Recent development has shown commercial application of the process and, concurrently, details pertaining to the key microorganisms involved in these processes have been described. Mission statement metal bulletin is the premier global intelligence service for metals and steel professionals. Therefore, production of a variety of metals in large quantities is necessary for. The recovery of rare and precious metals rpms from urban mines has. Scrubbing of the loaded organic phase before stripping with spent electrolyte significantly reduce ammonia concentration in strip liquors flett and melling, 1979. Create pdf files from any application with pdfcreator. New resources for metals must be developed with the aid of novel technologies.
To compare the reactivity of metals in acid and water. Further development is necessary with respect to both technical and biological aspects. The extraction and refining of metals provides a novel approach to the science and technology of both ferrous and nonferrous metal production. Notes 6 chemistry module 6 occurrence and extraction of metals chemistry of elements water or washed with a strong current of water. Methods of metal recovery by microorganisms 2 methods. Presently certain metals from sulfide ores and other ores are. The mechanism of bioleaching is rather complex and not well understood. Such metals may remain in elemental or native free state in nature. The bacteria feed on nutrients in the minerals, causing the metal to separate from its ore. Safety glasses, hair tied back, do not add calcium to acid part a metals in acid 1. Heavy metal leaching by sulfuroxidizing bacteria, one of the most promising sludge detoxification methods, uses elemental sulfur as a microbial energy substrate. Optimization of parameters affecting recovery of copper from sarcheshmeh lowgrade sulfide ore using bioleaching m. In nature, metals generally occur either in free form or in combined form.
Comparing the reactivity of metals refer to investigation 6b, pp. It was founded in 19 with the mission to provide musthave timely information. Bioleaching, or microbial ore leaching, is a process used to extract metals from their ores using bacterial microorganisms. Leaching of metals from waste printed circuit boards wpcbs. Bacteria can mine for bioleacihng, clean oil spills, purify gold, and use radioactive elements for energy. About 40% are metals, 30% are non metals and 30% are ceramics 2presented in pcb. This paper presents a promising hydrometallurgical process to recover precious metals from waste pcbs.
Leventhal introduction the fate of various metals, including chromium, nickel, copper, manganese, mercury, cadmium, and lead, and metalloids, including arsenic, antimony, and selenium, in the natural environment is of great concern adriano, 1986. As metals are largely used for manufacturing electronic products, the electrical and electronic equipment reaching the end of life, known as waste electrical and electronic equipment weee or ewaste, is regarded as a potential secondary source of these elements hageluken, 2006, lee and pandey, 2012, tuncuk et al. Bioleaching as far as the recovery of valuable metals is concerned is not being considered today only with respect to its ability to recover valuable metals. The environmental chemistry of metals strongly influences their.
The practice requires none of the environmentally damaging processes found in conventional refining methods. Pcb is composed of non metals such as polymer, fiber glass, ceramics and metals like cu, al, ni,fe, zn. Pdf recovery of rare and precious metals from urban minesa. School of mining engineering, college of engineering, university of tehran, tehran. This process was later on employed for recovering metals from ores containing low quantity of the metal.
Some metals are very unreactive, this means they do not easily take part in chemical reactions. Rather than the traditional treatment in which one metal at a time is considered, this new approach, which examines several metals at a time, reveals more clearly the versatility and limitations of each of the main types of process. The extraction and refining of metals colin bodsworth. Minerals and metals world bank documents world bank group. It complicates a technological process and negatively affects its economy. Generally, low reactive metals shows little affinity towards air, moisture, carbon dioxide or other non metals present in nature. Bioleaching application of biotechnology in mining industry. The pyrometallurgical technology for recovering nonferrous metals, particularly precious metals from wpcbs has several drawbacks.
Free pure physics, chemistry, geography and social studies revision notes. There is a demand for less expensive and more environmentally friendly processes. Usually, bioleaching is referring to the conversion of solid metal values into their water soluble forms using microorgan isms. Implications of a carbonconstrained future for mining and metals. Selective bioleaching and electrochemical recovery of. Pdf bioleaching copper recovery from mine waters in the mediterranean area 3000 years ago. Introduction, methods, application, copper, microorganisms, and processes.
Bioleaching of heavy metals by sulfur oxidizing bacteria. Bioleaching of metals from soils or sediments water. Extraction of iron in a blast furnace iron is also below carbon in the reactivity series, so therefore carbon can be used to reduce it note. The dissolution biochemistry signifies two types of. In this paper, we characterize the leaching of heavy metals ni, cu, zn, cd, and pb from eight contaminated soils over a wide range of ph ph 0. To simplify the metal leaching process, large pieces of pcbs were used instead of a pulverized sample. In this process, there is a direct enzymatic attack on the minerals which are susceptible to oxidation by the microorganisms. Bioleaching is one of latest technologiesthe used to recover many important metals like copper. Sep 29, 2015 the recovery of precious metals from waste printed circuit boards pcbs is an effective recycling process. Copper concentrates index methodology, specifications and use. The heavier ore settles down rapidly in the grooves and the lighter sandy and earthy materials gangue. Bioleaching can be one of few techniques applicable for the removal of toxic metals from polluted soils or sediments.
The results showed that the oxidation of elemental sulfur into sulfuric acid with indigenous sludge thiobacilli causes a sludge acidification, lowering the ph below 2. Generally, humans are exposed to these metals by ingestion drinking or. The chemical transformation of metals by microorganisms may occur by direct or indirect bioleaching. Some of these metals and minerals have the potential to consume cyanide and oxygen, as well as producing substances which can reduce the efficiency of gold leaching.
This is much cleaner than the traditional leaching processes like heap leaching using cyanide or other chemicals. Hydrometallurgical recovery of metals from large printed. Pdf urban mining is essential for continued natural resource extraction. Department of mining, shahrood branch, islamic azad university, shahrood, iran 2. Human health effects of heavy metals dd kansas state. Bioleaching is a method of extracting minerals and metals from their parent ores using naturally occurring biological.
Bioleaching of metals from sewage sludge by sulfur. 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. Decontamination of the mine tailings is necessary for the protection of the environment. Bioleaching is the extraction of metals from their ores through the use of living organisms. Resources for top a1 candidates taking the 2020 singaporecambridge gce o level exam. Create and merge pdfs with pdfcreator and let pdf architect help you edit pdfs, insert images to. Biomining is a technique of extracting metals from ores and other solid materials typically using.
Extraction of metals occurrence ores of some metals are very common iron, aluminium others occur only in limited quantities in selected areas ores need to be purified before being reduced to the metal this adds to the expense high grade ores are therefore cheaper to process. It is the main disadvantage of metals extraction from ammonia solutions. Investigation of procedures to leach insoluble metals in residues e. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Bioleaching of metals from weee shredding dust sciencedirect. They are used for making machines, railways, motor vehicles, bridges, buildings, agricultural tools, aircrafts, ships etc. Join our community just now to flow with the file extraction of metals and make our shared file collection even more complete and exciting. It is a chemoautotrophic acidophile, meaning that it obtains its energy from inorganic sources. In microbial leaching or bioleaching metals can be extracted from large quantities of low grade ores this process has been used for centuries to recover copper form the drainage water of mines the role of microbes in the bioleaching came into notice some 40 years ago. Bioleaching is a simple and effective technology for metal extraction from lowgrade ores. It finds application in the extraction of metals from their ores. Pdf format is a file format developed by adobe in the 1990s to present documents, including text formatting. Bioreactor for metal bioleaching in the geomicrobiology laboratory of bgr source. Bioleaching and biosorption of heavy metals from gold mine.
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. In the case of copper, copper sulfide is microbially oxidized to copper sulfate and metal values are present in the aqueous phase. Microbial leaching of metals from solid industrial wastes. A novel bioleaching process to recover valuable metals from. Leaching process was first observed in pumps and pipelines installed in mine pits containing acid water. Biomining is the process of using microorganisms microbes to extract metals of economic interest from rock ores or mine waste. Occurrence and extraction of metals module 6 notes chemistry of elements metals and their alloys are extensively used in our daytoday life. Mine tailings is an important source of heavy metal contamination in the environment. Minerals that cause excessive consumption of cyanide are called cyanocides. Firefox includes a builtin pdf viewer to display pdf files inside the browser window. Additional capabilities include the bioleaching of metals from sulfide materials, phosphate ore bioprocessing, and the bioconcentration of metals. Introduction in view of continuous depletion of landbased resources along with increasing consumption of valuable metals in india, development of environment friendly technologies for tapping alternate sources of metals has gained importance lately. Biotechnological applications for metal recovery have played a greater role in recovery of valuable metals from low grade sulfide minerals from the beginning of the middle era till the end of the twentieth century.
Its principle is a microbial production of sulphuric acid and leaching of metals with it. Microbial leaching is the process by which metals are dissolved from ore bearing rocks using microorganisms. Many other metals and minerals besides gold also dissolve in alkaline cyanide solution. How to split a pdf file adobe acrobat dc tutorials adobe support. Place 5 ml of dilute hydrochloric acid hcl in each of 4 clean test tubes in a test tube rack. The bacteria feed on nutrients in the minerals, causing the metal. A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous. Selective bioleaching and electrochemical recovery of metals from lowgrade mineral residues karel folens ugent, adam williamson, gijs du laing ugent.
This free online tool allows to combine multiple pdf or image files into a single pdf document. Bioleaching of metal sulfides is caused by diverse groups of bacteria. With depletion of oreminerals and implementation of stricter environmental rules, microbiological applications for metal recovery have been shifted towards solid industrial wastes. Unit 6 principles and processes of extraction of metals162. Extraction of iron in a blast furnace reduction haematite o. Optimization of parameters affecting recovery of copper from.
265 1108 278 1087 403 539 1511 1080 233 778 1371 268 240 851 574 1327 110 34 270 687 1250 255 1390 345 498 850 251 70 1212 51 123 1346 637