过去十年中,美国使用的新鋁土矿含有大量的一水氧化鋁,而1950年以前,美国使用的鋁土矿,可提取的氧化鋁几乎100％都是三水氧化鋁。欧洲鋁工业一开始就采用了含一水氧化鋁的鋁土矿。欧洲所采用的从一水鋁土矿中提取氧化鋁的方法,对美国来說是不經济的。因此美国又研究发明了許多新的方法。本文的目 The new bauxite used in the United States over the past decade contained a significant amount of alumina monohydrate, whereas before the United States bauxite was used in the United States, almost 100% of the extractable alumina was alumina trihydrate. The European aluminum industry started with bauxite containing alumina monohydrate. The method used in Europe to extract alumina from monohydrate bauxite is not economical for the United States. Therefore, the United States has studied and invented many new methods. The purpose of this article