The bioleaching of metals from electronic waste was investigated by using cyanogenic bacterial strains chromobacterium violaceum, pseudomonas aeruginosa and pseudomonas fluorescens. Jan 17, 2006 bioleaching is a simple and effective technology for metal extraction from low. Bioleaching is performed mostly by iron and sulfide oxidizing bacteria, or acid producing fungus. The leaching is carried out in a sequence of bioreactors with the first step bioleaching the fes2 and feass so that the gold can subsequently b eextracted. This is much cleaner than the traditional heap leaching using cyanide. Bioleaching of gold by metabolic products of microorganisms has received less attention.
Microbial oxidation of gold ores and gold bioleaching olson. Leaching process was first observed in pumps and pipelines installed in mine pits containing acid water. Introduction, methods, application, copper, microorganisms, and processes. Bioleaching is one of several applications within biohydrometallurgy and several methods are used to recover copper, zinc, lead, arsenic, antimony, nickel, molybdenum, gold, silver, and cobalt.
Bioleaching has also some potential for metal recovery and detoxification of industrial waste products, sewage sludge and soil contaminated with heavy metals. The low concentration of gold in primary rocks means that upgrading by a factor of 30004000 is usually. Leadville gold ore tailings containing auriferous pyrite were first concentrated by froth flotation. These bacteria need to be cultivated and adapted to achieve maximal results. Tank bioleaching of concentrates a niche technology. In fact, despite a plethora of hydrometallurgical processes being. Steps involved in the determination of bioleaching potential of gold bearing ores or concentrates. The dissolved gold in solution is adsorbed onto activated carbon. Although the tank bioleaching of refractory gold concentrates has found fairly widespread commercial application, the technology has not been transferred into the base metals industry. Microbial oxidation of gold ores and gold bioleaching fems. Technological advances have taken biooxidation from a concept to commercial reality.
The library will be expanded regularly, providing a valuable ongoing resource to the industry. Minerals free fulltext bioleaching of aucontaining ore. Gold from refractory gold concentrates by stirred tank leaching as a pretreatment step. Pdf bioleaching is a new method of refining minerals from their parent ores in order to obtain the. Natural bioleaching has been taking place for almost as long as the history of the world, but it is only in the last few decades that we have realized that bioleaching is responsible for acid production in some mining wastes, and that this bacterial activity can be used to liberate some metals. The bioleaching of the concentrate before cyanide leaching increased the gold extraction from 32 to 95% and that of silver from 48 to 98%. The leaching is carried out in a sequence of bioreactors with the first step bioleaching the fes2 and feass so that the gold can subsequently b. This process was later on employed for recovering metals from ores containing low quantity of the metal. In these cases metal extraction is due to the production of organic acids and chelating and complexing compounds excreted into the environment.
When the carbon is loaded with enough gold it is removed from the circuit and sent to elution where the adsorption process is reversed and the gold is stripped off the carbon back into solution, electrowon and smelted into bars. Auriferous sulfide ores often contain very finely disseminated gold and other precious metal particles inside the sulfide. Enhancing gold recovery by bioleaching of chalcopyrite low grade ore krstev b. Biooxidation of mouteh refractory goldbearing concentrate by an. Bioleaching is a simple and effective technology for metal extraction from low. Microbial oxidation of gold ores and gold bioleaching sciencedirect. A twostep bioleaching process was followed under cyanideforming conditions for maximum metals mobilization. The bacterial strain that was used in the leaching experiments was isolated from the jaduguda mine water sample. In case of the bioleaching of gold, bacteria such as acidobacillus. The biooxidation residue is further treated by cyanide leaching to recover gold.
The bacteria feed on nutrients in the minerals, causing the metal to separate from its ore. It finds application in the extraction of metals from their ores. The biooxidation section contributes to more than 50 percent of the total biox plant equipment cost. One of the many applications in biohydrometallurgy. The understanding and funding of bench, pilot, and fullscale programs is steadily increasing. Small samples of ground ore from shake flask experiments were leached by slurrying samples of the ore with one pound of cyanide per ton of solution and bottle rolling in the presence of carbon bench scale cll testing. The bioleaching and processing of refractory gold ore springerlink.
Because of this flexibility, biooxidation can be effectively integrated into goldprocessing. The liberation of the metal by use of bacteria involves a complex chemistry. Performed bioleaching of gold from waste pcb using chromobacterium violaceum. Pdf bioleaching strategies for the treatment of nickel. Gold extractability was measured by cyanide leaching in the same manner before and after biooxidation. Therefore, for the case of pyrite bioleaching the primary role of the bacteria is the oxidation of the ferrousiron to the ferric form, thereby maintaining a high redox potential within the system and. An alternative green mining technology for 21st century. Therefore, this study evaluated the tolerance to gold of four strains of aspergillus and the bioleaching efficiency of gold, copper and nickel from pcbs and gficms by. Bioleaching and biosorption of heavy metals from gold mine. Moreover other biological organisms also have an immense possibility in the bioleaching of. Bioleaching of gold ore table of contents title pagei table of contentsii abstractiii 1. This work has been done worldwide and has resulted in several pilot plant and commercial scale operations for gold ore biooxidation. The original mixed bacterial flora had been enrichedin acid mine drainage of dexing copper mine, jiangxi province, china. However, the contact time of the gold bioleaching with iob and iodide may not be as fast as that of gold leaching using cyanide, which was reported to be approximately 2472 h for gold ore.
Metals such as copper, gold, silver, uranium, zinc, nickel etc are now recoverable using. Planning the largestscale research project ever, focusing on geological prospecting and in situ fluidized bioleaching of copper, gold and uranium ores. Moreover other biological organisms also have an immense possibility in. The profit obtained from the speed and yield of smelting justifies its cost. The average concentration of gold in the world is about 0. Metal recovery from sulfide minerals is based on the activity of chemolithotrophic bacteria, mainly thiobacillus ferrooxidans and t. The bacteria feed on nutrients in the minerals, causing the. Copper from lowgrade secondary copper sulfide ores by heap bioleaching. Bioleaching of gold can be performed using a number of different techniques and various microbes depending on the factors of the operation in question. The bioleaching and processing of refractory gold ore.
Therefore, this study evaluated the tolerance to gold of four strains of aspergillus and the bioleaching efficiency of gold, copper and nickel from pcbs and gficms by aspergillusstrains with higher tolerance to gold. It was demonstrated that the degree of au bioleaching from carbonaceousargillaceous slates, containing 2. Bioleaching of heavy metals by sulfur oxidizing bacteria. Mine tailings is an important source of heavy metal contamination in the environment. This central government project, costing 10 billion dollars, will run until 2030. As sodium cyanide nacn, it reacts with gold, oxygen o, and water h2o to form a gold cyanide complex na. Microbial alchemy using bacteria to mine precious metals authors. Microbial oxidation of gold ores and gold bioleaching.
Cyanide cn has been used since 1889 to recover gold from hard rock. Some of the types of bacteria used in this process include leptospirillum ferrooxidans, thiobacillus ferrooxidans, and some species of sulfolobus, acidianus, and sulfobacillus. Rebgolds bioleaching process produces gold and other metals remediates old tailings hd. Because of this flexibility, biooxidation can be effectively integrated into goldprocessing mills to achieve economical recovery from refractory ores.
A blank experiment to characterize bioleaching of the pyrite concentrate at 50 wt. This study examined the impact of incubation conditions such as concentration of the nutrient and iodide, initial bacterial cell number, incubation temperature, and shaking condition on the performance of the gold dissolution. Studies on the bioleaching of refractory concentrates. Bioleaching, gold, silver, thiobacillus ferrooxidans, leptospirilum ferooxidans, introduction bucim copper and gold mine is the unique mine in the republic of macedonia located in the southern part of country on the southwest slopes of the plackovica mountain. Bioleaching of gold, copper and nickel from waste cellular. Bioleaching is the extraction of metals from their ores through the use of living organisms. Curtin university scientists have developed a gold and copper extraction process using an amino acidhydrogen peroxide system, which could provide an environmentally friendly and cheaper. It was induced by uv ultraviolet, ultrasonic, and microwave, and their. Because of this flexibility, biooxidation can be effectively integrated into gold processing. Rebgolds bioleaching process produces gold and other. In addition, the costs of the nutrient and iodide may be expensive, which may be a.
Pdf bioleaching copper recovery from mine waters in the mediterranean area 3000 years ago. At present bioleaching is used essentially for the recovery of copper, uranium and gold, and the main techniques employed are heap, dump and in. Presently certain metals from sulfide ores and other ores are. It may have been the first metal used by humans and was valued for ornamentation and rituals. Ajay kumar, aman jaiswal, deepak kumar, shekhar kumar page 2 of 5 version 1. Chile has become a major developer of bioleaching on an industrial scale. Some ores are resistant to cyanide treatment as the gold is enmeshed in pyrite fes2 and arsenopyrite feass and only 50 of the gold can be extracted. A novel bio leaching process to recover valuable metals from. Introduction gold has been known and highly valued since prehistoric times. Improvement of the metal recovery efficiency by means of fungal metabolism is also dis cussed. Pdf bioleaching is a biochemical mining technique in which specific biological organism is used for the removal of a specific. Oct 24, 2014 curtin university scientists have developed a gold and copper extraction process using an amino acidhydrogen peroxide system, which could provide an environmentally friendly and cheaper.
Minerals free fulltext copper bioleaching in china. Because the price of gold has risen many mineral companies now take 6. Studies on the bioleaching of refractory gold concentrates substrate, and that the bioleaching of pyrite occurs via a multiple subprocess mechanism. Microbial alchemy using bacteria to mine precious metals.
Mar 09, 2010 bioleaching of uranium was carried out with turamdih ore sample procured from uranium corporation of india limited, jaduguda. Today, biooxidation technology is successful in a range of conditions, from ideal to the most severe climates in the world. However, within a biooxidation heap, oxygen mass transfer limitations can limit the applicability of this technology, due to the large amount of oxygen. This work investigates the feasibility of pretreating these refractory tailings with bioleaching before using standard extraction techniques such as cyanidation. Without pretreatment, the gold leaching efficiency is only 19. Bioleaching of gold by metabolic products of microorganisms has received less attention, but also offers opportunities for industrial application, especially if future regulations restrict the use of cyanide. Bioleaching of arsenicrich gold concentrates by bacterial. The biox reactors and agitator are the brunt of this cost. Review on chromobacterium violaceum for gold bioleaching. At present bioleaching is used essentially for the recovery of copper, uranium and gold, and the main techniques employed are heap, dump and in situ leaching. Gold and copper are the dominating valuable metals that are commercially extracted. Jul 01, 2015 in contrast, knowledge of metal bioleaching from weee by filamentous fungi is still scarce. Arsenopyrite oxidation, bioleaching, biohydrometallurgy, pyrite oxidation, refractory.
Ppt biomining and bioleaching powerpoint presentation. Metals bioleaching from electronic waste by chromobacterium. It contributes to the substantial development of a sustainable gold mining sector in that country and has the. At the current time, it is more economical to smelt copper ore rather than to use bioleaching, since the concentration of copper in its ore is in general quite high. Bioleaching of lowgrade uranium ore using acidithiobacillus. The gold bioleaching from electronic waste was recently getting paid attractive attention because its available deposit is limited. A method for leaching or dissolving gold from ores or. Iodideoxidizing bacteria iob oxidize iodide into iodine and triiodide which can be utilized for gold dissolution.
Bioleaching technology in minerals processing john neale mintek, biotechnology division private bag x3015, randburg, 2125, south africa bioleaching is a process that employs microorganisms to dissolve leach sulphide minerals. Bioleaching of gold by metabolic products of microorganisms has received less attention, but also offers opportunities for industrial application. Decontamination of the mine tailings is necessary for the protection of the environment. To study the feasibility of a potential bioleaching project, we used the biox project, a process for the treatment of refractory gold concentrates, as an example d. Native gold contains usually eight to ten percent silver, but often much more alloys with a silver content over 20% are called electrum 1. Therefore, a method for leaching or dissolving gold from ores or precious. This investment is for the improvement of technology and equipment for. Agitation was provided by a 5 cm diam, 1 cm width pitchedblade. As a result, these fractions are frequently lost in the tailings. The challenge was to develop a an advantage of bioleaching processes is that lower grade bulk flo bioleaching process where the extraction of both copper and nickel tation concentrates can be treated, with the consequent advantage is maximised. Consideration of influential factors on bioleaching of. Bioleaching of gold, copper and nickel from waste cellular phone pcbs and computer goldfinger motherboards by two aspergillus niger strains jorge enrique madrigalarias1, rosalba argumedodelira2, alejandro alarcon4. The bench scale stirred reactor was made of a 15 cm height, cm diam.
In contrast, knowledge of metal bioleaching from weee by filamentous fungi is still scarce. Bioleaching has finally moved into the treatment of nickel sulphide ore and concentrates, with commercial heap and tank systems now in commercial operation in finland, and a commercial tank system planned for western australia. Bioleaching of uranium was carried out with turamdih ore sample procured from uranium corporation of india limited, jaduguda. Consideration of influential factors on bioleaching of gold. Bioleaching is the process by which metals are dissolved from ore bearing rocks using microorganisms. Bioleaching, or microbial ore leaching, is a process used to extract metals from their ores using bacterial microorganisms. Therefore, low recovery should be expected for gold extraction by cyanidation. Gold ores are classified freemilling and refractory based on their response to cyanide dissolution. Bioleaching of gold via heap biooxidation is proving to be an inexpensive method to oxidize sulfidic ores, including those that are low grade, difficult to concentrate or slow to biooxidize. In order to improve the bioleaching efficiency of arsenicrich gold concentrates, a mixed bacterial flora had been developed, and the mutation breeding method was adopted to conduct the research. What is cyanide and why do we need cyanidefree gold leaching process.
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