Identify three stages where aluminium is extracted from bauxite using the hall-heroult methods?

1. Crushing and Grinding: The first stage involves crushing and grinding the bauxite ore to a fine powder. This helps to increase the surface area of the ore, making it easier to extract the aluminium.

2. Digestion: In this stage, the powdered bauxite ore is mixed with a hot solution of sodium hydroxide, which dissolves the aluminium oxide present in the ore. This process is known as digestion and results in the formation of a solution of sodium aluminate.

3. Electrolysis: The final stage involves the electrolysis of the sodium aluminate solution using the Hall-Heroult method. This process involves passing an electric current through the solution, causing the aluminium ions to be reduced at the cathode and deposited as pure aluminium metal.

1. Purification of Bauxite: Bauxite is purified by removing impurities such as iron oxide and silica. This is achieved by grinding the bauxite and treating it with a strong base like sodium hydroxide. The impurities are dissolved in the base, leaving behind pure aluminum oxide.
2. Electrolysis of Aluminum Oxide: The purified aluminum oxide is dissolved in a molten electrolyte, which is typically a mixture of cryolite and aluminum fluoride. The electrolyte is heated to a temperature of around 950°C, and an electric current is passed through it. The current causes the aluminum oxide to break down into aluminum and oxygen. The aluminum is deposited on the cathode, while the oxygen is released as a gas.
3. Casting and Rolling: The molten aluminum is then cast into ingots. These ingots can be further processed by rolling them into sheets or plates. Aluminum sheets and plates are used in a wide variety of applications, including construction, transportation, and packaging.