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68-625: Traces of human presence in the area date back to the Chalcolithic era, c. 4,500 to 3,700 years ago. There are no remains of permanent settlements before the Iron Age (900-300 BC), but by Roman times, there were 15 settlements in the area. These were concentrated near the Cidacos River in El Busquil, La Pedrera, La Recueja, Los Cascajos, and El Escal. At Lobera, a funeral tombstone was found inscribed with

136-553: A Bessemer converter or by other means including smelting reduction processes such as the Corex Process . Smelting has serious effects on the environment , producing wastewater and slag and releasing such toxic metals as copper , silver, iron, cobalt , and selenium into the atmosphere. Smelters also release gaseous sulfur dioxide , contributing to acid rain , which acidifies soil and water. The smelter in Flin Flon, Canada

204-400: A blast furnace to produce pig iron , which is converted into steel . Plants for the electrolytic reduction of aluminium are referred to as aluminium smelters . Smelting involves more than just melting the metal out of its ore. Most ores are the chemical compound of the metal and other elements, such as oxygen (as an oxide ), sulfur (as a sulfide ), or carbon and oxygen together (as

272-405: A carbonate ). To extract the metal, workers must make these compounds undergo a chemical reaction . Smelting, therefore, consists of using suitable reducing substances that combine with those oxidizing elements to free the metal. In the case of sulfides and carbonates, a process called " roasting " removes the unwanted carbon or sulfur, leaving an oxide, which can be directly reduced. Roasting

340-568: A transitional Copper Age and the Bronze Age proper . He did not include the transitional period in the Bronze Age, but described it separately from the customary stone / bronze / iron system, at the Bronze Age's beginning. He did not, however, present it as a fourth age but chose to retain the tripartite system . In 1884, Gaetano Chierici , perhaps following the lead of Evans, renamed it in Italian as

408-429: A chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving the metal behind. The reducing agent is commonly a fossil-fuel source of carbon , such as carbon monoxide from incomplete combustion of coke —or, in earlier times, of charcoal . The oxygen in the ore binds to carbon at high temperatures, as the chemical potential energy of the bonds in carbon dioxide (CO 2 )

476-424: A hammer to produce wrought iron . Some of the earliest evidence to date for the bloomery smelting of iron is found at Tell Hammeh , Jordan, radiocarbon-dated to c.  930 BC . From the medieval period, an indirect process began to replace the direct reduction in bloomeries. This used a blast furnace to make pig iron , which then had to undergo a further process to make forgeable bar iron. Processes for

544-686: A low concentration of sulfur dioxide that was difficult to capture; a new generation of copper smelting technologies has supplanted them. More recent furnaces exploit bath smelting, top-jetting lance smelting, flash smelting , and blast furnaces. Some examples of bath smelters include the Noranda furnace, the Isasmelt furnace, the Teniente reactor, the Vunyukov smelter, and the SKS technology. Top-jetting lance smelters include

612-481: A range of more complex organic compounds known collectively as polycyclic aromatic hydrocarbons (PAH). Treatment technologies include recycling of wastewater; settling basins , clarifiers and filtration systems for solids removal; oil skimmers and filtration; chemical precipitation and filtration for dissolved metals; carbon adsorption and biological oxidation for organic pollutants; and evaporation. Pollutants generated by other types of smelters varies with

680-665: A seat in the Cortes among the "Good Towns," and declared the Tafallese free men. In the Civil War of Navarre, Tafalla first sided with the Beaumont confederacy, defending the rights of Carlos, Prince of Viana . After the Castilian-Aragonese invasion , Tafalla defended the legitimate kings of Navarre against the invaders. Felipe IV granted Tafalla the title of city in the year 1636. During

748-434: A secondary service after the reduction step is complete; they provide a molten cover on the purified metal, preventing contact with oxygen while still hot enough to readily oxidize. This prevents impurities from forming in the metal. The ores of base metals are often sulfides. In recent centuries, reverberatory furnaces have been used to keep the charge being smelted separately from the fuel. Traditionally, they were used for

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816-569: A single source. Knowledge of the use of copper was far more widespread than the metal itself. The European Battle Axe culture used stone axes modeled on copper axes, even with moulding carved in the stone. Ötzi the Iceman , who was found in the Ötztal Alps in 1991 and whose remains have been dated to about 3300 BC, was found with a Mondsee copper axe. Examples of Chalcolithic cultures in Europe include Vila Nova de São Pedro and Los Millares on

884-944: Is a Chalcolithic site in the eastern part of the Indian subcontinent . It is located on the south bank of Ajay River in West Bengal . Blackware , painted Koshi ware, pottery, various ornaments made of pearl and copper, various types of tools, pieces of fabric woven from Shimul cotton thread, human and various animal skeletons, burnt clay fragments have been found at the site. In March 2018, archaeologists had discovered three carts and copper artifacts including weapons dating to 1800 BC in Sanauli village of Uttar Pradesh. The artifacts belongs to Ochre Coloured Pottery culture . Andean civilizations in South America appear to have independently invented copper smelting. The term "Chalcolithic"

952-605: Is also applied to American civilizations that already used copper and copper alloys thousands of years before Europeans immigrated. Besides cultures in the Andes and Mesoamerica, the Old Copper complex mined and fabricated copper as tools, weapons, and personal ornaments in an area centered in the upper Great Lakes region (present-day Michigan and Wisconsin ). The evidence of smelting or alloying that has been found in North America

1020-479: Is also documented at the nearby site of Tell Maghzaliyah , which seems to be dated even earlier, and completely lacks pottery. The Timna Valley contains evidence of copper mining in 7000–5000 BC. The process of transition from Neolithic to Chalcolithic in the Middle East is characterized in archaeological stone tool assemblages by a decline in high quality raw material procurement and use. This dramatic shift

1088-605: Is doubtful; a lead bracelet, found in level XII of Yarim Tepe I, dated to the 6th millennium BC; a small cone-shaped piece of lead, found in the "Burnt House" in TT6 at Arpachiyah , dated to the Halaf period or slightly later than the Yarim Tepe bracelet; and more. Copper smelting is also documented at this site at about the same time period (soon after 6000 BC). However, the use of lead seems to precede copper smelting. Early metallurgy

1156-537: Is easily produced during the heating process, and as a gas comes into intimate contact with the ore. 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

1224-409: Is lower than that of the bonds in the ore. Sulfide ores such as those commonly used to obtain copper, zinc or lead, are roasted before smelting in order to convert the sulfides to oxides, which are more readily reduced to the metal. Roasting heats the ore in the presence of oxygen from air, oxidizing the ore and liberating the sulfur as sulfur dioxide gas. Smelting most prominently takes place in

1292-455: Is not another -lithic age. Subsequently, British scholars used either Evans's "Copper Age" or the term "Eneolithic" (or Æneolithic), a translation of Chierici's eneo-litica . After several years, a number of complaints appeared in the literature that "Eneolithic" seemed to the untrained eye to be produced from e-neolithic , "outside the Neolithic", clearly not a definitive characterization of

1360-408: Is occasionally found in commercially significant quantities. These minerals are primarily carbonates , sulfides , or oxides of the metal, mixed with other components such as silica and alumina . Roasting the carbonate and sulfide minerals in the air converts them to oxides. The oxides, in turn, are smelted into the metal. Carbon monoxide was (and is) the reducing agent of choice for smelting. It

1428-582: Is only marginally harder, and had even less impact by itself. The earliest evidence for iron-making is a small number of iron fragments with the appropriate amounts of carbon admixture found in the Proto-Hittite layers at Kaman-Kalehöyük and dated to 2200–2000 BC. Souckova-Siegolová (2001) shows that iron implements were made in Central Anatolia in very limited quantities around 1800 BC and were in general use by elites, though not by commoners, during

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1496-456: Is seen throughout the region, including the Tehran Plain , Iran. Here, analysis of six archaeological sites determined a marked downward trend in not only material quality, but also in aesthetic variation in the lithic artefacts. Fazeli & Coningham use these results as evidence of the loss of craft specialisation caused by increased use of copper tools. The Tehran Plain findings illustrate

1564-427: Is subject to some dispute and a common assumption by archaeologists is that objects were cold-worked into shape. Artifacts from some of these sites have been dated to 6500–1000 BC, making them some of the oldest Chalcolithic sites in the world. Some archaeologists find artifactual and structural evidence of casting by Hopewellian and Mississippian peoples to be demonstrated in the archaeological record. In

1632-562: Is unknown. The first such bronzes may have been a lucky accident from tin-contaminated copper ores. However, by 2000 BC, people were mining tin on purpose to produce bronze—which is remarkable as tin is a semi-rare metal, and even a rich cassiterite ore only has 5% tin. The discovery of copper and bronze manufacture had a significant impact on the history of the Old World . Metals were hard enough to make weapons that were heavier, stronger, and more resistant to impact damage than wood, bone, or stone equivalents. For several millennia, bronze

1700-423: Is usually carried out in an oxidizing environment. A few practical examples: Reduction is the final, high-temperature step in smelting, in which the oxide becomes the elemental metal. A reducing environment (often provided by carbon monoxide, made by incomplete combustion in an air-starved furnace) pulls the final oxygen atoms from the raw metal. The carbon source acts as a chemical reactant to remove oxygen from

1768-508: 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, while never mastering the smelting of metals such as iron for use with weapon craft. Copper was the first metal to be smelted. How the discovery came about is debated. Campfires are about 200 °C short of

1836-619: The Copper Age and Eneolithic ) was an archaeological period characterized by the increasing use of smelted copper . It followed the Neolithic and preceded the Bronze Age . It occurred at different periods in different areas, but was absent in some parts of the world, such as Russia, where there was no well-defined Copper Age between the Stone and Bronze Ages. Stone tools were still predominantly used during this period. The Chalcolithic covers both

1904-539: The Iberian Peninsula . Pottery of the Beaker people has been found at both sites, dating to several centuries after copper-working began there. The Beaker culture appears to have spread copper and bronze technologies in Europe, along with Indo-European languages. In Britain, copper was used between the 25th and 22nd centuries BC , but some archaeologists do not recognise a British Chalcolithic because production and use

1972-593: The New Hittite Empire (~1400–1200 BC). Archaeologists have found indications of iron working in Ancient Egypt , somewhere between the Third Intermediate Period and 23rd Dynasty (ca. 1100–750 BC). Significantly though, they have found no evidence of iron ore smelting in any (pre-modern) period. In addition, very early instances of carbon steel were in production around 2000 years ago (around

2040-536: The Stone Age despite the use of copper. Today, Copper Age , Eneolithic , and Chalcolithic are used synonymously to mean Evans's original definition of Copper Age. The emergence of metallurgy may have occurred first in the Fertile Crescent . Lead may have been the first ore that humans smelted , since it can be easily obtained by heating galena . Possible early examples of lead smelting, supported by

2108-507: The eneo-litica , or "bronze–stone" transition. The phrase was never intended to mean that the period was the only one in which both bronze and stone were used. The Copper Age features the use of copper, excluding bronze; moreover, stone continued to be used throughout both the Bronze Age and the Iron Age . The part -litica simply names the Stone Age as the point from which the transition began and

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2176-631: The 1870s, when, on the basis of the significant number of large copper objects unearthed within the Carpathian Basin , he suggested that the previous threefold division of the Prehistoric Age – the Stone , Bronze and Iron Ages – should be further divided with the introduction of the Copper Age. In 1881, John Evans recognized that use of copper often preceded the use of bronze, and distinguished between

2244-648: The 5th millennium BC copper artifacts start to appear in East Asia, such as in the Jiangzhai and Hongshan cultures , but those metal artifacts were not widely used during this early stage. Copper manufacturing gradually appeared in the Yangshao period (5000–3000 BC). Jiangzhai is the only site where copper artifacts were found in the Banpo culture. Archaeologists have found remains of copper metallurgy in various cultures from

2312-602: The Congosto dam failed, and again in 1886. During the 19th century the city was provided with modern urban services, including public lighting with oil lanterns (1843), construction of the railway that connects Pamplona and the Ebro (1860), and in 1866 a bridge across the Zidacos river to link the station with the city. Two schools were established in the 1880s: the College of PP Piarists (1883) and

2380-497: The Copper Age. Around 1900, many writers began to substitute Chalcolithic for Eneolithic, to avoid the false segmentation. The term chalcolithic is a combination of two words- Chalco+Lithic, derived from the Greek words "khalkos" meaning "copper", and "líthos" meaning "stone". But "chalcolithic" could also mislead: For readers unfamiliar with the Italian language, chalcolithic seemed to suggest another -lithic age, paradoxically part of

2448-536: The Mitsubishi smelting reactor. Flash smelters account for over 50% of the world's copper smelters. There are many more varieties of smelting processes, including the Kivset, Ausmelt, Tamano, EAF, and BF. Of the seven metals known in antiquity , only gold regularly occurs in nature as a native metal . The others – copper , lead , silver , tin , iron , and mercury – occur primarily as minerals, although native copper

2516-910: The San José School of the Daughters of the Cross (1888). The lighting system was electrified in 1895. In 1909, the Gorriti Theater opened, followed by the Spanish Casino (1922). Tafalla was in the news in 2010, after a bull jumped into the stands at the bullring, during a bull-fighting contest. In July 2019, Tafalla was hit by damaging flash floods following torrential rain. Chalcolithic West Asia (6000–3500 BC) Europe (5500–2200 BC) Central Asia (3700–1700 BC) South Asia (4300–1800 BC) China (5000–2900 BC) The Chalcolithic ( /ˈkælkoʊˌlɪθɪk/ cal-co- LI -thik ) (also called

2584-521: The War of Independence, the city was of strategic importance due to its proximity to Pamplona . Tafalla was occupied by the French in 1808, who turned it into a barracks. In 1812 Espoz y Mina retook the city, but in the battle the convent of San Francisco and the fifteenth century Palace were destroyed. The remains were demolished to build the current Plaza de Navarra in 1856. Tafalla suffered major floods in 1833 when

2652-418: The ancient world. It is too soft to use for structural elements or weapons, though its high density relative to other metals makes it ideal for sling projectiles. However, since it was easy to cast and shape, workers in the classical world of Ancient Greece and Ancient Rome used it extensively to pipe and store water. They also used it as a mortar in stone buildings. Tin was much less common than lead,

2720-461: The base metal ore. For example, aluminum smelters typically generate fluoride , benzo(a)pyrene , antimony and nickel, as well as aluminum. Copper smelters typically discharge cadmium, lead, zinc , arsenic and nickel, in addition to copper. Lead smelters may discharge antimony , asbestos, cadmium, copper and zinc, in addition to lead. Labourers working in the smelting industry have reported respiratory illnesses inhibiting their ability to perform

2788-408: The discovery happened several millennia before the invention of writing, there is no written record of how it was made. However, tin and lead can be smelted by placing the ores in a wood fire, leaving the possibility that the discovery may have occurred by accident. Recent scholarship however has called this find into question. Lead is a common metal, but its discovery had relatively little impact in

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2856-525: The early cold working (hammering) of near pure copper ores, as exhibited by the likes of North American Great Lakes Old Copper complex , from around 6,500 BC, through the later copper smelting cultures. The archaeological site of Belovode, on Rudnik mountain in Serbia , has the world's oldest securely dated evidence of copper smelting at high temperature, from c.  5,000 BC . The transition from Copper Age to Bronze Age in Europe occurred between

2924-520: The effects of the introduction of copper working technologies on the in-place systems of lithic craft specialists and raw materials. Networks of exchange and specialized processing and production that had evolved during the Neolithic seem to have collapsed by the Middle Chalcolithic ( c.  4500–3500 BC ) and been replaced by the use of local materials by a primarily household-based production of stone tools. Arsenical copper or bronze

2992-508: The establishment of trade networks that spanned large areas of Europe and Asia and had a major effect on the distribution of wealth among individuals and nations. The earliest known cast lead beads were thought to be in the Çatalhöyük site in Anatolia ( Turkey ), and dated from about 6500 BC. However, recent research has discovered that this was not lead, but rather cerussite and galena, minerals rich in, but distinct from, lead. Since

3060-801: The existence of a few exotic black-slipped pottery items from the Indus Valley . In India, Chalcolithic culture flourished in mainly four farming communities – Ahar or Banas , Kayatha , Malwa , and Jorwe . These communities had some common traits like painted pottery and use of copper, but they had a distinct ceramic design tradition. Banas culture (2000–1600 BC) had ceramics with red, white, and black design. Kayatha culture (2450–1700 BC) had ceramics painted with brown colored design. Malwa culture (1900–1400 BC) had profusely decorated pottery with red or black colored design. Jorwe culture (1500–900 BC) had ceramics with matte surface and black-on-red design. Pandu Rajar Dhibi (2000–1600 BC)

3128-417: The extreme rarity of native lead, include: lead beads , found on Level IX of Chatal/Çatal Hüyük in central Anatolia , though they might be made of galena, cerussite , or metallic lead, and accordingly might or might not be evidence of early smelting; a lead bead, found in a GK59 group test square in the 4th level of Jarmo , dated to the 7th millennium BCE, though it is small enough that its human usage

3196-577: The fields of Torreta and Barranquiel. After this, the Tafallese were granted the titles of Noble, Loyal and Strong. Sancho Ramírez granted Tafalla its first charter, later confirmed by Sancho the Wise in 1157 and Theobald II in 1255. Sancho VII the Strong granted another charter to the Tafallese, freeing them of taxes. In 1418, Carlos III the Noble granted the privilege of holding a fair, and in 1423 he granted Tafalla

3264-429: The first step of smelting: forming two liquids, one an oxide slag containing most of the impurities, and the other a sulfide matte containing the valuable metal sulfide and some impurities. Such "reverb" furnaces are today about 40 meters long, 3 meters high, and 10 meters wide. Fuel is burned at one end to melt the dry sulfide concentrates (usually after partial roasting) which are fed through openings in

3332-401: The first-century .) 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 must be consolidated with

3400-697: The late 5th and the late 3rd millennium BC . In the Ancient Near East the Copper Age covered about the same period, beginning in the late 5th millennium BC and lasting for about a millennium before it gave rise to the Early Bronze Age . A study in the journal Antiquity from 2013 reporting the discovery of a tin bronze foil from the Pločnik archaeological site dated to c.  4,650 BC , as well as 14 other artefacts from Bulgaria and Serbia dated to before 4,000 BC, showed that early tin bronze

3468-674: The late fourth to the early third millennia BC. These include the copper-smelting remains and copper artifacts of the Hongshan culture (4700–2900) and copper slag at the Yuanwozhen site. This indicates that inhabitants of the Yellow River valley had already learned how to make copper artifacts by the later Yangshao period. In the region of the Aïr Mountains , Niger, independent copper smelting developed between 3000 and 2500 BC. The process

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3536-559: The name of Thurscando. This tombstone is now in the House of Culture of Tafalla. The first historical mention of Tafalla dates from the tenth century in the Chronicle of Arib Ibn Said, which recounts a raid on Tafalla by Abd al-Rahman III during a campaign against the Kingdom of Pamplona , in the year 924. In 1043, the Tafallese helped King García III de Nájera defeat Ramiro I of Aragón in a battle on

3604-716: The oldest evidence, now appears to be hammered, native copper. Combining copper with tin and/or arsenic in the right proportions produces bronze , an alloy that is significantly harder than copper. The first copper/arsenic bronzes date from 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. Eventually, arsenic-bearing minerals were intentionally added during smelting. Copper–tin bronzes, harder and more durable, were developed around 3500 BC, also in Asia Minor. How smiths learned to produce copper/tin bronzes

3672-464: The ore during smelting to catalyze the desired reactions and to chemically bind to unwanted impurities or reaction products. Calcium carbonate or calcium oxide in the form of lime are often used for this purpose, since they react with sulfur, phosphorus, and silicon impurities to allow them to be readily separated and discarded, in the form of slag. Fluxes may also serve to control the viscosity and neutralize unwanted acids. Flux and slag can provide

3740-400: The ore, yielding the purified metal element as a product. The carbon source is oxidized in two stages. First, carbon (C) combusts with oxygen (O 2 ) in the air to produce carbon monoxide (CO). Second, the carbon monoxide reacts with the ore (e.g. Fe 2 O 3 ) and removes one of its oxygen atoms, releasing carbon dioxide (CO 2 ). After successive interactions with carbon monoxide, all of

3808-431: The oxygen in the ore will be removed, leaving the raw metal element (e.g. Fe). As most ores are impure, it is often necessary to use flux , such as limestone (or dolomite ), to remove the accompanying rock gangue as slag. This calcination reaction emits carbon dioxide. The required temperature varies both in absolute terms and in terms of the melting point of the base metal. Examples: Fluxes are materials added to

3876-430: The period. Originally, the term Bronze Age meant that either copper or bronze was being used as the chief hard substance for the manufacture of tools and weapons. Ancient writers, who provided the essential cultural references for educated people during the 19th century, used the same name for both copper- and bronze-using ages. The concept of the Copper Age was put forward by Hungarian scientist Ferenc Pulszky in

3944-401: The roof of the furnace. The slag floats over the heavier matte and is removed and discarded or recycled. The sulfide matte is then sent to the converter . The precise details of the process vary from one furnace to another depending on the mineralogy of the ore body. While reverberatory furnaces produced slags containing very little copper, they were relatively energy inefficient and off-gassed

4012-565: The second stage include fining in a finery forge . In the 13th century during the High Middle Ages the blast furnace was introduced by China who had been using it since as early as 200 b.c during the Qin dynasty . [1] Puddling was also introduced in the Industrial Revolution . Both processes are now obsolete, and wrought iron is now rarely made. Instead, mild steel is produced from

4080-546: The temperature needed, so some propose that the first smelting of copper may have occurred in pottery kilns . (The development of copper smelting in the Andes, which is believed to have occurred independently of the Old World , may have occurred in the same way. ) The earliest current evidence of copper smelting, dating from between 5500 BC and 5000 BC, has been found in Pločnik and Belovode, Serbia. A mace head found in Turkey and dated to 5000 BC, once thought to be

4148-497: Was a pottery workshop in province of Balochistan , Pakistan, that dates to 4,500 years ago; 12 blades and blade fragments were excavated there. These blades are 12–18 cm (5–7 in) long, 1.2–2.0 cm (0.5–0.8 in) wide, and relatively thin. Archaeological experiments show that these blades were made with a copper indenter and functioned as a potter's tool to trim and shape unfired pottery. Petrographic analysis indicates local pottery manufacturing, but also reveals

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4216-606: Was indeed taking place by the 4th millennium BC. Since the slag identified at Norşuntepe contains no arsenic, this means that arsenic in some form was added separately. A copper axe found at Prokuplje , Serbia contains the oldest securely dated evidence of copper-making, c.  5500 BC (7,500 years ago). The find in June ;2010 extends the known record of copper smelting by about 800 years, and suggests that copper smelting may have been invented in separate parts of Asia and Europe at that time rather than spreading from

4284-578: Was more common than previously thought and developed independently in Europe 1,500 years before the first tin bronze alloys in the Near East . In Britain, the Chalcolithic is a short period between about 2,500 and 2,200 BC, characterized by the first appearance of objects of copper and gold, a new ceramic culture and the immigration of Beaker culture people, heralding the end of the local late Neolithic. The multiple names result from multiple definitions of

4352-423: Was not in a developed state, indicating smelting was not foreign. It became mature about 1500 BC. Copper smelting Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron , copper , silver , tin , lead and zinc . Smelting uses heat and

4420-630: Was on a small scale. Ceramic similarities between the Indus Valley civilisation , southern Turkmenistan , and northern Iran during 4300–3300 BC of the Chalcolithic period suggest considerable mobility and trade. The term "Chalcolithic" has also been used in the context of the South Asian Stone Age . In Bhirrana , the earliest Indus civilization site, copper bangles and arrowheads were found. The inhabitants of Mehrgarh in present-day Pakistan fashioned tools with local copper ore between 7000 and 3300 BC. The Nausharo site

4488-978: Was one of the largest point sources of mercury in North America in the 20th century. Even after smelter releases were drastically reduced, landscape re-emission continued to be a major regional source of mercury. Lakes will likely receive mercury contamination from the smelter for decades, from both re-emissions returning as rainwater and leaching of metals from the soil. Air pollutants generated by aluminium smelters include carbonyl sulfide , hydrogen fluoride , polycyclic compounds , lead, nickel , manganese , polychlorinated biphenyls , and mercury . Copper smelter emissions include arsenic, beryllium , cadmium , chromium , lead, manganese, and nickel. Lead smelters typically emit arsenic, antimony , cadmium and various lead compounds. Wastewater pollutants discharged by iron and steel mills includes gasification products such as benzene , naphthalene , anthracene , cyanide , ammonia , phenols and cresols , together with

4556-437: Was produced in eastern Turkey ( Malatya Province ) at two ancient sites, Norşuntepe and Değirmentepe , around 4200 BC. According to Boscher (2016), hearths or natural draft furnaces, slag , ore, and pigment had been recovered throughout these sites. This was in the context of Ubaid period architectural complexes typical of southern Mesopotamian architecture. Norşuntepe site demonstrates that some form of arsenic alloying

4624-526: 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 , greaves (metal shin guards), and other body armor . Bronze also supplanted stone, wood, and organic materials in tools and household utensils—such as chisels , saws , adzes , nails , blade shears , knives , sewing needles and pins , jugs , cooking pots and cauldrons , mirrors , and horse harnesses . Tin and copper also contributed to

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