Smelting is a form of extractive metallurgy; its main use is to produce a metal from its ore. This includes iron extraction from iron ore, and copper extraction and other base metals from their ores. Smelting uses heat and a chemical reducing agent to change the oxidation state of the metal ore; the reducing agent is commonly a source of carbon such as coke, or in earlier times charcoal. The carbon or carbon monoxide derived from it removes oxygen from the ore to leave the metal. The carbon is thus oxidized in two stages, producing first carbon monoxide and then carbon dioxide. As most ores are impure, it is often necessary to use flux, such as limestone, to remove the accompanying rock gangue as slag.

Plants for the electrolytic reduction of aluminium are also generally referred to as smelters. These do not melt aluminum oxide but instead dissolve it in aluminum fluoride. They normally use carbon electrodes, and conversion of carbon to carbon dioxide provides an important part of deoxydation energy, rest of energy being provided by electricity, but novel smelter designs use electrodes that are not consumed in the process. The end product is molten aluminum.

Process

Smelting involves more than just "melting the metal out of its ore". Most ores are a chemical compound of the metal with other elements, such as oxygen (as an oxide), sulfur (as a sulfide) or carbon and oxygen together (as a carbonate). To produce the metal, these compounds have to undergo a chemical reaction. Smelting therefore consists of using suitable reducing substances that will combine with those oxidizing elements to free the metal.

Roasting

In the case of carbonates and sulfides, a process called "roasting" drives off the unwanted carbon or sulfur, leaving an oxide, which can be directly reduced. Roasting is usually carried out in an oxidizing environment. A few practical examples:

Malachite, a common ore of copper, is primarily copper carbonate (CuCO₃). This mineral undergoes thermal decomposition to CuO and CO₂ in several stages between 250°C and 350°C. The carbon dioxide is expelled into the atmosphere, leaving copper oxide which can be directly reduced to copper as shown below.

Galena, the most common mineral of lead, is primarily lead sulfide (PbS). The sulfide is oxidized to a sulfite (PbSO₃) which thermally decomposes into lead oxide and sulfur dioxide gas. (PbO and SO₂) The sulfur dioxide (like the carbon dioxide in the example above) is expelled, and the lead oxide is reduced as below.

Reduction

Reduction is the final, high-temperature step in smelting. It is here that the oxide becomes the elemental metal. A reducing environment, (often provided by carbon monoxide in an air-starved furnace) pulls the final oxygen atoms from the raw metal. The required temperature varies over a very large range, both in absolute terms, and in terms of the melting point of the base metal. A few examples:

iron oxide becomes metallic iron at roughly 1250°C, almost 300 degrees ''below'' iron's melting point of 1538°C

mercuric oxide becomes vaporous mercury near 550°C, almost 600 degrees ''above'' mercury's melting point of -38°C

Fluxes

Fluxes are used in smelting for several purposes, chief among them catalyzing the desired reactions and chemically binding to unwanted impurities or reaction products. Calcium oxide, in the form of lime, was often used for this purpose, since it could react with the carbon dioxide or sulfur dioxide produced during roasting and smelting to keep them out of the working environment.

History

Historically, the first smelting processes used carbon (in the form of charcoal) to reduce the oxides of tin (cassiterite, SnO₂), copper (cuprite, CuO) and lead (Lead(II) oxide, PbO), and eventually iron (hematite, Fe₂O₃) In all these reactions the reducing agent was actually carbon monoxide, as the charcoal and oxides remained solid and therefore could not react directly with each other. For copper and lead, important ores were actually the sulfides, chalcocite (CuS₂) and galena (PbS); these first had to be converted to oxides by roasting them in air

Silver was generally found in the form of sulfides mixed with galena; it was smelted together with lead and was afterwards separated from it by cupellation.

The primary source of mercury was the sulfide ore (cinnabar, HgS). This was roasted to produce the oxide HgO, which decomposed into oxygen and mercury, which both left the furnace as a (highly toxic) vapor, that was condensed in appropriate containers.

In the Old World, humans learned to smelt metals in prehistoric times, more than 8000 years ago. The discovery and use of the "useful" metals — copper and bronze at first, then iron a few millennia later — had an enormous impact on human society. The impact was so pervasive that scholars traditionally divide ancient history into Stone Age, Bronze Age, and Iron Age.

In the Americas, pre-Inca civilizations of the central Andes in Peru had mastered the smelting of copper and silver at least six centuries before the first Europeans arrived in the 16th century.

Tin and lead

In the Old World, the first metals smelted were tin and lead. The earliest known cast lead beads were found in the Çatal Höyük site in Anatolia (Turkey), and dated from about 6500 BC, but the metal may have been known earlier.

Since the discovery happened several millennia before the invention of writing, we have no evidence about how it was made. However, tin and lead can be smelted by placing the ores in a wood fire, so it is possible that the discovery may have occurred by accident.

Although lead is a common metal, its discovery had relatively little impact in the ancient world. It is too soft to be used for weapons (except possibly as sling projectiles) or for structural elements. However, being easy to cast and shape, it came to be extensively used in the classical world of Ancient Greece and Ancient Rome for piping and storage of water. It was also used as a mortar in stone buildings, and as a writing material for commemorative plaques and curses.

Tin was much less common than lead and is only marginally harder, and had even less impact by itself.

Copper and bronze

After tin and lead, the next metal to be smelted appears to have been copper. How the discovery came about is a matter of much debate. Campfires are about 200 °C short of the temperature needed for that, so it has been conjectured that the first smelting of copper may have been achieved in pottery kilns. The earliest known instances in Europe and the Near East were found in Iran, dated about 6000 BC. The first smelted copper artifact was thought to be a mace head found in Can Hasan, Turkey and dated to 5000 BC. However, this now appears to be hammered native copper. The earliest current evidence of copper smelting, dating from between 5500 BC and 5000 BC, has been found in Pločnik and Belovode, Serbia.

The development of copper smelting in the Andes, which is believed to have occurred independently of that in the Old World, may have occurred in the same way.

By combining copper with tin and/or arsenic in the right proportions one obtains bronze, an alloy which is significantly harder than copper. The first copper/arsenic bronzes date of 4200 BC from Asia Minor. The Inca bronze alloys were also of this type. Arsenic is often an impurity in copper ores, so the discovery could have been made by accident; but eventually arsenic-bearing minerals were intentionally added during smelting.

Copper/tin bronzes, harder and more durable, were developed around 1500 BC or 3200 BC,also in Asia Minor.

The discovery of copper smelting and bronze manufacture had a significant impact on the history of the Old World. The metal was hard enough to make weapons that were heavier, stronger, and more resistant to impact-related damage than their wood, bone, or stone equivalents. For several millennia, bronze was the material of choice for weapons such as swords, daggers, battle axes, and spear and arrow points, as well as protective gear such as shields, helmets, shin guards, and other body armor. Bronze also supplanted stone, wood, and organic materials in all sorts of tools and household utensils, such as chisels, saws, adzes, nails, blade shears, knives, sewing needles and pins, jugs, cooking pots and cauldrons, mirrors, horse harnesses, and much more. In turn, bronze tools brought about an increase in the quantity, quality, and complexity of manufactured products, from buildings to leather goods. Tin and copper also contributed to the establishment of trade networks spanning large areas of Europe and Asia, and had a major effect on the distribution of wealth among individuals and nations.

The process through which the smiths learned to produce copper/tin bronzes is once again a mystery. The first such bronzes were probably a lucky accident from tin contamination of copper ores, but by 2000 BC, we know that tin was being mined on purpose for the production of bronze. This is amazing, given that tin is a semi-rare metal, and even a rich cassiterite ore only has 5% tin. Also, it takes special skills (or special instruments) to find it and to locate the richer lodes. But, whatever steps were taken to learn about tin, these were fully understood by 2000 BC.

Early iron smelting

The earliest evidence to date for the bloomery smelting of iron is found at Tell Hammeh, Jordan (see also external link), and dates to 930 BC (C14 dating). However, based on the archaeological record of iron artifacts, it is clear that intentional reduction of iron metal from terrestrial ores (in the case of Hammeh a Haematite ore), must have started near the end of the Late Bronze Age (ca. 1600–1150 BC). Where and how iron smelting was discovered is widely debated, and remains uncertain due to the significant lack of production finds. Nevertheless, there is some consensus that iron technology originated in the Near East, perhaps in Eastern Anatolia.

In Ancient Egypt, somewhere between the Third Intermediate Period and 23rd Dynasty (ca. 1100–750 BC), there are indications of iron working. Significantly though, no evidence for the smelting of iron from ore has been attested to Egypt in any period. There is a further possibility of iron smelting and working in West Africa by 1200 BC. In addition, very early instances of carbon steel were found to be in production around 2000 years before the present in northwest Tanzania, based on complex preheating principles. These discoveries are significant for the history of metallurgy.

Most early processes in Europe and Africa involved smelting iron ore in a bloomery, where the temperature is kept low enough so that the iron does not melt. This produces a spongy mass of iron called a bloom, which then has to be consolidated with a hammer.

Later iron smelting

From the medieval period, the process of direct reduction in bloomeries began to be replaced by an indirect process. In this, a blast furnace was used to make pig iron, which then had to undergo a further process to make forgeable bar iron. Processes for the second stage include fining in a finery forge and, from the Industrial Revolution, puddling. However both processes are now obsolete, and wrought iron is now hardly made. Instead, mild steel is produced from a bessemer converter or by other means.

Base metals

thumb|[[Electric Smelting and Aluminum Company|Cowles Syndicate of Ohio in Stoke-upon-Trent England, late 1880s. British Aluminium used the process of Paul Héroult about this time.]]

The ores of base metals are often sulfides. In recent centuries, reverberatory smelters (sometimes called cupolas) have been used. These keep the fuel and the charge being smelted separate. Traditionally these were used for carrying out the first step: formation of two liquids, one an oxide slag containing most of the impurity elements, and the other a sulfide matte containing the valuable metal sulfide and some impurities. Such "reverb" furnaces are today about 40 m long, 3 m high and 10 m wide. Fuel is burned at one end and the heat melts the dry sulfide concentrates (usually after partial roasting), which is fed through the openings in the roof of the furnace. The slag floats on top of the heavier matte, and is removed and discarded or recycled. The sulfide matte is then sent to the converter. However the precise details of the process will vary for one metal to another.

See also

Aluminium smelting

Cast iron

Clinker

Metallurgy

Pyrometallurgy

Wrought iron

Zinc smelting

References

Bibliography

External links

Category:Dutch loanwords Category:Metallurgy Category:Metallurgical processes Category:Steelmaking

de:Verhüttung fr:Fusion des métaux he:היתוך (מתכת) ja:製錬 no:Smelteverk pt:Smelter sv:Smältverk uk:Плавка

Sofi Marinova (born 1975) (Bulgarian: Софи Маринова) is a chalga singer from Bulgaria.

Her boyfriend as of 2010 is "Dacho", who appeared on the third season of VIP Brother in Bulgaria.

Albums

Edinstven moi/Only Mine (1997)

Moiat sun/My Dream (1998)

Studen Plamak/Cold Fire (1999)

Nejna e noshta/The Night is Gently (2000)

Osudena liubov/Judged Love (2002)

5 oktavi liubov/5 Octaves of Love (2004)

Hitove/Hits (2005)

Obicham/I love (2005)

Ostani/Stay (2006)

Vreme spri/Time stop (2008)

VIP (2009)

References

Category:1975 births Category:Living people Category:Bulgarian female singers Category:Bulgarian pop singers

bg:Софи Маринова es:Sofi Marinova ja:ソフィ・マリノヴァ rmy:Sofi Marinova sr:Софи Маринова

.

Coordinates	39°44′21″N104°59′5″N
name	Stanislav Trifonov
pseudonym	Slavi Trifonov
birth name	Stanislav Todorov Trifonov
birth date	October 18, 1966
birth place	Pleven, Bulgaria
medium	singer, producer, presenter, showman, actor
nationality	Bulgarian
genre	Comedia, Talk show, Variety show
website	Official website
active	1990–present
notable work	Slavi's Show, Ku-ku, Canaletto, Outcasts

Stanislav Todorov Trifonov () (born 18 October 1966), known as Slavi Trifonov (), is a Bulgarian showman, actor, singer and viola player born in Pleven (Bulgarian: Плевен). Trifonov's music genres are pop-folk, pop-rock and punk, but he has experimented with other genres as a part of Ku-ku Band ().

He is the host of Slavi's Show, bTV's late-night talk show. It is styled after the standard U.S. late-night talk shows. Nevertheless, many topics and elements in the show's setup are aimed at providing a specific Bulgarian flavor.

Main script-writers of the Slavi show are Ivailo Vulchev, Ivo Siromahov, Toshko Iordanov, Dragomir Petrov, Kalinka Todorova.

Trifonov is a professionally trained violist. In the early 1990s, together with several of his classmates at NATFIZ, he created Ku-Ku. In 1996, as a cast member of Kanaleto, he took an active role in the protests that eventually led to the fall of the socialist government. He is both loved and hated in his home country. His current show is one of the most watched, although he is often criticized for his controversial humor. The concept of "Slavi's Show" has changed significantly over the years. Originally, it was based on the classic formula - half of the show he performed a type of "one-man show" (though not exactly - Trifonov was often accompanied by other actors and his Ku-Ku Band) and in the other half Trifonov introduced a guest. At one point, the show became an arena for political debates before some important elections. Later on, Trifonov and his team changed the concept and made the show more music-focused. He held a contest called "I sing in KuKu Band" in order to choose a singer for the band. Every phase of the contest was aired. The contestants had to deal with difficult singing tasks. Finally, because of the growing popularity of the contestants, Trifonov decided to continue the contest, turning it into a show. He chose the five most popular contestants (Lora, Liubena, Nadia, Svetlio, Vlado) and let them compete for the grand prize - the winner would have the chance to record an album and to have his or her own show. Meanwhile Trifonov participated in the competition Eurovision - Bulgaria. There he triggered a major scandal by stating that the winner was known in advance and the competition was not fair.

Trifonov has had a long running feud with Ivan Kostov, which started due to him thinking that Ivan Kostov, who at the time was Bulgaria's prime minister was the one who took ''Hushove'' off the air, this is untrue.

In 2005, Trifonov steered his show in a different direction. This time, the famous comedians Krasi Radkov, Liubomir Neikov and Viktor Kalev riveted the attention of thousаnds of viewers. Later, Nikolay Stanoev joined the team of actors after being picked by Trifonov himself after another contest, but left the show. In 2006, Liubomir Neikov left Slavi Show and joined Komitzite and on his place Slavi Trifonov hired a new comedian actress - Maia Bezhanska, who later also left the show.

In 2006 Trifonov started a new reality show "Dance with me" and in 2008 he recorded the song "My Love" featured on the Bulgarian edition of Ruslana's international album Wild Energy.

External links

Official website of Slavi Trifonov's show

A fansite

Category:1966 births Category:Living people Category:Bulgarian television actors Category:Bulgarian male singers Category:Pop folk singers Category:Idol series judges Category:People from Pleven

bg:Слави Трифонов de:Slawi Trifonow es:Slavi Trifonov ja:スラヴィ・トリフォノフ

Coordinates	39°44′21″N104°59′5″N
{{infobox person|name	Anthony Lewis
Birth date	March 27, 1927
Alma mater	Harvard College
Occupation	Journalist
Nationality	United States
Religion	Jewish
Spouse	Margaret H. Marshall }}

Anthony Lewis (born March 27, 1927, New York City) is a prominent liberal intellectual, writing for ''The New York Times'' op-ed page and ''The New York Review of Books'', among other publications. He was previously a columnist for the ''Times'' (1969–2001). Before that he was London bureau chief (1965–1972), Washington, D.C. bureau (1955–64), and deskman (1948–1952) all for the ''Times''. From 1952-55 he worked for the Democratic National Committee and the ''Washington Daily News''.

His first Pulitzer Prize was in 1955, during the period of McCarthyism, for reporting on the U.S. government's loyalty program; he reported specifically on the dismissal of Abraham Chasanow, a US Navy employee who was not informed of the nature of the accusations against him, nor of his accusers. Lewis's articles led to the employee's reinstatement. This story was fictionalized in the movie ''Three Brave Men'' starring Ernest Borgnine and Ray Milland. He won a second Pulitzer Prize in 1963 for his coverage of the United States Supreme Court. He has frequently written on the Court and matters of constitutional law.

Lewis has taught at Columbia University's Graduate School of Journalism since the mid-'70s, and has held the school's James Madison chair in First Amendment Issues since 1982. He lectured at Harvard from 1974 to 1989 and has been a visiting lecturer at several other colleges and universities, including the Universities of Arizona, California, Illinois, and Oregon.

Anthony Lewis was born in New York City; he attended the Horace Mann School in New York (where one of his classmates was Roy Cohn) and Harvard College, where he earned a A.B. in 1948. While at Harvard, he was an editor of the ''Harvard Crimson''. He is on the board of directors of the Committee to Protect Journalists.

In 1983, Lewis received the Elijah Parish Lovejoy Award as well as an honorary Doctor of Laws degree from Colby College. On January 8, 2001, he was presented with the Presidential Citizens Medal by President Clinton. On October 21, 2008, Lewis was honored by the National Coalition Against Censorship for his work in the area of First Amendment rights and free expression.

Noam Chomsky has said that Anthony Lewis is at "the far left of the spectrum" that is available in the mainstream media, and thus is useful in discovering the tacit assumptions that underlie all mainstream discussion. Henry Kissinger reportedly once said that Anthony Lewis is "always wrong", which Lewis attributed to his own open dislike of Kissinger.

He is Jewish and married to retired Chief Justice Margaret H. Marshall of the Supreme Judicial Court of Massachusetts, who was formerly the General Counsel and Vice-President at Harvard University. He has three children from his first marriage, Eliza, David, and Mia, and seven grandchildren: Zoe, Miranda, Lily, Thea, Evie, Beatrice and Jack.

Lewis and his wife are longtime residents of Cambridge, Massachusetts.

Quotations

"What future possibility could be more terrible than the reality of what is happening to Cambodia now?" -March 17, 1975

Reagan used “sectarian religiosity to sell a political program”…the “evil empire” speech was “primitive”…“a mirror image of crude Soviet rhetoric”… “What is the world to think when the greatest of powers is led by a man who applies to the most difficult human problem a simplistic theology?” -March 10, 1983

Books

Sole or primary author

''Gideon's Trumpet'' (Random House, 1964) - the story behind ''Gideon v. Wainwright'' (Reprint ISBN 0-679-72312-9)

* 1965 Edgar Award for Best Fact Crime book

* made into a film of the same name for the Hallmark Hall of Fame

''Portrait of a Decade: The Second American Revolution'' (Random House, 1964) (ISBN 0-394-44412-4)

''Make No Law: The Sullivan Case and the First Amendment'' ( Random House, 1991) The story behind New York Times v. Sullivan (ISBN 0-394-58774-X) (PB ed by Vintage)

''The Supreme Court and How It Works: The Story of the Gideon Case'' (Random House Children's Books, 1966) (ISBN 0-394-91861-4)

''Freedom for the Thought that we Hate: A Biography of the First Amendment'' (Basic Books, January 2008) (ISBN 0465039170)

Editor

''Written into History: Pulitzer Prize Reporting of the Twentieth Century from The New York Times'' (Holt, 2001) (ISBN 0-8050-6849-X)

Co-author or contributor

''In Time of War: Hitler's Terrorist Attack on America'' by Pierce O'Donnell and Anthony Lewis. (New Press, 2005) (ISBN 1-56584-958-2)

''Glory and Terror: The Growing Nuclear Danger'' by Steven Weinberg; preface by Anthony Lewis (New York Review Books, 2004) (ISBN 1-59017-130-6)

''The Other Israel: Voices of Refusal and Dissent'' by Tom Segev (Editor), Roane Carey (Editor), Jonathan Shainin (Introduction), and Anthony Lewis (Introduction) (New Press, 2004) (ISBN 1-56584-914-0)

''The Torture Papers: The Road to Abu Ghraib'' by Karen J. Greenberg (Editor), Joshua L. Dratel (Editor), and Anthony Lewis (Introduction) (Cambridge University Press, 2005) (ISBN 0-521-85324-9)

''The Myth of the Imperial Judiciary: Why the Right Is Wrong About the Courts'' by Mark Kozlowski Foreword by Anthony Lewis. (New York University Press, 2003) (ISBN 0-8147-4775-2)

''Irreparable Harm: A Firsthand Account of How One Agent Took on the CIA in an Epic Battle Over Free Speech'' by Frank Snepp and Anthony Lewis (University Press of Kansas, 2001) (ISBN 0-7006-1091-X) The story of CIA v. Snepp

Online articles by Lewis

One Liberty at a Time (''Mother Jones'', May/June 2004)

the Framers, the 1st Amendment and watchdog reporting

"Heroic" News media?

The Justices Take on the President

Sources

The White House - ''President Clinton Awards the Presidential Citizens Medals - Monday, January 8, 2001''

References

External links

New York Review of Books

Reporting Civil Rights

Fairness.com profile

Columbia faculty profile

Nieman Watchdog profile

John S Knight fellowship at Stanford

Lewis discusses why the Supreme Court’s overturning of the decision in ''The New York Times v. Sullivan'' case—the focus of his 1992 Make No Law—was a blow to those in the south who wished to overlook the first amendment and silence the national press’ coverage of the Civil Rights Movement

NYT bio

Middle East Warp: The Pathology of Anthony Lewis 1992 article by Andrea Levin highly critical of Lewis

links to various online articles mentioning Lewis

Front list--books by Lewis

Anthony Lewis discusses press issues with Ron Collins at Harvard University A transcript of that interview can be found here.

Anthony Lewis: bibliography of articles, columns, scholarly works and books on the First Amendment

Category:1927 births Category:Living people Category:American legal writers Category:American Jews Category:Pulitzer Prize for National Reporting winners Category:Edgar Award winners Category:Columbia University faculty Category:The Harvard Crimson people Category:University of Arizona faculty Category:Horace Mann School alumni Category:People from New York City Category:The New York Times columnists Category:Presidential Citizens Medal recipients

de:Anthony Lewis