What is Bioleaching?
Bioleaching uses bacterial microorganisms to extract precious metals, such as gold, from ore in which it is embedded. As an alternative to smelting or roasting, miners use bioleaching when there are lower concentrations of metal in ore and they need an efficient, environmentally responsible method. The bacteria feeds on nutrients in minerals, thereby separating the metal that leaves the organism’s system; then the metal can be collected in a solution. Bioleaching works because of how special microorganisms act on mineral deposits. They are a catalyst to speed up natural processes inside ore. The bacteria uses a chemical reaction called oxidation to turn metal sulphide crystals into sulfates and pure metals. These constituent parts of ore are separated into valuable metal and leftover sulphur and other acidic chemicals. Eventually, enough material builds up in the waste solution to filter and concentrate it into metal. For some types of metal, such as copper, bioleaching is not always e
Although the terms bioleaching and biooxidation are often used interchangeably, there are distinct technical differences between these process technologies. Bioleaching refers to the use of bacteria, principally Thiobacillus ferrooxidans, Leptospirillum ferrooxidans and thermophilic species of Sulfobacillus, Acidianus and Sulfolobus, to leach a metal of value such as copper, zinc, uranium, nickel and cobalt from a sulphide mineral. Bioleaching places the metal values of interest in the solution phase during oxidation. These solutions are handled for maximum metal recovery and the solid residue is discarded. Mineral biooxidation refers to a pretreatment process that uses the same bacteria as bioleaching to catalyze the degradation of mineral sulphides, usually pyrite or arsenopyrite, which host or occlude gold, silver or both. Biooxidation leaves the metal values in the solid phase and the solution is discarded.
Put simply, some metals are easy to separate from rock and some aren’t. BacTech uses naturally occurring bacteria (bioleaching) to help separate metal from the tougher rock. Our technology provides a suitable environment for the bacteria within the plant, creating a ‘garden of eden’ for them to live in. The separation technology achieves in 6 days what would normally take 20 years to occur in nature. That’s 500,000 times faster. And they work all day and demand very little. Now that’s a work force! Best of all, the tailings created are benign and no environmental damage occurs. We are one of only two companies worldwide who have commercally proven, bioleaching technology. BacTech has just signed a major deal with Yamana Gold, involving the purchase of two of their refractory gold deposits. Our team is continually searching for viable deposits that would benefit from our technology.
