Chemistry · Science General

Metallurgical Processes

1,403 Questions

This section explores key metallurgical processes including ore concentration, pyrometallurgy, and metal refining. It also covers corrosion and the properties of refractory materials. These chemistry questions are relevant for engineering and science entrance tests.

Pyrometallurgy furnacesMetal refining techniquesCorrosion protection methodsOre concentrationAuto reduction process

Metallurgical Processes Questions

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following sulphides when  heated strongly in air gives the corresponding metal without undergoing separate reduction of oxide?

  1. $Cu _2S$
  2. $FeS$
  3. $HgS$
  4. $ZnS$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$2Cu _2S+3O _2\longrightarrow 2Cu _2O+2SO _2$

$2ZnS+3O _2\longrightarrow 2ZnO+2SO _2$
$2PbS+3O _2\longrightarrow 2PbO+2SO _2$
$2HgS+3O _2\longrightarrow 2HgO+2SO _2$
$FeS+O _2\longrightarrow Fe+SO _2$
$FeS$ when heated directly in air gives $Fe$. 

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following reactions show the process of smelting?

  1. $2PbO + PbS \rightarrow 3Pb + SO _2$
  2. $2Na[Au(CN) _2]+Zn \rightarrow Na _2[Zn(CN) _4]+2Au$
  3. $PbO+C\rightarrow Pb + CO$
  4. $2HgS + 3O _2\rightarrow 2HgO+2SO _2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carbon reduction occurs in smelting from oxide ore. $PbO+C\longrightarrow Pb+CO$

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Fill in the blanks with the correct choice.
The undesired impurities present in the ores are called (i). To remove the volatile impurities from the ore, the (ii) process is carried out. Flux combines with non-fusible impurities to form (iii). $CaO$ acts as a (iv) flux.

  1. (i) - gangue, (ii) -roasting, (iii) - slag, (iv) -acidic

  2. (i) - gangue, (ii) - calcination, (iii) - slag, (iv) - basic

  3. (i) - anode mud, (ii) - leaching, (iii) - matrix, (iv) -acidic

  4. (i) - gangue, (ii) -roasting, (iii) - solution, (iv) -acidic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
$(i)$ The undesired impurities present in the ores are called gangue.
$(ii)$ To remove the volatile impurities from the ore calcination is carried out.
$(iii)$ Flux combines with non-fusible impurities to form slag.
$(iv)$ $CaO$ acts as basic flux.
Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

In the process of extraction of gold, Roasted gold ore$+CN^- _{(aq)}+H _2O\overset{O _2}{\rightarrow}[X]+[OH^-]$, $[X]+Zn\rightarrow [Y]+Au$
Identify the complexes [X] and [Y].

  1. $[Au(CN) _2]^-, [Zn(CN) _4]^{2-}$
  2. $[Au(CN) _4]^{3-}, [Zn(CN) _4]^{2-}$
  3. $[Au(CN) _2]^{2-}, [Zn(CN) _6]^{4-}$
  4. $[Au(CN) _4]^-, [Zn(CN) _4]^{2-}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
$4Au+8{ CN }^{ - }+2{ H } _{ 2 }O+{ O } _{ 2 }\longrightarrow 4{ \left[ Au{ \left( CN \right)  } _{ 2 } \right]  }^{ - }+4{ OH }^{ - }$
$2{ \left[ Au{ \left( CN \right)  } _{ 2 } \right]  }^{ - }+Zn\longrightarrow 2Au+{ \left[ Zn{ \left( CN \right)  } _{ 4 } \right]  }^{ 2- }$
It is Mc-Arthur process. Here
$X={ \left[ Au{ \left( CN \right)  } _{ 2 } \right]  }^{ - }$ & $Y={ \left[ Zn{ \left( CN \right)  } _{ 4 } \right]  }^{ 2- }$
Multiple choice chemistry principles of metallurgy extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

The major step involved in extraction of a metal after its ore is :

  1. concentration

  2. reduction

  3. purification

  4. all of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 The three steps involved in extraction are:
1) Concentration of the ore to remove impurities.
2) Reduction of the ore to get the metal.
3) Purification of the ore.

Multiple choice chemistry principles of metallurgy extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following is not a method of extraction of metals?

  1. Enrichment of ore

  2. Refining

  3. Magnetic separation

  4. None of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Refining and magnetic separation are methods of extraction of metals .Enrichment of ore is also known as concentration of ore. It means purification of ore.

Multiple choice chemistry principles of metallurgy extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Process of removal of gangue from the ore are based on:

  1. differences between physical and chemical properties of the gangue and the ore

  2. difference between densities of gangue and ore

  3. difference between melting point between of gangue and ore

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Impurities are removed prior to the extraction of metal. The process used for removal of gangue from the ore are based on the differences between physical and chemical properties of the gangue.

Multiple choice chemistry principles of metallurgy extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

What will happen during roasting?

  1. The sulphide ores are converted into oxides

  2. The oxide ores are converted into sulphides

  3. The sulphide ores are converted into carbonates

  4. The oxide ores are converted into carbonates.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During roasting, the sulphide ores are converted into oxides by heating strongly in excess of air.
$ZnS + 3O _2 \rightarrow 2ZnO + 2SO _2$

Multiple choice chemistry principles of metallurgy extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which if the following is a common reducing agent for extracting metals from ore?

  1. $CO$

  2. Carbon

  3. Hydrogen

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Reduction is the process of removal of oxygen for extraction of metals from their oxide ores. The common reducing agents used for reduction of metal oxides are: Carbon monoxide,  Carbon, Hydrogen.

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following technique uses high temperature to convert ore into raw metals?

  1. Pyrometallurgy

  2. Hydrometallurgy

  3. Both a and b

  4. None of above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

After the ore is mined, the metals must be extracted, usually by chemical or electrolytic reduction. Pyrometallurgy uses high temperatures  to convert ore into raw metals, while hydrometallurgy employs aqueous treatment for the same purpose.

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Metals more reactive than carbon are usually extracted by_________.

  1. Pyrolysis

  2. Electrolysis

  3. Fractional distillation

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

Metals more reactive than carbon are usually extracted by electrolysis. Electrolysis is the process of breaking down a compound using electrical energy and is needed to extract  the most reactive metals. 

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

What is the most common type of electrometallurgical processes to obtain pure metal?

  1. Electro-refining

  2. Electrowinning

  3. Both a and b

  4. Oxidation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The most common types of electrometallurgical processes are electrowinning and electro-refining. Electrowinning is an electrolysis process used to recover metals in aqueous solution, usually as the result of an ore having undergone one or more hydrometallurgical processes. Electro-refining is used to dissolve an impure metallic anode and produce a high purity cathode. 

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following is a physical mean for concentration of ore?

  1. Using sodium hydroxide

  2. Using electrolysis

  3. Froth flotation method

  4. None of above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In many cases, it is possible to separate the metal compound from unwanted rocky material by physical means. A common example of this involves froth flotation. In this method, the unwanted object binds with air and comes on the surface as bubbles.