lecture 17: use of metals

rocks

assemblage of minerals

mineral

naturally occurring chemical compound in solid state

metal

pure metallic element or an alloy

ore mineral

mineral smelted to extract metal

ore deposits

quantity of rock containing concentrations of ore minerals which may economically be exploited

discovery + use:

Gold and Silver

naturally occurring

ornamental

discovery + use:

other metals

extraction from ores

smelting

discovery + use:

copper

smelted with wood fires from 6,000BC

first metal tools

discovery + use:

bronze

4,000BC

alloy of copper and tin

needs charcoal for smelting

stronger

discovery + use:

Iron

1,000 BC

harder than bronze

charcoal

slightly burnt wood under oxygen starved conditions

cokes coal

impurities removed e.g. water, volatiles

coked coals + iron ores

smelting of high qualities iron

• Steam powered engines 

• Dewatering of mines  

• Deeper mines  

• Metals extractable from large volumes  

steel

not pure iron (Alloy)

→ easier to mold

stainless steel

iron + chromium ( + nickel)

bessemer converter

hot air blown through molten iron to oxidise impurities

uses of copper

conductivity

uses of galvanised steel

adding zinc to surface later to steel

more rust proof and protective

uses of aluminium

light metal for aircrafts

uses of lead

combustion for batteries

uses of neodymium

high strength magnets

transfer into currents

offshore wind turbines

uses of lithium

electricity storage for cars

uses of silicon/germanium

semiconductor chips for computers

platinum/palladium

catalytic converters

how many metals are used in phones?

<80

rare earth metals

• relatively rare

• high tech products

• major geopolitical context

• Can be substituted by substitutes that are less effective + costly