Extracting Metals from Low-Grade Ores

As the world's demand for metals continues to grow, high-grade ores — those containing a large percentage of the desired metal — are becoming scarce. Scientists have developed new methods to extract metals from low-grade ores (ores that contain only small amounts of the metal). This lesson covers phytomining and bioleaching as required by the AQA GCSE Chemistry specification.

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Why Do We Need New Extraction Methods?

Traditional methods of metal extraction (such as smelting with carbon or electrolysis) work well with high-grade ores. However:

Problem	Explanation
High-grade ores are running out	Centuries of mining have depleted the richest ore deposits
Low-grade ores are uneconomic to smelt	The energy cost of smelting a low-grade ore is too high relative to the small amount of metal obtained
Mining waste is a problem	Traditional mining produces huge amounts of waste rock that damages the landscape
Environmental damage	Large-scale mining causes habitat destruction, water pollution and air pollution