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107-623: Coppermine may refer, apart from the primary meaning of copper extraction , to: Coppermine Bay , Greenland Coppermine Herald , one of the heralds at the Canadian Heraldic Authority Coppermine Peninsula , Antarctica Coppermine River , in Nunavut and the Northwest Territories Kugluktuk, Nunavut , formerly known as Coppermine Pentium III ,

214-413: A heap leaching or dump leaching . The resulting pregnant leach solution is purified by solvent extraction (SX). It is treated with an organic solvent and an organic chelators. The chelators bind the copper ions (and no other ions, ideally), the resulting complexes dissolve in the organic phase. This organic solvent is evaporated, leaving a residue of the copper complexes. The copper ions are liberated from

321-442: A concentrates with 27–29% and 37–40% copper contents from chalcopyrite and chalcocite , respectively. Oxidised copper ores include carbonates such as azurite and malachite , the silicate chrysocolla , and sulfates such as atacamite . In some cases, sulfide ores are allowed to degrade to oxides. Such ores are amenable to hydrometallurgy. Specifically, such oxide ores are usually extracted into aqueous sulfuric acid , usually in

428-467: A decade. They - Utah Copper (Kennecott), Nevada Consolidated, Chino Copper, Ray Con and other Jackling firms - eventually settled, in 1922, paying a substantial fee for licenses to use the Minerals Separation process. One unfortunate result of the dispute was professional divisiveness among the mining engineering community for a generation. In 1913, the Minerals Separation paid for a test plant for

535-515: A few years before selling their copper assets. Reportedly gains were not as high as anticipated. Investments in copper mining concentrated in Chile in the 1980s and 1990s given that copper mining in other countries faced problems like political instability ( Peru ), increased environmental requirements (developed countries) or overall disinterest in foreign investment in a nationalized mining industry ( Zaire , Zambia ). The average grade of copper ores in

642-406: A high grade copper concentrate. The roasting process is generally undertaken in combination with reverberatory furnaces . In the roaster, the copper concentrate is partially oxidised to produce " calcine ". Sulfur dioxide is liberated. The stoichiometry of the reaction is: Roasting generally leaves more sulfur in the calcined product (15% in the case of the roaster at Mount Isa Mines ) than

749-488: A higher profit. This extraction process can be applied to large quantities of low-grade ores, at a lower capital cost with minimal environmental impact. Generally, direct froth flotation is not used to concentrate copper oxide ores, as a result of the largely ionic and hydrophilic structure of the copper oxide mineral surface. Copper oxide ores are typically treated via chelating-reagent flotation and fatty-acid flotation, which use organic reagents to ensure adsorption onto

856-482: A microprocessor code-named "Coppermine" Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Coppermine . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Coppermine&oldid=1217992766 " Category : Disambiguation pages Hidden categories: Short description

963-480: A more rapid investigation of oils, froths, and agitation led to proven workplace applications, especially in Broken Hill, Australia, that brought the technological innovation known as “froth flotation.” During the early 20th century, froth flotation revolutionized mineral processing. Initially, naturally occurring chemicals such as fatty acids and oils were used as flotation reagents in large quantities to increase

1070-490: A parallel reaction the iron sulfide is converted to slag: The purity of this product is 98%, it is known as blister because of the broken surface created by the escape of sulfur dioxide gas as blister copper pigs or ingots are cooled. By-products generated in the process are sulfur dioxide and slag . The sulfur dioxide is captured and converted to sulfuric acid and either sold on the open market or used in copper leaching processes. Froth flotation Froth flotation

1177-424: A significant portion of the sulfur has been eliminated during the roasting stage, and the calcine consists of a mixture of copper and iron oxides and sulfides. The reverberatory furnace acts to allow these species to approach chemical equilibrium at the furnace operating temperature (approximately 1600 °C at the burner end of the furnace and about 1200 °C at the flue end; the matte is about 1100 °C and

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1284-406: A significant position into the 1930s. During this period the company also developed and patented flotation processes for iron out of its Hibbing lab and of phosphate in its Florida lab. Another rapid phase of flotation process innovation did not occur until after 1960. In the 1960s the froth flotation technique was adapted for deinking recycled paper . The success of the process is evinced by

1391-515: A sinter plant leaves in the sintered product (about 7% in the case of the Electrolytic Refining and Smelting smelter ). As of 2005, roasting is no longer common in copper concentrate treatment because its combination with reverberatory furnaces is not energy efficient and the SO 2 concentration in the roaster offgas is too dilute for cost-effective capture. Direct smelting is now favored, and uses

1498-518: A specific feed grade and feed rate. The flotation process is also widely used in industrial waste water treatment plants, where it removes fats, oil, grease and suspended solids from waste water. These units are called dissolved air flotation (DAF) units. In particular, dissolved air flotation units are used in removing oil from the wastewater effluents of oil refineries , petrochemical and chemical plants , natural gas processing plants and similar industrial facilities. The ore to be treated

1605-594: A type of surfactant that increase the natural hydrophobicity of the surface, increasing the separability of the hydrophobic and hydrophilic particles. Collectors either chemically bond via chemisorption to the mineral or adsorb onto the surface via physisorption . The collision rates for fine particles (50 - 80 μm) can be accurately modeled, but there is no current theory that accurately models bubble-particle collision for particles as large as 300 μm, which are commonly used in flotation processes. For fine particles, Stokes law underestimates collision probability while

1712-409: Is "poised for increased activity due to their potential usefulness in environmental site cleanup operations" including recycling of plastics and metals, not to mention water treatment. Flotation processes are described in ancient Greek and Persian literature. During the late 19th century, the process basics were discovered through a slow evolutionary phase. During the first decade of the 20th century,

1819-474: Is a minor part of a supergene profile it will not be recovered and will report to the tailings . When rich enough, native copper ore bodies may be treated to recover the contained copper by gravity separation . Often, the nature of the gangue is important, as clay-rich native copper ores prove difficult to liberate. This is because clay minerals interact with flotation reagents used in extraction processes, that are then consumed, which results in minimal recovery of

1926-422: Is a mixture of copper, iron and sulfur that is enriched in copper, which is called matte or copper matte . The term matte grade is normally used to refer to the copper content of the matte. The purpose of the matte smelting stage is to eliminate as much of the unwanted iron, sulfur and gangue minerals (such as silica, magnesia, alumina and limestone) as possible, while minimizing the loss of copper. This

2033-474: Is a process for selectively separating hydrophobic materials from hydrophilic . This is used in mineral processing, paper recycling and waste-water treatment industries. Historically this was first used in the mining industry, where it was one of the great enabling technologies of the 20th century. It has been described as "the single most important operation used for the recovery and upgrading of sulfide ores ". The development of froth flotation has improved

2140-421: Is achieved by reacting iron sulfides with oxygen (in air or oxygen enriched air) to produce iron oxides (mainly as FeO , but with some magnetite (Fe 3 O 4 )) and sulfur dioxide . Copper sulfide and iron oxide can mix, but when sufficient silica is added, a separate slag layer is formed. Adding silica also reduces the melting point (or, more properly, the liquidus temperature) of the slag, meaning that

2247-608: Is an energy-efficient smelting process that was jointly developed from the 1970s to the 1990s by Mount Isa Mines (a subsidiary of MIM Holdings and now part of Glencore ) and the Government of Australia 's CSIRO . It has relatively low capital and operating costs for a smelting process. ISASMELT technology has been applied to lead, copper, and nickel smelting. As of 2021, 22 plants were in operation in eleven countries, along with three demonstration plants located at Mt Isa. The installed capacity of copper/nickel operating plants in 2020

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2354-465: Is constantly forced through the slurry. The air bubbles attach to the hydrophobic copper sulfide particles, which are conveyed to the surface where the froth is skimmed off. These skimmings are generally subjected to a cleaner-scavenger cell to remove excess silicates and to remove other sulfide minerals that can deleteriously impact the concentrate quality (typically, galena ), and the final concentrate sent for smelting. The rock that has not floated off in

2461-542: Is different from Wikidata All article disambiguation pages All disambiguation pages Copper extraction The Old Copper Complex in North America has been radiometrically dated to 9500 BP—i.e., about 7480 BCE—making it one of the oldest known examples of copper extraction in the world. The earliest evidence of the cold-hammering of native copper comes from the excavation at Çayönü Tepesi in eastern Anatolia , which dates between 7200 to 6600 BCE. Among

2568-411: Is eliminated from the concentrate). It is essentially a melting process. Consequently, wet-charged reverberatory furnaces have less copper in their matte product than calcine-charged furnaces, and they also have lower copper losses to slag. Gill quotes a copper in slag value of 0.23% for a wet-charged reverberatory furnace vs 0.37% for a calcine-charged furnace. In the case of calcine-charged furnaces,

2675-519: Is ground into particles ( comminution ). In the idealized case, the individual minerals are physically separated, a process known as full liberation . The particle sizes are typically in the range 2–500 micrometers in diameter. For froth flotation, an aqueous slurry of the ground ore is treated with the frothing agent. An example is sodium ethyl xanthate as a collector in the flotation of galena (lead sulfide) to separate it from sphalerite (zinc sulfide). The polar part of xanthate anion attaches to

2782-427: Is normally added to help form the slag. The furnace is fired with burners using pulverized coal, fuel oil or natural gas. Reverberatory furnaces can additionally be fed with molten slag from the later converting stage to recover the contained copper and other materials with a high copper content. Because the reverberatory furnace bath is quiescent, very little oxidation of the feed occurs (and thus very little sulfur

2889-505: Is often undertaken in specialized regrind mills , such as the IsaMill . The rougher flotation step is often followed by a scavenger flotation step that is applied to the rougher tailings to further recover any of the target minerals. To be effective on a given ore slurry, the collectors are chosen based upon their selective wetting of the types of particles to be separated. A good collector will adsorb , physically or chemically, with one of

2996-524: The Copper Age , aka Chalcolithic Age, and then the Bronze Age . The Bronze Age would not have been possible without the development of smelting technology. Until the latter half of the 20th century, smelting sulfide ores was almost the sole means of producing copper metal from mined ores ( primary copper production). As of 2002, 80% of global primary copper production was from copper–iron–sulfur minerals, and

3103-469: The refractory bricks lining the furnace. When the removal of the matte or slag is complete, the hole is normally plugged with clay, which is removed when the furnace is ready to be tapped again. Reverberatory furnaces were often used to treat molten converter slag to recover contained copper. This would be poured into the furnaces from ladles carried by cranes. However, the converter slag is high in magnetite and some of this magnetite would precipitate from

3210-473: The thiourea thiocarbanilide . Fatty acid carboxylates, alkyl sulfates , and alkyl sulfonates have also been used for oxide minerals. For some minerals (e.g., sylvinite for KCl), fatty amines are used as collectors. A variety of compounds are added to stabilize the foams. These additives include pine oil and various alcohols : methyl isobutyl carbinol (MIBC), polyglycols , xylenol (cresylic acid). According to one vendor, depressants "increase

3317-450: The 1960s. In the 1960s and 1970s large copper mining operations by U.S. companies were nationalized in many of the main copper producing countries. Thus by the 1980s state owned enterpises overtook the dominant role U.S. companies like Anaconda Copper and Kennecott had had until then. In the late 1970s and early 1980s various oil companies like ARCO , Exxon ( Exxon Minerals ) and Standard Oil Company expanded into copper mining for

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3424-517: The 21st century is below 0.6% copper, with a proportion of economic ore minerals being less than 2% of the total volume of the ore rock. Thus, all mining operations, the ore must usually be beneficiated (concentrated). The concentrate is typically sold to distant smelters , although some large mines have smelters located nearby. Such colocation of mines and smelters was more typical in the 19th and early 20th centuries, when smaller smelters could be economic. The subsequent processing techniques depend on

3531-653: The Elmore brothers installed the world's first industrial-size commercial flotation process for mineral beneficiation at the Glasdir mine. The process was not froth flotation but used oil to agglomerate (make balls of) pulverised sulphides and buoy them to the surface, and was patented in 1898 (revised 1901). The operation and process was described in the April 25, 1900 Transactions of the Institution of Mining and Metallurgy of England, which

3638-636: The Elmore brothers work. Recent writers, because of the interest in celebrating women in science, champion Carrie Everson of Denver as mother of the process based on her 1885 patent. Omitted from this list are the engineers, metallurgists and chemists of Minerals Separation, Ltd., which, at least in the American and Australian courts, won control of froth flotation patents as well as right of claimant as discoverers of froth flotation. But, as historian Martin Lynch writes, "Mineral Separation would eventually prevail after taking

3745-548: The Elmores who, ultimately, lost as the Elmore process was superseded by more advanced techniques. Another flotation process was independently invented in 1901 in Australia by Charles Vincent Potter and by Guillaume Daniel Delprat around the same time. Potter was a brewer of beer, as well as a chemist, and was likely inspired by the way beer froth lifted up sediment in the beer. This process did not use oil, but relied upon flotation by

3852-458: The Everson process had been made at Georgetown and Silver Cliff, Colorado, and Baker, Oregon. She abandoned the work upon the death of her husband, and before perfecting a commercially successful process. Later, during the height of legal disputes over the validity of various patents during the 1910s, Everson's was often pointed to as the initial flotation patent - which would have meant that the process

3959-572: The Inspiration Copper Company at Miami, Arizona. Built under the San Francisco office director, Edward Nutter, it proved a success. Inspiration engineer L. D. Ricketts ripped out a gravity concentration mill and replaced it with the Minerals Separation process, the first major use of the process at an American copper mine. A major holder of Inspiration stock were men who controlled the great Anaconda mine of Butte. They immediately followed

4066-579: The Inspiration success to build a Minerals Separation licensed plant at Butte, in 1915–1916, a major statement about the final acceptance of the Minerals Separation patented process. John M. Callow, of General Engineering of Salt Lake City , had followed flotation from technical papers and the introduction in both the Butte and Superior Mill, and at Inspiration Copper in Arizona and determined that mechanical agitation

4173-625: The Mammoth gold mill, Tintic district, Utah, but without success. Because of Butters' reputation and the news of his failure, as well as the unsuccessful attempt at the LeRoi gold mine at Rossland, B. C., the Elmore process was all but ignored in North America. Developments elsewhere, particularly in Broken Hill, Australia by Minerals Separation, Limited , led to decades of hard-fought legal battles and litigations (e. g. Minerals Separation, Ltd. v. Hyde ) for

4280-681: The Sulman-Picard-Ballot process after company officers and patentees. The process proved successful at their Central Block plant, Broken Hill that year. Significant in their "agitation froth flotation" process was the use of less than 1% oil and an agitation step that created small bubbles, which provided more surface to capture the metal and float into a froth at the surface. Useful work was done by Leslie Bradford at Port Pirie and by William Piper , Sir Herbert Gepp and Auguste de Bavay . Mineral Separation also bought other patents to consolidate ownership of any potential conflicting rights to

4387-451: The US had fallen to only 0.6 percent. Flotation is used for the purification of potassium chloride from sodium chloride and clay minerals. The crushed mineral is suspended in brine in the presence of fatty ammonium salts. Because the ammonium head group and K have very similar ionic radii (ca. 0.135, 0.143 nm respectively), the ammonium centers exchange for the surface potassium sites on

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4494-576: The United States had been less than spectacular. Butters's failures, as well as others, was followed after 1904, with Scotsman Stanley MacQuisten's process (a surface tension based method), which was developed with a modicum of success in Nevada and Idaho, but this would not work when slimes were present, a major fault. Henry E. Wood of Denver had developed his flotation process along the same lines in 1907, patented 1911, with some success on molybdenum ores. For

4601-436: The bottom of a tall column while introducing slurry above. The countercurrent motion of the slurry flowing down and the air flowing up provides mixing action. Mechanical cells generally have a higher throughput rate, but produce material that is of lower quality, while flotation columns generally have a low throughput rate but produce higher quality material. The Jameson cell uses neither impellers nor spargers, instead combining

4708-412: The bubble, with the perimeter of the collision tube corresponding to the grazing trajectory. The attachment of the particle to the bubble is controlled by the induction time of the particle and bubble. The particle and bubble need to bind and this occurs if the time in which the particle and bubble are in contact with each other is larger than the required induction time. This induction time is affected by

4815-525: The case to the US Supreme Court [and the House of Lords], and in so doing earned for itself the cordial detestation of many in the mining world." Froth flotation efficiency is determined by a series of probabilities: those of particle–bubble contact, particle–bubble attachment, transport between the pulp and the froth, and froth collection into the product launder. In a conventional mechanically-agitated cell,

4922-533: The collection and cleaning zone of a flotation column. Significant issues of entrainment of fine particles occurs as these particles experience low collision efficiencies as well as sliming and degradation of the particle surfaces. Coarse particles show a low recovery of the valuable mineral due to the low liberation and high detachment efficiencies. Flotation can be performed in rectangular or cylindrical mechanically agitated cells or tanks, flotation columns, Jameson Cells or deinking flotation machines. Classified by

5029-472: The commercial use of the process worldwide. In 1900, Charles Butters of Berkeley, California, acquired American rights to the Elmore process after seeing a demonstration at Llanelltyd, Wales. Butters, an expert on the cyanide process , built an Elmore process plant in the basement of the Dooley Building, Salt Lake City, and tested the oil process on gold ores throughout the region and tested the tailings of

5136-412: The concentrate is dispersed in an air or oxygen stream and the smelting reactions are largely completed while the mineral particles are still in flight. The reacted particles then settle in a bath at the bottom of the furnace, where they behave like calcine in a reverberatory furnace. A slag layer forms on top of the matte layer, and they can separately be tapped from the furnace. The ISASMELT process

5243-406: The converter slag (due to its higher melting point), forming an accretion on the hearth of the reverberatory furnace and necessitating shut downs of the furnace to remove the accretion. This accretion formation limits the quantity of converter slag that can be treated in a reverberatory furnace. While reverberatory furnaces have very low copper losses to slag, they are not very energy-efficient and

5350-421: The copper dissolved in slags from mattes containing less than 50% copper is sulfidic copper. Above this figure, oxidic copper begins to dominate. The loss of copper as prills suspended in the slag depends on the size of the prills, the viscosity of the slag and the settling time available. Rosenqvist suggested that about half the copper losses to slag were due to suspended prills. The mass of slag generated in

5457-467: The copper from the pregnant leach solution . To ensure the best recovery of copper, it is important to acknowledge the effect copper dissolution, acid consumption, and gangue mineral composition has on the efficacy of extraction. Supergene sulfide ores rich in native copper are refractory to treatment with sulfuric acid leaching on all practicable time scales, and the dense metal particles do not react with froth flotation media. Typically, if native copper

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5564-404: The crushed ore is wetted, suspended in a slurry, and mixed with reagents that render the sulfide particles hydrophobic . Typical reagents ("collectors") include potassium ethylxanthate and sodium ethylxanthate , but dithiophosphates and dithiocarbamates are also used. The slurry is introduced to a water-filled aeration tank containing a surfactant such as methylisobutyl carbinol (MIBC). Air

5671-409: The depletion of copper resources. Processes including in situ, dump, and heap leaching are cost-effective methods that are suitable for extracting copper from low-grade ores. Extraction processes for secondary copper sulfides and low-grade ores includes the process of heap bioleaching. Heap bioleaching presents a cost efficient extraction method that requires a less intensive energy input resulting in

5778-456: The early period of flotation as the mechanical phase while by the late 1910s it entered the chemical phase. Discoveries in reagents, especially the use of xanthates patented by Minerals Separations chemist Cornelius H. Keller, not so much increased the capture of minerals through the process as making it far more manageable in day-to-day operations. Minerals Separation's initial flotation patents ended 1923, and new ones for chemical processes gave it

5885-530: The efficiency of the flotation process by selectively inhibiting the interaction of one mineral with the collector." Thus a typical pulverized ore sample consists of many components, of which only one or a few are targets for the collector. Depressants bind to these other components, lest the collector be wasted by doing so. Depressants are selected for particular ores. Typical depressants are starch, polyphenols, lye, and lime. They are cheap, and oxygen-rich typically. A variety of other compounds are added to optimize

5992-462: The fifth and sixth millennium. The Pločnik archaeological site in southeastern Europe ( Serbia ) contains the oldest securely dated evidence of copper making at high temperature, from 5,000 BCE. The find in June 2010 extends for an additional 500 years, dated to 5th millennium BCE, representing the earlier record of copper smelting from Rudna Glava ( Serbia ). Copper smelting technology gave rise to

6099-543: The first "bulk oil flotation" patent, though there is no evidence of its being field tested, or used commercially. In 1877 the brothers Bessel (Adolph and August) of Dresden, Germany, introduced their commercially successful oil and froth flotation process for extracting graphite , considered by some the root of froth flotation. However, the Bessel process became uneconomical after the discovery of high-grade graphite in Sri Lanka and

6206-482: The first great flotation plant in America. Minerals Separation, Ltd., which had set up an office in San Francisco, sued Hyde for infringement as well as the Butte & Superior company, both cases were eventually won by the firm in the U. S. Supreme Court. Daniel Cowan Jackling and partners, who controlled Butte & Superior, also refuted the Minerals Separation patent and funded the ensuing legal battles that lasted over

6313-402: The flotation cell is either discarded as tailings or further processed to extract other metals such as lead (from galena) and zinc (from sphalerite ), should they exist. A variety of measures are taken to improve the efficiency of the froth flotation. Lime is used to raise the pH of the water bath, causing the collector to bond more efficiently to the copper sulfides. The process can produce

6420-563: The flotation process - except for the Elmore patents. In 1910, when the Zinc Corporation replaced its Elmore process with the Minerals Separation (Sulman-Picard-Ballot) froth flotation process at its Broken Hill plant, the primacy of the Minerals Separation over other process contenders was assured. Henry Livingston Sulman was later recognized by his peers in his election as President of the (British) Institution of Mining and Metallurgy , which also awarded him its gold medal. Developments in

6527-412: The fluid viscosity, particle and bubble size and the forces between the particle and bubbles. The detachment of a particle and bubble occurs when the force exerted by the surface tension is exceeded by shear forces and gravitational forces. These forces are complex and vary within the cell. High shear will be experienced close to the impeller of a mechanical flotation cell and mostly gravitational force in

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6634-449: The following smelting technologies: flash smelting , Isasmelt , Noranda, Mitsubishi or El Teniente furnaces. The initial melting of the material to be smelted is usually referred to as the smelting or matte smelting stage. It can be undertaken in a variety of furnaces, including the largely obsolete blast furnaces and reverberatory furnaces , as well as flash furnaces , Isasmelt furnaces, etc. The product of this smelting stage

6741-449: The froth are referred to as the flotation tailings or flotation tails . These tailings may also be subjected to further stages of flotation to recover the valuable particles that did not float the first time. This is known as scavenging . The final tailings after scavenging are normally pumped for disposal as mine fill or to tailings disposal facilities for long-term storage. Flotation is normally undertaken in several stages to maximize

6848-427: The furnace as separate streams. The slag layer is periodically allowed to flow through a hole in the wall of the furnace above the height of the matte layer. The matte is removed by draining it through a hole into ladles for it to be carried by crane to the converters. This draining process is known as tapping the furnace. The matte taphole is normally a hole through a water-cooled copper block that prevents erosion of

6955-405: The generation of gas formed by the introduction of acid into the pulp. In 1903, Potter sued Delprat, then general manager of BHP , for patent infringement. He lost the case for reasons of utility, with Delpat arguing that while Delprat's process, which used sulphuric acid to generate the bubbles in the process, was not as useful as Delprat's process, which used salt cake. Despite this, after the case

7062-426: The hydrophobicity of the valuable minerals. Since then, the process has been adapted and applied to a wide variety of materials to be separated, and additional collector agents, including surfactants and synthetic compounds have been adopted for various applications. Englishman William Haynes patented a process in 1860 for separating sulfide and gangue minerals using oil. Later writers have pointed to Haynes's as

7169-459: The loss of copper to slag in the smelting stage are: This means that there is a practical limit on how high the matte grade can be if the loss of copper to slag is to be minimized. Therefore, further stages of processing (converting and fire refining) are required. The following subsections briefly describe some of the processes used in matte smelting. Reverberatory furnaces are long furnaces that can treat wet, dry, or roasted concentrate. Most of

7276-463: The low concentrations of sulfur dioxide in their off-gases make its capture uneconomic. Consequently, smelter operators devoted a lot of money in the 1970s and 1980s to developing new, more efficient copper smelting processes. In addition, flash smelting technologies had been developed in earlier years and began to replace reverberatory furnaces. By 2002, 20 of the 30 reverberatory furnaces still operating in 1994 had been shut down. In flash smelting ,

7383-406: The metal as float off the concentration process. The 1886 patent was to capture this "float" using surface tension, the first of the skin-flotation process patents that were eclipsed by oil froth flotation. On August 24, 1886, Carrie Everson received a patent for her process calling for oil[s] but also an acid or a salt, a significant step in the evolution of the process history. By 1890, tests of

7490-436: The method of air absorption manner, it is fair to state that two distinct groups of flotation equipment have arisen:pneumatic and mechanical machines. Generally pneumatic machines give a low-grade concentrate and little operating troubles. Mechanical cells use a large mixer and diffuser mechanism at the bottom of the mixing tank to introduce air and provide mixing action. Flotation columns use air spargers to introduce air at

7597-437: The mineral chalcocite; a mineral formed from primary sulfides, like chalcopyrite , that undergo chemical processes such as oxidation or reduction. Typically, secondary sulfide ores are concentrated using froth flotation. Other extraction processes like leaching are effectively used for the extraction of secondary copper sulfides, but as demand for copper rises, extraction processes tailored for low-grade ores are required, due to

7704-426: The mineral surface through the formation of hydrophobic compounds on the mineral surface. Some supergene sulfide deposits can be leached using a bacterial oxidation heap leach process to oxidize the sulfides to sulfuric acid, which also allows for simultaneous leaching with sulfuric acid to produce a copper sulfate solution. For oxide ores, solvent extraction and electrowinning technologies are used to recover

7811-520: The most part, however, these were isolated attempts without fanfare for what can only be called marginal successes. In 1911, James M. Hyde , a former employee of Minerals Separation, Ltd., modified the Minerals Separation process and installed a test plant in the Butte and Superior Mill in Basin, Montana , the first such installation in the USA. In 1912, he designed the Butte & Superior zinc works, Butte, Montana,

7918-409: The nature of the ore. In the usual case when it is primarily sulfide copper minerals (such as chalcopyrite , FeCuS 2 ), the ore is treated by comminution , where the rock is crushed to produce small particles (<100 μm) consisting of individual mineral phases. These particles are then ready to be separated to remove gangue (silicate rocks residues) using froth flotation. In froth flotation,

8025-467: The number of claimants as "discoverers" of flotation. In 1961, American engineers celebrated "50 years of flotation" and enshrined James Hyde and his Butte & Superior mill. In 1977, German engineers celebrated the "hundredth anniversary of flotation" based on the brothers Bessel patent of 1877. The historic Glasdir copper mine site advertises its tours in Wales as site of the "discovery of flotation" based upon

8132-421: The ore bodies decreased, the energy costs of smelting the whole ore also became prohibitive, and it became necessary to concentrate the ores first. Initial concentration techniques included hand-sorting and gravity concentration. These resulted in high losses of copper. Consequently, the development of the froth flotation process was a major step forward in mineral processing. The modern froth flotation process

8239-563: The ore particles and the non-polar hydrocarbon part forms a hydrophobic layer. The particles are brought to the water surface by air bubbles. About 300  g / t of ore is required for efficient separation. With increasing length of the hydrocarbon chain in xanthates, the efficiency of the hydrophobic action increases, but the selectivity to ore type decreases. The chain is shortest in sodium ethyl xanthate that makes it highly selective to copper, nickel, lead, gold, and zinc ores. Aqueous solutions (10%) with pH = 7–11 are normally used in

8346-403: The oxygen potential of the slag increases. The oxygen potential generally increases as the copper content of the matte is increased. Thus, the loss of copper as oxide increases as the copper content of the matte increases. On the other hand, the solubility of sulfidic copper in slag decreases as the copper content of the matte increases beyond about 40%. Nagamori calculated that more than half

8453-413: The particle and bubble. The mechanisms for the bubble-particle attachment is complex but is viewed as consisting of three steps: collision, attachment, and detachment. The collision is achieved by particles being within the collision tube of a bubble and this is affected by the velocity of the bubble and radius of the bubble. The collision tube corresponds to the region in which a particle will collide with

8560-510: The particles of KCl, but not on the NaCl particles. The long alkyl chains then confer hydrophobicity to the particles, which enable them to form foams. Froth flotation is one of the processes used to recover recycled paper . In the paper industry this step is called deinking or just flotation. The target is to release and remove the hydrophobic contaminants from the recycled paper. The contaminants are mostly printing ink and stickies . Normally

8667-430: The process. This slurry (more properly called the pulp ) of hydrophobic particles and hydrophilic particles is then introduced to tanks known as flotation cells that are aerated to produce bubbles. The hydrophobic particles attach to the air bubbles, which rise to the surface, forming a froth. The froth is skimmed from the cell, producing a concentrate ("conc") of the target mineral. The minerals that do not float into

8774-402: The recovery of the target mineral or minerals and the concentration of those minerals in the concentrate, while minimizing the energy input. The first stage is called roughing , which produces a rougher concentrate . The objective is to remove the maximum amount of the valuable mineral at as coarse a particle size as practical. Grinding costs energy. The goal is to release enough gangue from

8881-579: The recovery of valuable minerals , such as copper - and lead -bearing minerals. Along with mechanized mining, it has allowed the economic recovery of valuable metals from much lower-grade ore than previously possible. Froth flotation is applied to a wide range of separations. An estimated one billion tons of materials are processed in this manner annually. Froth flotation is a process for separating minerals from gangue by exploiting differences in their hydrophobicity . Hydrophobicity differences between valuable minerals and waste gangue are increased through

8988-517: The residue with sulfuric acid. The barred (denuded) sulfuric acid recycled back on to the heaps. The organic ligands are recovered and recycled as well. Alternatively, the copper can be precipitated out of the pregnant solution by contacting it with scrap iron; a process called cementation . Cement copper is normally less pure than SX-EW copper. Secondary sulfides—those formed by supergene secondary enrichment—are resistant ( refractory ) to sulfuric leaching. Secondary copper sulfides are dominated by

9095-428: The reverberatory furnaces used in the latter years treated roasted concentrate because putting dry feed materials into the reverberatory furnace is more energy efficient, and because the elimination of some of the sulfur in the roaster results in higher matte grades. The reverberatory furnace feed is added to the furnace through feed holes along the sides of the furnace, and the solid charge is melted. Additional silica

9202-480: The selective adhesion of air bubbles to mineral surfaces in a mineral/water slurry. The air bubbles attach to more hydrophobic particles, as determined by the interfacial energies between the solid, liquid, and gas phases. This energy is determined by the Young–Dupré equation : where: Minerals targeted for separation may be chemically surface-modified with collectors so that they are more hydrophobic. Collectors are

9309-408: The separation process, these additives are called modifiers. Modifying reagents react either with the mineral surfaces or with collectors and other ions in the flotation pulp, resulting in a modified and controlled flotation response. Prior to 1907, nearly all the copper mined in the US came from underground vein deposits, averaging 2.5 percent copper. By 1991, the average grade of copper ore mined in

9416-570: The setup is a two-stage system with 3,4 or 5 flotation cells in series. As in any technology that has long been conducted on the multi-million ton per year scale, flotation technologies have the potential to threaten the environment beyond the disruption caused by mining. Froth flotation employs a host of organic chemicals and relies upon elaborate machinery. Some of the chemicals (cyanide) are acutely toxic but hydrolyze to innocuous products. Naturally occurring fatty acids are widely used. Tailings and effluents are contained in lined ponds. Froth flotation

9523-403: The slag is about 1195 °C ). In this equilibration process, oxygen associated with copper compounds exchanges with sulfur associated with iron compounds, increasing the iron oxide content of the furnace, and the iron oxides interact with silica and other oxide materials to form the slag. The main equilibration reaction is: The slag and the matte form distinct layers that can be removed from

9630-627: The slurry with air in a downcomer where high shear creates the turbulent conditions required for bubble particle contacting. For many ores (e.g. those of Cu, Mo, W, Ni), the collectors are anionic sulfur ligands. Particularly popular for sulfide minerals are xanthate salts, including potassium amyl xanthate (PAX), potassium isobutyl xanthate (PIBX), potassium ethyl xanthate (KEX), sodium isobutyl xanthate (SIBX), sodium isopropyl xanthate (SIPX), sodium ethyl xanthate (SEX). Related collectors include related sulfur-based ligands: dithiophosphates , dithiocarbamates . Still other classes of collectors include

9737-453: The smelting process can be operated at a lower temperature. The slag forming reaction is: Slag is less dense than matte, so it forms a layer that floats on top of the matte. Copper can be lost from the matte in three ways: as cuprous oxide (Cu 2 O) dissolved in the slag, as sulfide copper dissolved in the slag or as tiny droplets (or prills ) of matte suspended in the slag. The amount of copper lost as oxide copper increases as

9844-401: The smelting stage depends on the iron content of the material fed into the smelting furnace and the target matte grade. The greater the iron content of the feed, the more iron that will need to be rejected to the slag for a given matte grade. Similarly, increasing the target matte grade requires the rejection of more iron and an increase in the slag volume. Thus, the two factors that most affect

9951-419: The types of particles. The wetting activity of a surfactant on a particle can in principle be quantified by measuring the contact angles of the liquid/bubble interface. Another important measure for attachment of bubbles to particles is induction time, the time required for the particle and bubble to rupture the thin film separating the particle and bubble. This rupturing is achieved by the surface forces between

10058-425: The use of surfactants and wetting agents. The flotation process is used for the separation of a large range of sulfides , carbonates and oxides prior to further refinement. Phosphates and coal are also upgraded (purified) by flotation technology. "Grade-recovery curves" are tools for weighing the trade-off of producing a high grade of concentrate vs cost. These curves only compare the grade-recovery relations of

10165-440: The valuable mineral to get a high recovery. Some concentrators use a preflotation step to remove low density impurities such as carbonaceous dust. The rougher concentrate is normally subjected to further stages of flotation to reject more of the undesirable minerals that also reported to the froth, in a process known as cleaning . The resulting material is often subject to further grinding (usually called regrinding ). Regrinding

10272-482: The various items considered to be votive or amulets, there was one that looked like a fishhook and one like an awl. Another find, at Shanidar Cave in Mergasur, Iraq, contained copper beads, and dates back to 8,700 BCE. One of the world's oldest known copper mines, as opposed to usage of surface deposits, is at Timna Valley , Israel, and has been used since the fourth millennium BC, with surface deposit usage occurring in

10379-414: The vast majority of these were treated by smelting. Copper was initially recovered from sulfide ores by directly smelting the ore in a furnace. The smelters were initially located near the mines to minimize the cost of transport. This avoided the prohibitive costs of transporting the waste minerals and the sulfur and iron present in the copper-containing minerals. However, as the concentration of copper in

10486-419: The void fraction (i.e. volume occupied by air bubbles) is low (5 to 10 percent) and the bubble size is usually greater than 1 mm. This results in a relatively low interfacial area and a low probability of particle–bubble contact. Consequently, several cells in series are required to increase the particle residence time, thus increasing the probability of particle–bubble contact. Froth flotation depends on

10593-419: Was 9.76 million tonnes per year of feed materials and 750 thousand tonnes per year across lead operating plants. The matte, which is produced in the smelter, contains 30–70% copper (depending on the process used and the operating philosophy of the smelter), primarily as copper sulfide, as well as iron sulfide. The sulfur is removed at a high temperature as sulfur dioxide by blowing air through molten matte: In

10700-402: Was a drawback to the existing technology. Introducing a porous brick with compressed air, and a mechanical stirring mechanism, Callow applied for a patent in 1914 (some say that Callow, a Jackling partisan, invented his cell as a means to avoid paying royalties to Minerals Separation, which firms using his cell eventually were forced to do by the courts). This method, known as Pneumatic Flotation,

10807-598: Was developed in 1902 by Arthur C. Cattermole, who emulsified the pulp with a small quantity of oil, subjected it to violent agitation, and then slow stirring which coagulated the target minerals into nodules which were separated from the pulp by gravity. The Minerals Separation Ltd., formed in Britain in 1903 to acquire the Cattermole patent, found that it proved unsuccessful. Metallurgists on the staff continued to test and combine other discoveries to patent in 1905 their process, called

10914-529: Was independently invented in the early 1900s in Australia by C.V Potter and around the same time by G. D. Delprat . It made the development of the giant Bingham Canyon mine in Utah possible. In the twentieth century, most ores were concentrated before smelting. Smelting was initially undertaken using sinter plants and blast furnaces , or with roasters and reverberatory furnaces . Roasting and reverberatory furnace smelting dominated primary copper production until

11021-481: Was largely forgotten. Inventor Hezekiah Bradford of Philadelphia invented a "method of saving floating material in ore-separation” and received US patent No. 345951 on July 20, 1886. He would later go on to patent the Bradford Breaker, currently in use by the coal industry, in 1893. His "Bradford washer," patented 1870, was used to concentrate iron, copper and lead-zinc ores by specific gravity, but lost some of

11128-523: Was not patentable again by later contestants. Much confusion has been clarified recently by historian Dawn Bunyak. The generally recognized first successful commercial flotation process for mineral sulphides was invented by Frank Elmore who worked on the development with his brother, Stanley. The Glasdir copper mine at Llanelltyd , near Dolgellau in North Wales was bought in 1896 by the Elmore brothers in conjunction with their father, William. In 1897,

11235-497: Was over BHP began using sulphuric acid for its flotation process. In 1902, Froment combined oil and gaseous flotation using a modification of the Potter-Delprat process. During the first decade of the twentieth century, Broken Hill became the center of innovation leading to the perfection of the froth flotation process by many technologists there borrowing from each other and building on these first successes. Yet another process

11342-592: Was recognized as an alternative to the Minerals Separation process of flotation concentration. The American Institute of Mining Engineers presented Callow the James Douglas Gold Medal in 1926 for his contributions to the field of flotation. By that time, flotation technology was changing, especially with the discovery of the use of xanthates and other reagents, which made the Callow cell and his process obsolete. Montana Tech professor Antoine Marc Gaudin defined

11449-556: Was reprinted with comment, June 23, 1900, in the Engineering and Mining Journal , New York City. By this time they had recognized the importance of air bubbles in assisting the oil to carry away the mineral particles. As modifications were made to improve the process, it became a success with base metal ores from Norway to Australia. The Elmores had formed a company known as the Ore Concentration Syndicate Ltd to promote

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