Metals and their uses

Metals and their uses

1. What is an ore?

   • Ores are found in the earth's crust. A metal ore is a mineral or mixture of minerals of which economically viable amounts of pure metal may be extraced. If there is not enough pure metal to be economically viable then the metal is therefor eno extracted as to extract an ore is an expensive process.
     • After ores has been mined, they may be concentrated before the metal is extracted and purified.
       • Copper Ore

2. How do we obtain different metals from ores

   • We obtain different metals depending on the reactivity of the metal. Unreactive metals such as gold exist as a metal (native) and are extracted using a process called panning. Most metals are found as metal oxides. The extract the metal from its oxide the oxygen will be removed by heating the oxide with another element in a chemical reaction. This is called reduction.
   • Metals less than carbon are extracted by heating them with carbon.
     • Metals more reactive than carbon are exctracted by electrolysis. The ore is heated until it is molten (liquid) before the metal can be extracted.
       • Electrolysis
         • Expensive
           • Requires a lot of energy
             • A lot of steps to take
         • During electrolysis, positive ions move towards the negative electrode and form pure metal.

3. Properties and uses of different metals

   • Copper
     • used for electrical wiring and plumbing
       • Properties:
         • Good conductor of electricity
           • Malleable
             • Does not react with water
               • Can be drawn into wire (ductile)
     • Coppper is a valuable metal which can be extracted from copper rich ores using a furnace. This process is known as smelting. The resultant is then purified by electorlysis. As we are rapidly using up copper, our supplies are decreasing meaning copper rich ores are limited.
   • Iron
     • less reactive than carbon
       • can be extracted using reduction
         • Molten iron obtained from a blast furnace contains 96% iron and 4% carbon
           • Impure iron is very brittle and have limited uses
   • Aluminium & Titaninum
     • both useful metals as they both have a low density and are resistant to corrosion
       • Aluminium
         • Reacts with oxygen from the air so a layer of aluminium oxie coats the metal with prevents corrosion.
         • uses
           • Drink cans
             • Car bodies
               • Window Frames
                 • Aeroplanes
       • Titanium
         • Uses
           • Aeroplane nuclear reactors
             • Replacement hip joints
       • More reactive than carbon, extracted using electrolysis.
         • Electrolysis is expensive therefore if we recycle we can save money, energy, use up all the natural resources and reduce the amount of mining because it is damaging to the environment.

4. Alloys

   • Pure metals are arranged in layers which can slide over eachother making the metal soft and slippery and hard to bend and hold into place.
   • An alloy is a mixture of metals. The metals mixed in with eachother creates a distorted structure making it hard for the atoms to slide over eachother making the metal stronger
   • Steel
     • Pure iron is soft and iron from the blast furnace is brittle and easily corrdes so most iron is converted into ste. Carbon is added to iron to make steel (an alloy) however other steels like stainless steels are produced by adding other metals to the iron.
     • Properties:
       • High carbon content - Hard and strong
         • Low carbon content - soft and easily shaped
           • steel that contains chronium and nickel (stainless steel) - hard and resistant to corrosion
   • Smart alloys
     • Also called shape memory alloys
       • Can be deformed but will return to their original shape (usually when heated)

5. Impact on evironment

   • Metal ores are a limited resource. In order to preserve the metals we need to recycle them.
   • Extraction requires large amount of energy which is expensive and damaging to the environment. Extraction often leads to pollution and contamination of land.

6. Transition Metals

   • These are the metals located between groups 2 and 3 on the periodic table
     • Good conductors of heat and electricity.
       • All solid at room temperature except for mercury (liquid at room temp)

7. Phytomining and bioleaching

   • Phytomining
     • uses plants to absorb metal compounds. The plants are then burned and the metal can be separated out from the ash produced.
   • Bioleaching
     • Uses bacteria to produce leachate solutions that contain metal compounds. The metal can then be extracted from this solution.

8. Method

   • Extracting Metals
     • Recycling Metals
       • Structural Material
         • Smart Material

9. Advantage

   • provides jobs and income locally
     • raw materials for industry
       • Local Facilities imrpoved to cope with additional traffic
         • Saves energy
           • Less pollution produced
             • Less pressure on envirionment
               • Hard, tough and strong
                 • Does not corrode easily
                   • Malleable
                     • Alloys are harder than pure metals
                       • Relatively inexpensive
                         • Can be produced by mixing metals
                           • Good mechanical properties - strong, resist corrosion
                             • Return to original shape
                               • Bendier than normal metals
                                 • New properties such as pseudoelasticicity, eploited in diverse way such as glass frames, orthodontic arches
                                   • Can be changed by passing an electrical current
                                     • Not much temperature change required

10. Disadvantage

    • Damages landscapes
      • Reduction in tourism
        • noise and dust pollution
          • Traffic issues
            • Individual apathy
              • availability and collection of recycling
                • Iron is naturally very soft, needs to be mixed
                  • Conducts electiricty and heat - may not be wanted
                    • Some metals can be corroded by water and other chemicals
                      • limited supply of metal ores in Earth's crust
                        • Expensive
                          • Fatigue easily

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