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MacArthur-Forrest Process
Gold cyanidation (also known as the cyanide process or the MacArthur–Forrest process) is a hydrometallurgical technique for extracting gold from low-grade ore through conversion to a water-soluble coordination complex. It is the most commonly used leaching process for gold extraction. Cyanidation is also widely used in silver extraction, usually after froth flotation. Production of reagents for mineral processing to recover gold represents 70% of cyanide consumption globally. While other metals, such as copper, zinc, and silver, are also recovered using cyanide, gold remains the primary driver of this technology. The highly toxic nature of cyanide has led to controversy regarding its use in gold mining, with it being banned in some parts of the world. However, when used with appropriate safety measures, cyanide can be safely employed in gold extraction processes. One critical factor in its safe use is maintaining an alkaline pH level above 10.5, which is typically controlled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrometallurgy
Hydrometallurgy is a technique within the field of extractive metallurgy, the obtaining of metals from their ores. Hydrometallurgy uses solutions to recover metals from ores, concentrates, and recycled or residual materials. Usually the extracting solution is aqueous (water-based), often containing additives such as acids. In select cases, the extracting solvent is nonaqueous. Brent Hiskey "Metallurgy, Survey" in Kirk-Othmer Encyclopedia of Chemical Technology, 2000, Wiley-VCH, Weinheim. Processing techniques that complement hydrometallurgy are pyrometallurgy, vapour metallurgy, and molten salt electrometallurgy. Hydrometallurgy is typically divided into three general areas: *Leaching *Solution concentration and purification *Metal or metal compound recovery Leaching : Leaching (metallurgy), Leaching involves the use of aqueous solutions to extract metal from metal-bearing materials. The extracting solution is called a lixiviant. The lixiviant is optimized in terms of pH, ox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stoichiometry
Stoichiometry () is the relationships between the masses of reactants and Product (chemistry), products before, during, and following chemical reactions. Stoichiometry is based on the law of conservation of mass; the total mass of reactants must equal the total mass of products, so the relationship between reactants and products must form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of the products can be empirically determined, then the amount of the other reactants can also be calculated. This is illustrated in the image here, where the unbalanced equation is: : : However, the current equation is imbalanced. The reactants have 4 hydrogen and 2 oxygen atoms, while the product has 2 hydrogen and 3 oxygen. To balance the hydrogen, a coefficient of 2 is added to the product H2O, and to fix the imbalance of oxygen, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold Heap Leaching
Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal, a group 11 element, and one of the noble metals. It is one of the least reactive chemical elements, being the second-lowest in the reactivity series. It is solid under standard conditions. Gold often occurs in free elemental (native state), as nuggets or grains, in rocks, veins, and alluvial deposits. It occurs in a solid solution series with the native element silver (as in electrum), naturally alloyed with other metals like copper and palladium, and mineral inclusions such as within pyrite. Less commonly, it occurs in minerals as gold compounds, often with tellurium (gold tellurides). Gold is resistant to most acids, though it does dissolve in aqua regia (a mixture of nitric acid and hydrochloric acid), forming a soluble tetrachloroaurate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicyanoaurate(I)-3D-balls
Potassium dicyanoaurate (or potassium gold cyanide) is an inorganic compound with formula . It is a colorless to white solid that is soluble in water and slightly soluble in alcohol. The salt itself is often not isolated, but solutions of the dicyanoaurate ion () are generated on a large scale in the extraction of gold from its ores. Production In mining of gold from dilute sources, gold is selectively extracted by dissolution in aqueous solutions of cyanide, provided by dissolving sodium cyanide, potassium cyanide and/or calcium cyanide. The reaction for the dissolution of gold, the "Elsner Equation", is: : In this process, oxygen is the oxidant. It can also be produced by reaction of gold(I) salts with excess potassium cyanide. : Structure : Potassium dicyanoaurate is a salt. The dicyanoaurate anion is linear according to X-ray crystallography. On the basis of infrared spectroscopy, the dicyanoaurate anion adopts a very similar structure in sodium dicyanoaurate (). Uses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merrill–Crowe Process
The Merrill–Crowe Process is a separation technique for removing gold from the solution obtained by the cyanide leaching of gold ores. It is an improvement of the MacArthur-Forrest process, where an additional vacuum is managed to remove air in the solution (invention of Crowe), and zinc dust is used instead of zinc shavings (improvement of Merrill). The solution is separated from the ore by methods such as filtration (e.g. vertical leaf type clarifier filters) and counter current decantation (CCD). Afterwards a very clear solution is achieved by using pre-coated filters applying diatomaceous earth. Oxygen is then removed by passing the solution through a vacuum de-aeration column. Zinc dust is added to the clarified, de-aerated solution which precipitates the gold; zinc having a higher affinity for the cyanide ion than gold. Other precious metals, silver, and base metals, like copper, will also precipitate, if present. Automated membrane filtration offers a cost savings alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Washington Merrill
Charles Washington Merrill (December 21, 1869 – February 5, 1958) was an American mining metallurgist. Biography He was born in Concord, New Hampshire, to Sylvester and Clara L. (née French) Merrill. He attended elementary and high school in Alameda, California, and then attended the College of Mining of the University of California, where he received a Bachelor of Science in 1891. After his graduation he was first connected with the noted old Standard Consolidated mine in Bodie, California, and from there went to the Harqua Hala mine in Arizona, thence to the Montana Mining Company in Marysville, California. In 1899, he became affiliated with the widely known Homestake Mining Company of South Dakota as a metallurgist, and in this capacity he manifested the brilliant talents which became the foundation of his future career. He became extensively known by his work, and acquired material prosperity, and his creation of new methods, particularly in the process of extracting g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used as both a monopropellant and an oxidizer in rocketry. Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly into water and elemental oxygen when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a Stabilizer (chemistry), stabilizer in a weakly acidic solution in an opaque bottle. Hydrogen peroxide is found in biological systems including the human body. Enzymes that u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercur, Utah
Mercur is a historical Underground mining (hard rock), hard rock mining ghost town in Tooele County, Utah, Tooele County, Utah, United States. In 1891, it became the site of the first successful use of the cyanide process of gold extraction in the United States, the dominant metallurgy today. Its elevation above sea level is approximately 2,042 m. The nearby Mercur Gold Mine was re-opened by Barrick Gold in 1985, with mining operations again coming to an end in 1997. The reclamation and restoration project was set to continue up to 2010. History The town first came into being in 1870 as ''Lewiston'' (not to be confused with the present-day city of Lewiston, Utah, Lewiston in Cache County, Utah, Cache County), when gold was discovered at the head of the Lewiston Canyon, six miles west of present-day Cedar Fort, Utah, Cedar Fort. A small gold rush began, peaking about 1873; the population reached as high as 2000. During the mid-1870s, silver boomed, and silver mines were ope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gilbert S
Gilbert may refer to: People and fictional characters *Gilbert (given name), including a list of people and fictional characters * Gilbert (surname), including a list of people Places Australia * Gilbert River (Queensland) * Gilbert River (South Australia) Kiribati * Gilbert Islands, a chain of atolls and islands in the Pacific Ocean United States * Gilbert, Arizona, a town * Gilbert, Arkansas, a town * Gilbert, Florida, the airport of Winterhaven * Gilbert, Iowa, a city * Gilbert, Louisiana, a village * Gilbert, Michigan, and unincorporated community * Gilbert, Minnesota, a city * Gilbert, Nevada, ghost town * Gilbert, Ohio, an unincorporated community * Gilbert, Pennsylvania, an unincorporated community * Gilbert, South Carolina, a town * Gilbert, West Virginia, a town * Gilbert, Wisconsin, an unincorporated community * Mount Gilbert (other), various mountains * Gilbert River (Oregon) Outer space * Gilbert (lunar crater) * Gilbert (Martian crater) Arts and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glasgow
Glasgow is the Cities of Scotland, most populous city in Scotland, located on the banks of the River Clyde in Strathclyde, west central Scotland. It is the List of cities in the United Kingdom, third-most-populous city in the United Kingdom and the 27th-most-populous city in Europe, and comprises Wards of Glasgow, 23 wards which represent the areas of the city within Glasgow City Council. Glasgow is a leading city in Scotland for finance, shopping, industry, culture and fashion, and was commonly referred to as the "second city of the British Empire" for much of the Victorian era, Victorian and Edwardian eras. In , it had an estimated population as a defined locality of . More than 1,000,000 people live in the Greater Glasgow contiguous urban area, while the wider Glasgow City Region is home to more than 1,800,000 people (its defined functional urban area total was almost the same in 2020), around a third of Scotland's population. The city has a population density of 3,562 p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Tennant
Charles Tennant (3 May 1768 – 1 October 1838) was a Scottish chemist and industrialist. He discovered Calcium hypochlorite, bleaching powder and founded an industrial dynasty. Biography Charles Tennant was born at Laigh Corton, Alloway, Ayrshire, the sixth of thirteen surviving children of farmer John "Auld Glen" Tennant (1725–1810), later of Glenconner, Ochiltree, Ayrshire, and his second wife, Margaret McClure (1738–1784). He was educated at home and at the Ochiltree parish school, then was apprenticed by his father to a master handloom weaver at Kilbarchan in Renfrewshire. The Tennant family were friends with the poet Robert Burns (1759–1796); in his epistle to "James Tennant of Glenconner" Tennant is mentioned as "wabster (Scots language: weaver) Charlie", in reference to the occupation Tennant had undertaken. Impetus Tennant was quick to learn his trade, but also to see that the growth of the weaving industry was restricted by the primitive methods used to bleach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Stewart MacArthur
John Stewart MacArthur was a chemist from Glasgow. Born on 9 December 1856, he is credited with the development of the MacArthur-Forrest cyanidation process in 1887, used to extract gold in South Africa. His patent for the process was voided. With the long-lasting legal issues about the cyanidation patents, MacArthur turned to other businesses. First, he investigated vanadium extraction from ore containing significant amounts of radium. From this enterprise he turned to the production of radium. He founded the Radium Works in Halton in 1911. In 1915 he moved it to Balloch, West Dunbartonshire and renamed it as Loch Lomond Radium Works. MacArthur died on 16 March 1920, aged 63. See also *Gold cyanidation Gold cyanidation (also known as the cyanide process or the MacArthur–Forrest process) is a hydrometallurgical technique for extracting gold from low-grade ore through conversion to a water-soluble coordination complex. It is the most commonly ... References Further r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
