Extraction of Metals

Question 1

Step 1 of Extraction of Aluminum

Answer 1

Purify the ore by crushing it up and dissolve it with sodium hydroxide

Question 2

Step 2 of Extraction of Aluminum

Answer 2

Aluminum needs to be molten however aluminum oxide melts at around 2000 degrees
It’s too difficult and costly to keep the electrolyte at a high temperature
As a result, Aliminium oxide is dissolved in cryolite to decrease its melting point

Question 3

Step 3 of Extraction of Aluminum

Answer 3

Carbon electrodes are used during the electrolysis and the aluminum metal forms on the negative electrode and the oxygen forms on the positive electrode

Question 4

Step 4 of Extraction of Aluminum

Answer 4

Aluminum ions gain electrons and are reduced to aluminum metal at the cathode
Oxide ions lose electrons and are oxidized to oxygen at the anode

Question 5

Overall equation for Aluminum Extraction

Answer 5

2Al2O3 –> 4Al + 3O2

Question 6

Why do anodes need replacing regularly?

Answer 6

Because they are burned away by the oxygens