Titanium is extracted from its main ore, rutile (TiO2\text{TiO}_2TiO2), in a three-stage process.
Stage 1: Titanium dioxide is heated with chlorine and coke (carbon) at a temperature of about 900 ∘C900\ ^\circ\text{C}900 ∘C.
TiO2+2Cl2+2C→TiCl4+2CO \text{TiO}_2 + 2\text{Cl}_2 + 2\text{C} \rightarrow \text{TiCl}_4 + 2\text{CO} TiO2+2Cl2+2C→TiCl4+2COStage 2: Titanium tetrachloride (TiCl4\text{TiCl}_4TiCl4) is then reacted with liquid sodium at a temperature of about 1000 ∘C1000\ ^\circ\text{C}1000 ∘C... in an atmosphere of argon.
TiCl4+4Na→Ti+4NaCl \text{TiCl}_4 + 4\text{Na} \rightarrow \text{Ti} + 4\text{NaCl} TiCl4+4Na→Ti+4NaClStage 3: The sodium chloride is removed by distillation from the mixture formed in stage 2, leaving behind pure titanium.
In stage 1, is the carbon oxidised or reduced? Give a reason for your answer.
What does the reaction in stage 2 indicate about the reactivity of sodium compared to the reactivity of titanium? Explain your answer.
In stage 3, suggest why distillation can be used to remove sodium chloride from titanium.
Titanium has these properties:
Complete the table below to suggest an important property of titanium for each use. Choose from the four properties listed above. You must choose a different property for each use.
| Use | Property |
|---|---|
| structural frames of high-performance aircraft | |
| artificial hip joints and bone screws | |
| containers and pipes for storing strong acids |
