Chemistry - Metallurgy Question with Solution | TestHub

ChemistryMetallurgyPurification of Ores, Calcination and roastingMedium2 minQB
ChemistryMediummultiple choice
Passage / Comprehension

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.

When red bauxite is treated with KOH solution & filtered, then

Options:(select one or more)

Answer:
A, D
Solution:

In Bayer process, Al₂O₃ in bauxite is amphoteric and dissolves in strong alkali to form soluble aluminate.

When red bauxite (Fe₂O₃ + Al₂O₃) is treated with KOH, Al₂O₃ dissolves forming potassium aluminate (KAlO₂).

Fe₂O₃ does not react with KOH and remains as insoluble residue (red mud).

Hence, residue contains Fe₂O₃ and filtrate contains KAlO₂.

Stream:JEESubject:ChemistryTopic:MetallurgySubtopic:Purification of Ores, Calcination and roasting
2mℹ️ Source: QB

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