Sc 4.3

• • Metal extraction is the process of obtaining pure metal from its ore
  • Metal extraction can be done using more reactive metals to displace the less reactive metal from its oxide
  • The thermite process is used to extract iron from iron oxide on a small scale
  • This reaction releases so much heat that it is able to melt iron which has a melting point of 1,538 ° C
  • Metal extraction in the industry is done using two main methods, namely heating of oxide logs with carbon (cheap and easy) and electrolysis of molten metal compounds
• Iron extraction:

  • High temperature in the furnace
  • The reaction takes place and iron is extracted as molten iron and flows to the bottom part of the furnace. From time to time, the molten iron is tapped off and channeled into moulds and allowed to cool and freeze. This molten iron that has solidified is known as cast iron.
  • Slag produced will melt then flows to the bottom part of the furnace. Slag will float on the top of the molten iron (less dense). Then, Slag is tapped off and used to make the base of buildings and road
• Iron extraction:

  • A mixture of iron ore, limestone, and carbon (coke charcoal) is put in a blast furnace and heated at 1,900 ° C
• Iron extraction:

  Reaction occur in high temperature

  Production of iron

  1. Coke or carbon reacts with oxygen in the hot air to produce carbon dioxide and heat
  2. Carbon dioxide that is produced reacts with the rest of the hot coke to form carbon monoxide which is a strong reducing agent
  3. Carbon monoxide and carbon reduces iron oxide into iron

  Production of slag

  1. Limestone or calcium carbonate decomposes to form calcium oxide and carbon dioxide
  2. Calcium oxide reacts with impurities such as sand or silicon dioxide in iron ore to form slag or calcium silicate
• Mining issues in Malaysia

  • Air pollution due to burnings of fuels
  • Usage of large amount of electrical energy
  • Air pollution by gases released from blast furnace
  • Destruction of habitat due to construction of mines
  • Sound pollution from mining machinery
  • Soil erosion due to mining of ore
  • Water pollution due to cleaning of ore