Tag: principles of metallurgy

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Questions Related to principles of metallurgy

Multiple choice chemistry principles of metallurgy concentration of ore concentration of ores general principles of metallurgy

The purpose of stream of air in leaching process of $Ag _2S$ is to?

  1. Oxidises $Na _2S$ formed into $Na _2S _2O _3$
  2. Oxidises $Na _2S$ formed into $Na _2S _2O _4$
  3. Oxidises $Na _2S$ formed into $Na _2O$

  4. Act as catalyst
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the leading of ${ Ag } _{ 2 }S$ (silver sulphide) with $NaCN$, a stream of air is passed because reversible nature of reaction between ${ Ag } _{ 2 }S$ and $NaCN$ and to oxidise ${ Na } _{ 2 }S$ formed into ${ Na } _{ 2 }{ SO } _{ 4 }$ and sulphur.

${ Na } _{ 2 }{ SO } _{ 4 }$ and sulphur $\Rightarrow { Na } _{ 2 }{ S } _{ 2 }{ O } _{ 4 }$

Multiple choice chemistry principles of metallurgy concentration of ore concentration of ores general principles of metallurgy

Froth flotation process is based upon :

  1. Magnetic property of gangue

  2. Specific gravity of ore particle

  3. Preferential wetting of ore particle by oil

  4. Preferential wetting of gangue particle by oil
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Froth flotation relies on the difference in surface properties between ore and gangue. Ore particles are preferentially wetted by oil (hydrophobic), while gangue particles are wetted by water (hydrophilic).

Multiple choice chemistry principles of metallurgy concentration of ore concentration of ores general principles of metallurgy

Leaching is commercially carried out for in the concentration of:

  1. galena

  2. argentite

  3. copper pyrites

  4. tin stone
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Leaching is a process in which the ore is dissolved in a suitable solvent, where the impurities remain undissolved. This method is used in the extraction of $Ag$ from Argentite where is, the ore is dissolved in sodium cyanide solution.

Multiple choice chemistry principles of metallurgy concentration of ore concentration of ores general principles of metallurgy

Which of the following method used for the concentration of copper pyrites?

  1. Magnetic seperation

  2. Gravity seperation

  3. Froth Floatation process

  4. None
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
This method is used when a higher ore contains impurities with higher density. This method is used for the concentration of Sulphide ores. (Eg: Copper pyrites, iron pyrites, Galena, Zinc blende etc.) Copper is mainly extracted from copper pyrites. After the concentration of its ore by froth flotation process, the ore is roasted in a current of air to remove arsenic, antimony and much of sulphur.
Multiple choice chemistry principles of metallurgy concentration of ore concentration of ores general principles of metallurgy

Which of the following process is used for concentration of ore?

  1. Froth flotation

  2. Electrolytic methods

  3. Smelting

  4. Hoop's process
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Froth flotation method is used for the concentration of sulphide ores. 


The method is based on the preferential wetting properties with the frothing agent and water. In the given options, Galena (PbS) is the only sulphide ore.

Hence, option A is correct.

Multiple choice chemistry principles of metallurgy concentration of ore concentration of ores general principles of metallurgy

During concentration of Tin stone separation of wolframates of $Fe^({II})$ and $Mn^({II})$ is based on the fact that:

  1. $SnO _2$ is paramagnetic
  2. $SnO _2$ is diamagnetic
  3. $FeWO _4$ and $MnWO _4$ are paramagnetic

  4. Both B and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

During concentration of Tin stone separation of wolframates of $Fe({II})$ and $Mn({II})$ is based on the fact $SnO _2$ is diamagnetic and both $FeWO _4$ & $MnWO _4$ are paramagnetic so magnetic separation method is used for concentration of ore.

Multiple choice chemistry principles of metallurgy concentration of ore concentration of ores general principles of metallurgy

Which compound is used to separate two metal sulphide in forth flotation process :

  1. $ Na _2CO _3 $

  2. KCI

  3. NaCN
  4. $ (SCN) _2 $
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

NaCN (Sodium Cyanide) is used as a depressant in the froth flotation of sulphide ores to prevent one specific sulphide (like ZnS) from floating while allowing another (like PbS) to float.