Tag: general principles of metallurgy

Questions Related to general principles of metallurgy

Leaching is commercially carried out for in the concentration of:

  1. galena

  2. argentite

  3. copper pyrites

  4. tin stone


Correct Option: B
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.

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

  1. Magnetic seperation

  2. Gravity seperation

  3. Froth Floatation process

  4. None


Correct Option: C
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.

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

  1. Froth flotation

  2. Electrolytic methods

  3. Smelting

  4. Hoop's process


Correct Option: A
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.

Which ore is concentrated by froth flotation method?

  1. Horn silver

  2. Bauxite

  3. Cinnabar

  4. Haemattie


Correct Option: C
Explanation:

Generally sulphide ores are concentrated by "Froth floatation" and cinnabar(HgS) is a sulphide ore.

Collectors are the substances which combine with sulphide ore and make them water repellant. Which of the following substance can act as collector?

  1. Sodium ethyl xanthate

  2. Sodium xenate

  3. Sodium pyrophosphate

  4. Adsorption


Correct Option: A
Explanation:

Sodium ethyl xanthate is used as collector in froth floatation process.

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


Correct Option: D
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.

An ore containing the impurity of $FeCr 2 O _4$ is concentrated by _________.

  1. magnetic-separation

  2. gravity separation

  3. froth-floatation method

  4. electrostatic method


Correct Option: A
Explanation:

As impurity $FeCr _2 O _4$ contains iron so magnetic-separation process is used.

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

  1. $ Na _2CO _3 $

  2. KCI

  3. NaCN

  4. $ (SCN) _2 $


Correct Option: C

The ore which do not contain iron is:

  1. Limonite

  2. Siderite

  3. Carnallite

  4. Chalcopyrites


Correct Option: C
Explanation:
1) Limonite $\rightarrow Fe _2 O _3 . 3H _2O$

2) Siderite $\rightarrow FeCO _3$

3) Carnallite $\rightarrow KCl . MgCl _2 . 6 H _2O$

4) Chalcopyrites $\rightarrow CuFeS _2$

Therefore carnallite does not contain iron.

Hence, the correct option is $\text{C}$

Silver is displaced when zinc is added to aqueous sodium argento cyanide.This method os extracting silver is an example for 

  1. Leaching

  2. Hydro metallurgy

  3. Pyrometallurgy

  4. Liquation


Correct Option: B