Engineering Materials

Background

History

Processing

Uses

Properties

Copper

part of the boron group in the periodic table

third most abundant element in the Earth’s crust

ability to resist corrosion due to passivation

capable of being a super conductor

almost never found in its elemental state

aluminum is found only in chemical compounds with other elements

lightweight, strong, nonmagnetic, and nontoxic

conducts heat and electricity and reflects heat and light

strong but easily workable

aluminum can easily and economically be recycled into new products

surface of aluminum quickly oxidizes to form an invisible barrier to corrosion

potters made their strongest vessels from clay that contained aluminum oxide

aluminum compounds in fabric dyes, cosmetics, and medicines

Bauxite is most useful for producing pure aluminum

consists of 45-60% aluminum oxide

4 lb (2 kg) of bauxite to produce 1 lb (0.5 kg) of aluminum metal

Caustic soda is used to dissolve the aluminum compounds

the Bayer process and Hall-Heroult process

Cryolite used as the electrolyte in smelting

Aluminum fluoride is added to lower the melting point of the electrolyte solution

Carbon electrodes transmit the electric current through the electrolyte

production of 2 lb (1 kg) of aluminum requires 15 kilowatt-hours (kWh) of energy

refining the bauxite ore to obtain aluminum oxide

1. The bauxite ore is mechanically crushed

2. It is mixed with caustic soda and processed into a slurry

3. The slurry is pumped into a digester

4. It is passed through a series of flash tanks that reduce the pressure

5. The slurry is pumped into a settling tank

6. The remaining liquid is pumped through cloth filters

7. The filtered liquid is pumped through a series of precipitation tanks

8. Seed crystals of alumina hydrate are added

9. The crystals precipitate and are removed.

10. After washing, they are transferred to a kiln for calcining.

11. After leaving the kiln, the crystals pass through a cooler.

process of smelting the aluminum oxide to release pure aluminum

12. Smelting of alumina into metallic aluminum takes place in a steel vat called a reduction pot

13. Within the reduction pot, alumina crystals are dissolved in molten cryolite at a temperature of 1,760-1,780° F (960-970° C)

14. A crucible is moved down the potline, collecting molten aluminum, which is 99.8% pure

15. The metal is transferred to a holding furnace and then cast as ingots

Alumina is used in laundry detergents, toothpaste, and fluorescent light bulbs

Also an important ingredient in ceramic materials

largest waste product generated in bauxite refining is the tailings (red mud)

Aluminum plants in the United States create significant amounts of greenhouse gases

Lightweight: a third of the weight of steel, brass, or copper of equal volume

Strength: can stand heavy pressures and loads

Electrical Conductivity: conductivity is twice of copper

Thermal Conductivity: can quickly spread heat in an even and quick manner

Non-toxic: makes it ideal for packing cooking material

Reflectivity: reflects light as well as other forms of radiant energy.

Ductility: it can be drawn into wires

Miscible: alloying it with metals make it more malleable, conductive, and resilient

Finishing: coatings and finishes can be used over it

Costing: cheap and economical

Recyclable: cheaper than newly mined and processed aluminum

Durability

Aerospace: percentage in aircraft frames is 70%

Automotive: advantage of lightness, resistance and recyclability

Marine: lightening hulls by 40% to 50% over steel

Rail: lighter structures, resistance and durability

Building: commonly used in extruded, sheet-rolled or molded forms

Packaging: modern packaging is one of the leading consumers of aluminum

Mechanical Industry and Engineering: aluminum parts can reduce inertia

HVAC exchangers and the plastics industry

Energy Distribution: low density and excellent electrical conductivity

Sports and leisure

CopperBackground

History

Processing

Uses

Properties

With very high thermal and electrical conductivity

Soft, malleable, and has a reddish-orange color

Ductile, non-magnetic, and corrosion resistant

Melting point at 1981 F or 1083 C

Bronze Age (3500BC)

An alloy of copper and tin

Used to make tools and weapons

Brass, a copper and zinc alloy

Used in decoration and later, weapons

Continued use of brass

Copper used as a conductor

Brass continued use in instruments

Copper in electrical applications

Copper in electronics

Excellent heat conductivity

Excellent electrical conductivity

Good corrosion resistance

Good biofouling resistance

Machinability

Retention of electrical and mechanical properties at cryogenic temperatures

Non-magnetic

Power transmission lines

Electrical wiring, cables and busbars

Spark plugs

Electrodes

Cooking utensils

Heat exchangers

Plumbing

Refrigeration tubing

Water-cooled copper crucibles

most common source are sulfide ores

most common sulfide ore is chalcopyrite

varies according to type of ore and desired purity

unwanted materials are physically or chemically removed

concentration of copper is progressively increased

1. sulfide ores are taken from huge open-pit mines

2. material located above the ore is called overburden

3. exposed ore is scooped up by large power shovels

1. ore is crushed in a series of cone crushers

2. crushed ore is ground even smaller by mills

3. mixed with water and placed in a rod mill

4. mixture is further broken up in ball mills

5. slurry mixed with various chemical reagents

6. A liquid, called a frother, is also added

7. mixture pumped into flotation cells

8. copper particles cling to bubbles as they rise

1. concentrate is fed into a furnace along with a silica material, flux

2. concentrate and flux melt and collect in the bottom

3. iron chemically combines with flux to form slag

4. sulfur combines with the oxygen to form sulfur dioxide

5. molten material in the bottom is called the matte

6. molten matte is drawn and poured into a converter

7. resulting molten material is called the blister

1. blister copper is heated in a refining furnace

2. poured into molds to form electrical anodes

3. copper anode is placed in an individual tank

4. sheet of copper is placed on the opposite end

5. tanks are filled with an acidic copper sulfate solution

6. electrical current is passed through each tank

7. copper is stripped off the anode and deposits on the cathode

8. After 9-15 days, the current is turned off

9. Copper is cast into ingots, rolls, etc.

sulfuric acid

Gold, silver, and other precious metals

overburden, tailings and slag

http://www.madehow.com/Volume-4/Copper.html

http://www.azom.com/article.aspx?ArticleID=2856

http://www.chemistryexplained.com/elements/A-C/Aluminum.html

http://resources.schoolscience.co.uk/CDA/14-16/chemistry/copch0pg2.html

http://education.jlab.org/itselemental/ele029.html

http://www.madehow.com/Volume-5/Aluminum.html#ixzz398Y6sFuh

http://www.constellium.com/technology-center/aluminium-alloy-applications

http://www.buzzle.com/articles/aluminum-uses-of-aluminum.html