Is Aluminum a metal? Yes, aluminum is a metal. It is a silvery-white, soft, nonmagnetic, and ductile metal. It’s the most spread metal on the earth, making up more than 8% of the earth’s core mass. It’s also the third most common chemical element on our planet after oxygen and silicon.
What is Metal?
A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable or ductile. Metals are sometimes described as a lattice of positive ions surrounded by a cloud of delocalized electrons.
The metals are one of the three groups of elements as distinguished by their ionization and bonding properties, along with the metalloids and nonmetals.
On the periodic table, a diagonal line drawn from boron (B) to polonium (Po) separates the metals from the nonmetals. Most elements on this line are metalloids, sometimes called semi-metals; elements to the lower left are metals; elements to the upper right are nonmetals. A modern definition of metals is that they have overlapping conduction bands and valence bands in their electronic structure.
Following are some facts about Aluminum :
- Symbol: Al
- Atomic mass
- Atomic number: 13
- Electron configuration: Ne 3s²3p
- Melting point: 660.3 °C
- Density: 2.7 g/cm³
Background of Aluminum
Aluminum compounds have proven useful for thousands of years. Around 5000 B.C. , Persian potters made their strongest vessels from clay that contained aluminum oxide. Ancient Egyptians and Babylonians used aluminum compounds in fabric dyes, cosmetics, and medicines. However, it was not until the early nineteenth century that aluminum was identified as an element and isolated as a pure metal. The difficulty of extracting aluminum from its natural compounds kept the metal rare for many years; half a century after its discovery, it was still as rare and valuable as silver.
History of Aluminum
In 1886, two 22-year-old scientists independently developed a smelting process that made economical mass production of aluminum possible. Known as the Hall-Heroult process after its American and French inventors, the process is still the primary method of aluminum production today. The Bayer process for refining aluminum ore, developed in 1888 by an Austrian chemist, also contributed significantly to the economical mass production of aluminum.
In 1884, 125 lb (60 kg) of aluminum was produced in the United States, and it sold for about the same unit price as silver. In 1995, U.S. plants produced 7.8 billion lb (3.6 million metric tons) of aluminum, and the price of silver was seventy-five times as much as the price of aluminum.
Advantages/Properties Of Aluminium
Physically, chemically and mechanically, aluminum is a metal similar to steel, brass, copper, zinc, lead, or titanium. It can be melted, cast, formed, and machined in a similar way to these metals and conducts electric currents. In fact, often the same equipment and fabrication methods are used for steel.
Aluminum is a very light metal with a specific weight of 2.7 g/cm3, about a third of that of steel. This cuts the costs of manufacturing with aluminum. Again, its use in vehicles reduces dead-weight and energy consumption while increasing load capacity. This also reduces noise and improves comfort levels.
Its strength can be adapted to the application required by modifying the composition of its alloys. Aluminum-magnesium-manganese alloys are an optimum mix of formability with strength, while aluminum-magnesium-silicon alloys are ideal for automobile body sheets, which show good age-hardening when subjected to the bake-on painting process.
Aluminum naturally generates a protective thin oxide coating which keeps the metal from making further contact with the environment. It is particularly useful for applications where it is exposed to corroding agents, as in kitchen cabinets and in vehicles. In general, aluminum alloys are less corrosion-resistant than pure aluminum, except for marine magnesium-aluminum alloys. Different types of surface treatment such as anodizing, painting, or lacquering can further improve this property.
Electrical and Thermal Conductivity
Aluminum is an excellent heat and electricity conductor and in relation to its weight is almost twice as good a conductor as copper. This has made aluminum the first choice for major power transmission lines. It is also a superb heat sink for many applications that require heat to be drained away rapidly, such as in computer motherboards and LED lights.
Aluminum is a good reflector of visible light as well as heat, and that together with its low weight makes it an ideal material for reflectors in, for example, light fittings or rescue blankets. Cool roofs made of coated aluminum are invaluable in reducing internal solar heat within a house, by reflecting up to 95% of sunlight.
Aluminum is ductile and has a low melting point and density. It can be processed in several ways in a molten condition. Its ductility allows aluminum products to be formed close to the end of the product’s design. Whether sheets, foil, geometrical configurations, tubes, rods, or wires, aluminum is up to them all.
Strength at Low Temperatures
In contrast to steel, which rapidly becomes brittle at low temperatures, aluminum shows increased tensile strength as temperatures drop.
Impermeable and Odorless
Aluminum foil is only 0.007 mm in thickness, but is still durable and completely impermeable, keeping any food wrapped in it free of external tastes or smells. It keeps out ultraviolet rays as well.
Moreover, the metal itself is non-toxic and odorless, which makes it ideal for packaging sensitive products such as food or pharmaceuticals. The fact that recycled aluminum can be used reduces the carbon footprint for this stage of food and beverage manufacturers as well.
Aluminum is non-magnetic, making it useful for electrical shieldings as in computer disks, dish antennas, busbars, or magnet housings.
Aluminum is non-toxic and is used to make woks, pressure cookers, and many other cooking utensils without fear. It is easily cleaned and does not contaminate the food at any stage.
Sound and Shock Absorption
Aluminum is an excellent sound absorber and is used for constructing ceilings. It is also used in auto bumpers due to its shock-absorbing properties.
Aluminum produces no sparks when it comes into contact with itself or non-ferrous metals.
Aluminum is 100% recyclable and recycled aluminum is identical to the virgin product. This makes it a much more cost-effective source material for production runs. The re-melting of aluminum requires little energy: only about 5% of the energy required to produce the primary metal initially is needed in the recycling process.
How Aluminum is made?
Aluminum originates from bauxite, an ore typically found in the topsoil of various tropical and subtropical regions. Once mined, aluminum within the bauxite ore is chemically extracted into alumina, an aluminum oxide compound, through the Bayer process.
Aluminum compounds occur in all types of clay, but the ore that is most useful for producing pure aluminum is bauxite. Bauxite consists of 45-60% aluminum oxide, along with various impurities such as sand, iron, and other metals. Although some bauxite deposits are hard rock, most consist of relatively soft dirt that is easily dug from open-pit mines. Australia produces more than one-third of the world’s supply of bauxite. It takes about 4 lb (2 kg) of bauxite to produce 1 lb (0.5 kg) of aluminum metal.
Caustic soda (sodium hydroxide) is used to dissolve the aluminum compounds found in the bauxite, separating them from the impurities. Depending on the composition of the bauxite ore, relatively small amounts of other chemicals may be used in the extraction
Aluminum is manufactured in two phases: the Bayer process of refining the bauxite ore to obtain aluminum oxide, and the Hall-Heroult process of smelting the aluminum oxide to release pure aluminum.
of aluminum. Starch, lime, and sodium sulfide are some examples.
Cryolite, a chemical compound composed of sodium, aluminum, and fluorine, is used as the electrolyte (current-conducting medium) in the smelting operation. Naturally occurring cryolite was once mined in Greenland, but the compound is now produced synthetically for use in the production of aluminum. Aluminum fluoride is added to lower the melting point of the electrolyte solution.
The other major ingredient used in the smelting operation is carbon. Carbon electrodes transmit the electric current through the electrolyte. During the smelting operation, some of the carbon is consumed as it combines with oxygen to form carbon dioxide. In fact, about half a pound (0.2 kg) of carbon is used for every pound (2.2 kg) of aluminum produced. Some of the carbon used in aluminum smelting is a byproduct of oil refining; additional carbon is obtained from coal.
Because aluminum smelting involves passing an electric current through a molten electrolyte, it requires large amounts of electrical energy. On average, the production of 2 lb (1 kg) of aluminum requires 15 kilowatt-hours (kWh) of energy. The cost of electricity represents about one-third of the cost of smelting aluminum.
The Manufacturing Process
Aluminum manufacture is accomplished in two phases: the Bayer process of refining the bauxite ore to obtain aluminum oxide, and the Hall-Heroult process of smelting the aluminum oxide to release pure aluminum.
There are two main types of processes to make Aluminum.
The Bayer process
1 First, the bauxite ore is mechanically crushed. Then, the crushed ore is mixed with caustic soda and processed in a grinding mill to produce a slurry (a watery suspension) containing very fine particles of ore.
2 The slurry is pumped into a digester, a tank that functions like a pressure cooker. The slurry is heated to 230-520°F (110-270°C) under a pressure of 50 lb/in 2 (340 kPa). These conditions are maintained for a time ranging from half an hour to several hours. Additional caustic soda may be added to ensure that all aluminum-containing compounds are dissolved.
3 The hot slurry, which is now a sodium aluminate solution, passes through a series of flash tanks that reduce the pressure and recover heat that can be reused in the refining process.
4 The slurry is pumped into a settling tank. As the slurry rests in this tank, impurities that will not dissolve in the caustic soda settle to the bottom of the vessel. One manufacturer compares this process to fine sand settling to the bottom of a glass of sugar water; the sugar does not settle out because it is dissolved in the water, just as the aluminum in the settling tank remains dissolved in the caustic soda. The residue (called “red mud”) that accumulates in the bottom of the tank consists of fine sand, iron oxide, and oxides of trace elements like titanium.
5 After the impurities have settled out, the remaining liquid, which looks somewhat like coffee, is pumped through a series of cloth filters. Any fine particles of impurities that remain in the solution are trapped by the filters. This material is washed to recover alumina and caustic soda that can be reused.
6 The filtered liquid is pumped through a series of six-story-tall precipitation tanks. Seed crystals of alumina hydrate (alumina bonded to water molecules) are added through the top of each tank. The seed crystals grow as they settle through the liquid and dissolved alumina attaches to them.
7 The crystals precipitate (settle to the bottom of the tank) and are removed. After washing, they are transferred to a kiln for calcining (heating to release the water molecules that are chemically bonded to the alumina molecules). A screw conveyor moves a continuous stream of crystals into a rotating, cylindrical kiln that is tilted to allow gravity to move the material through it. A temperature of 2,000° F (1,100° C) drives off the water molecules, leaving anhydrous (waterless) alumina crystals. After leaving the kiln, the crystals pass through a cooler.
The Hall-Heroult Process
Smelting of alumina into metallic aluminum takes place in a steel vat called a reduction pot. The bottom of the pot is lined with carbon, which acts as one electrode (conductor of electric current) of the system. The opposite electrodes consist of a set of carbon rods suspended above the pot; they are lowered into an electrolyte solution and held about 1.5 in (3.8 cm) above the surface of the molten aluminum that accumulates on the floor of the pot. Reduction pots are arranged in rows (potlines) consisting of 50-200 pots that are connected in series to form an electric circuit. Each potline can produce 66,000-110,000 tons (60,000-100,000 metric tons) of aluminum per year. A typical smelting plant consists of two or three potlines.
Within the reduction pot, alumina crystals are dissolved in molten cryolite at a temperature of 1,760-1,780° F (960-970° C) to form an electrolyte solution that will conduct electricity from the carbon rods to the carbon-lined bed of the pot. A direct current (4-6 volts and 100,000-230,000 amperes) is passed through the solution. The resulting reaction breaks the bonds between the aluminum and oxygen atoms in the alumina molecules. The oxygen that is released is attracted to the carbon rods, where it forms carbon dioxide. The freed aluminum atoms settle to the bottom of the pot as molten metal. The smelting process is a continuous one, with more alumina being added to the cryolite solution to replace the decomposed compound. A constant electric current is maintained.
The heat generated by the flow of electricity at the bottom electrode keeps the contents of the pot in a liquid state, but a crust tends to form atop the molten electrolyte. Periodically, the crust is broken to allow more alumina to be added for processing. The pure molten aluminum accumulates at the bottom of the pot and is siphoned off. The pots are operated 24 hours a day, seven days a week.
A crucible is moved down the potline, collecting 9,000 lb (4,000 kg) of molten aluminum, which is 99.8% pure. The metal is transferred to a holding furnace and then cast (poured into molds) as ingots. One common technique is to pour the molten aluminum into a long, horizontal mold. As the metal moves through the mold, the exterior is cooled with water, causing the aluminum to solidify.
The solid shaft emerges from the far end of the mold, where it is sawed at appropriate intervals to form ingots of the desired length. Like the smelting process itself, this casting process is also continuous.
Alumina, the intermediate substance that is produced by the Bayer process, and that constitutes the raw material for the Hall-Heroult process, is also a useful final product. It is a white, powdery substance with a consistency that ranges from that of talcum powder to that of granulated sugar. It can be used in a wide range of products such as laundry detergents, toothpaste, and fluorescent light bulbs. It is an important ingredient in ceramic materials; for example, it is used to make false teeth, spark plugs, and clear ceramic windshields for military airplanes.
An effective polishing compound, it is used to finish computer hard drives, among other products. Its chemical properties make it effective in many other applications, including catalytic converters and explosives. It is even used in rocket fuel—400,000 lb (180,000 kg) is consumed in every space shuttle launch. Approximately 10% of the alumina produced each year is used for applications other than making aluminum.
The largest waste product generated in bauxite refining is the tailings (ore refuse) called “red mud.” A refinery produces about the same amount of red mud as it does alumina (in terms of dry weight). It contains some useful substances, like iron, titanium, soda, and alumina, but no one has been able to develop an economical process for recovering them.
Other than a small amount of red mud that is used commercially for coloring masonry, this is truly a waste product. Most refineries simply collect the red mud in an open pond that allows some of its moisture to evaporate; when the mud has dried to a solid enough consistency, which may take several years, it is covered with dirt or mixed with soil.
Several types of waste products are generated by the decomposition of carbon electrodes during the smelting operation. Aluminum plants in the United States create significant amounts of greenhouse gases, generating about 5.5 million tons (5 million metric tons) of carbon dioxide and 3,300 tons (3,000 metric tons) of perfluorocarbons (compounds of carbon and fluorine) each year.
Approximately 120,000 tons (110,000 metric tons) of spent pot lining (SPL) material is removed from aluminum reduction pots each year. Designated a hazardous material by the Environmental Protection Agency (EPA), SPL has posed a significant disposal problem for the industry. In 1996, the first in a planned series of recycling plants opened; these plants transform SPL into glass frit, an intermediate product from which glass and ceramics can be manufactured. Ultimately, the recycled SPL appears in such products as ceramic tile, glass fibers, and asphalt shingle granules.
The Future of Aluminum
Virtually all of the aluminum producers in the United States are members of the Voluntary Aluminum Industrial Partnership (VAIP), an organization that works closely with the EPA to find solutions to the pollution problems facing the industry. A major focus of research is the effort to develop an inert (chemically inactive) electrode material for aluminum reduction pots. A titanium-diboride-graphite compound shows significant promise. Among the benefits expected to come when this new technology is perfected are the elimination of greenhouse gas emissions and a 25% reduction in energy use during the smelting operation.
How Aluminum Works
If there were ever an element that could have been voted “least likely to succeed,” it would be aluminum. Although ancient Persian potters added aluminum to their clay to strengthen their pottery, pure aluminum wasn’t discovered until 1825. By then, humans had been using several metals and metal alloys (or mixtures of metal such as bronze) for thousands of years.
Even after its discovery, aluminum seemed destined for obscurity. Chemists could only isolate a few milligrams at a time, and it was so rare that it sat beside gold and silver as a semiprecious metal. Indeed, in 1884, the total U.S. production of aluminum was just 125 pounds (57 kilograms)
How people call Aluminum in the United States and the rest of the world
Are Two I’s Better Than One?
In the United States, we call it “aluminum.” But the rest of the world, including the International Union Pure and Applied Chemistry, calls it “aluminum.” You can trace the confusion back to Sir Humphry Davy, who first identified the then-unknown element as “aluminum.” This he later changed to “aluminum” and finally to “aluminum,” which carried an ending similar to potassium and sodium, other metals Davy discovered.
Like dozens of other elements on the periodic table, aluminum is naturally occurring. As with all elements, aluminum is a pure chemical substance that can’t be broken down into something simpler. All elements are arranged in the periodic table by their atomic number the number of protons in their nucleus. Aluminum’s lucky number is 13, so an aluminum atom has 13 protons. It also has 13 electrons.
The elements located above and below aluminum on the periodic table form a family, or group, that shares similar properties. Aluminum belongs to group 13, which also includes boron (B), gallium (Ga), indium (In), and thallium (Tl). The table to the right shows how these elements would be arranged on the periodic table. Notice that each element is represented by a symbol and that the symbol for aluminum is Al. The number above each symbol is the element’s atomic weight, measured in atomic mass units (AI). Atomic weight is the average mass of an element determined by considering the contribution of each natural isotope. Aluminum’s atomic weight is 26.98 AMU.
Chemists classify the elements in group 13 as metals, except for boron, which isn’t a full-fledged metal. Metals are generally shiny elements that conduct heat and electricity well. They’re also malleable able to be hammered into various shapes and ductile able to be drawn into wires. These characteristics certainly apply to aluminum. In fact, aluminum is often used in cookware because it conducts heat so efficiently. And only copper conducts electricity better, which makes aluminum an ideal material for electrical material, including light bulbs, power lines, and telephone wires. Other important properties of aluminum are listed below:
- Melting point: 660 degrees C (933 K; 1,220 degrees F)
- Boiling point: 2,519 degrees C (2,792 K; 4,566 degrees F)
- Density: 2.7 g/cm3
- High reflectivity
- Resistant to corrosion
These final two properties make aluminum particularly useful. Its corrosion resistance is due to chemical reactions that take place between the metal and oxygen. When aluminum reacts with oxygen, a layer of aluminum oxide forms on the outside of the metal. This thin layer shields the underlying aluminum from the corrosive effects of oxygen, water, and other chemicals. As a result, aluminum is especially valuable for use outdoors. It also doesn’t produce sparks when struck, which means you can use it near flammable or explosive materials.
Aluminum exists in nature in various compounds. To take advantage of its properties, it must be separated from the other elements that combine with it – a long, complex process that starts with a rock-hard material known as bauxite.
After it undergoes that process, aluminum is very soft and lightweight in its pure form. Sometimes it’s desirable to change these properties to make aluminum stronger and harder, for instance.
To accomplish this, metallurgists will combine aluminum with other metallic elements, forming what is known as alloys. Aluminum is commonly alloyed with copper, magnesium, and manganese. Copper and magnesium increase the strength of aluminum, while manganese enhances aluminum’s corrosion resistance.
Mining and Refining Aluminum
Aluminum isn’t found in nature as a pure element. It exhibits relatively high chemical reactivity, which means it tends to bond with other elements to form compounds. More than 270 minerals in Earth’s rocks and soils contain aluminum compounds. This makes aluminum the most abundant metal and the third most abundant element in Earth’s crust. Only silicon and oxygen are more common than aluminum. The next most common metal after aluminum is iron, followed by magnesium, titanium and manganese.
The primary source of aluminum is an ore known as bauxite. An ore is any naturally occurring solid material from which a metal or valuable mineral can be obtained. In this case, the solid material is a mixture of hydrated aluminum oxide and hydrated iron oxide. Hydrated refers to water molecules that are chemically bound to the two compounds. The chemical formula for aluminum oxide is Al2O3. The formula for iron oxide is Fe2O3.
Deposits of bauxite occur as flat layers lying near the Earth’s surface and may cover many miles. Geologists locate these deposits by prospecting taking core samples or drilling in soils suspected of containing the ore. By analyzing the cores, scientists are able to determine the quantity and quality of the bauxite.
An aerial view of a bauxite mine and alumina processing plant in Australia
After the ore is discovered, open-pit mines typically provide the bauxite that will eventually become aluminum. First bulldozers clear land above a deposit. Then workers loosen the soil with explosives, which bring the ore to the surface. Giant shovels then scoop up the bauxite-rich soil and dump it into trucks, which carry the ore to a processing plant. France was the first site of large-scale bauxite mining. In the United States, Arkansas was a major supplier of bauxite before, during, and after World War II. But today, the material is predominantly mined in Australia, Africa, South America, and the Caribbean.
The first step in the commercial production of aluminum is the separation of aluminum oxide from the iron oxide in bauxite. This is accomplished using a technique developed by Karl Joseph Bayer, an Austrian chemist, in 1888. In the Bayer process, bauxite is mixed with caustic soda, or sodium hydroxide, and heated under pressure. The sodium hydroxide dissolves the aluminum oxide, forming sodium aluminate.
The iron oxide remains solid and is separated by filtration. Finally, aluminum hydroxide introduced to the liquid sodium aluminate causes aluminum oxide to precipitate, or come out of the solution as a solid. These crystals are washed and heated to get rid of the water. The result is pure aluminum oxide, a fine white powder also known as alumina.
Alumina is a handy material in its own right. Its hardness makes it useful as an abrasive and as a component in cutting tools. It can also be used to purify water and to make ceramics and other building materials. But its primary use is to act as a starting point to extract pure alum.
Transforming alumina – aluminum oxide – into aluminum represented a major milestone in the industrial revolution. Until modern smelting techniques evolved, only small quantities of aluminum could be obtained. Most early processes relied on displacing aluminum with more reactive metals, but the metal remained expensive and relatively elusive. That all changed in 1886 – the year two aspiring chemists and industrialists developed a smelting process based on electrolysis.
Electrolysis literally means “breaking down by electricity,” and it can be used to decompose one chemical into component chemicals. The traditional setup for electrolysis requires two metal electrodes being submerged in a liquid or molten sample of a material containing positive and negative ions.
When the electrodes are connected to a battery, one electrode becomes a positive terminal or anode. The other electrode becomes a negative terminal or cathode. Because the electrodes are electrically charged, they attract or repel charged particles dissolved in the solution. The positive anode attracts negatively charged ions, while the negative cathode attracts positively charged ions.
Sir Humphry Davy, the British chemist credited with giving aluminum its name, tried unsuccessfully to produce aluminum by electrolysis in the early 1800s. The French schoolteacher and amateur chemist Henri Saint-Claire Deville also came up empty-handed. Then, in February 1886, after several years of experimentation, American Charles Martin Hall came across just the right formula:
passing a direct current through a solution of alumina dissolved in molten cryolite, or sodium aluminum fluoride (Na3AlF6). Until 1987, cryolite was mined from deposits found on the west coast of Greenland. Today, chemists synthesize the compound from the mineral fluorite, which is much more common.
Aluminum smelting Process
The steps in aluminum smelting are described below:
Alumina is dissolved in molten cryolite at 1,000 degrees C (1,832 degrees F). This may seem like an extraordinarily high temperature until you realize that the melting point of pure alumina is 2,054 degrees C (3,729 degrees F). Adding cryolite allows the electrolysis to occur at a much lower temperature.
The electrolyte is placed in an iron vat lined with graphite. The vat serves as the cathode.
Carbon anodes are immersed in the electrolyte.
Electrical current is passed through the molten material.
At the cathode, electrolysis reduces aluminum ions to aluminum metal. At the anode, carbon is oxidized to form carbon dioxide gas.
Molten aluminum metal sinks to the bottom of the vat and is drained periodically through a plug.
2Al2O3 + 3C -> 4Al + 3CO2
The aluminum smelting process developed by Hall resulted in large amounts of pure aluminum. Suddenly, the metal was no longer rare. The idea of producing aluminum via an electrolytic reduction in cryolite wasn’t rare, either.
A Frenchman by the name of Paul L.T. Heroult came up with the same idea just a few months later. Hall, however, received a patent for the process in 1889, one year after he founded the Pittsburgh Reduction Company, which would later become the Aluminum Company of America or Alcoa. By 1891, aluminum production reached well over 300 tons (272 metric tons).
On the left, you can see one of the giant pots, full of aluminum ready to be poured into molds.
The vats used in the Hall-Heroult process are known as pots. A large pot can produce more than 2 tons of aluminum each day. But companies can and do multiply that output by connecting several pots together in potlines. One smelting plant may contain one or more potlines, each with 200 to 300 pots. Inside these pots, aluminum production continues day and night to make sure the metal remains in its liquid form.
Once a day, workers siphon aluminum from the potlines. Much of the metal is set aside to become fabricating ingots. To make a fabricating ingot, molten aluminum proceeds to large furnaces where it can be mixed with other metals to form alloys. From there, the metal undergoes a cleaning process known as fluxing. Fluxing uses gases such as nitrogen or argon to separate impurities and bring them to the surface so they can be skimmed away. The purified aluminum is then poured into molds and cooled rapidly by spraying cold water over the metal.
Some of the aluminum siphoned from the potlines isn’t alloyed or cleaned. Instead, it’s poured directly into molds, where it cools slowly and hardens to form foundry (or remelt) ingots. Primary aluminum plants sell remelt ingots to foundries. Foundries return the aluminum to its liquid state and proceed with the alloying and fluxing themselves. They then turn the aluminum into various parts – for appliances, automobiles, and other applications – by using the following fabricating techniques.
Casting: Aluminum can be cast into an infinite variety of shapes by pouring the molten metal into a mold. As the aluminum cools and hardens, it takes the shape of the mold. Casting is used to make solid, uniquely shaped objects, such as parts for car engines, aluminum hammers, and the bottoms of electric irons.
Rolling: By repeatedly passing heated aluminum ingots through heavy rollers, the metal can be flattened into thin sheets or even wafer-thin foils. It takes about 10 to 12 passes to make the thinnest foils, which can be a mere 0.15-millimeter thick.
Extruding: Extrusion involves forcing softened aluminum through a die. The shape of the die opening determines the shape of the extruded aluminum.
Forging: Forging, a process whereby aluminum is hammered or pressed, results in superstrong metal. This method makes forged aluminum ideal for stress-bearing parts of aircraft and automobiles.
A Beverage Can Is Born
A beverage can starts with a circular piece of metal punched from an aluminum sheet. This circle, which is 5.5 inches (14.0 cm) in diameter, is called a blank. One machine draws the blank into a cup with a diameter of 3.5 inches (8.9 cm). A second machine redraws the cup, elongating it, ironing it, and thinning out the sides. Finally, the can is cleaned, decorated, and “necked” to accommodate the lid.
* Drawing: To make wire, an aluminum rod is pulled through a series of successively smaller dies, a process known as drawing. Drawing aluminum can produce wire that is less than 10 millimeters in diameter.
- Machining: Traditional machining operations, such as turning, milling, boring, tapping, and sawing, are easily performed on aluminum and its alloys. Machining is often used to produce bolts, screws, and other small pieces of hardware.
Aluminum is an attractive metal and often requires no finish. But it can be polished, painted, and electroplated. For example, beer and soda makers use a printing process to affix their labels on aluminum cans (see sidebar). Typical printing formulations are often lacquer coatings that both adhere well to the aluminum and provide aesthetic appeal. Of course, such finishes are a concern when it comes to recycling because they must be removed. In the next section, we’ll explore how aluminum is recycled in detail.
Using and Recycling of Aluminum
Due to its versatility, aluminum lends itself to numerous applications. In fact, it’s the second-most used metal after steel, with annual primary production reaching 24.8 million tons (22.5 million metric tons) in 2007 International Aluminum Institute. Much of that output goes to the 187 billion aluminum cans produced worldwide Novelis.
The automotive industry is aluminum’s fastest-growing market. Making car parts from aluminum – everything from wheel rims to cylinder heads, pistons, and radiators makes a car lighter, reducing fuel consumption and pollution levels. By some estimates, a car incorporating 331 pounds (150 kg) of aluminum should see fuel consumption reduced by 0.43 gallons per 100 miles
Here are some other important uses of aluminum.
Automotive and transportation: car and motorcycle parts, airplane bodies and parts, license plates
Building and construction: siding and roofing, gutters, window frames, interior, and exterior paint, hardware
Cans and closures: beverage and food cans, bottle closures
Packaging: aluminum foil, foil wraps, aluminum trays, candy, and gum wrappers
Electrical: power and telephone lines, light bulbs
Health and hygiene: antacids, astringents, buffered aspirin, food additives
Cooking: utensils, pots, and pans
Sporting goods and recreation: golf clubs and baseball bats, lawn furniture
Frequently Asked Questions (FAQs)
Following are most common questions asked about the aluminum
Is aluminum metal or nonmetal?
Aluminum is a Metal. It is a silvery-white, soft, non-magnetic, and ductile metal in the boron group.
Aluminum is the most abundant metallic element in Earth’s crust and the most widely used nonferrous metal.
What metals is Aluminium made of?
A few of the metals commonly used to make aluminum alloys include boron, copper, lithium, magnesium, manganese, silicon, tin, and zinc.
Who named Aluminum?
The metal was named by the English chemist Sir Humphry Davy (who, you may recall, “abominated gravy, and lived in the odium of having discovered sodium”), even though he was unable to isolate it: that took another two decades’ work by others.
Is aluminum foil a metal?
A foil is a very thin sheet of metal, usually made by hammering or rolling. Foils are most easily made with malleable metals, such as aluminum, copper, tin, and gold. Foils usually bend under their own weight and can be torn easily.
Is Aluminium made from steel?
Today, aluminum is the most commonly used metal in the world after iron and steel Aluminum is at its most versatile when it’s combined with other metals to form aluminum alloys. The alloying process gives aluminum improved properties to suit a range of applications.
Is Aluminum considered a metalloid?
Aluminum is just on the mental side of the border between metals and metalloids, so it is not considered to be a metalloid. Metalloids have properties of both metals and non-metals. Some of the metalloids, such as silicon and germanium, are semi-conductors., whereas aluminum is a good conductor of electricity.
What can I do to know if a metal is Aluminum or not?
There are some things you can do to get an idea of what kind of metal you have. These are by no means precise, but you can at least make an educated guess.
Is it magnetic? If yes, it’s not aluminum. If not, it could be aluminum but might be non ferritic stainless steel or something.
Is it heavy? The aluminum is pretty light. Much lighter than the same volume of steel. This is a very subjective test and might take some experience to be able to tell.
Is it coated? Painted or otherwise coated aluminum isn’t uncommon, but in some applications a coating isn’t necessary to prevent corrosion on aluminum because of the oxide layer that forms naturally. Bare aluminum is light grey, lighter than steel, for reference.
Is it rusty? If so, definitely not aluminum. Aluminum can corrode, but it looks like a crumbly white substance, not orange like rust.
Is it soft? Even mild steel is harder than most aluminum alloys. Try scratching or striking it with something, if it deforms readily it’s probably aluminum.
Is Aluminum found as pure Metal?
Actually No, because aluminum was quite reactive ( reactivity series) and exists as metal oxide, conversely, it is found on the earth’s crust as aluminum oxide, Al2O3. in fact, aluminum ore namely bauxite in order to get pure aluminum, Al. You have to extract bauxite by electrolysis (decomposition of aluminum oxide into aluminum and oxide) through the Hall-Heroult process in industrial terms.
In short of this article, it is mentioned that Aluminum is a Metal which is a silvery-white, soft, non-magnetic, and ductile metal in the boron group. There are many properties of Aluminum that are mentioned in this article. They are :
- Symbol: Al
- Atomic mass
- Atomic number: 13
- Electron configuration: Ne 3s²3p
- Melting point: 660.3 °C
- Density: 2.7 g/cm³
Aluminum is made in the following stages:
- Finding Aluminum Ore
- Mining Aluminum
- Refining the Bauxite
4 .Aluminum Smelting
In the making of Aluminum, all the raw materials are combined to form a mixture which then is turned into Aluminum
There are 2 processes in which the Aluminum is made.
The Bayer process
The Hall-Heroult process