What is bioleaching ?
Bioleaching is the process of extracting precious metals from ore with the use of bacterial microorganisms. This process is the alternative for roasting a smelting used by miners if there is low metal concentration in ore and they need an effective and efficient environmentally friendly method. The bacteria feed on the mineral’s nutrients separating the metal. Afterwards, metal are collected in a solution.
Bioleaching becomes successful due to the special microorganisms’ response in mineral deposits. They serve as the catalyst to make the processes inside an ore faster. The bacteria use a chemical reaction called oxidation to transform metal sulphide crystals into sulfides and sheer metal. These constituent parts of ore are separated into precious metal and leftover sulfur and other chemicals. Finally, enough materials build up in waste solution and allow to be filtered and concentrate in into pure metal.
For some types of metal, such as copper, bioleaching is not always economically possible or fast enough, even with its low cost. However, in certain areas of the world or with other metals, this easy, effective, and low cost process offers a smart choice. For example, developing countries often do not have the infrastructure or capital asset to start smelting, yet their land contains enough ore that its mining can significantly progress their national economy.
In the future, we may use bioleaching to mine other metals like zinc and nickel, on the Moon.
After gaining popularity, about 20% of the copper extracted in the world currently comes from bioleaching. Mining companies must be cautious of pollution that might result from solutions getting a groundwater source. Yet overall, bioleaching creates less air pollution and minimal damage to geological formations, since the bacteria take place there naturally. A best metal deposit must permit a certain amount of water into the rock to bear the bacteria. However, it should be surrounded by rock that is resistant to water to make sure no ground water get polluted with sulphur.
