Page 14 - Curriculum Visions Dynamic Book

Dissolving aluminium compounds
Aluminium is a reactive metal. When exposed to the air
it immediately develops an oxide coating that prevents further corrosion. However, along with a few other metals, aluminium compounds can be dissolved by both acids and alkalis. Metal compounds with
this special property are called amphoteric metals.
This property has been exploited in the aluminium industry as a way of dissolving the aluminium compounds from bauxite while leaving the rest of the
ore as a solid. This process, called the Bayer process,
is shown on pages 16 and 17.
 The completely intact aluminium container used in the demonstration.
 Sodium hydroxide is poured into the container. It immediately begins to fizz and bubble.
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