The Properties and Applications of the Metal Aluminum - Essay Example

Table of Contents ………………………………………………………………………………………………………………..2 Introduction …………………………………………………………….………………………………………………….2 Properties …………………………….…………………………………………………………………………........3 Occurrence ...................................................................................................................4 Extraction and Refinement …………………………………………………………………………………………5 Applications ………………………………………………………………………………………………………………..6 Conclusions and Discussion ….........................................................................................8 Works Cited ....................................................................................................................10 Abstract The paper discusses the properties and applications of the metal aluminum. The various physical and chemical properties aluminum are mentioned in the beginning, followed by a brief discussion of the various forms in which aluminum exists. The occurrence of aluminum with reference to its ores and regions of existence is discussed along with the processes through which aluminum can be extracted. The applications of aluminum according to various distinctive properties in several diverse fields of engineering, industry, manufacturing, technology and everyday life are brought up with an analysis of importance of aluminum for the industrial and economic progress of a country is also presented along with the applications on the basis of which conclusions are drawn in the end. Introduction Aluminum is a member of the group III of the periodic table and is classified as a metal with properties lying midway between metals and metalloids. The 8% by weight of the Earth’s crust is made up of aluminum which makes it the most abundant metal in the Earth’s crust and also the third most abundant element. Though insoluble in water, aluminum is a very reactive material. For using in various applications across different engineering and technology fields aluminum has to be extracted from its ores, a majority of which are oxides of aluminum. The most abundant ore of aluminum is bauxite ore. Aluminum has vast applications and is considered to be the most widely used material in all types of engineering. The property of aluminum which makes it suitable for use in various different kinds of engineering applications is its low density and ability to resist corrosion. The ability to resist corrosion is developed through forming a thin layer of aluminum oxide on the surface of aluminum which makes it a passive material as aluminum oxide is a very less reactive. This phenomenon of placing a layer of oxide on the surface of a metal is known as passivation. The light weight of aluminum makes it useful in aerospace industry and the use of aluminum cladding is also getting popularity in architectural and construction industry. There are many chemical reactions in which aluminum can be used as a catalyst due to its reactive nature. Moreover aluminum has found its applications in various chemical industries. Properties Aluminum is classified as a metal which is very lightweight. The ductility of aluminum lies midway between irons and copper. It can be easily molded into different shapes. The physical appearance of aluminum is very pleasant, varying from shiny gray or silver to dull gray. This why well polished and sometimes painted aluminum is used to enhance the aesthetics of concrete and steel structures. Aluminum is a nonmagnetic material which is soluble in water in some forms and combined states. Aluminum can be combined with various other metals to form alloys, which customizes the properties of aluminum to a great extent, for example pure aluminum has a yield strength of 7-13 MPa, however various aluminum alloys with iron, chromium and cobalt have yield strength which is 80-100 times of the yield strength of pure aluminum, and these alloys can substitute structural steel in various applications in construction. Aluminum exhibits a crystalline molecular structure with face-centered cubic crystals. Such a layered structure gives good electricity and heat conduction properties to aluminum. Aluminum exhibits mechanical properties which are far more flexible as compared to iron or steel. Its low density and relative softness makes it a very workable material and can easily machined and casted. The corrosion resistance of pure aluminum is more than that of aluminum alloys because of the inclusion of other metals such as copper which are more likely to corrode. The silvery appearance of aluminum is greatly enhanced in powdered form and it serves as a silver pigment in silver-colored paints. The reflective and optical properties of aluminum are better than all other metals including gold and silver. Occurrence Aluminum is found in abundance in the earth crust but due to its reactive nature and affinity for oxygen it exists in combined state, either in the form of oxides or silicates. Aluminum has to be extracted from its ores through various metallurgical processes. The various aluminum ores are found very easily in the earth crust and occur in almost all parts of the world but the aluminum present in most of the ores cannot be extracted very easily and almost all of the aluminum for industrial, manufacturing and construction purposes is obtained from the ore bauxite which is formed as a result of hydrolysis of various silicates and oxides of aluminum in the earth crust. When rain and river water flows over the silicates and oxides of aluminum present at the surface of earth crust, they get dissolved in water and flow with it to get deposited at various different sites. These sites are the sources of bauxite ore. Large reserves of bauxite have been found in Australia, Brazil, Guinea, Ghana, Indonesia, Russia, Surinam and Jamaica. The extraction and refining process of aluminum is mostly carried out away from the sites of mining of bauxite where the fuels are easily available because the extraction and refining process of aluminum consumes a lot of energy. The various other ores of aluminum include Bauxite, Feldspar, Cryolite, Corundum, Beryl, Garnet, Spinel, Turquoise etc. Aluminum can also be obtained from volcanic beds and is sometimes obtain as a product of reduction of tetrahdroxoaluminate by bacteria. In addition to these sources of aluminum, pure and stable aluminum can also be created using nuclear process but such a fusion reaction for the formation of aluminum requires a lot of energy and naturally takes place in large stars and sun. Extraction and Refinement Aluminum exists in combined state in the form of oxides and silicates and has to be extracted from its ores to use it in different forms. The bond between aluminum and oxygen is very strong and therefore requires a lot of energy to be broken. For obtaining pure aluminum from its ores a temperature of almost 2000 degree Celsius is required. The most common and widely used method for aluminum extraction is the Hall-Heroult process in which electrolysis takes place at high temperature. The electrolyte used for this purpose is molten Cryolite with calcium fluoride. Another process which is used for refining aluminum is the Bayer’s process. The production of aluminum and the industrial and economic growth of aluminum are directly related to each other and that’s the reason behind the high rates of production of aluminum in the most developed countries including China, USA and Russia. Applications of Aluminum: Due to the properties of aluminum discussed above, it has found numerous applications in industry, transportation, buildings and architecture, and items of daily use including kitchen utensils. Aluminum made articles are found everywhere around us, ranging from cars to aircrafts, pumps to pipelines, utensils to aluminum foils on food items. A few prominent applications are discussed here, Transportation: Aluminum and its alloys are most extensively used in transportation industry due to its very high strength to weight ratio as compared to iron and steels. Passenger cars, motorbikes and light trucks have their bodies made up of aluminum. This helps in reducing the overall weight of the vehicle and hence increases mileage. Ford Motors, General Motors and other prominent automotive manufacturers have come up with automotive designs made up of aluminum which are as much as 55% lighter than equivalent steel designs without compromising on the safety of the vehicle (‘The Aluminum Association’). Use of aluminum has also resulted in cost reduction of the vehicles both in production and manufacturing. Pure aluminum is not suitable for use in aircraft manufacturing except for a few components such as fuel tanks. However, aluminum alloys are extensively used in the aviation industry and has virtually replaced other metals mainly because of their high strength to weight ratio. Aluminum use in the ship building industry can be dated back to 1890 when its properties were appreciated for the particular use. Later, the development of Aluminum – Magnesium alloys made this material most desirable for ship manufacturing. Use of aluminum resulted in development of high speed sea vehicles with better fuel efficiency. The salt water of sea is highly corrosive for pure aluminum metal. Hence, it readily dissolves in the sea water and cannot be used in this form. Passivation is carried out for pure aluminum to deposit a strong layer of aluminum oxide over the aluminum body which resists corrosion. Buildings and Architecture: Owing to its attractive and shinny appearance, aluminum has found its use in many different building applications such as window panes, doors, shelves, partition walls etc. where it is primarily used to enhance the aesthetics of the area. However, recent discoveries have made it clear that aluminum has far important uses than just being aesthetically desirable. Aluminum is a construction material that is “infinitely recyclable” (‘The Aluminum Association’). According to estimates, more than 90% of aluminum used in buildings is recycled. Hence, it is considered an important material for the sustainable building design. Moreover, the shinny surface of aluminum is highly reflecting and it can be effectively used in roofs and window panes etc. to reflect the incoming heat energy in order to avoid heating in summers. Food and Beverages: Aluminum is a nontoxic material. This property combined with its high malleability and formability makes it useful for various applications in food industry. Aluminum foil is a well-known article used to pack sandwiches cakes and other food items. Food items maintain their freshness and taste within the foil. Due to its attractive appearance, it is also being used for garnishing purposes. Aluminum cans are also very popular in the beverages industry. The main reasons for widespread use of aluminum cans are the malleability, recyclability, low cost, and the fact that it is nontoxic. Aluminum cooking utensils were the first aluminum products to appear in the market. These are light weight, durable, cheap yet attractive products readily available in the market in various sizes and forms. Again, the most important reason for their popularity is the nontoxic behavior of aluminum in humans. Aluminum is also very popular in manufacturing of cutlery items. Industrial Machinery: Aluminum is extensively used in industry for various applications where its properties such as corrosion resistance (due to oxide formation), high strength to weight ratio, formability and economy can be put to best use. This includes casings of pumps, gearboxes, small bearings and machine elements, pipes and piping components etc. Aluminum pumps are specially popular in small scale and low pressure applications. Miscellaneous Uses: The list of aluminum applications is not limited to the above mentioned fields only. Aluminum and its alloys are being used as anti – perspiring additives in deodorants. However, its use is being discouraged by medical practitioners. Thermite process is a welding technique which involves large amount of heat generation from reaction of aluminum with other metals such as copper, zinc etc. Conclusions and Discussion Aluminum is a metal whose mechanical and physical properties are best among the metals and that’s why it is used in almost all engineering and technology applications. The light weight and high strength to weight ratio has made it possible for engineers to use it in transportation and for construction purposes. The shiny appearance of aluminum when polished makes it aesthetically a favorable material and it is used in architectural works of a building. The non-toxic and passive nature of aluminum (when covered with aluminum oxide layer) makes it a very useful material for preserving and storing food and beverages. Aluminum metal is very important for the economic and technological growth of a country as most of the industry is based on aluminum directly (in the form of aluminum fabricated equipment) or indirectly in the form of aluminum applied products. Works Cited The Aluminum Association. N.p., n.d. Web. 25 Apr. 2011. . Green, John. Aluminum Recycling and Processing for Energy Conservation and Sustainability. N.p.: ASM International, 2007. Print. Hasan, Heather. Aluminum. N.p.: The Rosen Publishing Group, 2006. Print. Hatch, John. Aluminum: properties and physical metallurgy. N.p.: ASM International, 1984. Print. Kaufman, John. Introduction to aluminum alloys and tempers. N.p.: ASM International, 2000. Print. Kissell, Randolph, and Robert Ferry. Aluminum Structures: a guide to their specifications and design. N.p.: John Wiley and Sons., 2002. Print. Richards, Joseph. Aluminum: Its history, occurence, properties, metallurgy and applications including its alloys. N.p.: Nabu Press, 2010. Print. Totten, George, Scott Mackenzie, and Marcel Dekker. Handbook of Aluminum: alloy production and materials manufacturing. N.p.: CRC Press, 2003. Print. Read More