Metals

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Point 1

Metals:substances form minerals which contain one or more metallic elements.

Many uses and key elements in much things

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Point 1.1

Carried out in surface mine (close to surface), or underground mine (deeper under surface)

The useful minerals:ore

The useless minerals: gangue

They both are together so they must be separated by different physical process. When the ore is separated from the gangue, we make metal from the ore, the ore is taken to an ironworks.

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Point 1.2

Ferrous metals: Main component iron, Include pure iron, steel and cast iron

Non-ferrous metals: Main component non iron,(or very little of it) Include copper, bronze, aluminium and zinc

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1.3

Metals are hard, non-adhesive,cold and very smooth

Some characteristics:

-Good electrical, thermal and acoustic conductors

-Ductile and malleable

-Tough

-They melt at high temperatures, also used for welding

-They expand when the temperature rises and contract when it cools

-Some are magnetic

-Most them rust in contact to air and oxygen

-Can be recycled and reused

-Some are toxic

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Point 2

There are differents process to obtain pure iron and it’s alloy, steel and cast iron:

Depending on the percentage of carbon, ferrous metals are classified:

-Pure iron:Between 0.008% and 0.03%

-Steel:Between 0.03% and 1.76%

-Cast iron:Between 1.76% and 6.67

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Point 2.1

Pure iron:

Properties: Greyish white colour, good magnetic properties, disadvantage only metals at high temperatures, difficult to machine, fragile and brittle.

Uses: Rarely used, used in electronic and electric components

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Point 2.2

Cast Iron:

Properties: Very hard and resistant. Uses: Machine parts, casing for engines, stand for machines, pistons, street lamps, drain covers…

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Point 2.(3)

Steel:

Properties: Very hard and resistant, easy to weld, alloys with chrome and nickel to make stainless steel. Uses: Structures in construction, car chassis,boat trans,machinery,tools,screw, domestic appliances, kitchen utensils, taps...

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Point 3

The steel-making process

-Iron mineral is washed to eliminate impurities

-It’s crushed and sieved to separate the gangue from the ore

-The ore is mixed with coke and limestone, then put into blast furnace with temperatures over 1500ºC

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Point 3.1

Slag obtained: Is a by-product made up of carbon and other impurities

Pig iron is taken to a convert to:

reduce the percentage of carbon

eliminate impurities

adjust composition of the steel by adding other elements such as nickel or chrome

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Point 3.2

To improve the mechanical properties of steel, it undergoes different thermal processes

Quenching: Cooling the metal very quickly when is red hot

Tempering: Hot metal is cooled very slowly

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Point 4

Non-ferrous metals are classifed into the following categories:

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Point 4.1

Metal: Magnesium

From:magnesite, dolomite,carnalilite, epsomite and olivine

Properties:

Shiny, silvery,white; very light, soft malleable,but not very strongly with oxygen

Uses: Pyrotechnics, the aerospace and the car industries, and bicycles

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Point 5

Light metals:

Metal: Aluminium

From: Bauxite

Properties: Silvery white; highly resistant to corrosion; very soft, low density, high malleability and ductility, good at conducting electricity and heat

Uses: High voltage power lines, planes,cars, bicycles, light metalwork, roofing, decoration, kitchen, and drinks cans

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5.1

Titanium:

From: rutile and ilmenite

Properties: Silvery white, shiny, light very hard and strong

Uses: The aerospace industry, building structures and medical prostheses