Bacterial leaching process pdf

Glossary for chemists of terms used in biotechnology iupac recommendations 1992 on page 158 terms paper. It is shown that the models of the chemical leaching of sphalerite and the bacterial oxidation of ferrous ions are in excellent agreement with the experimental results. There are two methods of bacterial leaching, namely stirred reactor bioleaching and bioheap leach processes. Gigafren the type of bacterial populations in thermophilic microbial leaching and digestion, as well as the thermophilic digestion process control, were the same, while only the relative concentrations changed. Firstly, the solvent comes in contact with the solid matrix. Microbial leaching for heavy metals removal from municipal sewage sludge is a complex biological process.

Bacterial leaching, the biooxidation of metal sulfides to soluble metal sulfates and sulfuric acid, is effected by specialized bacteria. It describes the mechanisms of this process and the factors influencing the chemical reaction. Process performance of bacterial leaching reactors therefore, not only does the number balance account for the effect of particle size on the performance of the reactor, but it also yields valuable new insight into the relationship between various competing leaching technologies. This facilitated leaching of metals ni, mo, and v from the spent catalyst. Bacterial leaching process mechanism of bacteria action a generalised reaction can be used to express the biological oxidation of a mineral sulphide involved in bacterial leaching. The economics of leaching a number of british columbia ore bodies was discussed. Pdf bioleachingbiooxidation is essentially a dissolution process with the involvement of acidophilic bacteria acting as the catalyst to accelerate. Bacterial leaching synonyms, bacterial leaching pronunciation, bacterial leaching translation, english dictionary definition of bacterial leaching. Leaching is the process of a solute becoming detached or extracted from its carrier substance by way of a solvent leaching is a naturally occurring process which scientists have adapted for a variety of applications with a variety of methods. The paper presents the results of laboratory tests of bacterial leaching of metals from electronic scrap.

Thus, the solvent will become the liquid and the solute would be the substance we. Specific extraction methods depend on the soluble characteristics relative to the sorbent material such as concentration, distribution, nature, and size. Groves 2 abstract the bureau of mines conducted a largescale 6. Heap leaching process is sometimes preferred instead of the in situ technique. Test programmes carried out have included use of a range of bioreactors for oxidation of concentrates and aerated columns for heap leach simulation studies.

Bacterial leaching is a well established, proven method of treating refractory gold and base metal ores and concentrates in a heap, vat or column leaching setting. Bacterial leaching is the extraction of metals from their ores. Abstract mathematical models of the chemical leaching of a sulphide mineral and the bacterial oxidation of ferrous ions are combined in a mathematical model of bacterial leaching. Apr 30, 2015 indirect bacterial leaching in this process the microbes are not in direct contact with minerals, but leaching agents are produced by these microbes which oxidize the ores. The catalytic role of bacteria in the bioleaching process involves at least two different mechanisms. Copper leaching throughout the world copper leaching plants have been widely used for many years. Table of contentsresearch to datebacterial nutrientscurrent leaching results bacterial attack of sulfide minerals has been going on for centuries but only recently was it discovered that the acid and iron often found in coal mine drainage is produced by bacterial action on the iron sulfides in the coals. The process of recovering metals from ores by using a number of different techniques. The bacteria feed on nutrients in the minerals, causing the. The thinlayer leaching process originally conceived and developed for leaching oxide ores has been successfully adapted to bacterial leaching of mixed and secondary sulphide ores. Accurate testing of your ore and the development of a fitforpurpose flowsheet is essential for the success of your fullscale bacterial leaching process. View bioleaching bacterial leaching research papers on academia.

Mar 23, 1993 the present invention provides for a bacterial assisted heap leaching process a method wherein the ore is agglomerated with an effective amount of a certain acrylamide polymer, as an agglomeration aid, prior to heaping, which maintains a sufficient degree of heap permeability that endures through both the bio oxidation and the metal leaching steps. Bacterial leaching has been shown in numerous dump and heap leaching situations to be. Pdf bacterial leaching as a pretreatment step for gold recovery. Other processes for treating refractory ores include pressure oxidation pox and bacterial leaching biox. Microbial technology offers an eco nomic alternative for the mining industry, at a time. Bacterialassisted heap leaching of ores nalco chemical company.

Covellite, chalcocite and chalcopyrite are generally used as copper ores for bioleaching processes. The naturally occurring mineral leaching is very slow. Diagnostic leaching is based on the concept that the least stable mineral in the ore matrix will be the first to be solubilized. Not until 1950 was it proven that bacteria were playing a role in the dump leaching of. Bacterial leaching biotechnology in the mining industry preston devasia and k a natarajan bacterial leaching is the extraction of metals from their ores using microorganisms.

View academics in bioleaching bacterial leaching on academia. Figure 6 from microbial leaching process to recover. Indirect bacterial leaching in this process the microbes are not in direct contact with minerals, but leaching agents are produced by these microbes which oxidize the ores. The study was conducted under a wide range of experimental conditions, i. The metallurgy of cyanide gold leaching an introduction. Experiences and future challenges of bioleaching research in. Bioleaching of metal sulfides is caused by diverse groups of bacteria. The albion process, developed at cores laboratories in the 1990s, is one such process and is now in use globally see a recent report on a gold albion process plant here. Bacterial leaching definition of bacterial leaching by the. Bioleaching bacterial leaching research papers academia.

Jul 20, 1998 bacterial leaching, the biooxidation of metal sulfides to soluble metal sulfates and sulfuric acid, is effected by specialized bacteria. Bacterial leaching definition of bacterial leaching by. After the leaching process is complete, the soluble gold must be concentrated and separated from the process slurry. This process was later on employed for recovering metals from ores containing low quantity of the metal. Bacterial leaching is the extraction of metals from their ores using microorganisms. Adsorption is a term used to describe the attraction of a mineral compound to the surface of another material. Microbial technology offers an economic alternative for the mining industry, at a. The process of recovering metals from ores by using a number of different techniques microbial ore leaching bioleaching is the process of extracting metals from ores with the use of microorganisms. Rates of solubilization with and without iron correspond to total and to direct mechanism respectively. Bacterial leaching core has extensive experience in testwork relating to bacterially assisted leaching of base metal sulphide and refractory gold ores. Us3455679a bacterial leaching of ores with an alkaline.

Adsorption is a term used to describe the attraction of a mineral. Bioleaching, or microbial ore leaching, is a process used to extract metals from their ores using bacterial microorganisms. Microbial leaching bioleaching, biomining environmental. Fathi habashi, 1970 bacterial leaching bacterial leaching is the extraction of metals from their ores using the microorganism. The leach residue is cyanided to extract liberated gold and the process repeated using still higher oxidative acid leach until all the nonrefractory and refractory gold are liberated and cyanided 2729. Thus biomining has emerge as an important branch of biotechnology in recent years. A bacterialassisted heap leach process is employed for the solubilization of a metal from a refractory ore containing fines andor clay wherein at least a portion of the metal is solubilized by the bacterial oxidation of sulfides and the concomitant or sequential dissolution of the. The bioleaching process has been restricted to copper and uranium extraction using heap, dump and in situ leaching technologies from mining wastes and low. The bacteria which are naturally associated with the rocks can lead to bioleaching by one of the following ways. Another recovery process is the use of iron exchanges. Apart from containing copper, the ores also contain other elements like iron, zinc and sulphur. An overview of bioleaching of each metal substrate and opportunities for.

The bacteria do this to gain energy you can think of it as food for the bacteria. The dissolution biochemistry signifies two types of. Presently certain metals from sulfide ores and other ores are. To have an idea of bioleaching process copper leaching by bacteria is described as an example. Metallurgical applications of bacterial leaching and. The method of recovery of gold from the process slurry is by carbon adsorption. Get a printable copy pdf file of the complete article. Sulfidic iron ores can be added to speed up the process and provide a source of.

Leaching is widely used in the biological and food processing industries, such as the separation of sugar from sugar beets with hot water, the extraction of oils from peanuts, soybeans, sunflower seeds, cotton seeds, and halibut livers. Introduction, methods, application, copper, microorganisms, and processes. This method is used to recover many different precious metals like copper, lead, zinc, gold, silver, and nickel. Leaching process was first observed in pumps and pipelines installed in mine pits containing acid water. We work with you to develop and test the bacterial leaching process that best meets the needs of your site and the composition of your ore. Bearing ore at ambient and elevated temperatures with bacteria by b. Bacterial leaching of metal sulfides proceeds by two. Direct action of bacteria on the ore to extract metal. Methods of metal recovery by microorganisms 2 methods. Bacterial leaching is an established method of treating refractory gold and base metal ores or concentrates.

Sgs has the expertise and the experience to be a leader in biox, geocoat, bactech and activox leaching technologies. Direct and indirect mechanisms in the bacterial leaching of. Bacterial leaching of metal sulfides proceeds by two indirect. Microbiological investigations reveal that certain bacteria are the main agent in this process. Introduction leaching is the process of extracting a soluble constituent from a solid by means of a solvent. Gigafren the type of bacterial populations in thermophilic microbial leaching and digestion, as well as the thermophilic digestion process control, were. Sociedad minera pudahuel bacterial thinlayer leaching. Bacterial leachings of sample of covellite using a strain of thiobacillus ferrooxidans in 9 k medium with and without iron were made at several pulp densities. Oct 20, 2014 the albion process, developed at cores laboratories in the 1990s, is one such process and is now in use globally see a recent report on a gold albion process plant here. Dilute sulphuric acid ph 2 is percolated down through the pile. Bioleaching process, also known as microbial leaching or biohydrometallurgy, refers to the solubilisation of metals from insoluble ores by using certain naturally occurring microorganisms 1.

Naveke, institut fur mikrobiologie, technische universitat braunschweig, fed. Academics in bioleaching bacterial leaching academia. Extraction of metals from electronic waste by bacterial leaching. The process is currently being applied at the socicdad minera pudahuel lo aguirre plant. Recent development has shown commercial application of the process and, concurrently, details pertaining to the key microorganisms involved in these processes have been described. Microbial ore leaching bioleaching is the process of extracting metals from ores with the use of microorganisms. Indirect leaching entails oxidation of the minerals by ferric iron produced by the bacterial oxidation of the soluble ferrous iron that is present in the bioleaching solutions. Orders of reaction at each pulp density for each mechanism at two temperatures were calculated. Biomining is a technique of extracting metals from ores and other solid materials typically using.

Kennecotts basic process is a cyclic one using ferric sulphatesulphuric acid carrying cultures of suitably tolerant bacteria in a sulphide mineral leaching stage which then passes through a regeneration stage within which the bacteriacarrying solution is subject to aeration and recycled to the process. A diagrammatic representation of general bioleaching process is depicted in fig. Thiobacillus ferrooxidans, thiobacillus thiooxidans, and leptospirillum ferrooxidans. Figure 6 from microbial leaching process to recover valuable. Thus, the fine grinding and leaching process decreases t and l, and increases. Sgs minerals services has undertaken testing for numerous projects for flowsheet development and optimization including bench scale and pilot plant testing, and audits and troubleshooting at operating plants in south africa, brazil, ghana. A solvent is usually a liquid substance that functions for dissolving a substance or the solute. Introduction the indirect mechanism is represented as follows. It is operated as simple heap leaching process or combination of both heap leaching and in situ leaching process. There are three commercial process used in bioleaching. Extraction of metals from electronic waste by bacterial. Pdf parameters for control and optimization of bioleaching of.

Process performance of bacterial leaching reactors. Expired lifetime application number us619455a inventor albert a mayling. Bacterial leaching of millerite, bornite, and chalcocite was greatest at ph 2. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed. Bacterial leaching of two swedish zinc sulfide ores fems. Each of these leaching technologies balances the leaching number, nc, at roughly the same value as that obtained in bacterial leaching by changing the values of the parameters of nc. Liquidsolid leaching preparation of solids for leaching. Microbial leaching is the process by which metals are dissolved from ore bearing rocks using microorganisms. Percolation leaching of a chalcopyritebearing ore at. Sgss expertise with the biox process mesophyllic bacteria spans amenability testing to plant commissioning. Youll still be able to search, browse and read our articles, but you wont be able to register, edit your account, purchase content, or activate tokens or eprints during that period. Three species of mesoacidophilic, chemolithotrophic bacteria are mainly involved.

Full text full text is available as a scanned copy of the original print version. The process of leaching metals from ore by using bacteria or fungi to convert the metals into a soluble form. Pdf ferrous ions and sulfide minerals may be oxidized by chemical or bacterial leaching. For the last 10 centuries, microorganisms have assisted in the recovery of copper dissolved in drainage from water. Direct and indirect mechanisms in the bacterial leaching. The microbial bioleaching process can be optimized by creating ideal conditions temperature, ph, and nutrient, o 2 and co 2 supply etc. The uranium process is quite significant because of moving such a vast amounts of uranium.