揽瓜阁做题小分队 第15天 铝的作用及价格演变-从天价到白菜价

B及站士

P1. 介紹鋁的特性, 可得知缺點"極度活性所以在自然中找到純鋁", 但也知道優點"緻密的氧化層保護底材"
P2. 引申出鋁很難產出的問題, 後面說道一個新方法導致生產成本大幅降低
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P1
1. Context: aluminum – though common in Earth’s crust – until 1825 discovered – so reactive that it is never found in natural (most found as ore)
2. Disadvantage: elemental aluminum is difficult to separate from ores – by traditional methods
3. Advantage: extreme reactivity helps protect – pure aluminum + oxygen = “passivation” – aluminum oxide prevents further corrosion (unlike iron)
P2
1. Problem: aluminum was considered precious – not because of scarcity – hard to produce
2. Solution: 1886 two inventors use electrolytic process to separate pure aluminum from aluminum salts

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打卡

木柚籽

P1
a discovery of aluminum -- the unique characterstic of aluminum and the advantage -- compare with irron       
P2
the cost of the production is expensive.(承接上文铝的特点引出）-- however, the new method was invented --- the price of aluminum fall down

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主旨：
P1: 铝含量高但非常活泼，常以化合物的形态出现，单质难以被分离，并且容易形成致密的氧化膜防腐蚀；
P2: 铝价因为量产困难而居高不下，直到电解铝的发现。
ADE

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EDE

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ADE