Concentration of Aluminium Ore

Q. Which of the following method is used for the concentration of bauxite ore?

1. Levigation
2. Leaching
3. Magnetic seperation
4. Froth floatation

Q. Give reason why carbonate and sulphide ores are usually converted into oxides during the process of extraction?

Q.

Write the name of the compound KMNO_4.

Q. (i) What is meant by concentration of ores?
(ii) Name the process of concentration,
(a) based on densities
(b) based on magnetic nature
(iii) How an ore is concentrated by froth flotation process?

Q. The chemical formula of bauxite ore is ______.

1. $ZnC{O}_3$
2. $A{l}_2{O}_3.2H_{2}O$
3. $F{e}_2{O}_3$
4. $C{u}_{2}O$

Q.

Which of the following is not related to the extraction of aluminium?

1. Bayer’s process

2. Bauxite

3. Wilfley table method

4. Hall-Heroult process

Q. is the principle ore of aluminium and is concentrated by process.

1. Bauxite
2. Bayer's
3. Cassiterite
4. Froth flotation

Q.

Cryolite is added to alumina to reduce its:

1. boiling point

2. electrical conductivity

3. melting point

4. metallic lustre

Q. The reagent used to leach alumina from bauxite in Bayer's process is:

1. NaOH
2. NaCl
3. KCl
4. HCl

Q. In Hall's process the ore is leached by heating it with .

1. sodium carbonate
2. sodium bicarbonate
3. sodium hyroxide

Q.

Aluminium oxide reacts with hot concentrated solution of sodium hydroxide to form:

1. aluminous hydroxide

2. sodium aluminate

3. aluminium hydride

4. sodium aluminate hydroxide

Q.

It is given that Bayer's process is employed. Which of the following steps are observed in this process?

1. Concentration of ore

2. Conversion of ore into its oxide form

3. Reduction of metal oxide to metal

4. Refining of metal