Which one of the following is most abundant in earth crust?

1

(a)

Mg

(b)

Na

(c)

Al

(d)

Fe

Ore dressing of iron ore is done by

1

(a)

Froth floatation

(b)

Magnetic separation

(c)

Hand picking

(d)

All the above

For which of the following ores,froth floatation process is applicable?

1

(a)

Oxide

(b)

Sulphide

(c)

Carbonate

(d)

Sulphate

Which of the following benefaction processes is used for the mineral,Al₂O₃.2H₂O?

1

(a)

Froth floatation

(b)

Leaching

(c)

Liquation

(d)

Magnetic separation

Heating pyrites to remove sulphur is called

1

(a)

smelting

(b)

calcination

(c)

liquation

(d)

roasting

What is the role of collectors in Froth Floatation process?

1

(a)

Collectors like pine oil, fatty acids, xanthates enhance non-wettability of mineral particles.

Differentiate between a mineral and an ore.

1

(a)

Mineral is a naturally occuring substance from which metal may or may not be extracted profitably.

Ore is a naturally occuring rocky material which contains sufficient quantity of mineral from which metal can be extracted profitably and conveniently.

What type of ores can be concentrated by magnetic separation method?

1

(a)

Those ores which are magnetic in nature, i.e. attracted by magnet, whereas impurities are non-magnetic in nature or vice-versa are concentrated by magnetic separation method.

Copper matte is charged into a silica lined converter in extraction of copper. What is the role of silica lining here?

1

(a)

Silica acts as a flux.

What is meant by the term 'pyrometallurgy'?

1

(a)

The process of reducing a metal oxide with coke or any other reducing agent at high temperature is called pyrometallurgy. In other words, it is a thermal process of extracting a metal from its ore.

What do you mean by benefaction process?

1

(a)

The process used to concentrate an ore is called the benefaction process.For example,froth floatation,electromagnetic separation,leaching,etc.

What is gangue?

1

(a)

The earthy and silicious impurities associated with the ores is called gangue

Name the method used for removing gangue from sulphide ores

1

(a)

Froth Floatation

(a) Why is it that only sulphide ores are concentrated by froth floatation process?
(b) Which of the following ores can be concentrated by froth floatation method and Why?

1

(a)

(a) This is because the sulphide ore particles are preferentially wetted by oil and gangue particles are preferentially wetted by water.
(b) Froth floatation is the process employed for the extraction of metals from their sulphide ores like ZnS.

What is the role of a stabilizer in the froth floatation process?

1

(a)

Chemical compounds like cresols and aniline which tend to stabilize the froth are called froth stabilizers.

Why are sulphide ores converted into oxide before reduction?

1

(a)

It is because oxides ores can be easily reduced, whereas sulphide ores cannot be reduced easily.

What is role of flux in metallurgical processes?

1

(a)

Flux is used for making the molten mass more conducting and it reacts with gangue to form slag which can be easily removed.

Define aluminothermy.

1

(a)

The process of reduction of a metal oxide to the metal with the help of aluminium powder is called aluminothermy.

Define calcination.

1

(a)

The process of heating the ore strongly either in a limited supply of oxygen or air or in the absence of air is called calcination.

What does copper matte contain?

1

(a)

Copper matte contains Cu2S and Fes.