Page "Bioleaching" Paragraph 1

Bioleaching can involve numerous ferrous iron and sulfur oxidizing bacteria, including Acidithiobacillus ferrooxidans and Acidithiobacillus ( formerly known as Thiobacillus ).

As a general principle, Fe < sup > 3 +</ sup > ions are used to oxidize the ore.

This step is entirely independent of microbes.

The role of the bacteria is the further oxidation of the ore, but also the regeneration of the chemical oxidant Fe < sup > 3 +</ sup > from Fe < sup > 2 +</ sup >.

For example, bacteria catalyse the breakdown of the mineral pyrite ( FeS < sub > 2 </ sub >) by oxidising the sulfur and metal ( in this case ferrous iron, ( Fe < sup > 2 +</ sup >)) using oxygen.

This yields soluble products that can be further purified and refined to yield the desired metal.