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

Define roasting.

  1. Heating of sulphide ores in the presence of excess air to convert them into oxides

  2. Heating of carbonate ores in the limited supply of air to convert them into oxides

  3. Heating of oxides of metals to turn them into metal

  4. Heating of carbonate ores in the limited supply of air to convert them into sulphide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ores found in the form of sulphide and carbonates are first converted to their oxides by the process of roasting and calcination. Heating of sulphide ores in the presence of excess air to convert them into oxides is known as roasting.

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

During electrolytic refining of Alumina, the molten electrolyte used contains _______ .

  1. Cryolite

  2. Fluorspar

  3. Pure alumina

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

During electrolytic refining of Alumina, the molten electrolyte used contains pure alumina $(Al _2O _3)$. The electrolyte consists of alumina dissolved in fused Cryolite (Na$ _3$AlF$ _6$) and Fluorspar(CaF$ _2$).


Hence, the correct option is $D$.

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

During calcination:

  1. carbonate ores are changed into oixdes

  2. oxide ores are changed into carbonates

  3. carbonate ores are changed into sulhides

  4. oxide ores are changed into sulphides
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During calcination, carbonate ores are changed into oxides by heating strongly in limited air.
$ZnCO _3 \rightarrow ZnO + CO _2$

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

Usually refractory metals are used in construction of furances because:

  1. they are chemically inert

  2. their melting point is high

  3. they can withstand high temperature

  4. none of the above
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

The walls of a furnace should not react with metals or ore. So retractory metals are used as they are chemically inert.

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore
Given below are the steps for extraction of copper from its ore. The balance reaction involved in reduction of copper(I) oxide with copper(I) sulphide is given in the reaction below.

      $2Cu _{2}O + Cu _{2}S \xrightarrow{Heat} 6Cu + SO _{2}$. 

This reaction is known as:

  1. auto-reduction

  2. catalytic- reduction

  3. acid reduction

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

Auto-reduction is a process in which sulphide ores of less electropositive metals like Hg, Pb, Cu etc., are heated in air so as to convert part of the ore into oxide or sulphate which then reacts with the remaining of sulphide ore in absence of air to give the metal and sulphur dioxide.

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

When $FeCr _2O _4$ (chromite) is reduced with Carbon in an electric-arc furnace:

  1. Cr and $Fe _2O _3$ are formed
  2. Fe and $Cr _2O _3$ are formed

  3. Fe and Cr (ferrochrome) are formed
  4. $FeCrO _4$ is formed
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When chromite $(FeCr _2O _4)$ is reduced with carbon in an electric-arc furnace, ferrochrome (Fe and Cr) is obtained.

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

Carbon reduction process is not comrnerically applicable for which of the following set of oxides to extract the respective metal?
(I) ZnO  (II)$Fe _2O _3$   (III)$Al _2O _3$  (IV) $SnO _2$  (V) MgO

  1. $ZnO, Fe _2O _3, SnO _2$
  2. $ZnO, SnO _2, MgO$
  3. $MgO, AI _2O _3$
  4. $MgO, SnO _2, Al _2O _3$,
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carbon reduction process is used to reduce less electropositive metals.
$Mg, Al$ have high electropositivity. Hence, cannot be extracted from oxides through carbon reduction process.

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

Identify the metal $M$ whose extraction is based on the following reactions:
$MS+2{ O } _{ 2 }\longrightarrow M{ SO } _{ 4 }$
$2MS+3{ O } _{ 2 }\longrightarrow 2MO+2S{ O } _{ 2 }$
$MS+2MO\longrightarrow 3M+S{ O } _{ 2 }$
$MS+M{ SO } _{ 4 }\longrightarrow 2M+2S{ O } _{ 2 }\quad $

  1. magnesium

  2. aluminium

  3. lead

  4. tin
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice chemistry adsorption and colloids adsorption theory of heterogeneous catalysis enzymes and catalysts catalysis

In which of the following processes, a catalyst is not used? 

  1. Haber's process and Deacon's process

  2. Deacon's process and Solvay process

  3. Solvay process and Lead chamber process

  4. None of these can proceed without catalyst
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Haber's process catalyst is finely divided iron

Deacon's process catalyst is copper chloride

Solvay process catalyst is ammonia-soda

Lead chamber process catalyst is platimnum.

So in the all above process is catalyst is used.

Multiple choice geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

Magnesium oxide is used for the lining in steel making furnace because:

  1. $MgO$ acts as an acidic flux to remove impurities of $Si,\ P$ and $S$
  2. $MgO$ acts as a basic flux to remove impurities of $Si,\ P$ and $S$
  3. $MgO$ acts as an oxidising agent to remove impurities of oxides
  4. $MgO$ does not react with any type of impurities
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The impurities of the furnace are acidic. So to remove them, basic fluxes are added to remove it as slag.


Example: $MgO+SiO _2\rightarrow MgSiO _3$
                                                 slag

Multiple choice geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

During the formation of the slag by the reaction of flux and impurities which of the following is an example of acidic and basic flux?
(i) $FeO + SiO _2\rightarrow FeSiO _3$
(ii) $SiO _2+MgO\rightarrow MgO\rightarrow MgSiO _3$

  1. (i) $SiO _2$ - Acidic flux (ii) $MgO$ - Basic flux
  2. (i) $SiO _2$ - Basic flux (ii) $MgO$ - Acidic flux
  3. (i) $SiO _2$ - Basic flux (ii) $MgO$ - Basic flux
  4. (i)$ SiO _2$ - Acidic flux (ii) $MgO$ - Acidic flux
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
i) $FeO+Si{ O } _{ 2 }\longrightarrow FeSi{ O } _{ 3 }$
In it $Si{ O } _{ 2 }$ is acidic flux and used to remove basic impurities.
ii) $Si{ O } _{ 2 }+MgO\longrightarrow MgSi{ O } _{ 3 }$
$Si{ O } _{ 2 }$ is acidic impurity. $MgO$ is basic flux used to remove $MgSi{ O } _{ 3 }$ as slag.
Multiple choice geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

Impurities of sulphur, silicon, and phosphorus can be removed from cast iron by adding:

  1. carbon which reduces the impurities

  2. water which dissolves the impurities

  3. limestone which changes impurities into oxides and pass into slag

  4. iron oxide which reacts with impurities by forming slag
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Flux is added to remove impurities as slag. So impurities like Sulphur, Silicon and Phosphorous are removed from case Iron by adding flux. Here flux is $CaC{ O } _{ 3 }$

Multiple choice geography in the land of kerala introduction to metallurgy occurrence of metals study of kerala

In the extraction of some metals from their ores, coke can be used as:

  1. Oxidizing agent

  2. Reducing agent

  3. Catalyst

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

Metals below carbon in the reactivity series can be extracted using carbon. Carbon reduces the metal oxides that are extracted when heated. 


For example, the common ores of iron are both iron oxides, and these can be reduced to iron by heating them with carbon in the form of coke. 

Hence, option B is correct.