(2.22C-2.27C) Metal extraction + use

Where are most metals extracted from?

Ores in the Earth’s crust

What is an ore?

A rock containing enough of the desired metal to make it worth extracting

What is the difference in the forms of reactive and unreactive metals when they are found? Why?

Reactive metals are often chemically bonded to other substances (making ores)

higher reactivity = greater chance of having bonded with something

Unreactive methods are often found as uncombined elements.

What is the common ore form of a metal?

Metal oxide

State the reactivity series.

Perhaps Southern Liverpool Can Handle A Couple Zebras. I Honestly Can’t Stand Giraffes.

Potassium

Sodium

Lithium

Calcium

Magnesium

Aluminium

(Carbon)

Zinc

Iron

(Hydrogen)

Copper

Silver

Gold

How is the reactivity series linked to the form of the metal when it is mined?

The higher up it is, the more likely it is to have bonded with another substance

Which metals require electrolysis of the molten substance?

the ones above carbon in the series

Potassium - Aluminium

(Potassium, Sodium, Lithium, Calcium, Magnesium, Aluminium)

What are the cons of electrolysis for metal extraction?

Large amounts of electricity is required, making it an expensive process

Which substances can be separated by carbon as a reducing agent in a blast furnace?

Zinc-Copper

(Zinc, Iron, Copper)

What is carbon extraction?

Carbon displaces the metal from its compound, leaving the metal as a single element.

Carbon needs to be higher than the metal desired for this process.

What are the pros of carbon extraction?

Cheap process because carbon in cheap.

Describe the extraction of iron from hematite.

Occurs in a blast furnace

• Raw materials (coke, hematite, limestone) added to the top

  • coke = carbon

  • hematite = iron

  • limestone = neutralisation of impurities

• Zone 1:

  • hot air is blown in from the bottom

  • the coke burns, forming carbon dioxide

  • exothermic reaction gives off heat

• Zone 2:

  • as temp increases, more coke reacts with CO₂ forming CO

  • carbon dioxide has been reduced

• Zone 3:

  • CO reduces iron(|||) oxide in the iron ore, forming iron

  • this will melt and collect at the bottom of the furnace where is is tapped off

Limestone:

• calcium carbonate thermally decomposes to form calcium oxide

• which reacts with the silicon dioxide, an impurity in the iron ore

• forming calcium silicate by neutralisation

• this melts and collects as molten slag on top of the molten iron

• this is tapped off separately

Describe the extraction of aluminium from bauzite.

Aluminium is above carbon, so cannot be displaced. It is electrolysed.

• Bauxite is purified to make aluminium oxide.

• Dissolved in molten cryolite

  • Al₂O₃ has a high melting point, the resulting solution is lower and doesn’t affect the reaction

• Placed in a chamber which

  • is lined in graphite

    • acts as negative electrode (several blocks act as positive electrode)

  • made from steel

Molten aluminium forms at the bottom of the cell. (cathode)

Oxygen forms at the anode, bonding with the carbon in the graphite, forming CO₂

What are some cons of the aluminium electrolysis?

Anode needs to be replaced as it wears away.

High amounts of electricity is needed- expensive.

What are the properties of aluminium and what is it used for?

Aircraft bodies - low density

Saucepans - conductive, unreactive

electrical cables - conductive

Food cans - non-toxic, corrosion resistance

What are the properties of copper and what is it used for?

Electrical wires - conductive, ductile

Saucepans - conductive, malleable, unreactive

Water pipes - unreactive, malleable

What are the properties of iron and what is it used for?

Building material - strong, ductile, relatively inexpensive

What are the 3 types of steel?

low-carbon, high carbon, stainless

What are the properties of low-carbon steel and what is it used for?

Car body panels - strong, malleable

Wiring - ductile, soft

What are the properties of high-carbon steel and what is it used for?

Cutting tools - hard, wear resistant

more brittle than LCS

What are the properties of stainless steel and what is it used for?

Chemical plants, cutlery, sinks - strong, corrosion resistant

What is an alloy?

A mixture of 2 or more metals / metal + non-metal (normally carbon)

What are the properties of alloys?

stronger/harder than the metals they contain

resistant to corrosion/extreme temperatures

Why are alloys hard?

They contain atoms of different sizes.

This distorts the regular arrangement

making it more difficult for layers to slide over each other.