Zone refining is a well-known technique, usually using pure initial materials to produce high purity metals. However, the effectiveness of zone refining in the purification of different purity levels of metals as well as its feasibility for use as a recycling technique for low quality metals are rarely investigated. In this work, conducted at IME/RWTH Aachen University, three kinds of Al with different purities, i.e., three-layer electrolysis (4N), commercial pure (2N8) and recycled Al (1N7), were put on focus to address the above-mentioned issue. The experiments were conducted with an optimized zone length combination at the moving rate of 1.2 mm/min for five zone passes. The results showed that the 4N pure initial Al was improved to 5N5 after five passes, much higher than the results for commercial pure- or recycled Al, where less than 50% reduction of total impurities was achieved.

中文翻译：

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初始纯度对区域精炼铝精炼效率的影响

区域精炼是一项众所周知的技术，通常使用纯净的初始材料来生产高纯度的金属。然而，很少研究区提纯在纯化不同纯度的金属中的有效性以及用作低质金属回收技术的可行性。在IME / RWTH亚琛大学进行的这项工作中，着重解决了三种纯度不同的铝，即三层电解（4N），商业纯（2N8）和再生铝（1N7）。提到的问题。实验以优化的区域长度组合以1.2 mm / min的移动速率进行了五次区域通过。结果表明，经过5次通过后，4N纯初始Al改善为5N5，远高于商业纯铝或回收Al的结果，