Metals and Materials: Properties, Extraction, and Uses of Tin, Aluminum, Copper, and More

Metals and Materials: Properties, Extraction, and Uses

Tin (Sn)

Tin is obtained from cassiterite (SnO₂). It has a bright, pure color and malleability, and it is very soft and fragile when hot. At -18 °C it becomes brittle, and when bent it produces a cracking sound known as the "cry of tin."

Alloys: bronze, soft solder, and low melting point alloys.

Extraction process:

• Crushing and grinding in mills
• Concentration of the ore by flotation
• Oxidation in a furnace to remove impurities
• Reduction of the metal in a furnace to obtain tin of 99% purity

Aluminum (Al)

Aluminum is obtained from bauxite. It has very good resistance to air and stainless properties. It is a good conductor of electricity and heat, malleable, and very ductile.

Bayer process:

1. The bauxite is mined and transported to the plant.
2. It is ground into a fine powder and stored in silos.
3. The powder is mixed with caustic soda, lime, and hot water, which dissolves the alumina.
4. The solution is heated and then cooled in heat exchangers.
5. After cooling, the solution is diluted with water and alumina precipitates.
6. The precipitate is filtered and heated in a furnace to eliminate moisture.
7. The alumina is dissolved in molten cryolite and subjected to electrolysis, which decomposes it into aluminum and oxygen.

Alloys: aluminum + copper + silicon.

Production: molded parts obtained by injection.

Glass

Glass is obtained by mixing quartz sand and carbonate with sodium lime. It is hard, transparent, light, and resistant to acids. It is also an insulating material and a good thermal conductor.

Refractory Materials

Refractory materials are made from clay mixed with oxides of thorium, beryllium, and zirconium. They are fired at 1300 °C and then cooled slowly. They are used in refractory bricks and ultra-ceramic products.

Fine-Grained Ceramics

Clay is mixed with metallic oxides and fired at 1300 °C. Sea salt interacts with the surface layer, forming a thin vitrified layer of alkaline aluminosilicate that gives the material its resistance.

Copper (Cu)

Copper has high thermal and electrical conductivity. It is a reddish, bright metal that is very ductile, malleable, and used in electrical cables. It is used to manufacture telephone motors and coils, and it forms the basis of many aluminum alloys.

• Brass: an alloy of copper and zinc, used to manufacture tubes, valves, and turned parts.
• Bronze: copper and tin. It is used in gears and bells.

Cupro-aluminum: copper + aluminum, used in boat propellers and turbines.

Lead (Pb)

Lead is obtained from galena. It has a blue-gray color, is malleable, and resists sulfuric acid. It is a poor conductor of heat and electricity.

Applications: pure lead is used in antioxidant paints, pipes, and battery coatings.

Alloys: lead and tin, used in soldering.

Zinc (Zn)

Zinc is obtained from calamine and blende. It resists oxidation and corrosion in air and water but is attacked by acids and salts. It is malleable and expands between 100 and 150 °C.

Uses:

• Zamak (Al + Cu + Zn): high-quality surface parts with precision shapes, such as gutters and fittings.
• Galvanizing: electrolytic coating of a metal with zinc through electrolysis.

Titanium (Ti)

Titanium is obtained from ilmenite. It has a rutile color, is silver-colored, hard, and highly resistant. It is used in industry, in the manufacture of special structures and medical prostheses. Alternative methods of Kroll process are used in architectural applications. Its extraction is expensive.

Magnesium (Mg)

Magnesium is obtained from carnallite, dolomite, and magnesite. It is a bright, silver-like metal, malleable, but flammable and ductile. It reacts violently with oxygen and is used in pyrotechnics. It is very light and is used in aeronautics.