Metals

Metals

1. 1.1 How metals are obtained:

   • Metals come from mineral which are part of rocks
     • Mining is carried out in surface mines or in underground mines
       • Useful minerals: ore
         • Useless minerals: gangue
           • Metallurgy is the group of industries involved in mining and transforming metallic minerals
         • 1. separe ore from the gangue
           • 2. make metal from the ore
   • 1.2 Classifying metals:
     • Ferrous metals:
       • Non-ferrous metals:
         • Not iron or very little of it + copper, bronze, aluminium and zinc
       • Iron + pure iron, steel and cast iron
     • 1.3 Properties of metals:
       • They are:
         • Hard, non-adhesive, cold, smooth, magnetic (sometimes), toxic (sometimes), thermal, good electrical...

2. 2. Ferrous metals:

   • IRON MINERALS
     • Pure iron
       • Good magnetic propeties
       • Only melts at high Tº, difficult to machine, fragile, brittle.
         • Uses: rarely used, to electronic
     • and its alloys
       • Steel
         • Cast iron
           • Hard, resistant and easy to weld
             • Uses: in construction, car chassis, doing transports, tools...
         • Hard, resistant
           • Uses: machine parts, casing for engines, pistons, street lamps...
   • 2.1 The steel-making process
     • The iron mineral is washed
       • It is crushed and sieved to separate the gangue from the ore
         • Mix the ore with coke and limestone
           • Put it into a blast furnace (+ 1500ºC)
             • Slag is obtained (by-product made up of carbon and more)
               • The pig iron is taken to a converter to:
                 • Reduce the percentage of carbon
                 • Eliminate impurities
                 • Adjust the composition of the steel by adding other elements such as nickel or chrome
                 • Thermal processes to improve the mechanical properties of steel
                   • Quenching
                     • Tempering
                       • The hot metal cools very slowly
                     • The metal cools very quickly when is red hot

Images and files in the map