In
metallurgy
Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys.
Metallurgy encompasses both the ...
, non-ferrous metals are metals or
alloy
An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...
s that do not contain
iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
(
allotropes of iron,
ferrite, and so on) in appreciable amounts.
Generally more costly than
ferrous
In chemistry, iron(II) refers to the chemical element, element iron in its +2 oxidation number, oxidation state. The adjective ''ferrous'' or the prefix ''ferro-'' is often used to specify such compounds, as in ''ferrous chloride'' for iron(II ...
metals, non-ferrous metals are used because of desirable properties such as low weight (e.g.
aluminium
Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
), higher
conductivity (e.g.
copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...
),
non-
magnetic
Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, m ...
properties or
resistance to corrosion (e.g.
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 ...
). Some non-ferrous materials are also used in the iron and
steel
Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...
industries. For example,
bauxite
Bauxite () is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium and gallium. Bauxite consists mostly of the aluminium minerals gibbsite (), boehmite (γ-AlO(OH)), and diaspore (α-AlO(OH) ...
is used as
flux
Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications in physics. For transport phe ...
for
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 ...
s, while others such as
wolframite,
pyrolusite
Pyrolusite is a mineral consisting essentially of manganese dioxide ( Mn O2) and is important as an ore of manganese.. It is a black, amorphous appearing mineral, often with a granular, fibrous, or columnar structure, sometimes forming reniform ...
, and
chromite
Chromite is a crystalline mineral composed primarily of iron(II) oxide and chromium(III) oxide compounds. It can be represented by the chemical formula of Iron, FeChromium, Cr2Oxygen, O4. It is an oxide mineral belonging to the spinel group. The ...
are used in making ferrous alloys.
Important non-ferrous metals include aluminium, copper,
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 ...
,
tin,
titanium
Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
, and zinc, and alloys such as
brass
Brass is an alloy of copper and zinc, in proportions which can be varied to achieve different colours and mechanical, electrical, acoustic and chemical properties, but copper typically has the larger proportion, generally copper and zinc. I ...
.
Precious metal
Precious metals are rare, naturally occurring metallic chemical elements of high Value (economics), economic value. Precious metals, particularly the noble metals, are more corrosion resistant and less reactivity (chemistry), chemically reac ...
s such as
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 ...
,
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. ...
, and
platinum
Platinum is a chemical element; it has Symbol (chemistry), symbol Pt and atomic number 78. It is a density, dense, malleable, ductility, ductile, highly unreactive, precious metal, precious, silverish-white transition metal. Its name origina ...
and exotic or rare metals such as
mercury,
tungsten
Tungsten (also called wolfram) is a chemical element; it has symbol W and atomic number 74. It is a metal found naturally on Earth almost exclusively in compounds with other elements. It was identified as a distinct element in 1781 and first ...
,
beryllium
Beryllium is a chemical element; it has Symbol (chemistry), symbol Be and atomic number 4. It is a steel-gray, hard, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with ...
,
bismuth
Bismuth is a chemical element; it has symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs nat ...
,
cerium
Cerium is a chemical element; it has Chemical symbol, symbol Ce and atomic number 58. It is a hardness, soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it ...
,
cadmium
Cadmium is a chemical element; it has chemical symbol, symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12 element, group 12, zinc and mercury (element), mercury. Like z ...
,
niobium
Niobium is a chemical element; it has chemical symbol, symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and Ductility, ductile transition metal. Pure niobium has a Mohs scale of mineral hardness, Mohs h ...
,
indium
Indium is a chemical element; it has Symbol (chemistry), symbol In and atomic number 49. It is a silvery-white post-transition metal and one of the softest elements. Chemically, indium is similar to gallium and thallium, and its properties are la ...
,
gallium
Gallium is a chemical element; it has Chemical symbol, symbol Ga and atomic number 31. Discovered by the French chemist Paul-Émile Lecoq de Boisbaudran in 1875,
elemental gallium is a soft, silvery metal at standard temperature and pressure. ...
,
germanium
Germanium is a chemical element; it has Symbol (chemistry), symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid or a nonmetal in the carbon group that is chemically ...
,
lithium
Lithium (from , , ) is a chemical element; it has chemical symbol, symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard temperature and pressure, standard conditions, it is the least dense metal and the ...
,
selenium
Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elem ...
,
tantalum
Tantalum is a chemical element; it has Symbol (chemistry), symbol Ta and atomic number 73. It is named after Tantalus, a figure in Greek mythology. Tantalum is a very hard, ductility, ductile, lustre (mineralogy), lustrous, blue-gray transition ...
,
tellurium
Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally fou ...
,
vanadium
Vanadium is a chemical element; it has Symbol (chemistry), symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an ...
, and
zirconium
Zirconium is a chemical element; it has Symbol (chemistry), symbol Zr and atomic number 40. First identified in 1789, isolated in impure form in 1824, and manufactured at scale by 1925, pure zirconium is a lustrous transition metal with a greyis ...
are also non-ferrous.
They are usually obtained through minerals such as
sulfide
Sulfide (also sulphide in British English) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to large families o ...
s,
carbonate
A carbonate is a salt of carbonic acid, (), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate group ...
s, and
silicate
A silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is also used ...
s. Non-ferrous metals are usually refined through
electrolysis
In chemistry and manufacturing, electrolysis is a technique that uses Direct current, direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of c ...
.
Recycling and pollution control
Due to their extensive use, non-ferrous
scrap metals are usually
recycle
ReCycle is a music loop editor designed and developed by Sweden, Swedish software developers Propellerhead Software. It runs on Microsoft Windows and Apple Macintosh based Personal Computer, PCs. The software debuted in 1994.
The principal idea ...
d. The secondary materials in scrap are vital to the metallurgy industry, as the production of new metals often needs them. Some recycling facilities re-smelt and recast non-ferrous materials; the
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 ...
is collected and stored onsite while the metal fumes are filtered and collected.
Non-ferrous scrap metals are sourced from industrial scrap materials, particle emissions and obsolete technology (for example,
copper cables) scrap.
Ancient history
Non-ferrous metals were the first metals used by humans for metallurgy. Gold, silver and copper existed in their native
crystal
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...
line yet metallic form. These metals, though rare, could be found in quantities sufficient to attract the attention of humans. Less susceptible to oxygen than most other metals, they can be found even in weathered outcroppings. Copper was the first metal to be forged; it was soft enough to be fashioned into various objects by
cold forging and could be melted in a
crucible
A crucible is a container in which metals or other substances may be melted or subjected to very high temperatures. Although crucibles have historically tended to be made out of clay, they can be made from any material that withstands temperat ...
. Gold, silver and copper replaced some of the functions of other resources, such as wood and stone, owing to their ability to be shaped into various forms for different uses.
Due to their rarity, these gold, silver and copper artifacts were treated as luxury items and handled with great care. The use of copper also heralded the transition from the
Stone Age
The Stone Age was a broad prehistory, prehistoric period during which Rock (geology), stone was widely used to make stone tools with an edge, a point, or a percussion surface. The period lasted for roughly 3.4 million years and ended b ...
to the
Copper Age
The Chalcolithic ( ) (also called 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 dif ...
. The
Bronze Age
The Bronze Age () was a historical period characterised principally by the use of bronze tools and the development of complex urban societies, as well as the adoption of writing in some areas. The Bronze Age is the middle principal period of ...
, which succeeded the Copper Age, was again heralded by the invention of
bronze
Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloid ...
, an alloy of copper with the non-ferrous metal
tin.
Mechanical and structural use
Non-ferrous metals are used in residential,
commercial and industrial applications. Material selection for a mechanical or structural application requires some important considerations, including how easily the material can be shaped into a finished part and how its properties can be either intentionally or inadvertently altered in the process. Depending on the end use, metals can be simply cast into the finished part, or cast into an intermediate form, such as an
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 ...
, then worked, or wrought, by rolling,
forging
Forging is a manufacturing process involving the shaping of metal using localized compression (physics), compressive forces. The blows are delivered with a hammer (often a power hammer) or a die (manufacturing), die. Forging is often classif ...
, extruding, or other deformation process. Although the same operations are used with ferrous as well as nonferrous metals and alloys, the reaction of nonferrous metals to these forming processes is often more severe. Consequently, properties may differ considerably between the cast and wrought forms of the same metal or alloy.
References
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Metals
Alloys
Metallurgy