Chemistry · Science General

Metallurgical Processes

1,436 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 thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

The reaction which is not associated with the middle region of blast furnace during smelting is _______ .

  1. ${CO} _{2}+C\rightarrow 2CO$
  2. $Ca{CO} _{3}\rightarrow CaO+{CO} _{2}$
  3. $CaO+Si{O} _{2}\rightarrow CaSi{O} _{3}$
  4. $C+{O} _{2}\rightarrow {CO} _{2}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally iron, but also others such as lead or copper. With the first being that preheated blast air blown into the furnace reacts with the carbon in the form of coke to produce carbon monoxide and heat.
$2 C _{(s)} + {O _2} _{(g)} \rightarrow 2 CO _{(g)}$
All other reactions are associated with the middle region of blast furnace during smelting.The hot carbon monoxide is the reducing agent for the metal ore and reacts with the metal oxide to produce molten metal and carbon dioxide. 

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Compound $X$ and aluminium are used to join railway tracks.

Identify the compound $X$ :

  1. $FeO$
  2. $ Fe _{2}O _{3}$
  3. $Fe _{3}O _{4}$

  4. All of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The reaction of iron oxide with aluminium is used to join railway tracks. 


Aluminium powder is used for the thermite reaction as it reacts with iron $(II) $ oxide to give molten $Fe$.

Hence the correct option is B.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Which of the following processes is involved in the smelting process?

  1. $ZnCO _{3} \rightarrow ZnO + CO _{2}$
  2. $PbS + 3O _{2} \rightarrow 2PbO + 2SO _{2}$
  3. $Fe _{2}O _{3} + 3C \rightarrow 2Fe + 3CO$
  4. $ Al _{2} O _{3}. 2H _{2}O \rightarrow Al _{2}O _{3} + 2H _{2}O$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In smelting process, ferric oxide gets reduced to Iron with the help of coke. The redox reaction is given by the option C.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

In the metallurgical extraction of iron, which of the following processes takes place in reverberatory furnace?

  1. Conversion of iron oxide to iron

  2. Conversion of cast iron to wrought iron

  3. Conversion of cast iron to steel

  4. Conversion of pig iron to cast iron
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Wrought iron or malleable iron is the purest form of commercial iron and is prepared from cast iron by oxidising impurities in a reverberatory furnace lined with haematite.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Compound $X$ and aluminium are used to join railway tracks.
Name the reaction.

  1. Galvanic reaction

  2. Thermal reaction

  3. Thermite reaction

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

The reaction is called thermite reaction, in which $Al$ reduces the oxide of another metal as it forms stronger and more stable bonds with oxygen than the other metal.

$Fe _2O _3 + 2 Al \rightarrow  2 Fe + Al _2O _3$

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

The electrolytic reduction technique is used in the extraction of:

  1. Metalliods

  2. Highly electro positive metals

  3. Transition metals

  4. Highly electronegative metals
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Oxides of strong elecropositive metals such as K, Ca, Na, Al and Mg are very stable. It is difficult to reduce them into metallic state by carbon reduction.
Such metals are extracted by passing electricity through their fued chlorides/oxides/hydroxides.
So electrolytic extraction technique is used in extraction of highly electro positive metals.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Which of the following oxides cannot be reduced by coke?

  1. $Cu _2O,\: K _2O$
  2. $Fe _2O,\: ZnO$
  3. $CaO, \: K _2O$
  4. $PbO,\: Fe _3O _4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Oxides of strong elecropositive metals such as $K, Ca, Na, Al$ and $Mg$ are very stable. It is difficult to reduce them into metallic state by carbon reduction.
Such metals are extracted by passing electricity through their fused chlorides/oxides/hydroxides.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Which of the following is not correctly matched?

  1. Red bauxite - Purification by Serpeck's method

  2. Iron from haematite - Carbon monoxide reduction

  3. Calamine - Carbonate ore
  4. $FeSiO _3$ - Slag obtained in the extraction of copper
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Red bauxite is purified by Bayer's process, not Serpeck's method. Serpeck's method is typically used for the purification of white bauxite (containing silica as impurity).

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Which one of the following is not a method of concentration of ore? 

  1. Electromagnetic separation

  2. Smelting

  3. Gravity separation

  4. Froth floatation process
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The process of removal of unwanted materials from the ore is known as ore concentration. 


Froth floatation, electromagnetic separation, and gravity separation are few of the processes used for ore concentration.

 
Smelting, however, is a process of heating the ore in order to extract the base metal. 


Hence B is the correct answer

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Heating mixture of $Cu _2O$ and $Cu _2S$ will give:

  1. $Cu+SO _2$
  2. $Cu+SO _3$
  3. $CuO+CuS$
  4. $Cu _2O+S$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Reaction of the process:


$ 2Cu _2 O+ Cu _2S \overset{\Delta}{\longrightarrow} 6Cu+SO _2$

The heating mixture of Cu$ _2$O and Cu$ _2$S will give Cu and SO$ _2$ mixture.

Hence, the correct option is $A$

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

In extractive metallurgy of zinc partial fusion of ZnO with coke is called ______ and reduction of the ore to the molten metal is called________ .

  1. sintering, smelting

  2. roasting, smelting

  3. sintering, roasting

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sintering is the process of forming a solid mass of material by heat and/or pressure without melting it to the point of liquefaction. Sintering happens naturally in mineral deposits or as a manufacturing process used with metals, ceramics, plastics, and other materials.

Smeltings main use is to produce a metal from its ore. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gasses or slag and leaving just the metal behind. The reducing agent is commonly a source of carbon.The carbon removes oxygen from the ore, leaving behind elemental metal. 

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Carbon reduction method is employed for commercial extraction of :

  1. haematite

  2. cassiterite

  3. iron pyrite

  4. corundum
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

In extraction of tin from cassiterite-
$SnO _2+2C\rightarrow Sn+2CO$

In extraction of iron from haematite -
$Fe _2O _3+3CO\rightarrow 2Fe+3CO _2$

Iron pyrite $FeS _2$ is a sulphide ore for which froth floatation method is used.
Corundum is a crystalline form of aluminium oxide $Al _2O _3$ with traces of iron, titanium and chromium; for which electrolytic reduction method is used.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Highly electropositive metals cannot be extracted by carbon reduction process because, these:

  1. metals combine with carbon to form carbides

  2. metals do not react with carbon

  3. metal oxides are not reduced by carbon

  4. loss of metal is more in vaporisation
Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation

Highly electropositive metals cannot be extracted by carbon reduction process because of two reasons
(i) Metals combine with carbon to form carbides.
(ii) Loss of metal is more in vaporization.