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9 décembre 2011 5 09 /12 /décembre /2011 03:12

Wrought iron is an iron alloy with a very low carbon content, in comparison to steel, and has fibrous inclusions, known asslag. This is what gives it a "grain" resembling wood, which is visible when it is etched or bent to the point of failure. Wrought iron is tough, malleable, ductile and easily welded.HP Pavilion DV4-1199EA Battery

Historically, it was known as "commercially pure iron"; however, it no longer qualifies because current standards for commercially pure iron require a carbon content of less than 0.008 wt%.

Before the development of effective methods of steelmaking and the availability of large quantities of steel, wrought iron was the most common form of malleable iron.HP Pavilion DV4-1199EE Battery

A modest amount of wrought iron was used as a raw material for manufacturing of steel, which was mainly to produce swords, cutlery, chisels, axes and other edge tools as well as springs and files. Demand for wrought iron reached its peak in the 1860s with the adaptation of ironclad warships and railways, but then declined asmild steel became more available.HP Pavilion DV4-1199EF Battery

Before they came to be made of mild steel, items produced from wrought iron included rivets, nails, wire, chains, railway couplings, water and steam pipes, nuts, bolts, horseshoes, handrails, straps for timber roof trusses, and ornamental ironwork.[5]

Wrought iron is no longer produced on a commercial scale.HP Pavilion DV4-1199EO Battery

Many products described as wrought iron, such as guard rails,garden furniture[6] and gates, are made of mild steel.[7] They retain that description because they are wrought (worked) by hand.

Terminology

The word "wrought" is an archaic past tense form of the verb "to work," and so "wrought iron" literally means "worked iron".HP Pavilion DV4-1199EP Battery

Wrought iron is a general term for the commodity, but is also used more specifically for finished iron goods, as manufactured by a blacksmith or other smith. It was used in this narrower sense in British Customs records, such manufactured iron being subject to a higher rate of duty than what might be called "unwrought" iron.HP Pavilion DV4-1199ER Battery

Cast iron, unlike wrought iron, is brittle and cannot be worked either hot or cold. Cast iron can break if struck with a hammer.

In the 17th, 18th and 19th centuries, wrought iron went by a wide variety of terms according to its form, origin, or quality.HP Pavilion DV4-1199ES Battery

While the bloomery process produced wrought iron directly from ore, cast iron or pig iron were the starting materials used in thefinery forge and puddling furnace. Pig iron and cast iron have high carbon content which make them very brittle, but they have a lower melting point than iron or steel.HP Pavilion DV4-1199ET Battery

Cast and especially pig iron have excess slag which must be at least partially removed to produce quality wrought iron.

For several years after the introduction of Bessemer and open hearth steel there were different opinions as to what differentiated iron from steel, some thinking it was the chemical composition and others believing it was whether the iron heated sufficiently to melt and "fuse".HP Pavilion DV4-1200 CTO Battery

Fusion eventually became generally accepted as relatively more important than composition below a given low carbon concentration.[9] Another difference is that steel can be hardened by heat treating.

Form or shapes

  • Bar iron—iron in bars, which are the usual product of the finery forge, but not necessarily made by that process. These might be square or flat, and flat bars might be narrow or broad.HP Pavilion DV4-1200 Battery
  • Rod iron—cut from flat bar iron in a slitting mill to provide the raw material for nails.
  • Hoop iron—suitable for the hoops of barrels, made by passing rod iron through flat rolls.
  • Plate iron—sheets of iron suitable for use as boiler plate.HP Pavilion DV4-1201AU Battery
  • Blackplate—sheets of iron, perhaps thinner than plate iron, from the black rolling stage of tinplate production.
  • Voyage iron—narrow flat bar iron, made or cut into bars of a particular weight, a commodity for sale in Africa for the Atlantic slave trade.HP Pavilion DV4-1201TU Battery
  • The number of bars per ton gradually increased from 70 per ton in the 1660s to 75–80 per ton in 1685 and "near 92 to the ton" in 1731.
  • Charcoal Iron — Until the end of the eighteenth century, wrought iron was smelted from ore using charcoal, by the bloomery process.HP Pavilion DV4-1201TX Battery
  • Wrought iron was also produced from pig iron using a finery forge or from the industrial revolution in a Lancashire hearth. The resulting metal was highly variable, both in chemistry and slag content.
  • Puddled Iron — By the late eighteenth century there was a demand from pig iron, an impure form of cast iron, to be refined with coal as fuel.HP Pavilion DV4-1202AU Battery
  • This resulted in ‘puddled iron’, which contained less slag, sulfur and had a very low carbon content. The iron was kept separate from the fire in a reverberatory furnace to prevent harmful sulphur and phosphorus from entering the finished iron.HP Pavilion DV4-1202TU Battery
  • Puddled iron, although also variable in its properties, was generally more consistent than the earlier irons, and the method lent itself to the production of far greater quantities. By 1876, annual production of puddled iron in the UK alone was over 4 million tons.HP Pavilion DV4-1202TX Battery
  • Oregrounds iron—a particularly pure grade of bar iron made ultimately from iron ore from the Dannemora mine in Sweden. Its most important use was as the raw material for the cementation process of steelmaking.
  • Danks iron — originally iron imported to Great Britain from Gda?sk, but in the 18th century more probably the kind of iron (from eastern Sweden) that once came from Gda?sk.HP Pavilion DV4-1203AU Battery
  • Forest iron — iron from the English Forest of Dean, where haematite ore enabled tough iron to be produced.
  • Lukes iron — iron imported from Liège, whose Dutch name is "Luik."
  • Ames iron or amys iron — another variety of iron imported to England from northern Europe.HP Pavilion DV4-1203TU Battery
  • Its origin has been suggested to be Amiens, but it seems to have been imported from Flanders in the 15th century and Holland later, suggesting an origin in the Rhine valley. Its origins remain controversial.
  • Botolf iron or Boutall iron — from Bytów (Polish Pomerania) or Bytom (Polish Silesia).HP Pavilion DV4-1203TX Battery
  • Sable iron (or Old Sable) — iron bearing the mark (a sable) of the Demidov family of Russian ironmasters, one of the better brands of Russian iron.

Tough iron

Tough iron, also spelled "tuf", is not brittle and strong enough to be used for tools.

Blend iron

Blend iron is made using a mixture of different types of pig iron.HP Pavilion DV4-1204AU Battery

Best iron

Best iron is iron that had gone through several stages of piling and rolling, might reach the stage of being best iron (in the 19th century).

Marked bar iron

This is iron made by members of the Marked Bar Association and marked with the maker's brand mark as a sign of its quality.HP Pavilion DV4-1204TU Battery

Defects

Wrought iron is redshort if it contains sulfur in excess quantity. It has sufficient tenacity when cold, but cracks when bent or finished at a red heat. It is therefore useless for welding or forging.

Coldshort iron, also known as coldshear, colshire or bloodshot, contains excessive phosphorus.HP Pavilion DV4-1204TX Battery

It is very brittle when it is cold. It cracks if bent. It may, however, be worked at high temperature. Historically, coldshort iron was considered good enough for nails.

Nevertheless, phosphorus is not necessarily detrimental to iron. Ancient Indian smiths did not add lime to their furnaces;HP Pavilion DV4-1205AU Battery

the absence of CaO in the slag, and the deliberate use of wood with high phosphorus content during the smelting, induces a higher P content (> 0.1%, average 0.25%) than in modern iron. Analysis of the Iron Pillar of Delhi gives 0.10% in the slags for .18% in the iron itself, for a total P content of 0.28% in the metal and accounts for much of its corrosion resistance.HP Pavilion DV4-1205TU Battery

Furthermore, the presence of phosphorus (without carbon) produces a ductile iron suitable for wire drawing, for piano wire.

Wrought iron has been used for many centuries, and is the "iron" that is referred to throughout western history. The other form of iron, cast iron, was not introduced into Western Europe until the 15th century;HP Pavilion DV4-1205TX Battery

even then, due to its brittleness, it could only be used for a limited number of purposes. Throughout much of the Middle Ages iron was produced by the direct reduction of ore in manually operated bloomeries, although waterpower had begun to be employed by 1104.HP Pavilion DV4-1206TU Battery

The raw material produced by all indirect processes is pig iron. It has a high carbon content and as a consequence it is brittle and could not be used to make hardware. The osmond process was the first of the indirect processes, developed by 1203, but bloomery production continued in many places.HP Pavilion DV4-1206TX Battery

The process depended on the development of the blast furnace, of which medieval examples have been discovered at Lapphyttan, Sweden and in Germany.

The bloomery and osmond processes were gradually replaced from the 15th century by finery processes, of which there were two versions, the German and Walloon.HP Pavilion DV4-1207TU Battery

They were in turn replaced from the late 18th century by puddling, with certain variants such as the Swedish Lancashire process. These too are now obsolete, and wrought iron is no longer manufactured commercially.

Bloomery process

Wrought iron was originally produced by a variety of smelting processes, all described today as bloomeries. HP Pavilion DV4-1207TX Battery

Different forms of bloomery were used at different places and times. The bloomery was charged with charcoal and iron ore and then lit. Air was blown in through a tuyere to heat the bloomery to a temperature somewhat below the melting point of iron.HP Pavilion DV4-1208TU Battery

In the course of the smelt, slag would melt and run out, and carbon monoxide from the charcoal would reduce the ore to iron, which formed a spongy mass. The iron remained in the solid state. If the bloomery was allowed to become hot enough to melt the iron, carbon would dissolve into it and form pig or cast iron, but that was not the intention.HP Pavilion DV4-1208TX Battery

After smelting was complete, the bloom was removed, and the process could then be started again. It was thus a batch process, rather than a continuous one. The spongy mass contained iron and also silicate (slag) from the ore; this was iron bloom from which the technique got its name.HP Pavilion DV4-1209TU Battery

The bloom had to be forged mechanically to consolidate it and shape it into a bar, expelling slag in the process.

During the Middle Ages, water-power was applied to the process, probably initially for powering bellows, and only later to hammers for forging the blooms.HP Pavilion DV4-1209TX Battery

However, while it is certain that water-power was used, the details of this remain uncertain. This was the culmination of the direct process of ironmaking. It survived in Spain and southern France as Catalan Forges to the mid 19th century, in Austria as the stuckofento 1775, and near Garstang in England until about 1770;HP Pavilion DV4-1210EA Battery

it was still in use with hot blast in New York State in the 1880s.

Osmond process

Osmond iron consisted of balls of wrought iron, produced by melting pig iron and catching the droplets on a staff, which was spun in front of a blast of air so as to expose as much of it as possible to the air and oxidise its carbon content.HP Pavilion DV4-1210EF Battery

The resultant ball was often forged into bar iron in a hammer mill.

Finery process

In the 15th century, the blast furnace spread into what is now Belgium and was improved. From there, it spread via the Pays de Bray on the boundary of Normandy and then to the Weald in England.HP Pavilion DV4-1210EO Battery

With it, the finery forge spread. These remelted the pig iron and (in effect) burnt out the carbon, producing a bloom, which was then forged into a bar iron. If rod iron was required, a slitting mill was used.

The finery process existed in two slightly different forms. In Great Britain, France, and parts of Sweden, only the Walloon process was used.HP Pavilion DV4-1210ER Battery

This employed two different hearths, a finery hearth for fining the iron and a chafery hearth for reheating it in the course of drawing the bloom out into a bar. The finery always burnt charcoal, but the chafery could be fired with mineral coal, since its impurities would not harm the iron when it was in the solid state.HP Pavilion DV4-1210TU Battery

On the other hand, the German process, used in Germany, Russia, and most of Sweden used a single hearth for all stages.

The introduction of coke for use in the blast furnace by Abraham Darby in 1709 (or perhaps others a little earlier) initially had little effect on wrought iron production.HP Pavilion DV4-1210TX Battery

Only in the 1750s was coke pig iron used on any significant scale as the feedstock of finery forges. However, charcoal continued to be the fuel for the finery.

Potting and stamping

From the late 1750s, ironmasters began to develop processes for making bar iron without charcoal. There were a number of patented processes for this, which are referred to today as potting and stamping.HP Pavilion DV4-1211EA Battery

The earliest were developed by John Wood of Wednesbury and his brother Charles Wood of Low Mill at Egremont, patented in 1763.Another was developed for the Coalbrookdale Company by the Cranage brothers.[24] Another important one was that of John Wright and Joseph Jesson of West Bromwich.HP Pavilion DV4-1211TU Battery

Puddling process

A number of processes for making wrought iron without charcoal were devised as the Industrial Revolution began during the latter half of the 18th century. The most successful of these was puddling, using a puddling furnace (a variety of thereverberatory furnace). This was invented by Henry Cort in 1784.HP Pavilion DV4-1211TX Battery

It was later improved by others including Joseph Hall. In this type of furnace, the metal does not come into contact with the fuel, and so is not contaminated by impurities in it. The flame from the fire is reverberated or sent back down onto the metal on the fire bridge of the furnace.HP Pavilion DV4-1212LA Battery

Unless the raw material used is white cast iron, the pig iron or other raw material first had to be refined into refined ironor finers metal. This would be done in a refinery where raw coal is used to remove silicon and convert carbon from a graphitic form to a combined form.HP Pavilion DV4-1212TU Battery

This metal was placed into the hearth of the puddling furnace where it was melted. The hearth was lined with oxidizing agents such as haematite and iron oxide. This mixture is subjected to a strong current of air and stirred with long bars, called puddling bars or rabbles, through working doors.HP Pavilion DV4-1212TX Battery

The air, stirring, and "boiling" action of the metal help the oxidizing agents to oxidize the impurities and carbon out of the pig iron to their maximum capability. As the impurities oxidize, they form a molten slag while the retaining iron particles solidifiy into spongy wrought iron balls, called puddle balls.HP Pavilion DV4-1213LA Battery

Shingling

There is still some slag left in the puddle balls, so while they are still hot they must be shingled to remove the remaining slag and cinder. It may be achieved by forging the balls under a power hammer, or by squeezing the bloom in a machine. The material obtained at the end of shingling is known as bloom and it is still red-hot.HP Pavilion DV4-1213TU Battery

The blooms are not useful in this form, so they must be rolled into a final product.

Sometimes European ironworks would skip this step completely and roll the puddle balls. The only drawback to this is that the edges of the rough bars are not as well compressed. When the rough bar is reheated, the edges may separate and be lost into the furnace.HP Pavilion DV4-1213TX Battery

Rolling

The bloom is passed through grooved rollers and flat bars were produced. These bars of wrought iron were of poor quality, called muck bars or puddle bars. To improve the quality of wrought iron, these bars were cut up, piled and tied together by wires, a process known as faggoting or piling.HP Pavilion DV4-1214LA Battery

They were then reheated and rolled again in merchant rolls. This process may be repeated several times to get wrought iron of desired quality. Wrought iron that has been rolled multiple times is called merchant bar or merchant iron.

Lancashire process

The advantage of puddling was that it used coal, not charcoal as fuel. However this was little advantage in Sweden, which lacks coal.HP Pavilion DV4-1214TU Battery

Gustaf Ekman observed charcoal fineries at Ulverstone, which were quite different from any in Sweden. After his return to Sweden in the 1830s, he experimented and developed a process similar to puddling but using forewood and charcoal, which was widely adopted in the Bergslagen in the following decades.HP Pavilion DV4-1214TX Battery

The Aston process

In 1925, James Aston of the United States developed a process for manufacturing wrought iron quickly and economically. It involves taking molten steel from aBessemer converter and pouring it into cooler liquid slag. The temperature of the steel is about 1500 °C and the liquid slag is maintained at approximately 1200 °C.HP Pavilion DV4-1215EF Battery

The molten steel contains a large amount of dissolved gases so when the liquid steel hits the cooler surfaces of the liquid slag the gases are liberated. The molten steel then freezes to yield a spongy mass having a temperature of about 1370 °C.[27] This spongy mass must then be finished by being shingled and rolledas described under puddling (above).HP Pavilion DV4-1215TU Battery

Three to four tons can be converted per batch with this method.

Wrought iron as Pure Iron

Dr Gerry McDonnell in 2010 England, demonstrated by analysis that a wrought iron bloom, from a traditional smelt, could be worked into 99.7% pure iron with no evidence of carbon.HP Pavilion DV4-1215TX Battery

It was found that the stringers common to other wrought irons were not present thus making it very malleable for the smith to work hot and cold. A commercial source of pure iron is available and is used by smiths as an alternative to traditional wrought iron and other new generation ferrous metals.HP Pavilion DV4-1216TU Battery

The end of wrought iron

Steel began to replace iron for rails as soon as Bessemer production began (ca. 1860s). Iron remained dominant for structural applications until the 1880s because of problems with brittle steel, caused by high carbon, excess phosphorous or excessive temperature during rolling or too rapid rolling.HP Pavilion DV4-1216TX Battery

By 1890 steel had largely replaced iron for structural applications.

Sheet iron (Armco 99.97% pure iron) had good properties for use in appliances including being well suited for enameling and welding and being rust resistant.HP Pavilion DV4-1217LA Battery

In the 1960s the price of steel production was dropping due to recycling and even using the Aston process wrought iron production was a labor-intensive process. It has been estimated that the production of wrought iron costs approximately twice as much as the production of low carbon steel.HP Pavilion DV4-1217TX Battery

In the United States the last plant closed in 1969. The last in Great Britain (and the world) was the Atlas Ironworks of Thomas Walmsley Ltd in Bolton, which closed in 1973. Its equipment, of a type dating from the 1860s, was moved to the Blists Hill site of Ironbridge Gorge Museum for preservation.HP Pavilion DV4-1218TX Battery

Some wrought iron is still being produced for heritage restoration purposes, but only by recycling scrap.

Properties

The slag inclusions, or stringers, in wrought iron give it properties not found in other forms of ferrous metal. There are approximately 250,000 inclusions per square inch.HP Pavilion DV4-1219TX Battery

A fresh fracture shows a clear bluish color with a high silky luster and fibrous appearance.

Wrought iron lacks the carbon content necessary for hardening through heat treatment, but in areas where steel was uncommon or unknown, tools were sometimes cold-worked (hence cold iron) in order to harden them. An advantage of its low carbon content is its excellent weldability.HP Pavilion DV4-1220BR Battery

Furthermore, sheet wrought iron cannot bend as much as steel sheet metal (when cold worked). Wrought iron can be cast, however there is no engineering advantage as compared to cast iron; cast iron is much easier to produce and thus cheaper, so it is exclusively chosen over wrought iron.HP Pavilion DV4-1220TX Battery

Due to the variations in iron ore origin and iron manufacture, wrought iron can be inferior or superior in corrosion resistance compared to other iron alloys. There are many mechanisms behind this corrosion resistance. Chilton and Evans found that nickel enrichment bands reduce corrosion.HP Pavilion DV4-1220US Battery

They also found that in puddled and forged and piled the working over of the iron spread out copper, nickel and tin impurities, which produce electrochemical conditions that slow down corrosion. The slag inclusions have been shown to disperse corrosion in to an even film to resist pitting.HP Pavilion DV4-1221TX Battery

Another study has shown that slag inclusions are pathways to corrosion.Other studies show that sulfur impurities in the wrought iron decrease corrosion resistance, but phosphorus increase corrosion resistance. Environments with a high concentration of chlorine ions also decreases wrought iron's corrosion resistance.HP Pavilion DV4-1222LA Battery

Wrought iron may be welded in the same manner as mild steel, but the presence of oxide or inclusions will give defective results.[50]The material has a rough surface so it can hold platings and coatings better. For instance, a galvanic zinc finish is approximately 25–40% thicker than the same finish on steel.HP Pavilion DV4-1222NR Battery

In Table 1, the chemical composition of wrought iron is compared to that of pig iron and carbon steel. Although it appears that wrought iron and plain carbon steel have similar chemical compositions, this is deceiving. Most of the manganese, sulfur, phosphorus, and silicon are incorporated into the slag fibers present in the wrought iron, so wrought iron really is purer than plain carbon steel.HP Pavilion DV4-1222TX Battery

Amongst its other properties, wrought iron becomes soft at red heat, and can be easily forged and forge welded.[55] It can be used to form temporary magnets, but cannot be magnetized permanently,[56][57] and is ductile, malleable and tough.HP Pavilion DV4-1223LA Battery

The importance of ductility

For most purposes, ductility is a more important measure of the quality of wrought iron than tensile strength. In tensile testing, the best irons are able to undergo considerable elongation before failure. Higher tensile wrought iron is brittle.HP Pavilion DV4-1223TX Battery

Because of the large number of boiler explosions on steamboats, the U.S. Congress passed legislation in 1830 which approved funds for correcting the problem. The treasury awarded a $1500 contract to the Franklin Institute to conduct a study.HP Pavilion DV4-1224LA Battery

As part of the study Walter R. Johnson and Benjamin Reeves conducted strength tests on various boiler iron using a tester they had built in 1832 based on the design of one by Lagerhjelm in Sweden. Unfortunately, because of the misunderstanding of tensile strength and ductility, this work did little to reduce failures.HP Pavilion DV4-1224TX Battery

The importance of ductility was recognized by some very early in the development of tube boilers, such as Thurston's comment:

‘If made of such good iron as the makers claimed to have put into them “which worked like lead,” they would, as also claimed, when ruptured, open by tearing, and discharge their contents without producing the usual disastrous consequences of a boiler explosion.’HP Pavilion DV4-1225DX Battery

By the late 19 th century when metallurgy was able to better understand what properties and processes made good iron, it was being displaced by steel.

Applications

Wrought iron furniture has a long history, dating back to Roman times.HP Pavilion DV4-1225EE Battery

There are thirteenth century wrought iron gates in Westminster Abbey in London, and wrought iron furniture appeared to reach its peak popularity (in Britain) in the seventeenth century during the reign of William and Mary . However, cast iron and cheaper steel caused a gradual decline in wrought iron manufacture, with the last wrought ironworks in Britain closing in 1974.HP Pavilion DV4-1225LA Battery

It is also used to make home decor items such as baker's racks, wine racks, pot racks, etageres, table bases, desks, gates, beds, candle holders, curtain rods, bars and bar stools.

Zinc smelting is the process of converting zinc concentrates (ores that contain zinc) into pure zinc.HP Pavilion DV4-1225TX Battery

The most common zinc concentrate processed is zinc sulfide,[1] which is obtained by concentratingsphalerite using the froth flotation method. Secondary (recycled) zinc material, such as zinc oxide, is also processed with the zinc sulfide.[2] Approximately 30% of all zinc produced is from recycled sources.HP Pavilion DV4-1226TX Battery

There are two methods of smelting zinc: the pyrometallurgical process and the electrolysis process. Both methods are still used.[2][4] Both of these processes share the same first step: roasting.

Roasting is a process of oxidizing zinc sulfide concentrates at high temperatures into an impure zinc oxide, called "Zinc Calcine". The chemical reactions taking place during the process are:HP Pavilion DV4-1227LA Battery

Approximately 90% of zinc in concentrates are oxidized to zinc oxide, but at the roasting temperatures around 10% of the zinc reacts with the iron impurities of the zinc sulfide concentrates to form zinc ferrite. A byproduct of roasting is sulfur dioxide, which is further processed into sulfuric acid, a commodity.HP Pavilion DV4-1227TX Battery

The linked refinery flow sheet shows a schematic of Noranda's eastern Canadian zinc roasting operation[5]

The process of roasting varies based on the type of roaster used. There are three types of roasters: multiple-hearth, suspension, and fluidized-bed.HP Pavilion DV4-1227US Battery

Multiple-hearth roaster

In a multiple-hearth roaster, the concentrate drops through a series of 9 or more hearths stacked inside a brick-lined cylindrical column. As the feed concentrate drops through the furnace, it is first dried by the hot gases passing through the hearths and then oxidized to produce calcine.HP Pavilion DV4-1228CA Battery

The reactions are slow and can be sustained only by the addition of fuel. Multiple hearth roasters are unpressurized and operate at about 690 °C (1,270 °F). Operating time depends upon the composition of concentrate and the amount of the sulfur removal required. Multiple hearth roasters have the capability of producing a high-purity calcine.HP Pavilion DV4-1228LA Battery

Suspension roaster

In a suspension roaster, the concentrates are blown into a combustion chamber very similar to that of a pulverized coal furnace. The roaster consists of a refractory-lined cylindrical steel shell, with a large combustion space at the top and 2 to 4 hearths in the lower portion, similar to those of a multiple hearth furnace.HP Pavilion DV4-1228TX Battery

Additional grinding, beyond that required for a multiple hearth furnace, is normally required to ensure that heat transfer to the material is sufficiently rapid for the desulfurization and oxidation reactions to occur in the furnace chamber. Suspension roasters are unpressurized and operate at about 980 °C(1,800 °F).HP Pavilion DV4-1229LA Battery

Fluidized-bed roaster

In a fluidized-bed roaster, finely ground sulfide concentrates are suspended and oxidized in a feedstock bed supported on an air column. As in the suspension roaster, the reaction rates for desulfurization are more rapid than in the older multiple-hearth processes.HP Pavilion DV4-1229TX Battery

Fluidized-bed roasters operate under a pressure slightly lower than atmospheric and at temperatures averaging 1,000 °C (1,830 °F). In the fluidized-bed process, no additional fuel is required after ignition has been achieved. The major advantages of this roaster are greater throughput capacities, greater sulfur removal capabilities, and lower maintenance.HP Pavilion DV4-1230BR Battery

Electrolysis process

The electrolysis process, also known as the hydrometallurgical process, Roast-Leach-Electrowin (RLE) process, or electrolytic process, is more widely used than the pyrometallurgical processes.

The electrolysis process consists of 4 steps: leaching, purification, electrolysis, and melting and casting.HP Pavilion DV4-1230TX Battery

Leaching

The basic leaching chemical formula that drives this process is:

\mathrm{ZnO + SO_3 \rarr ZnSO_4}

This is achieved in practice though a process called double leaching. The calcine is first leached in a neutral or slightly acidic solution (of sulfuric acid) in order to leach the zinc out of the zinc oxide.HP Pavilion DV4-1231TX Battery

The remaining calcine is then leached in strong sulfuric acid to leach the rest of the zinc out of the zinc oxide and zinc ferrite. The result of this process is a solid and a liquid; the liquid contains the zinc and is often called leach product; the solid is called leach residue and contains precious metals (usually lead and silver) which are sold as a by-product.HP Pavilion DV4-1232TX Battery

There is also iron in the leach product from the strong acid leach, which is removed in an intermediate step, in the form of goethite, jarosite, and haematite. There is still cadmium, copper, arsenic, antimony, cobalt, germanium, nickel, andthallium in the leach product. Therefore it needs to be purified.HP Pavilion DV4-1233TX Battery

Purification

The purification process utilizes the cementation process to further purify the zinc. It uses zinc dust and steam to remove copper, cadmium, cobalt, and nickel, which would interfere with the electrolysis process. After purification, concentrations of these impurities are limited to less than 0.05 milligram per liter (4×10?7 pound per U.S. gallon).HP Pavilion DV4-1234TX Battery

Purification is usually conducted in large agitated tanks. The process takes place at temperatures ranging from 40 to 85 °C (104 to 185 °F), and pressures ranging from atmospheric to 2.4 atm (240 kPa) (absolute scale). The by-products are sold for further refining.HP Pavilion DV4-1235EE Battery

The zinc sulfate solution must be very pure for electrowinning to be at all efficient. Impurities can change the decomposition voltage enough to where the electrolysis cell produces largely hydrogen gas rather than zinc metal.[6]

Electrolysis

Zinc is extracted from the purified zinc sulfate solution by electrowinning, which is a specialized form of electrolysis.HP Pavilion DV4-1235EI Battery

The process works by passing an electric current through the solution in a series of cells. This causes the zinc to deposits on the cathodes (aluminium sheets) and oxygen to form at the anodes. Sulfuric acid is also formed in the process and reused in the leaching process.HP Pavilion DV4-1235TX Battery

Every 24 to 48 hours, each cell is shut down, the zinc-coated cathodes are removed and rinsed, and the zinc is mechanically stripped from the aluminium plates.

Electrolytic zinc smelters contain as many as several hundred cells. A portion of the electrical energy is converted into heat, which increases the temperature of the electrolyte.HP Pavilion DV4-1236TX Battery

Electrolytic cells operate at temperature ranges from 30 to 35 °C (86 to 95 °F) and at atmospheric pressure. A portion of the electrolyte is continuously circulated through the cooling towers both to cool and concentrate the electrolyte through evaporation of water. The cooled and concentrated electrolyte is then recycled to the cells.HP Pavilion DV4-1237TX Battery

This process accounts for approximately one-third of all the energy usage when smelting zinc.

There are two common processes for electrowinning the metal: the low current density process, and the Tainton high current density process.HP Pavilion DV4-1238TX Battery

The former uses a 10% sulfuric acid solution as the electrolyte, with current density of 270–325 amperes per square meter. The latter uses 22–28% sulfuric acid solution as the electrolyte with a current density of about 1,000 amperes per square metre.HP Pavilion DV4-1239TX Battery

The latter gives better purity and has higher production capacity per volume of electrolyte, but has the disadvantage of running hotter and being more corrosive to the vessel in which it is done. In either of the electrolytic processes, each metric ton of zinc production expends about 3,900 kW·h (14 GJ) of electric power.HP Pavilion DV4-1240TX Battery

Melting and casting

The final step is to melt the cathodes in an induction furnace. It is then either cast into pure zinc (99.995% pure) ingots or alloyed and cast into ingots.

Pyrometallurgical processes

There are also several pyrometallurgical processes that reduce zinc oxide using carbon, then distil the metallic zinc from the resulting mix in an atmosphere of carbon monoxide.HP Pavilion DV4-1241TX Battery

The major downfall of any of the pyrometallurgical process is that it is only 98% pure; a standard composition is 1.3% lead, 0.2% cadmium, 0.03% iron, and 98.5% zinc.  This may be pure enough for galvanization, but not enough for die casting alloys, which requires special high-grade zinc (99.995% pure).HP Pavilion DV4-1242TX Battery

In order to reach this purity the zinc must be refined.

The four types of commercial pyrometallurgical processes are the Belgian-type horizontal retort process, the New Jersey Zinc continuous vertical-retort process, theblast furnace process and the St. Joseph Minerals Corporation's (electrothermic) process.HP Pavilion DV4-1243TX Battery

St. Joseph Mineral Company (electrothermic) process

This process was developed by the St. Joseph Mineral Company in 1930, and is the only pyrometallurgical process still used in the US to smelt zinc. The advantage of this system is that it is able to smelt a wide variety of zinc-bearing materials, including electric arc furnace dust.HP Pavilion DV4-1244TX Battery

The disadvantage of this process is that it is less efficient than the electrolysis process.

The process begins with a downdraft sintering operation. The sinter, which is a mixture of roaster calcine and EAF calcine, is loaded onto a gate type conveyor and then combustions gases are pumped through the sinter. HP Pavilion DV4-1245BR Battery

The carbon in the combustion gases react with some the impurities, such as lead, cadmium, and halides. These impurities are driven off into filtration bags. The sinter after this process, called product sinter, usually has a composition of 48% zinc, 8% iron, 5% aluminium, 4% silicon, 2.5% calcium, and smaller quantities of magnesium, lead, and other metals.HP Pavilion DV4-1245TX Battery

The sinter product is then charged with coke into an electric retort furnace. A pair of graphite electrodes from the top and bottom furnace produce current flow through the mixture. The coke provides electrical resistance to the mixture in order to heat the mixture to 1,400 °C (2,550 °F) and produce carbon monoxide.HP Pavilion DV4-1246TX Battery

These conditions allow for the following chemical reaction to occur:

The zinc vapour and carbon dioxide pass to a vacuum condenser, where zinc is recovered by bubbling through a molten zinc bath. Over 95% of the zinc vapour leaving the retort is condensed to liquid zinc. The carbon dioxide is regenerated with carbon, and the carbon monoxide is recycled back to the retort furnace.HP Pavilion DV4-1247TX Battery

Blast furnace process

This process was developed by the Imperial Smelting Corporation at Avonmouth, England, in order to increase production, increase efficiency, and decrease labour and maintenance costs. L. J. Derham proposed using a spray of molten lead droplets to rapidly chill and absorb the zinc vapour, despite the high concentration of carbon dioxide.HP Pavilion DV4-1248TX Battery

The mixture is then cooled, where the zinc separates from the lead. The first plant using this design opened up in 1950. One of the advantages of this process is that it can co-produce lead bullion and copper dross. In 1990, it accounted for 12% of the world's zinc production.HP Pavilion DV4-1249TX Battery

The process starts by charging solid sinter and heated coke into the top of the blast furnace. Preheated air at 190 to 1,050 °C (370 to 1,920 °F) is blown into the bottom of the furnace. Zinc vapour and sulfides leave through the top and enter the condenser. Slag and lead collect at the bottom of the furnace and are tapped off regularly.HP Pavilion DV4-1250TX Battery

The zinc is scrubbed from the vapour in the condenser via liquid lead. The liquid zinc is separated from the lead in the cooling circuit. Approximately 5,000 metric tons (5,500 short tons) of lead are required each year for this process, however this process recovers 25% more lead from the starting ores than other processes.HP Pavilion DV4-1251TX Battery

New Jersey Zinc continuous vertical retort

The New Jersey Zinc process is no longer used to produce primary zinc in the U.S., Europe and Japan, however it still is used to treat secondary operations. This processes peaked in 1960, when 5% of the world production was done by this process.HP Pavilion DV4-1252TX Battery

A modified version of this process is still used at Huludao, China, which produced 65,000 metric tons per year.

This process begins by roasting concentrates that are mixed with coal and briquetted in two stages. The briquettes are then heated in an autogenous coker at 700 °C(1,292 °F) and then charged into the retort.HP Pavilion DV4-1253TX Battery

There are three reasons to briquette the calcine: to ensure free downward movement of the charge; to permit heat transfer across a practical size cross-section; to allow adequate porosity for the passage of reduced zinc vapour to the top of the retort. The reduced zinc vapour that is collected at the top of the retort is then condensed to a liquid.HP Pavilion DV4-1254TX Battery

Overpelt improved upon this design by using only one large condensation chamber, instead of many small ones, as it was originally designed. This allowed for the carbon monoxide to be recirculated into the furnaces for heating the retorts.HP Pavilion DV4-1255TX Battery

This process was licensed to the Imperial Smelting Company (ISC), in Avonmouth, England, which had a large vertical retort (VR) plant in production for many years. It was used until the mid 1970s when it was superseded by the company's Imperial Smelting Furnace (ISF) plant. The VR plant was demolished in 1975.HP Pavilion DV4-1256TX Battery

Belgian-type horizontal retort process

This process was the main process used in Britain from the mid-19th century until 1951. The process was very inefficient as it was designed as a small scale batch operation. Each retort only produced 40 kilograms (88 lb) so companies would put them together in banks and used one large gas burner to heat all of them.HP Pavilion DV4-1257TX Battery

The Belgian process requires redistillation to remove impurities of lead, cadmium, iron, copper, and arsenic.
Although some zinc artifacts appear to have been made during classical antiquity in Europe,  the first production of zinc in quantity seems to have been in Indiaand China.HP Pavilion DV4-1258TX Battery

In India, zinc was produced at Zawar from the 12th to the 18th centuries. The sphalerite ore found here was presumably converted to zinc oxide via roasting, although no archaeological evidence of this has been found. Smelting is thought to have been done in sealed cylindrical clay retorts which were packed with a mixture of roasted ore,HP Pavilion DV4-1259TX Battery

dolomite, and an organic material, perhaps cow dung, and then placed vertically in a furnace and heated to around 1100 °C. Carbon monoxideproduced by the charring of the organic material would have reduced the zinc oxide to zinc vapour, which then liquefied in a conical clay condenser at the bottom of the retort, dripping down into a collection vesselww.laptopbattery-pack.co.uk/hp-pavilion-dv4-1260tx-battery-13679.htm" title="HP PAVILION DV4-1260TX laptop battery">HP Pavilion DV4-1260TX Battery

Over the period 1400–1800, production is estimated to have been about 200 kg/day.[11] Zinc was also smelted in China from the mid-sixteenth century on.

Large-scale zinc production in Europe began with William Champion, who patented a zinc distillation process in 1738.HP Pavilion DV4-1265DX Battery

In Champion's process, zinc ore (in this case, the carbonate, ZnCO3) was sealed in large reduction pots with charcoal and heated in a furnace. The zinc vapor then descended through an iron condensing pipe until reaching a water-filled vessel at the bottom.HP Pavilion DV4-1272CM Battery

Champion set up his first zinc works in Bristol, England, but soon expanded to Warmley and by 1754 had built four zinc furnaces there. Although Champion succeeded in producing about 200 tons of zinc, his business plans were not successful and he was bankrupt by 1769.[14] However, zinc smelting continued in this area until 1880.HP Pavilion DV4-1275MX Battery

Early European zinc production also took place in Silesia, in Carinthia, and in Liège, Belgium. In the Carinthian process, used in works established in 1798 by Bergrath Dillinger, a wood-fueled furnace heated a large number of small vertical retorts, and zinc vapor then dropped through a ceramic pipe into a common condensation chamber below.HP Pavilion DV4-1280US Battery

This process was out of use by 1840. The Belgian and Silesian processes both used horizontal retorts. In Silesia, Johann Ruhberg built a furnace to distill zinc in 1799, at first using pots but later changing to flat-bottomed retorts called "muffles", attached to horizontal tubes bent downwards in which the zinc condensed.HP Pavilion DV4-1281US Battery

The Silesian process eventually merged with the Belgian process. This process, developed by Jean-Jacques Daniel Dony, was introduced 1805–1810, and used retorts with a cylindrical cross-section. Condensers were horizontal clay tubes extending from the ends of the retorts.HP Pavilion DV4-1282CM Battery

The merged "Belgo-Silesian" horizontal retort process was widely adopted in Europe by the third quarter of the 19th century, and later in the United States.

Experimental attempts to extract zinc via electrolysis begun in the 19th century, but the only commercially successful application before 1913 was a process,HP Pavilion DV4-1283CL Battery

used inGreat Britain and Austria, where zinc and chlorine were co-produced by electrolysis of an aqueous zinc chloride solution. The Anaconda Copper Company, atAnaconda, Montana, and the Consolidated Mining and Smelting Company, at Trail, British Columbia, both built successful electrolytic plants in 1915 using the currently used zinc sulfate process.HP Pavilion DV4-1287CL Battery

This method has continued to grow in importance and in 1975 accounted for 68% of world zinc production.

The continuous vertical retort process was introduced in 1929 by the New Jersey Zinc Company. This process used a retort with silicon carbide walls, around 9 meters high and with a cross section of 2 by 0.3 meters.HP Pavilion DV4-1290BR Battery

The walls of the retort were heated to 1300 °C and briquettes consisting of sintered zinc ore, coke, coal, and recycled material were fed into the top of the retort. Gaseous zinc was drawn off from the top of the column and, after a 20-hour journey through the retort, spent briquettes were removed from the bottom.HP Pavilion DV4-1290EL Battery

To condense the gaseous zinc, the company first used a simple brick chamber with carborundum baffles, but efficiency was poor. During the 1940s a condenser was developed which condensed the zinc vapor on a spray of liquid zinc droplets, thrown up by an electrical impeller.HP Pavilion DV4-1292CM Battery

The electrothermic process, developed by the St. Joseph's Lead Company, was somewhat similar. The first commercial plant using this process was built in 1930 at the present site of Josephtown, Pennsylvania. The electrothermic furnace was a steel cylinder around 15 meters high and 2 meters in diameter, lined with firebrick.HP Pavilion DV4-1299EE Battery

A mixture of sintered ore and coke was fed into the top of the furnace, and a current of 10,000–20,000 amperes, at a potential difference of 240 volts, was applied between carbon electrodes in the furnace, raising the temperature to 1200–1400 °C.HP Pavilion DV4-1300 CTO Battery

An efficient condenser was devised for this process from 1931–1936; it consisted of a bath of liquid zinc which the exhaust gases were drawn through by suction. The zinc content of the gas stream was absorbed into the liquid bath.

The blast-furnace process was developed starting in 1943 at Avonmouth, England by the Imperial Smelting Corporation. It uses a spray of molten lead droplets to condense the zinc vapor.HP Pavilion DV4-1301TU Battery

Nickel (  /?n?k?l/) is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrousmetal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile. Pure nickel shows a significant chemical activity, though larger pieces of the metal are slow to react with air at ambient conditions due to the formation of a protective oxide surface.HP Pavilion DV4-1301TX Battery

However, nickel is reactive with oxygen to the extent that native nickel is rare on Earth's surface, and is mostly confined to the interiors of larger nickel iron meteorites, which were protected from oxidation in space. Such native nickel is always found on Earth alloyed with iron,HP Pavilion DV4-1302TU Battery

in keeping with the element's origin as a major end-product of the nucleosynthesis process, along with iron, in supernovas. An iron-nickel alloy is thought to compose the Earth's core.

The use of nickel (as a natural meteoric nickel-iron alloy) has been traced as far back as 3500 BC.HP Pavilion DV4-1302TX Battery

Nickel was first isolated and classified as a chemical element in 1751 by Axel Fredrik Cronstedt, who initially mistook its ore for a copper mineral. Its most important ore minerals are laterites, including limonite, garnierite, and pentlandite. Major production sites include Sudbury region in Canada (which is thought to be of meteoric origin), New Caledonia and Norilsk in Russia.HP Pavilion DV4-1303TU Battery

Because of nickel's slow rate of oxidation at room temperature, it is considered corrosion-resistant. Historically this has led to its use for plating metals such as iron and brass, to its use for chemical apparatus, and its use in certain alloys that will retain a high silvery polish, such as German silver.HP Pavilion DV4-1303TX Battery

About 6% of world nickel production is still used for corrosion-resistant pure-nickel plating. Nickel was once a common component of coins, but has largely been replaced by cheaper iron for this purpose, especially since the metal has proven to be a skin allergen for some people.HP Pavilion DV4-1304TU Battery

Nickel is one of the four elements that are ferromagnetic around room temperature. Alnico permanent magnets based partly on nickel are of intermediate strength between iron-based permanent magnets and rare earth magnets. The metal is chiefly valuable in the modern world for the alloys it forms; about 60% of world production is used in nickel-steels (particularlystainless steel). HP Pavilion DV4-1304TX Battery

Other common alloys, as well as some new superalloys, make up most of the remainder of world nickel use, with chemical uses for nickel compounds consuming less than 3% of production. As a compound, nickel has a number of niche chemical manufacturing uses, such as a catalyst for hydrogenation.HP Pavilion DV4-1305TU Battery

Enzymes of some microorganisms and plants contain nickel as an active center, which makes the metal an essential nutrient for them.

Atomic and physical properties

Nickel is a silvery-white metal with a slight golden tinge that takes a high polish.HP Pavilion DV4-1305TX Battery

It is one of only four elements that are magnetic at or near room temperature, the others being iron, cobalt and gadolinium. Its Curie temperature is 355 °C, meaning that bulk nickel is non-magnetic above this temperature. The unit cell of nickel is a face centered cube with the lattice parameter of 0.352 nm giving an atomic radius of 0.124 nm.HP Pavilion DV4-1306TU Battery

Nickel belongs to the transition metals and is hard and ductile.

The nickel atom has two electron configurations, [Ar] 4s2 3d8 and [Ar] 4s1 3d9, which are very close in energy, where the symbol [Ar] refers to the argon-like core structure. There is some disagreement as to which should be considered the lowest energy configuration.HP Pavilion DV4-1306TX Battery

Chemistry textbooks quote the electron configuration of nickel as [Ar] 4s2 3d8,[6] or equivalently as [Ar] 3d8 4s2.[7] This configuration agrees with the Madelung energy ordering rule, which predicts that 4s is filled before 3d. It is supported by the experimental fact that the lowest energy state of the nickel atom is a 4s2 3d8 energy level, specifically the 3d8(3F) 4s2 3F, J=4 level.HP Pavilion DV4-1307TU Battery

However each of these two configurations in fact gives rise to a set of states at different energies.[8] The two sets of energies overlap, and the average energy of states having configuration [Ar] 4s1 3d9 is in fact lower than the average energy of states having configuration [Ar] 4s2 3d8.HP Pavilion DV4-1307TX Battery

For this reason the research literature on atomic calculations quotes the ground state configuration of nickel as 4s1 3d9.

Naturally occurring nickel is composed of 5 stable isotopes; 58Ni, 60Ni, 61Ni, 62Ni and 64Ni with 58Ni being the most abundant (68.077% natural abundance).HP Pavilion DV4-1308TU Battery

62Ni is the "most stable" nuclide of all the existing elements, with binding energy greater than both 56Fe, often incorrectly cited as "most stable", and 58Fe.[9] 18 radioisotopes have been characterised with the most stable being 59Ni with a half-life of 76,000 years, 63Ni with a half-life of 100.1 years, and 56Ni with a half-life of 6.077 days.HP Pavilion DV4-1308TX Battery

All of the remaining radioactive isotopes have half-lives that are less than 60 hours and the majority of these have half-lives that are less than 30 seconds. This element also has 1 meta state.

Nickel-56 is produced by the silicon burning process and later set free in large quantities during type Ia supernovae.HP Pavilion DV4-1309TU Battery

Indeed, the shape of the light curve of these supernovae at intermediate to late-times corresponds to the decay via electron capture of nickel-56 to cobalt-56 and ultimately to iron-56. Nickel-59 is a long-lived cosmogenic radionuclide with a half-life of 76,000 years. 59Ni has found many applications in isotope geology.HP Pavilion DV4-1309TX Battery

59Ni has been used to date the terrestrial age of meteorites and to determine abundances of extraterrestrial dust in ice and sediment. Nickel-60 is the daughter product of the extinct radionuclide 60Fe, which decays with a half-life of 2.6 million years.HP Pavilion DV4-1310TU Battery

Because 60Fe has such a long half-life, its persistence in materials in the solar system at high enough concentrations may have generated observable variations in the isotopic composition of 60Ni. Therefore, the abundance of 60Ni present in extraterrestrial material may provide insight into the origin of the solar system and its early history.HP Pavilion DV4-1310TX Battery

Nickel-62 has the highest binding energy per nucleon of any isotope for any element (8.7946 Mev/nucleon).[12] Isotopes heavier than 62Ni cannot be formed by nuclear fusion without losing energy. Nickel-48, discovered in 1999, is the most proton-rich heavy element isotope known.HP Pavilion DV4-1311TU Battery

With 28 protons and 20 neutrons 48Ni is "double magic" (like 208Pb) and therefore unusually stable.

The isotopes of nickel range in atomic weight from 48 u (48Ni) to 78 u (78Ni). Nickel-78's half-life was recently measured to be 110 milliseconds and is believed to be an important isotope involved in supernova nucleosynthesis of elements heavier than iron.HP Pavilion DV4-1311TX Battery

On Earth, nickel occurs most often in combination with sulfur and iron in pentlandite, with sulfur in millerite, with arsenic in the mineral nickeline, and with arsenic andsulfur in nickel galena.[15] Nickel is commonly found in iron meteorites as the alloyskamacite and taenite.HP Pavilion DV4-1312TU Battery

The bulk of the nickel mined comes from two types of ore deposits. The first are lateriteswhere the principal ore minerals are nickeliferous limonite: (Fe, Ni)O(OH) and garnierite(a hydrous nickel silicate): (Ni, Mg)3Si2O5(OH)4. The second are magmatic sulfide deposits where the principal ore mineral is pentlandite: (Ni, Fe)9S8.HP Pavilion DV4-1312TX Battery

In terms of supply, the Sudbury region of Ontario, Canada, produces about 30% of the world's supply of nickel. The Sudbury Basin deposit is theorized to have been created by ameteorite impact event early in the geologic history of Earth. Russia contains about 40% of the world's known resources at the Norilsk deposit in Siberia.HP Pavilion DV4-1313DX Battery

The Russian mining company MMC Norilsk Nickel obtains the nickel and the associated palladium for world distribution. Other major deposits of nickel are found in New Caledonia, France, Australia, Cuba, and Indonesia. Deposits found in tropical areas typically consist of laterites,HP Pavilion DV4-1313TU Battery

which are produced by the intense weathering of ultramafic igneous rocks and the resulting secondary concentration of nickel bearing oxide and silicate minerals.

Based on geophysical evidence, most of the nickel on Earth is postulated to be concentrated in the Earth's core. Kamacite andtaenite are naturally occurring alloys of iron and nickel.HP Pavilion DV4-1313TX Battery

For kamacite the alloy is usually in the proportion of 90:10 to 95:5 although impurities such as cobalt or carbon may be present, while for taenite the nickel content is between 20% and 65%. Kamacite and taenite occur in nickel iron meteorites.[16]

The most common oxidation state of nickel is +2, but compounds of Ni0, Ni+, and Ni3+ are well known, and Ni4+ has been demonstrated.HP Pavilion DV4-1314TU Battery

Nickel(0)

Tetracarbonylnickel (Ni(CO)4), discovered by Ludwig Mond,  is a volatile liquid at room temperature. On heating, the complex decomposes back to nickel and carbon monoxide:HP Pavilion DV4-1314TX Battery

Ni(CO)4 Ni + 4 CO

This behavior is exploited in the Mond process for purifying nickel, as described above. The related nickel(0) complexbis(cyclooctadiene)nickel(0) is a useful catalyst in organonickel chemistry due to the easily displaced cod ligands.HP Pavilion DV4-1315TU Battery

xNickel(II)

Nickel(II) compounds are known with all common anions, i.e. the sulfide, sulfate, carbonate, hydroxide, carboxylates, and halides.Nickel(II) sulfate is produced in large quantities by dissolving nickel metal or oxides in sulfuric acid. It exists as both a hexa- and heptahydrates.[19] This compound is useful for electroplating nickel.HP Pavilion DV4-1315TU Battery

The four halogens form nickel compounds, all of which adopt octahedral geometries. Nickel(II) chloride is most common, and its behavior is illustrative of the other halides. Nickel(II) chloride is produced by dissolving nickel residues in hydrochloric acid.HP Pavilion DV4-1315TX Battery

The dichloride is usually encountered as the green hexahydrate, but it can be dehydrated to give the yellow anhydrous NiCl2. Some tetracoordinate nickel(II) complexes form both tetrahedral and square planar geometries. The tetrahedral complexes are paramagnetic and the square planar complexes are diamagnetic.HP Pavilion DV4-1316TU Battery

This equilibrium as well as the formation of octahedral complexes contrasts with the behavior of the divalent complexes of the heavier group 10 metals, palladium(II) and platinum(II), which tend to adopt only square-planar complexes.[17]

Nickelocene is known; it has an electron count of 20, making it relatively unstable.HP Pavilion DV4-1316TX Battery

Nickel(I), (III), and (IV)

For simple compounds, nickel(III) and nickel(IV) only occurs with fluoride and oxides. Nickel(III) oxide is used as the cathodein many rechargeable batteries, including nickel-cadmium, nickel-iron, nickel hydrogen, and nickel-metal hydride, and used by certain manufacturers in Li-ion batteries.HP Pavilion DV4-1317TU Battery

Because the ores of nickel are easily mistaken for ores of silver, understanding of this metal and its use dates to relatively recent times. However, the unintentional use of nickel is ancient, and can be traced back as far as 3500 BC. Bronzes from what is now Syria had contained up to 2% nickel.HP Pavilion DV4-1317TX Battery

Further, there are Chinese manuscripts suggesting that "white copper" (cupronickel, known as baitung) was used there between 1700 and 1400 BC. This Paktong white copper was exported to Britain as early as the 17th century, but the nickel content of this alloy was not discovered until 1822.HP Pavilion DV4-1318TU Battery

In medieval Germany, a red mineral was found in the Erzgebirge (Ore Mountains) that resembled copper ore. However, when miners were unable to extract any copper from it, they blamed a mischievous sprite of German mythology, Nickel (similar to Old Nick), for besetting the copper.HP Pavilion DV4-1318TX Battery

They called this ore Kupfernickel from the GermanKupfer for copper. This ore is now known to be nickeline or niccolite, a nickel arsenide. In 1751, Baron Axel Fredrik Cronstedt was attempting to extract copper from kupfernickel and obtained instead a white metal that he named after the spirit which had given its name to the mineral, nickel.HP Pavilion DV4-1319TU Battery

In modern German, Kupfernickel or Kupfer-Nickel designates the alloy cupronickel.

After its discovery, the only source for nickel was the rare Kupfernickel, but, from 1824 on, the nickel was obtained as byproduct of cobalt blue production.HP Pavilion DV4-1319TX Battery

The first large-scale producer of nickel was Norway, which exploited nickel-rich pyrrhotite from 1848 on. The introduction of nickel in steel production in 1889 increased the demand for nickel, and the nickel deposits of New Caledonia, which were discovered in 1865, provided most of the world's supply between 1875 and 1915.HP Pavilion DV4-1320CA Battery

The discovery of the large deposits in the Sudbury Basin, Canada in 1883, in Norilsk-Talnakh, Russia in 1920, and in the Merensky Reef, South Africa in 1924 made large-scale production of nickel possible.

Nickel has been a component of coins since the mid-19th century.HP Pavilion DV4-1320TX Battery

In the United States, the term "nickel" or "nick" was originally applied to the copper-nickel Flying Eagle cent, which replaced copper with 12% nickel 1857–58, then the Indian Head cent of the same alloy from 1859–1864. Still later in 1865, the term designated the three-cent nickel, with nickel increased to 25%.HP Pavilion DV4-1321TX Battery

In 1866, the five-cent shield nickel (25% nickel, 75% copper) appropriated the designation. Along with the alloy proportion, this term has been used to the present in the United States. Coins of nearly pure nickel were first used in 1881 in Switzerland, and more notably 99.9% nickel five-cent coins were struck in Canada (the world's largest nickel producer at the time) during non-war years from 1922–1981, and their metal content made these coins magnetic.HP Pavilion DV4-1322TX Battery

During the wartime period 1942–45, more or all nickel was removed from Canadian and U.S. coins, due to nickel's war-critical use in armor. Canada switched alloys again to plated steel during the Korean war, but was forced to stop making pure nickel "nickels" in 1981, reserving the pure 99.9% nickel alloy after 1968 only to its higher-value coins.HP Pavilion DV4-1322US Battery

Finally, in the 21st century, with rising nickel prices, most countries that formerly used nickel in their coins have abandoned the metal for cost reasons, and the U.S. five-cent coin remains one of the few in which the metal is still used, save for exterior plating.HP Pavilion DV4-1323TX Battery

In 2005, Russia was the largest producer of nickel with about one-fifth world share closely followed by Canada, Australia, and Indonesia, as reported by the British Geological Survey. A nickel deposit in western Turkey had been exploited, with this location being especially convenient for European smelters, steelmakers, and factories.HP Pavilion DV4-1324TX Battery

The one locality in the United States where nickel was commercially mined isRiddle, Oregon, where several square miles of nickel-bearing garnierite surface deposits are located. The mine closed in 1987. The Eagle mine project is a proposed new nickel mine in Michigan's upper peninsula.HP Pavilion DV4-1325TX Battery

Extraction and purification

Nickel is recovered through extractive metallurgy. Nickel is extracted from its ores by conventional roasting and reduction processes that yield a metal of greater than 75% purity. In many stainless steel applications, 75% pure nickel can be used without further purification, depending on the composition of the impurities.HP Pavilion DV4-1326TX Battery

Most sulfide ores have traditionally been processed using pyrometallurgical techniques to produce a matte for further refining. Recent advances in hydrometallurgyhave resulted in significant nickel purification using these processes.HP Pavilion DV4-1327TX Battery

Most sulfide deposits have traditionally been processed by concentration through a froth flotation process followed by pyrometallurgical extraction. In hydrometallurgical processes, nickel sulfide ores undergo flotation (differential flotation if Ni/Fe ratio is too low) and then smelted.HP Pavilion DV4-1328TX Battery

After producing the nickel matte, further processing is done via the Sherritt-Gordon process. First, copper is removed by addinghydrogen sulfide, leaving a concentrate of only cobalt and nickel. Then, solvent extraction is used to separate the cobalt and nickel, with the final nickel concentration greater than 99%.HP Pavilion DV4-1329TX Battery

Electrorefining

A second common form of further refining involves the leaching of the metal matte into a nickel salt solution, followed by the electro-winning of the nickel from solution by plating it onto a cathode as electrolytic nickel.HP Pavilion DV4-1330TX Battery

Purification of nickel oxides to obtain the purest metal is performed via the Mond process, which increases the nickel concentrate to greater than 99.99% purity. This process was patented by L. Mond and has been in industrial use since before the beginning of the 20th century.HP Pavilion DV4-1331TX Battery

In the process, nickel is reacted with carbon monoxide at around 40–80 °C to formnickel carbonyl in the presence of a sulfur catalyst. Iron gives iron pentacarbonyl too, but this reaction is slow. If necessary, it may be separated by distillation. Dicobalt octacarbonyl is also formed in this process, but it decomposes to tetracobalt dodecacarbonyl at the reaction temperature to give a non-volatile solid.HP Pavilion DV4-1332TX Battery

Nickel is re-obtained from the nickel carbonyl by one of two processes. It may be passed through a large chamber at high temperatures in which tens of thousands of nickel spheres, called pellets, are constantly stirred. It then decomposes depositing pure nickel onto the nickel spheres.HP Pavilion DV4-1365DX Battery

Alternatively, the nickel carbonyl may be decomposed in a smaller chamber at 230 °C to create fine nickel powder. The resultant carbon monoxide is re-circulated and reused through the process. The highly pure nickel produced by this process is known as "carbonyl nickel."HP Pavilion DV4-1400 CTO Battery

Metal value

The market price of nickel surged throughout 2006 and the early months of 2007; as of April 5, 2007, the metal was trading at 52,300 USD/tonne or 1.47 USD/oz. The price subsequently fell dramatically from these peaks, and as of 19 January 2009 the metal was trading at 10,880 USD/tonne.HP Pavilion DV4-1404TX Battery

The US nickel coin contains 0.04 oz (1.25 g) of nickel, which at the April 2007 price was worth 6.5 cents, along with 3.75 grams of copper worth about 3 cents, making the metal value over 9 cents. Since the face value of a nickel is 5 cents, this made it an attractive target for melting by people wanting to sell the metals at a profit.HP Pavilion DV4-1405TX Battery

However, the United States Mint, in anticipation of this practice, implemented new interim rules on December 14, 2006, subject to public comment for 30 days, which criminalize the melting and export of cents and nickels. Violators can be punished with a fine of up to $10,000 and/or imprisoned for a maximum of five years.HP Pavilion DV4-1406TX Battery

As of September 16, 2011, the melt value of a U.S. nickel is $0.0600409, which is 20% higher than the face value.

Applications

The fraction of global nickel production presently used for various applications is as follows: 60% for making nickel steels; 14% in nickel-copper alloys and nickel silver;HP Pavilion DV4-1407TX Battery

9% to make malleable nickel, nickel clad, Inconel, and other superalloys; 6% in plating; 3% for nickel cast irons; 3% in heat and electric resistance alloys, such as Nichrome; 2% for nickel brasses and bronzes; 3% in all other applications combined.HP Pavilion DV4-1408TX Battery

Nickel is used in many specific and recognizable industrial and consumer products, including stainless steel, alnico magnets, coinage, rechargeable batteries, electric guitar strings, microphone capsules, and special alloys. It is also used for plating and as a green tint in glass.HP Pavilion DV4-1409TX Battery

Nickel is preeminently an alloy metal, and its chief use is in the nickel steels and nickel cast irons, of which there are many varieties. It is also widely used in many other alloys, such as nickel brasses and bronzes, and alloys with copper, chromium, aluminium, lead, cobalt, silver, and gold (Inconel, Incoloy, Monel, Nimonic).HP Pavilion DV4-1413LA Battery

Because of its resistance to corrosion, nickel has been occasionally used historically as a substitute for decorative silver. Nickel was also occasionally used in some countries after 1859 as a cheap coinage metal (see above) but beginning the later years of the 20th century has largely replaced by cheaper stainless steel (i.e., iron) alloys, except notably in the United States.HP Pavilion DV4-1414LA Battery

Nickel is an excellent alloying agent for certain other precious metals, and so used in the so-called fire assay, as a collector of platinum group elements (PGE). As such, nickel is capable of full collection of all 6 PGE elements from ores, in addition to partial collection of gold.HP Pavilion DV4-1416LA Battery

High-throughput nickel mines may also engage in PGE recovery (primarily platinum and palladium); examples are Norilsk in Russia and the Sudbury Basin in Canada.

Nickel foam or nickel mesh is used in gas diffusion electrodes for alkaline fuel cells.HP Pavilion DV4-1425LA Battery

Nickel and its alloys are frequently used as catalysts for hydrogenation reactions. Raney nickel, a finely-divided nickel-aluminium alloy, is one common form, however related catalysts are also often used, including related 'Raney-type' catalysts.HP Pavilion DV4T Battery

Nickel is a naturally magnetostrictive material, meaning that, in the presence of a magnetic field, the material undergoes a small change in length.[42] In the case of nickel, this change in length is negative (contraction of the material), which is known as negative magnetostriction and is on the order of 50 ppm.HP Pavilion DV4T-1000 CTO Battery

Nickel is used as a binder in the cemented tungsten carbide or hardmetal industry and used in proportions of six to 12% by weight. Nickel can make the tungsten carbide magnetic and adds corrosion-resistant properties to the cemented tungsten carbide parts, although the hardnesses are lower than those of parts made of the binder cobalt.HP Pavilion DV4T-1100 CTO Battery

Biological role

Although not recognized until the 1970s, nickel plays important roles in the biology of microorganisms and plants.[44] In fact,urease (an enzyme that assists in the hydrolysis of urea) contains nickel. The NiFe-hydrogenases contain nickel in addition toiron-sulfur clusters.HP Pavilion DV4T-1200 CTO Battery

Such [NiFe]-hydrogenases characteristically oxidise H2. A nickel-tetrapyrrole coenzyme, Cofactor F430, is present in the methyl coenzyme M reductase, which powers methanogenic archaea. One of the carbon monoxide dehydrogenase enzymes consists of an Fe-Ni-S cluster.HP Pavilion DV4T-1200SE CTO Battery

Other nickel-containing enzymes include a rare bacterial class of superoxide dismutase[46] and glyoxalase I enzymes in bacteria and several parasitic eukaryotic trypanosomal parasites  (this enzyme in higher organisms, including yeast and mammals, uses divalent zinc, Zn2+).HP Pavilion DV4T-1300 CTO Battery

Toxicity

Exposure to nickel metal and soluble compounds should not exceed 0.05 mg/cm³ in nickel equivalents per 40-hour work-week. Nickel sulfide fume and dust are believed to be carcinogenic, and various other nickel compounds may be as well.HP Pavilion DV4T-1300SE CTO Battery

Nickel carbonyl, [Ni(CO)4], is an extremely toxic gas. The toxicity of metal carbonyls is a function of both the toxicity of the metal as well as the carbonyl's ability to give off highly toxic carbon monoxide gas, and this one is no exception; nickel carbonyl is also explosive in air.HP Pavilion DV4T-1400 CTO Battery

Sensitized individuals may show an allergy to nickel, affecting their skin, also known as dermatitis. Sensitivity to nickel may also be present in patients with pompholyx. Nickel is an important cause of contact allergy, partly due to its use in jewellery intended for pierced ears.HP Pavilion DV4Z Battery

Nickel allergies affecting pierced ears are often marked by itchy, red skin. Many earrings are now made nickel-free due to this problem. The amount of nickel allowed in products that come into contact with human skin is regulated by the European Union. In 2002, researchers found amounts of nickel being emitted by 1 and 2 Euro coins far in excess of those standards.HP Pavilion DV4Z-1000 CTO Battery

This is believed to be due to a galvanic reaction.

It was voted Allergen of the Year in 2008 by the American Contact Dermatitis Society.HP Pavilion DV4Z-1100 CTO Battery

Reports also showed that both the nickel-induced activation of hypoxia-inducible factor (HIF-1) and the up-regulation of hypoxia-inducible genes are due to depleted intracellular ascorbate levels. HP Pavilion DV4Z-1200 CTO Battery

The addition of ascorbate to the culture medium increased the intracellular ascorbate level and reversed both the metal-induced stabilization of HIF-1- and HIF-1?-dependent gene expression.HP Pavilion DV4 Battery,HP Pavilion DV4-1000 Battery,HP Pavilion DV4-1000EA Battery,HP Pavilion DV4-1000ET Battery,HP Pavilion DV4-1001 Battery,HP Pavilion DV4-1001AX Battery,HP Pavilion DV4-1001TU Battery,HP Pavilion DV4-1001TX Battery

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