Chemistry - Metallurgy Question with Solution | TestHub
The Bayer Process for alumina, as we know it today, involves two steps:
1. The pressure leaching of bauxite with NaOH solution.
2. The precipitation of pure aluminum hydroxide from solution by seeding with fine crystals of Al(OH)₃.
Identify the process to which the following reaction belongs :
Al₂O₃·2H₂O + Na₂CO₃ 2NaAlO₂ + 2H₂O + CO₂
2NaAlO₂ + 2H₂O + CO₂ Al₂O₃·2H₂O + Na₂CO₃
Options:
Answer:
Solution:
The given reactions show conversion of hydrated alumina with Na₂CO₃ to sodium aluminate (NaAlO₂) followed by regeneration of alumina using CO₂ and water.
This cyclic formation and decomposition of sodium aluminate is characteristic of Hall’s process (not Bayer process).
In Bayer process, only NaOH is used for leaching bauxite, not Na₂CO₃.
Hence, the process described corresponds to Hall’s process.