4.1.3 Extraction of Metals & Reduction

Methods of Metal Extraction

The extraction method depends on the reactivity of the metal, which is determined by its position in the Reactivity Series:

1. Reduction by Carbon:

• Metals that are less reactive than carbon (such as iron) can be extracted by heating their oxides with carbon. This process is known as smelting.

2. Electrolysis:

• More reactive metals, such as aluminium, cannot be reduced by carbon and must be extracted using electrolysis. This process involves passing an electric current through molten metal oxides, which decomposes them into pure metal and oxygen.
• Although effective, electrolysis is energy-intensive and therefore more expensive.

The Role of the Reactivity Series

The Reactivity Series helps determine which extraction method to use:

• Highly reactive metals (above carbon) require electrolysis.
• Less reactive metals (below carbon) can be reduced using carbon, which is a more cost-effective method.

Exception: Native Metals

Some metals, like gold and platinum, are so unreactive that they do not combine with other elements to form ores. These native metals can be found in their pure form in nature, requiring no chemical reduction for extraction.