BIOLEACHING AND BIOMINING PDF
Microbial Leaching (Bioleaching, Biomining). Microbial leaching is the process by which metals are dissolved from ore bearing rocks using microorganisms. Biomining is a technique of extracting metals from ores and other solid materials typically using . Additional capabilities include the bioleaching of metals from sulfide materials, phosphate ore bioprocessing, and the bioconcentration of metals. Bioleaching is the extraction of metals from their ores through the use of living organisms. This is much cleaner than the traditional heap leaching using cyanide .
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Sulfidic iron ores can be added to speed up the process and provide a source of iron. Some microbes can oxidize those metals, allowing them to dissolve in water.
In the microbial leaching process A. The net products of the reaction are soluble ferrous sulfate and sulfuric acid. Valuable metals are commonly bound up in solid minerals. Effect of elevated pressure on ferric iron reduction coupled to sulfur oxidation by biomining microorganisms. Some microbes can use stable metals such as ironcopperzincand gold as well as unstable atoms such as uranium and thorium.
This page was last edited on 5 Decemberat Populations of bacteria and archaea were used to rejuvenate the coast after the oil spill.
In the industrial microbial leaching process popularly known as bioleachinglow grade ore is dumped in a large pile the leach dump and a dilute sulfuric acid solution pH 2 is percolated down through the pile. Several smaller operations recover metals from existing acid mine drainage. Jeannette Marrero Coto, Literature: Iron-and sulfur-oxidizing microorganisms are used to release occluded coppergold and uranium from mineral sulfides.
Some examples of past projects in biotechnology include a biologically assisted in situ mining program, biodegradation methods, passive bioremediation of acid rock drainage, and bioleaching of ores and concentrates.
Electrons are pulled off of sulfur metal through oxidation and then put onto iron, producing reducing equivalents in the cell in the process.
Biomining is mineral processing with microbes. Mining releases many pollutants while the only chemicals released from biomining is any metabolites or gasses that the bacteria secrete. Microbes are especially good at oxidizing sulfidic bioleachng, converting metals like iron and copper into forms that can dissolve more easily. What metals are currently biomined? The most efficient minerals are supergene minerals such as chalcociteCu 2 S and covelliteCuS. Recovery of nickel and cobalt from laterite tailings by reductive dissolution under aerobic conditions using Acidithiobacillus species.
Bioleaching of non-sulfidic ores such as pitchblende also uses ferric iron as an oxidant e. Three possible reactions for the bioleacging of copper ore are:. Normally pyrite is shielded from contact with oxygen and not accessible for microorganisms.
BGR – Metal Bioleaching (Biomining)
World Journal of Microbiology and Biotechnology. In subsequent studies the dissimulatory iron-reducing archaea Pyrococcus furiosus and Pyrobaculum islandicum were shown to reduce gold chloride to insoluble gold.
At the current time, it is more economical to smelt copper ore rather than bioleacning use bioleaching, since the concentration of copper in its ore is in general quite high. Economically it is also very expensive and many companies once started can not keep up with the demand and end up in debt. From Wikipedia, the free encyclopedia. An electric current is passed through the resulting solution of copper ions. The bkomining is removed by bonding to a ligand, which is a large molecule consisting of a number of smaller groupseach possessing a lone electron pair.
Some past projects include in situ mining, biodegradation, bioremediation, and bioleaching of ores. Bioleaching can involve numerous ferrous iron and sulfur oxidizing bacteria, including Acidithiobacillus ferrooxidans formerly known as Thiobacillus ferrooxidans and Acidithiobacillus thiooxidans formerly known as Thiobacillus thiooxidans.
What is biomining?
It is produced by the following reaction:. Projects like Finnish Talvivaara proved to be environmentally and economically disastrous. How common is biomining? Fundamental and Applied Aspects”. Retrieved from ” https: In Temple’s experiment, A. The sulfur containing ore pyrite FeS 2 is at the start of this process. Skip to main content. Nonetheless, at the largest copper mine of the znd, Escondida in Chile the process seems to be favorable.
Copper is the oxidising agent it accepts electronsand iron is the reducing agent it loses electrons. Enhanced chalcopyrite dissolution in stirred tank reactors by temperature increase during bioleaching.
Bioleaching of non-sulfidic ores by layering of waste sulfides and elemental sulfur, colonized by Acidithiobacillus spp. The development of industrial mineral processing using microorganisms has been established now in several countries including South Africa, Brazil and Australia.
BGR For biomining specialized microorganisms are used in order to recover valuable metals from ores via bioleaching. Other metals, like gold, biileaching not directly dissolved by this microbial process, but are made more accessible to traditional mining techniques because the minerals surrounding these metals are dissolved and removed by microbial processes.
April Learn how and when to remove this template message. This step is entirely independent of microbes. In the microbial leaching process At. The copper can also be concentrated and separated by displacing the copper with Fe from scrap iron:.
Oxidation means increasing the number of bonds between an bioleachjng to oxygen. Other uses of biomining New biomining techniques that do not involve oxidation are being tested, which would enable large-scale biomining for different types of minerals and metals. This page was last edited on 15 Decemberat Microbial leaching is especially useful for copper ores because biolexching sulfate, as formed during the oxidation of copper sulfide ores, is very water-soluble.
The resulting electrons will reduce iron, releasing energy that can be used by the cell.