Importance—Aluminum Electrical Wires

Electricity flows through silver more easily than it does through any other metal. In most cases, however, metals such as copper or aluminum are used because they are less expensive. But sometimes, an electrical device is so important that cost is not a consideration. For example, electrical devices on spacecraft, satellites, and aircraft must work reliably and effi-ciendy. The cost of using silver is not as important as it would be in a home appliance. Thus, silver is used for electrical wiring and connections in these devices. 

Copper, however, is used in applications where purity is important. Copper, when pure, is ductile and an excellent electrical conductor, so it needs to be refined to be used in electrical wiring. Copper anodes (blister copper) are suspended in a water solution containing sulfuric acid and copper sulfate with steel cathodes. Electrolysis results in dissolution of copper from the anode and migration of copper ions to the cathode, where purified metal is deposited. The result is copper of 99.9 percent purity. A similar procedure may be used in recycling copper. Other metals that are electrorefined include aluminum. 

For electrical wire and cables, the combination of conductivity and low weight is very important. In the metallurgical industry, aluminum is used as a deoxidation agent in steel manufacturing (see Chapter 8 Iron) and as an alloying element in magnesium, titanium and copper alloys. 

The uses of aluminum are similar to those of the light metals, some of which have previously been discussed under magnesium. Aluminum is also used in fabricating wire cables for electric-power transmission lines in the manufacture of kitchen utensils, furniture, and paint and in producing a wide variety of other useful articles. In connection with the general topic of alloys, attention is called to several important alloys containing aluminum. 

Aluminum. Aluminum is used extensively in modem India particularly in house wiring and the transmission of electrical power, about 50% of the production going for this use. All of the technology has been imported primarily from the United States. Production has increased from about 3000 metric tons in 1951 to 180,000 metric tons in 1977. It is estimated that the demand for aluminum in 1984 will be 400,000 metric tons. The demand is likely to increase dramatically since the per capita use in India is 0.4 vs. 22 kg in the United States and of 2.9 kg in the rest of the world. Aluminum today is produced in five producing plants, four of them in the private sector and one in the pubhc sector. The most serious problem with the aluminum industry is the pricing pohcy. By law, 50% of production goes to the government at a fixed price, so-called levy metal. The current levy price is 903 a metric ton vs. a production cost of 1,084 per metric ton. 

The metals are solids at room temperature (mercury is an exception). They have high luster, are good conductors of heat and electricity, are malleable (can be rolled or hammered into sheets), and are ductile (can be drawn into wires). Most metals have a high melting point and a high density. Familiar metals are aluminum, chromium, copper, gold, iron, lead, magnesium, mercury, nickel, platinum, silver, tin, and zinc. Less familiar but still important metals are calcium, cobalt, potassium, sodium, uranium, and titanium. 

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