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Pattison's Process
Pattinson's Process, or pattinsonisation is a method for removing silver from lead discovered by Hugh Lee Pattinson in 1829 and patented in 1833. The process is dependent on the fact that lead which has least silver in it solidifies first on liquefaction, leaving the remaining liquid richer in silver. In practice several crystallisations were required, so Pattinson's equipment consisted basically of nothing more complex than a row of up to 13 iron pots, which were heated from below. Some lead, naturally containing a small percentage of silver, was loaded into the central pot and melted. This was then allowed to cool. As the lead solidified it was removed using large perforated iron ladles and moved to the next pot in one direction, and the remaining metal which was now richer in silver was then transferred to the next pot in the opposite direction. The process was repeated from one pot to the next, the lead accumulating in the pot at one end and metal enriched in silver in the pot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver
Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earth's crust in the pure, free elemental form ("native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining. Silver has long been valued as a precious metal. Silver metal is used in many bullion coins, sometimes alongside gold: while it is more abundant than gold, it is much less abundant as a native metal. Its purity is typically measured on a per-mille basis; a 94%-pure alloy is described as "0.940 fine". As one of the seven metals of antiquity, silver has had an enduring role in most human cultures. Oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is toxic, even in small amounts, especially to children. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hugh Lee Pattinson
Hugh Lee Pattinson FRS (25 December 1796 – 11 November 1858) was an English industrial chemist. He was also an entrepreneur, sharing the risk of major industrial developments with famous ironmaster Isaac Lowthian Bell and cable manufacturer Robert Stirling Newall. Although known in his time for his 1833 patent "An improved method for separating silver from lead", a process that bears his name, he is best remembered today for his daguerreotype photographs taken in 1840. Among these is the earliest known photograph of the Niagara Falls. Biography Pattinson was the son of Thomas Pattinson, a shopkeeper in the country town of Alston, Cumberland, and his wife Margaret Lee; they were Quakers.Lonsdale, 1873. pp273-287. He was educated at local private schools. He was interested in science from an early age, doing experiments with electricity when he was 17, and also studying the chemistry of metals. He began his working life by helping his father in his shop in Alston. In aroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquefaction
In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics. It occurs both naturally and artificially. As an example of the latter, a "major commercial application of liquefaction is the liquefaction of air to allow separation of the constituents, such as oxygen, nitrogen, and the noble gases." Another is the conversion of solid coal into a liquid form usable as a substitute for liquid fuels. Geology In geology, soil liquefaction refers to the process by which water-saturated, unconsolidated sediments are transformed into a substance that acts like a liquid, often in an earthquake. Soil liquefaction was blamed for building collapses in the city of Palu, Indonesia in October 2018. In a related phenomenon, liquefaction of bulk materials in cargo ships may cause a dangerous shift in the load. Physics and chemistry In physics and chemistry, the phase trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cupellation
Cupellation is a refining process in metallurgy where ores or alloyed metals are treated under very high temperatures and have controlled operations to separate noble metals, like gold and silver, from base metals, like lead, copper, zinc, arsenic, antimony, or bismuth, present in the ore. The process is based on the principle that precious metals do not oxidise or react chemically, unlike base metals. When they are heated at high temperatures, the precious metals remain apart, and the others react, forming slags or other compounds.Bayley, J. 2008 Since the Early Bronze Age, the process was used to obtain silver from smelted lead ores.Rehren, Th., Eckstein, K. 2002 By the Middle Ages and the Renaissance, cupellation was one of the most common processes for refining precious metals. By then, fire assays were used for assaying minerals: testing fresh metals such as lead and recycled metals to know their purity for jewellery and coin making. Cupellation is still in use today.Hoove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patio Process
The patio process is a process for extracting silver from ore. Smelting, or refining, was necessary because silver does not occur by itself in a natural state like some metals. Instead, it is made up of a larger ore body. Thus, smelting, or refining, is necessary to remove other byproducts to get at pure silver. The process, which uses mercury amalgamation to recover silver from ore, was reportedly invented by Bartolomé de Medina in Pachuca, Mexico, in 1554. It replaced smelting as the primary method of extracting silver from ore at Spanish colonies in the Americas. Although some knowledge of amalgamation techniques were likely known since the classical era, it was in the New World that it was first used on a large industrial scale. Other amalgamation processes were later developed, importantly the pan amalgamation process, and its variant, the Washoe process. The silver separation process generally differed from gold parting and gold extraction, although amalgamation with merc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pan Amalgamation
The pan amalgamation process is a method to extract silver from ore, using salt and copper(II) sulfate in addition to mercury. The process was widely used from 1609 through the 19th century; it is no longer used. The patio process had been used to extract silver from ore since its invention in 1557. One drawback of the patio process was the long treatment time, usually weeks. Alvaro Alonso Barba invented the faster ''pan'' process (in Spanish the ''cazo'' or ''fondo'' process) in 1609 in Potosí, Bolivia, in which ore was mixed with salt and mercury (and sometimes copper(II) sulfate) and heated in shallow copper vessels. The treatment time was reduced to 10 to 20 hours. Whether patio or pan amalgamation was used at a particular location often depended on climate (warmer conditions speeded the patio process) and the availability and cost of fuel to heat the pans. The amount of salt and copper(II) sulfate varied from one-quarter to ten pounds of one or the other, or both, per t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parkes Process
The Parkes process is a pyrometallurgical industrial process for removing silver from lead during the production of bullion. It is an example of liquid–liquid extraction. The process takes advantage of two liquid-state properties of zinc. The first is that zinc is immiscible with lead, and the other is that silver is 3000 times more soluble in zinc than it is in lead. When zinc is added to liquid lead that contains silver as a contaminant, the silver preferentially migrates into the zinc. Because the zinc is immiscible in the lead it remains in a separate layer and is easily removed. The zinc-silver solution is then heated until the zinc vaporizes, leaving nearly pure silver. If gold is present in the liquid lead, it can also be removed and isolated by the same process.Pauling, Linus ''General Chemistry'' W.H.Freeman 1947 ed. The process was patented by Alexander Parkes in 1850. Parkes received two additional patents in 1852. The Parkes process was not adopted in the United Stat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
