Numerical simulation of early stages of oxide formation in molten aluminium-magnesium alloys in a reverberatory furnace
Numerical simulation of early stages of oxide formation in molten aluminium-magnesium alloys in a reverberatory furnace
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反射炉中熔融铝镁合金氧化物形成早期阶段的数值模拟
DOI：
10.1088/0965-0393/12/3/003
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
I. Puri
中科院分区：
文献类型：
--
作者：
A. K. De;A. Mukhopadhyay;S. Sen;I. Puri
大量的铝是通过熔化含有少量镁的废铝来加工的。在二次熔炼炉中生产铝的一个主要缺点是熔融金属的氧化会形成熔渣或氧化铝。由于废铝是二次铝加工中金属的主要来源，合金元素的存在在氧化过程中起着关键作用。在这里，我们考虑铝镁合金氧化的早期阶段，在此阶段主要发生镁的氧化为其氧化物。我们的模型模拟了铝熔炉中的氧化过程，并认为金属的氧化是扩散受限的。这种现象被认为是一维的，Al/Mg与O2的反应是无限快的。我们能够得到蒸发速率和生成的氧化物量的封闭形式的解析解。我们发现，金属蒸气的蒸发和氧化取决于炉子尺寸、熔体组成、熔体温度、气体温度和气体中的氧浓度。氧化物生成量随着炉膛高度的增加、氧气浓度的降低和熔体温度的降低而减少。熔渣的形成弱依赖于环境温度和合金成分。结果表明，燃料-空气混合物的当量比(控制环境氧浓度)和熔体温度是影响实际炉膛中氧化物生成的两个基本参数。
A significant amount of aluminium is processed by melting aluminium scrap that contains small amounts of magnesium. A major drawback of aluminium production in secondary melt furnaces is the formation of dross or aluminium oxide by the oxidation of the molten metal. Since aluminium scrap forms a major source of the metal in secondary aluminium processing, the presence of alloying elements plays a key role in the oxidation process. Here, we consider the early stage of oxidation of an Al–Mg alloy during which primarily the oxidation of magnesium to its oxide occurs. Our model simulates the process in an aluminium melting furnace and considers metal oxidation to be diffusion limited. The phenomenon is assumed to be one-dimensional and the reaction of Al/Mg with O2 to be infinitely fast. We are able to obtain a closed form analytical solution of the evaporation rate and the amount of oxide that is formed. We find that the evaporation of the metal vapour and its oxidation depend on the furnace size, melt composition, melt temperature, gas temperature and oxygen concentration in the gas. Oxide formation decreases with increasing furnace height and with decreasing oxygen concentration and melt temperature. Dross formation is weakly dependent on the ambient temperature and alloy composition. The results indicate that there are essentially two parameters, namely, the equivalence ratio of the fuel–air mixture (which controls the ambient oxygen concentration) and the melt temperature that can be manipulated to influence oxide formation in practical furnaces.