Plants for the production of

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

are generally referred to as lead smelters. Primary lead production begins with

sintering Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing process used with metals, ceramics, plas ...

. Concentrated lead ore is fed into a sintering machine with iron, silica, limestone fluxes, coke,

soda ash Sodium carbonate (also known as washing soda, soda ash, sal soda, and soda crystals) is the inorganic compound with the formula and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water ...

pyrite The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue ...

zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...

, caustics or

pollution control Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...

particulates.

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-making, iron, copper extraction, copper ...

uses suitable reducing substances that will combine with those

oxidizing Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

elements to free the metal. 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. Lead is usually smelted in a

blast furnace A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally pig iron, but also others such as lead or copper. ''Blast'' refers to the combustion air being supplied above atmospheric pressure. In a ...

, using the lead sinter produced in the sintering process and coke to provide the heat source. As melting occurs, several layers form in the furnace. A combination of molten lead and slag sinks to the bottom of the furnace, with a layer of the lightest elements referred to as speiss, including

arsenic Arsenic is a chemical element; it has Symbol (chemistry), symbol As and atomic number 33. It is a metalloid and one of the pnictogens, and therefore shares many properties with its group 15 neighbors phosphorus and antimony. Arsenic is not ...

and

antimony Antimony is a chemical element; it has chemical symbol, symbol Sb () and atomic number 51. A lustrous grey metal or metalloid, it is found in nature mainly as the sulfide mineral stibnite (). Antimony compounds have been known since ancient t ...

floating to the top of the molten material. The crude bullion and lead slag layers flow out of the 'furnace front' and into the 'forehearth', where the two streams are separated. The lead slag stream, containing most of the 'fluxing' elements added to the sintering machine (predominantly silica, limestone, iron and zinc) can either be discarded or further processed to recover the contained zinc. The crude lead bullion, containing significant quantities of copper will then undergo 'copper drossing'. In this step elemental sulphur, usually in solid form is added to the molten crude lead bullion to react with the contained copper. A "

matte Matte may refer to: Art * paint with a non-glossy finish. See diffuse reflection. * a framing element surrounding a painting or watercolor within the outer frame Film * Matte (filmmaking), filmmaking and video production technology * Matte pai ...

" layer forms in this step, containing most of the copper originating from the crude lead bullion and some other impurities as metal sulfides. The speiss and the matte are usually sold to copper smelters where they are refined for copper processing. The lead from the blast furnace, called lead bullion, then undergoes the drossing process. The bullion is agitated in kettles then cooled to 700–800 degrees. This process results in molten lead and

dross Dross is a mass of solid impurities floating on a molten metal or dispersed in the metal, such as in wrought iron. It forms on the surface of low- melting-point metals such as tin, lead, zinc or aluminium or alloys by oxidation of the metal. Fo ...

. Dross refers to the

lead oxide Lead oxides are a group of inorganic compounds with formulas including lead (Pb) and oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), gr ...

s, copper, antimony and other elements that float to the top of the lead. Dross is usually skimmed off and sent to a dross furnace to recover the non-lead components which are sold to other metal manufacturers. The

Parkes process The Parkes process is a pyrometallurgical industrial process for removing silver from lead during the production of bullion. It is an example of liquid–liquid extraction. The process takes advantage of two liquid-state properties of zinc. The fi ...

is used to separate

silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...

gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...

from lead. Finally, the molten lead is refined. Pyrometallurgical methods are usually used to remove the remaining non-lead components of the mixture, for example the Betterton-Kroll process and the Betts electrolytic process. The non-lead metals are usually sold to other metal processing plants. The refined lead may be made into alloys or directly cast. People who operate or work in such plants are also referred to as smelters.

Lead ores

lang=en, Evolution of the extracted lead ores grade in different countries (Canada, Australia).

Galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crysta ...

, 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 Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...

(like the

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

in the example above) is expelled, and the lead oxide is reduced.

Anglesite Anglesite is a lead sulfate mineral with the chemical formula PbSO4. It occurs as an oxidation product of primary lead sulfide ore, galena. Anglesite occurs as prismatic orthorhombic crystals and earthy masses, and is isomorphous with barite and ...

Cerussite Cerussite (also known as lead carbonate or white lead ore) is a mineral consisting of lead carbonate with the chemical formula PbCO3, and is an important ore of lead. The name is from the Latin ''cerussa'', white lead. ''Cerussa nativa'' was ...

, Pyromorphite,

Mimetite Mimetite is a lead arsenate chloride mineral () which forms as a secondary mineral in lead deposits, usually by the Redox, oxidation of galena and arsenopyrite. The name derives from the Greek ''mimetes'', meaning "imitator" and refers to mimeti ...

and

Wulfenite Wulfenite is a lead molybdate mineral with the formula Pb Mo O4. It often occurs as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is some ...

are other lead ores. Other elements frequently present with lead ores include

and

Secondary lead processing

Most of the lead produced comes from secondary sources. Lead scrap includes lead-acid batteries, cable coverings, pipes, sheets and lead coated, or terne bearing, metals. Solder, product waste and dross may also be recovered for its small lead content. Most secondary lead is used in batteries. To recover lead from a battery, the battery is broken and the components are classified. The lead containing components are processed in blast furnaces for hard lead or rotary reverberatory furnaces for fine particles. The blast furnace is similar in structure to a cupola furnace used in iron foundries. The furnace is charged with slag, scrap iron, limestone, coke, oxides, dross, and reverberatory slag. The coke is used to melt and reduce the lead. Limestone reacts with impurities and floats to the top. This process also keeps the lead from oxidizing. The molten lead flows from the blast furnace into holding pots. Lead may be mixed with alloys, including antimony, tin, arsenic, copper and nickel. It is then cast into

ingot An ingot is a piece of relatively pure material, usually metal, that is Casting, cast into a shape suitable for further processing. In steelmaking, it is the first step among semi-finished casting products. Ingots usually require a second procedu ...

Lead exposure

Humans have been smelting lead for thousands of years, poisoning themselves in the process. Although

lead poisoning Lead poisoning, also known as plumbism and saturnism, is a type of metal poisoning caused by lead in the body. Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, infertility, numbness and paresthesia, t ...

is one of the oldest known work and environmental hazards, the modern understanding of the small amount of lead necessary to cause harm did not come about until the latter half of the 20th century. No safe threshold for lead exposure has been discovered—that is, there is no known amount of lead that is too small to cause the body harm. The US

Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency under the United S ...

and the

World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...

state that a

blood lead level Blood lead level (BLL), is a measure of the amount of lead in the blood. Lead is a toxic heavy metal and can cause neurological damage, especially among children, at any detectable level. High lead levels cause decreased vitamin D and haemo ...

of 10 μg/dL or above is a cause for concern; however, lead may impair development and have harmful health effects even at lower levels, and there is no known safe exposure level. Authorities such as the

American Academy of Pediatrics The American Academy of Pediatrics (AAP) is the largest professional association of pediatricians in the United States. It is headquartered in Itasca, Illinois, and maintains an office in Washington, D.C. The AAP has published hundreds of poli ...

define lead poisoning as blood lead levels higher than 10 μg/dL. Lead smelters with little pollution controls contribute to several environmental problems, especially raised blood lead levels in the surrounding population. The problem is particularly significant in many children who have grown up in the proximity to a lead smelter.

History

The earliest known cast lead beads were thought found in the Çatalhöyük site in

Anatolia Anatolia (), also known as Asia Minor, is a peninsula in West Asia that makes up the majority of the land area of Turkey. It is the westernmost protrusion of Asia and is geographically bounded by the Mediterranean Sea to the south, the Aegean ...

(

Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...

), and dated from about 6500 BC. They were later identified in fact to be made from

cerussite Cerussite (also known as lead carbonate or white lead ore) is a mineral consisting of lead carbonate with the chemical formula PbCO3, and is an important ore of lead. The name is from the Latin ''cerussa'', white lead. ''Cerussa nativa'' was ...

and

galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crysta ...

, minerals rich in, but distinct from, lead. Ancient smelting was done using loads of lead ore and charcoal in outdoor hearths and furnaces. 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 Ancient Greece () was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity (), that comprised a loose collection of culturally and linguistically r ...

and

Ancient Rome In modern historiography, ancient Rome is the Roman people, Roman civilisation from the founding of Rome, founding of the Italian city of Rome in the 8th century BC to the Fall of the Western Roman Empire, collapse of the Western Roman Em ...

for piping and storage of water. It was also used as a mortar in stone buildings, and as a

writing material A writing material, also called a writing medium, is a surface that can be written on with suitable instruments, or used for symbolic or representational drawings. Building materials on which writings or drawings are produced are not included. ...

Smeltmill Smeltmills were water-powered water mill, mills used to smelting, smelt lead or other metals. The older method of smelting lead on wind-blown bole hills began to be superseded by artificially-blown smelters. The first such furnace was built by Bu ...

s were water-powered mills used to smelt lead or other metals. The Roman lead smelting has led to evidence of global pollution. Greenland ice cores from 500 BC to 300 AD show measurably elevated lead content in the atmosphere. Researchers studying an ice core from Colle Gnifetti, in the Swiss part of the

Monte Rosa Monte Rosa (; ; ; or ; ) is a mountain massif in the eastern part of the Pennine Alps, on the border between Italy (Piedmont and Aosta Valley) and Switzerland (Valais). The highest peak of the massif, amongst several peaks of over , is the D ...

massif A massif () is a principal mountain mass, such as a compact portion of a mountain range, containing one or more summits (e.g. France's Massif Central). In mountaineering literature, ''massif'' is frequently used to denote the main mass of an ...

, have found that higher historical European airborne lead pollution levels are associated with changes in the monetary system from gold to silver from the year 640 AD, with the principal source likely to be the Melle mines in

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. Later airborne pollution, between the years 1170 and 1216, correlates even more strongly with contemporaneous records of lead and silver production from mines in the

Peak District The Peak District is an Highland, upland area in central-northern England, at the southern end of the Pennines. Mostly in Derbyshire, it extends into Cheshire, Greater Manchester, Staffordshire, West Yorkshire and South Yorkshire. It is subdivi ...

of England, at levels similar to those seen in the

Industrial Revolution The Industrial Revolution, sometimes divided into the First Industrial Revolution and Second Industrial Revolution, was a transitional period of the global economy toward more widespread, efficient and stable manufacturing processes, succee ...

Georgius Agricola Georgius Agricola (; born Georg Bauer; 24 March 1494 – 21 November 1555) was a German Humanist scholar, mineralogist and metallurgist. Born in the small town of Glauchau, in the Electorate of Saxony of the Holy Roman Empire, he was b ...

(1494–1555) presented details of lead smelting methods and facilities current in Europe in the first half of the 16th century in Book IX of his treatise on mining and metallurgy, ''De Re Metallica''. Methods ranged from primitive open-hearth arrangements (essentially bonfires on which lead ore was piled) to blast furnaces capable of continuous operation. In the US there are 400 forgotten lead smelting firms that operated in the 1930s to 1960s and may have deposited dangerous levels of lead contamination in nearby soil.

Historic mining and smelting sites

Asia

* Gazimursky Zavod * Bupyeong silver mine

Australia

* Boolaroo, New South Wales * Argenton, New South Wales *

Cockle Creek Smelter Cockle Creek Smelter was a zinc and lead smelter located at the northern end of Lake Macquarie near Boolaroo in Newcastle, New South Wales. The smelter was built in by the Sulphide Corporation in 1896 and the first attempts to refine zinc using t ...

Europe

* Grinton Smelt Mill,

North Yorkshire North Yorkshire is a Ceremonial counties of England, ceremonial county in Northern England.The Unitary authorities of England, unitary authority areas of City of York, York and North Yorkshire (district), North Yorkshire are in Yorkshire and t ...

, England *

Milford, Derbyshire Milford is a village in the civil parish of Belper, in the Amber Valley district, in the county of Derbyshire, England. It is on the River Derwent, Derbyshire, River Derwent, between Duffield, Derbyshire, Duffield and Belper on the A6 road (Grea ...

Mendip Hills The Mendip Hills (commonly called the Mendips) is a range of limestone hills to the south of Bristol and Bath, Somerset, Bath in Somerset, England. Running from Weston-super-Mare and the Bristol Channel in the west to the River Frome, Somerset ...

Wirksworth Wirksworth is a market town and civil parish in the Derbyshire Dales district of Derbyshire, England. Its population was 4,902 in the 2021 United Kingdom census, 2021 census.Area E04002820 (Wirksworth parish) in Table PP002 - Sex, from Wirkswor ...

* The tin and lead smelter in

Arnhem Arnhem ( ; ; Central Dutch dialects, Ernems: ''Èrnem'') is a Cities of the Netherlands, city and List of municipalities of the Netherlands, municipality situated in the eastern part of the Netherlands, near the German border. It is the capita ...

, the

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

, was shut down in the 1990s. *

Upper Harz The Upper Harz (, ) is the northwestern and higher part of the Harz mountain range in Germany. The exact boundaries of this geographical region may be defined differently depending on the context. In its traditional sense, the term Upper Harz cover ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

* Copșa Mică works,

Transylvania Transylvania ( or ; ; or ; Transylvanian Saxon dialect, Transylvanian Saxon: ''Siweberjen'') is a List of historical regions of Central Europe, historical and cultural region in Central Europe, encompassing central Romania. To the east and ...

Rammelsberg The Rammelsberg is a mountain, high, on the northern edge of the Harz range, south of the historic town of Goslar in the North German state of Lower Saxony. The mountain is the location of an important silver, copper, and lead mine. When it close ...

, Germany * Ballycorus Leadmines * Dalnegorsk * Eas Anie *

Silberhütte (Harzgerode) Silberhütte is a village in the town of Harzgerode in the district of Landkreis Harz, Harz in the German state of Saxony-Anhalt. Its name means "silver works", a place where silver ore is smelted. Geography Silberhütte lies in the Selke (riv ...

North America

* Noonday Camp, California * Tri-State district (SE Kansas, SW Missouri, NE Oklahoma) * Southeast Missouri Lead District * Old Mines, Missouri *

ASARCO ASARCO (American Smelting and Refining Company) is a mining, smelting, and refining company based in Tucson, Arizona, which mines and processes primarily copper. The company has been a subsidiary of Grupo México since 1999. Its three largest ...

Murray, Utah * Midvale, Utah * International Smelting and Refining Company Tooele, Utah *

Silver City, Utah Silver City is a ghost town located at the mouth of Dragon Canyon on the west flank of the East Tintic Mountains in northeast Juab County in central Utah, United States. It was a silver mining town approximately south-southwest of Salt Lake ...

* Carondelet, St. Louis * Bunker Hill Mine and Smelting Complex,

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

* Ketchum, Idaho *

El Paso, Texas El Paso (; ; or ) is a city in and the county seat of El Paso County, Texas, United States. The 2020 United States census, 2020 population of the city from the United States Census Bureau, U.S. Census Bureau was 678,815, making it the List of ...

* Dewey-Humboldt, Arizona * Priest Mine, Canada * Cerro Gordo Mines *

Butte, Montana Butte ( ) is a consolidated city-county and the county seat of Silver Bow County, Montana, United States. In 1977, the city and county governments consolidated to form the sole entity of Butte-Silver Bow. The city covers , and, according to the 2 ...

* Harbor Island (Seattle) *

Sinsinawa, Wisconsin Sinsinawa () is an unincorporated area, unincorporated community in Grant County, Wisconsin, United States. The community is in the towns of Jamestown, Wisconsin, Jamestown and Hazel Green (town), Wisconsin, Hazel Green, one mile north of the bord ...

East Chicago, Indiana East Chicago is a city in Lake County, Indiana, United States. The population was 26,370 at the 2020 United States census, 2020 census. Centered around heavy industry, the city is home to the Indiana Harbor and Ship Canal, an artificial freshwa ...

South America

Active lead mines and smelters

Africa

* Kitwe, Zambia

Australia

* Nyrstar

Port Pirie Port Pirie is a small city on the east coast of the Spencer Gulf in South Australia, north of the state capital, Adelaide. Port Pirie is the largest city and the main retail centre of the Mid North region of South Australia. The city has an ex ...

Broken Hill, New South Wales Broken Hill is a city in the Far West (New South Wales), far west region of outback New South Wales, Australia. An inland mining city, it is near the border with South Australia on the crossing of the Barrier Highway (A32) and the Silver City Hi ...

Mount Isa Mines Mount Isa Mines Limited ("MIM") operates the Mount Isa copper, lead, zinc and silver mines near Mount Isa, Queensland, Australia as part of the Glencore group of companies. For a brief period in 1980, MIM was Australia's largest company. It has ...

Asia

* Chanderiya Smelter Complex in the Chittorgarh district of

Rajasthan Rajasthan (; Literal translation, lit. 'Land of Kings') is a States and union territories of India, state in northwestern India. It covers or 10.4 per cent of India's total geographical area. It is the List of states and union territories of ...

state of

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

Europe

*Rönnskär copper smelter is in Skelleftehamn,

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

and its main products are copper, zinc clinker, lead and precious metals. *Bergsöe lead smelter outside Landskrona in southern Sweden extracts lead from scrap car batteries. * Tara Mine *KCM in Plovdiv which has produced lead for over 60 years using a blast furnace and is now in the process of bringing a new 60 million euro smelter TSL furnace online in order to replace the ageing blast furnace.

North America

* Doe Run Resources Corporation is the largest integrated

producer in North America and the largest primary lead producer in the

western world The Western world, also known as the West, primarily refers to various nations and state (polity), states in Western Europe, Northern America, and Australasia; with some debate as to whether those in Eastern Europe and Latin America also const ...

. * Hayden Smelter,

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

* Belledune, New Brunswick * Red Dog mine, Alaska * Teck Trail Operations, Trail, BC, Canada.

South America

* La Oroya *

Cerro de Pasco Cerro de Pasco is a city in central Peru, located at the top of the Andean Mountains. It is the capital of both the Pasco Province and the Department of Pasco, and an important mining center of silver, copper, zinc and lead. At an elevation of ...

, Peru

References

External links

The Charles Bathurst Smelt Mill, Arkengarthdale, England
{{Extractive metallurgy Lead Smelting

Lead ores

Secondary lead processing

Lead exposure

History

Historic mining and smelting sites

Asia

Australia

Europe

North America

South America

Active lead mines and smelters

Africa

Australia

Asia

Europe

North America

South America

See also

References

External links