metals

metals

1. how metals are obtained

   • metals are obtained by minerals wich are part of rocks. Ex: aluminium is taken from minerals such as bauxite mining is carried out in surface or underground mines 

2. classifing metals

   • metals can classified as: ferrous metals: their main component is iron. non-ferrus metals: their main component is not iron - or their contain very little for it.

3. Properties of metals

   • Metals are hard, non adhesive, cold and very smooth. Some characteristics are: - they are good electrical, thermal, and acoustic conductors - they are ductile, malleable and tought - they expand when the temperature rises and contract when it cools

4. Ferrous metals

   • Iron minerals from the Earth surface undergo different processes to obtain pure iron and its allons. Are classified as: - Pure iron: Greyish white colour. Good magnetic properties - Steel: Very hard and resistant. Very resistant to traction. Easy to weld - Cast iron: Very hard and resistant The steel-making process: This process includes the following stages: - Iron mineral is washed to eliminate any impurities - It crushed and sieved to separate yhe gsngue from th ore - The ore is mixed with coke and limestone, and then put into a blast furnace with temperatures of over 1.500 ºC  

5. Non-ferrous metals

   • There are classified onto the following categories, according to their density: Ultra-light metals: - Magnesium: shiny, silvery ehite; very light, soft and malleable, but not very ductile Light metals: - Aluminium: silvery white; highly resistant to corrosion; very soft; low density and ductilly - Titanium: Silvery ehite, shiny; light; very hard and strong Heavy metals - Copper: Reddish, very shiny, soft, good electrical and thermal conductor - Brass: Very resistant yo corrosion - Bronze: Resistant to general wear and corrosion - Zinc: Bluish grey; fragile; not very hard - Tin: Shiny white, very soft and maileable, does not oxidise at room temperature - Lead: Silvery grey; soft and malleable, lead fumes are toxic when inhaled