Aluminium

Question 1

What factors influence the location of a chemical industry?

Answer 1

nearness to the source of raw materials
good communication network
labour
environmental and social factors

Question 2

Describe aluminium

Answer 2

aluminium is the most abundant metal in the earth, its comprised about 7.5% of the earth crust joined together with silica from clay, shale, granite and slate, its extracted from bauxite ore which contains hydrated aluminium oxide eg gibbsite

Question 3

What are the main impurities of bauxite?

Answer 3

iron, silicon and titanium

Question 4

What properties do white bauxite and red bauxite contain?

Answer 4

white bauxite contains about 1-4% of silica and very little iron
red bauxite contain 3-25% of iron oxide and 1-7% of silica

Question 5

Describe the steps in aluminium production

Answer 5

powdered bauxite is mixed with 10% of sodium hydroxide and is heated under pressure at 140 C, takes about 1-2 to complete
the sodium aluminate is soluble in sodium hydroxide but contaminating metal oxides are not, impurities are settle and filtered off
the sodium aluminate is seeded with pure aluminium oxide and agitated with air, slow cooling produces a precipitate of pure aluminium oxide trihydrate
after 36 hours, the alumina is removed by vacuum filtration and is dehydrated in a rotary kiln in 1000 C, the sodium hydroxide is recycled

Question 6

What are some uses of aluminium?

Answer 6

malleability and conductivity
non magnetic
good reducing agent
low density
good strength/mass ratio

Question 7

Why does aluminium have a cost?

Answer 7

quarrying the bauxite ore
production of alumina
electrolysis of alumina