59-514: Capper Pass and Son Ltd. was a British smelting and refining company specialising in non-ferrous metal refining, particularly tin. Originally established in Bristol in the early 1800s, the company relocated to a site on the banks of the Humber Estuary at Melton, East Riding of Yorkshire , in the 1930s, with the Bristol factories closing in the 1960s. Rio Tinto Zinc acquired the firm in
118-565: 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
177-453: A sulfide ), or carbon and oxygen together (as 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
236-445: A 600 ft (180 m) chimney was built, replacing the 200 ft (61 m) chimney built in 1938. In 1980 the plant was the largest smelter of tin from secondary sources, and contributed 10% of the world capacity for tin production. In 1985 the world tin price collapsed, making the plant uneconomic. It closed in 1991 and was decommissioned; the site was sold in 1995. In the 1970s levels of arsenic and lead found in farms near to
295-498: 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 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
354-424: 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
413-709: 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
472-481: 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
531-434: 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
590-407: A similar process to remove impurities from a metal. Both processes use electroplating on a large scale and are important techniques for the economical and straightforward purification of non-ferrous metals . The resulting metals are said to be electrowon . In electrowinning, an electrical current is passed from an inert anode through a leach solution containing the dissolved metal ions so that
649-542: 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
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#1732793010480708-455: Is electrowinning. In an ideal case, ore is extracted into a solution which is then subjected to electrolysis . The metal is deposited on the cathode . In a practical sense, this idealized process is complicated by some or all of the following considerations: the metal content is low (a few percent is typical), other metals deposit competitively with the desired one, the ore is not easily or efficiently dissolved. For these reasons, electrowinning
767-408: 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
826-597: 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
885-562: 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
944-423: 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
1003-444: Is usually only used on purified solutions of a desired metal, e.g. cyanide-extracts of gold ores. Because metal deposition rates are related to available surface area, maintaining properly working cathodes is important. Two cathode types exist, flat-plate and reticulated cathodes , each with its own advantages and disadvantages. Flat-plate cathodes can be cleaned and reused, and plated metals recovered by either mechanically scraping
1062-517: 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
1121-619: 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
1180-604: The West Midlands , but moved to the St. Philips area of Bristol in 1812. In 1819 Capper Pass himself was convicted of handling stolen metal and transported to Australia. The sentence was for 14 years, but he stayed there, remarried and had a family, whilst the Bristol operation was run by his descendants. In the 1840s the business relocated to Bedminster . The factory there extracted the non-ferrous metals copper and lead from their ores, as well as processing silver and gold. By 1860
1239-657: The 1960s. The Melton plant was a tin smelter of worldwide significance, producing 10% of world output at its peak. By-products of the tin refining process including arsenic caused local pollution, and in the 1980s an additional radioactive hazard due to polonium was discovered. Emissions from the Melton plant were implicated in a child cancer cluster in East Yorkshire; as of 2012 a link has not been scientifically established. The plant's owners Rio Tinto Zinc became involved in long running litigation due to diseases amongst
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#17327930104801298-546: 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
1357-418: 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,
1416-454: The anode often contain valuable rare elements such as gold , silver and selenium . Electrowinning is the oldest industrial electrolytic process. The English chemist Humphry Davy obtained sodium metal in elemental form for the first time in 1807 by the electrolysis of molten sodium hydroxide . Electrorefining of copper was first demonstrated experimentally by Maximilian, Duke of Leuchtenberg in 1847. James Elkington patented
1475-461: 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
1534-557: The cathode (or, if the electrolyzed metal has a lower melting point than the cathode, heating the cathode to the electrolyzed metal's melting point causing the electrolyzed metal to liquify and separate from the cathode, which remains solid). Reticulated cathodes have a much higher deposition rate compared to flat-plate cathodes due to their greater surface area. However, reticulated cathodes are not reusable and must be sent off for recycling. Alternatively, starter cathodes of pre-refined metals can be used, which become an integral part of
1593-410: The cathode and the anode. Most metal ores contain metals of interest (e.g. gold , copper , nickel ) in some oxidized states and thus the goal of most metallurgical operations is to chemically reduce them to their pure metallic form. The question is how to convert highly impure metal ores into purified bulk metals. A vast array of operations have been developed to accomplish those tasks, one of which
1652-499: The claimants did not need to prove negligence. Over 600 claimants lodged 1,788 claims: 29 claims for lung cancer and 9 claims for chronic obstructive pulmonary disease were settled. The remaining 1,750 claims were rejected. A study publisher in 2005 led by Sir Richard Doll showed an elevated risk of lung cancer amongst workers at the plant, which was found to be statistically associated with exposure to arsenic and other heavy metals. A study in 2005 of lead and tin levels in soil around
1711-686: The commercial process in 1865 and opened the first successful plant in Pembrey , Wales in 1870. The first commercial plant in the United States was the Balbach and Sons Refining and Smelting Company in Newark, New Jersey in 1883. Nickel and copper are often obtained by electrowinning. These metals have some noble character, which enables their soluble cationic forms to be reduced to their pure metallic form at mild applied potentials applied between
1770-547: The company in 1967. On opening the plant had one blast furnace, and 75 employees; by the beginning of the Second World War three furnaces were operating. During the war ore was difficult to obtain due to shipping warfare. Alternative sources of tin were sought and tin slags from former works in Cornwall were smelted. In 1946 the plant employed 226 people; by 1952 the number of employees had risen to 400, after which
1829-408: 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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1888-546: The employment numbers levelled. The plant specialised in smelting low-grade ores and other feedstocks, particularly Bolivian tin ore, and the recycling of flue dust, processing materials other facilities or countries were unable or had refused to process. Tin was the plant's main product; it also produced silver, cadmium, lead, copper, antimony, bismuth, indium, and gold. The plant employed rectangular blast furnaces for tin production, with additional processes such as electrorefining employed to obtain purified by-products. In 1971
1947-513: 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
2006-470: The factory had begun to manufacture solder . The company was developed and expanded by Alfred Capper Pass , doubling in size between 1872 and 1888. He was born in Bristol in 1837, and took over the business in 1870 when his father died. He became a paternalistic Victorian industrialist, building houses for his workers in Windmill Hill , and donating to the newly founded Bristol University . In 1894
2065-721: The family business was converted to a limited company . He died in 1905, after which the company was run by non-family members. A chair in chemistry was established at the university in his name. The works in Bedminster was constrained by its locality, and in 1928 a new factory site was acquired at Melton, East Riding of Yorkshire ; the great depression delayed the project; the factory construction and opening occurred in 1936/7. The Bristol works closed in 1963. 53°42′57″N 0°31′42″W / 53.71585°N 0.52822°W / 53.71585; -0.52822 ( Capper Pass, Melton works ) , Melton works Construction of
2124-429: 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
2183-454: 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
2242-593: The former smelter showed deposition up to 15 miles (24 km) with a distribution trend towards the north-east; the study estimated that about 2,500 tons of lead and 830 tons of zinc had been introduced into the soil surrounding the plant. The former industrial site at Melton has been converted into a 32 acres (0.13 km) industrial development named Melton Park used for open storage and warehousing including two industrial units of over 400,000 sq ft (37,000 m) total, and another unit of approximately 100,000 sq ft (9,300 m). As of 2012
2301-421: The metal is recovered as it is reduced and deposited in an electroplating process onto the cathode . In electrorefining, the anode consists of the impure metal (e.g., copper ) to be refined. The impure metallic anode is oxidized and the metal dissolves into solution. The metal ions migrate through the electrolyte towards the cathode where the pure metal is deposited. Insoluble solid impurities sedimenting below
2360-522: The metallurgical refining industry be made. The Baxter report could not establish a link between the smelter and the cancer cases. After closure of the plant and sale of the site, the former owner Rio Tinto Zinc (RTZ) denied any responsibility or liability for its former asset for over two decades. In 2002 RTZ began proceedings to offer compensation to persons associated with the plant who were affected by disease, which would be reviewed through an independent panel; RTZ did not accept legal liability , whilst
2419-722: 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
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2478-455: The ore and liberating the sulfur as sulfur dioxide gas. Smelting most prominently takes place in 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
2537-430: The ore binds to carbon at high temperatures, as the chemical potential energy of the bonds in carbon dioxide (CO 2 ) 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
2596-464: 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
2655-400: 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
2714-431: 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
2773-486: The physical tasks demanded by their jobs. In the United States, the Environmental Protection Agency has published pollution control regulations for smelters. Electrorefining Electrowinning , also called electroextraction , is the electrodeposition of metals from their ores that have been put in solution via a process commonly referred to as leaching. Electrorefining uses
2832-587: The plant to a company in Germany was found to be radioactive: alpha radiation was found to be emitted by by-products of the smelting process due to the presence of polonium 210 (a radioisotope with a half-life of about 140 days), thought to be produced via radioactive decay of naturally occurring isotopes in tin-bearing ore bodies such as granite. The plant was subsequently licensed to emit 592 MBq (16 mCu ) (1985) and typically emitted less than 10% of that amount, less than background radiation. Most (about 95%) of
2891-739: The plant was part of a feature on radiation in Channel 4 's Dispatches documentary "Radioactive Britain". A report from Professor M.S. Baxter of Glasgow University was commissioned by the East Yorkshire Health Authority ; which found the previous statistical limits on radioactive exposure to be too high (by a factor of more than 100 times) and recommended revision of the Radioactive Substances Act 1960 . A 1996 report recommended improvements in assessment, mitigation and monitoring of radioactive agents in
2950-591: The plant were such that crops and livestock were condemned. The plant also discharged into the Humber Estuary, resulting in significant arsenic pollution; in 1997, levels remained slightly elevated in estuary sediments, and it has also been speculated that arsenic discharge has been carried into the North Sea , resulting in high levels in sediments off the Norfolk coast. In 1984 a bismuth alloy supplied by
3009-495: The plant's workers, as well as those in the surrounding area. RTZ paid compensation to 29 ex-employees with lung conditions in 2002 after two decades of denying responsibility. The Melton plant closed in 1991; its site was cleared and redeveloped for industrial use. 51°26′29″N 2°35′42″W / 51.441332°N 2.595112°W / 51.441332; -2.595112 ( Capper Pass, Bedminster works ) , Bedminster works The Capper Pass family business originated in
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#17327930104803068-468: The polonium bearing materials and radioactivity were confined to the factory, as a result of the high temperature smelting process causing it to volatilize and condense within the plant. The plant's polonium emissions license did not become public knowledge until over two years after it was given. The works gained notoriety because they were linked in the 1980s with a child cancer cluster in west Hull and surrounding villages; (Willerby and Kirk Ella) in 1988
3127-401: 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
3186-585: 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
3245-525: The site is under development. During the Second World War two companies were acquired: Victor G. Stevens Ltd , of Felling-on-Tyne ; and Messrs George Pizey (London). The Pizey plant was moved to Felling. In 1959 plant and equipment of the Stevens' works was relocated to Bristol. Smelting Smelting is a process of applying heat and a chemical reducing agent to an ore to extract
3304-632: The smelter in the East Riding of Yorkshire began in 1936, and the plant became operational in 1937. The plant was located west of Hull on the banks of the Humber Estuary . It was served by the Hull and Selby railway line , and was close to old clay pits on the bank of the Humber. The plant was designed by civil engineering firm Sir Alexander Gibb & Partners for £170,000, including a row of houses for plant workers built in 1936. Rio Tinto Zinc acquired
3363-651: 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
3422-1041: 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
3481-526: 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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