Name: bioleaching in metal recovery
Uploaded: 2026-03-12T13:57:46.000Z
Duration: 1 min 27 s
Channel: JoVE

Microbial leaching, or bioleaching, uses microorganisms to extract metals from low-grade ores.For example, in copper leaching, crushed ore containing copper sulfides and iron sulfide minerals is sprinkled with dilute sulfuric acid.This process creates an acidic environment and releases ferrous iron in the ore.The acidic conditions favor Acidithiobacillus ferrooxidans, which oxidizes ferrous iron to ferric iron.Ferric iron reacts with copper sulfides, releasing copper ions in the ore.A. ferrooxidans also oxidize the sulfur left behind, regenerating sulfuric acid and keeping conditions acidic.The copper-rich liquid flowing down the ore, the leachate, is collected and treated with scrap iron in recovery tanks.The scrap iron displaces the copper, which precipitates as metallic copper and releases ferrous iron into the solution.Ferrous iron is pumped to an aerated pond, where bacteria A. ferrooxidans reoxidize it to ferric iron.This ferric iron is pumped back to the heap, sustaining the iron cycle that enables continuous copper extraction.

microbial leaching

Microbial Leaching

Microbial leaching, also known as bioleaching, is an environmentally favorable method for extracting metals from low-grade ores using specific microorganisms. This biotechnological approach is particularly valuable for mining operations targeting copper, gold, and uranium, where traditional extraction methods may be economically or environmentally impractical.<h3>Copper Leaching and Microbial Catalysis</h3>In copper bioleaching, crushed ore is arranged into heaps and irrigated with a dilute sulfuric acid solution. This acid dissolves some copper and creates an environment conducive to acidophilic bacteria, notably Acidithiobacillus ferrooxidans. These bacteria play a critical role by oxidizing ferrous iron (Fe&#178;&#8314;) into ferric iron (Fe&#179;&#8314;), which chemically attacks copper sulfide minerals (CuFeS&#8322;), converting them into copper sulfate (CuSO&#8324;) and simultaneously regenerating sulfuric acid. This cycle facilitates continual copper solubilization.The leachate, now containing copper ions, is collected and chemically reduced using scrap iron, leading to the precipitation of metallic copper and the reformation of ferrous iron. The ferrous iron is recirculated into an aerated bioreactor pond, where microbial oxidation regenerates ferric iron, sustaining the bioleaching process. As the heap's internal temperature increases, mesophilic bacteria like A. ferrooxidans are gradually replaced by thermophilic oxidizers such as Leptospirillum (iron-oxidizer) and Sulfolobus (sulfur-oxidizer).<h3>Bioleaching of Gold and Uranium</h3>Gold bioleaching typically involves bioreactors where bacteria degrade sulfide minerals like arsenopyrite (FeAsS), liberating gold and oxidizing associated compounds into less toxic byproducts such as carbon dioxide. In uranium bioleaching, A. ferrooxidans oxidizes uranous ions (U&#8308;&#8314;) into soluble uranyl sulfate (UO&#8322;SO&#8324;), facilitating downstream recovery through solvent extraction or ion-exchange techniques.This biologically driven extraction method offers a sustainable alternative by reducing reliance on high-temperature smelting and toxic reagents, aligning with modern goals for greener mining technologies.

Microbial leaching, also known as bioleaching, is an environmentally favorable method for extracting metals from low-grade ores using specific ...

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bioleaching in metal recovery

Bioleaching uses microorganisms to help extract metals from low-grade ores. It is also called microbial leaching. This method is useful in mining for copper, gold, and uranium, especially when traditional extraction is too costly or causes too much environmental damage.

Copper bioleaching begins with crushed ore piled into heaps. The heaps are irrigated with dilute sulfuric acid. The acid dissolves some copper and creates conditions that favor acid-loving bacteria such as Acidithiobacillus ferrooxidans. These bacteria oxidize ferrous iron into ferric iron. The ferric iron then attacks copper sulfide minerals and converts them into copper sulfate while sulfuric acid is regenerated.

This reaction cycle keeps copper moving into solution. The leachate, which is the liquid that drains from the heap, contains copper ions and is collected for recovery. Scrap iron is then used to reduce the copper, which causes metallic copper to precipitate. At the same time, ferrous iron forms again. The ferrous iron is sent back to an aerated bioreactor pond, where microbes oxidize it back to ferric iron and keep the process going.

As the heap gets hotter, the microbial community changes. Mesophilic bacteria, which grow best at moderate temperatures, such as A. ferrooxidans, are gradually replaced by thermophilic oxidizers that prefer higher temperatures. Examples include Leptospirillum, an iron-oxidizer, and Sulfolobus, a sulfur-oxidizer.

Bioleaching is also used for gold and uranium. Gold recovery often takes place in bioreactors, where bacteria break down sulfide minerals such as arsenopyrite and release the gold. They also oxidize associated compounds into less toxic products like carbon dioxide. In uranium bioleaching, A. ferrooxidans oxidizes uranous ions into soluble uranyl sulfate. The uranium can then be recovered by solvent extraction or ion-exchange methods. This biologically driven process offers a greener alternative to high-temperature smelting and toxic chemicals.

Bioleaching in Metal Recovery

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Bioleaching uses microorganisms to help extract metals from low-grade ores. It is also called microbial leaching. This method is useful in mining for copper, gold, and uranium, especially when traditional extraction is too costly or causes too much environmental damage. Copper bioleaching begins with crushed ore piled into heaps. The heaps are irrigated with dilute sulfuric acid. The acid dissolves some copper and creates conditions that favor acid-loving bacteria such as Acidithiobacillus...

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key terms and concepts

Learn how bioleaching uses microbes, acid, and iron cycling to recover copper, gold, and uranium from low-grade ores in greener mining methods.

Bioleaching in Metal Recovery | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Bioleaching in Metal Recovery

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