【导师】 伍成波；

【作者基本信息】 重庆大学 ， 钢铁冶金， 2004， 硕士

【摘要】 电解槽是铝电解生产的主体设备。电解槽的寿命是铝工业的一个综合性的技术经济指标，它不仅反映了铝电解生产技术水平的高低，而且也直接关系着铝电解生产的稳定性和产品成本。新建电解槽或大修后的电解槽在投入生产之前必须经过焙烧启动。而电解槽的焙烧预热方法对槽的寿命起着决定性的作用。 1999年电解槽的热焙烧启动在重庆大学首次试验成功，填补了国内此项技术的空白。与电阻焙烧相比，热焙烧提供了更好的预热控制，因此热焙烧是很好的预热铝电解槽的方法。但是，由于在焙烧过程中，电解槽的电极一直暴露在高温烟气中，这就会使阴极和阳极的表面以及捣固糊和边部扎固糊发生氧化。这个问题如果不能很好地处理，必将会极大地限制这种良好的电解槽焙烧启动方法的使用以及推广。 本文利用电阻炉来加热铝电解槽的碳阴极、阳极以及扎固糊试样，使用温度控制器来控制电阻炉的升温，用高温烟气通入炉膛内作为氧化气氛。根据上述条件来模拟铝电解槽的高温烟气焙烧过程，在温度、气氛不同的情况下利用电子天平测定试样的失重情况。 实验研究表明，铝电解槽的阴极、阳极和扎固糊在高温烟气中的氧化速率在700℃以前，虽然上升较快，但其绝对值处于较低的水平上；在温度上升到700℃以后，氧化速率趋于平缓，整个实验过程中，电极试样的氧化速率最高约为空气中的9％左右。当空气过剩系数大于1.1以后，电极的氧化速率增加较大，在小于1的情况下，电极试样的氧化速率较小。 通过计算分析，铝电解槽在高温烟气焙烧过程中，界面化学反应在850℃以前一直占据主导作用。因为铝电解槽在850℃左右时就开始启动，因此在整个焙烧过程中，界面化学反应是电极氧化的限制性环节。 在实际焙烧过程中，为了减少高温烟气对电极的氧化，建议燃烧的空气过剩系数控制在1以下；700℃以前缓慢升温，以达到焙烧彻底、均匀的目的；在700℃以后，加快升温速度，以减少电极的氧化。 本文的研究结果对高温烟气焙烧铝电解槽技术的使用和推广提供了很好的参考依据。更多还原

【Abstract】 Aluminum reduction cell is the major equipment in aluminum reduction production. The life of cells is an all-round technical and economic target in aluminum industry. It not only reflects high or low level of manufacturing technique for aluminum reduction, but also affects the stability of aluminum reduction and the cost of products as well. For new reduction cells or cells after being heavily repaired, bake-out and start-up must be made before putting into production. But the method of bake-out for reduction cells plays a decisive role for the life of cells.In 1999, the thermal bake-out for the reduction cell was first put on trial and obtained success in Chongqing University, which fills in a gap for this technology in China. Compared with electric resistance bake-out, thermal bake-out provides better preheating control, so thermal bake-out is a kind of very good method for preheating aluminum reduction cells. But by reason that the electrode of cells is exposed in the high temperature mixed fume all the time during the thermal bake-out, oxidation may occur in the surface of the cathode and anode and also the ramming paste and ramming paste of the edge. If this problem cannot be handled very well, it will greatly restrict the application and popularization of this kind of good bake-out method for cells.In this article, the electric resistance furnace is used to heat the carbon cathode , anode and ramming paste samples of aluminum reduction cell, the temperature regulator used to regulate heating-up of the electric resistance furnace and high temperature mixed fume is inlet into melting chamber as oxidizing atmosphere. According to the conditions mentioned above, it simulates the bake-out process of high temperature fume for aluminum reduction cell and determines the situation of weight loss by electronic balance on the condition of different temperature and atmosphere.Experiment shows that the oxidation rate of cathode, anode and the ramming paste of the aluminum reduction cell in high temperature fume rises very fast when the temperature is below 700 C, but the absolute value is still in lower level; and when the temperature rises to 700 C, the oxidation rate is tending towards stability. During the whole experimental process, the maximum oxidation rate of the electrode sample is approximately 9% of that in air. After the air excess coefficient is greater than 1.1, the oxidation rate of the electrode is increased more quickly; when the coefficient is less than 1.1, the oxidation rate is increased slowly.After calculation and analysis, the interface chemical reaction plays a leading role when the temperature is below 850 C during the process of high temperature fume bake-out for aluminum reduction cells. The aluminum reduction cell begins to start up when the temperature is about 850 C, so the interface chemical reaction is a restrictive link of electrode oxidation in the whole bake-out process.In the real bake-out process, it suggests that the air excess coefficient of burning should be controlled within 1 in order to avoid electrode being oxidized by high temperature fume; when the temperature is below 700 C, it rises slowly in temperature to bake out thoroughly and uniformly; when above 700 C, it speeds up in heating-up to reduce the electrode oxidation.The study result of this article provides very good reference basis for the application and popularization of the technology of high temperature fume bake-out for aluminum reduction cells.更多还原