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

Sequence the following steps involved generally in the extraction of a metal in pure form from its ore.
(a) The metal obtained from its oxide require further purification for end use.
(b) The ore should be converted to its oxide form.
(c) The ore is beneficial to us if it is handpicked then metal crushed and ground, and later subjected to pulverization as per the requirement
(d) The ore in the form of oxide is required to be reduced.
(e) Dressed ore is required for it to be concentrated.

  1. e c b d a

  2. c e b d a

  3. c e b a d

  4. c e d b a
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(c) The ore is beneficial to us if it is handpicked then metal crushed and ground, and later subjected to pulverization as per the requirement
(e) Dressed ore is required for it to be concentrated.
(b) The ore should be converted to its oxide form.
(d) The ore in the form of oxide is required to be reduced.
(a) The metal obtained from its oxide require further purification for end use.

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

Prior to reduction, metal sulphide and carbonates are converted into oxides because:

  1. carbonates, sulphides are heavy molecules

  2. it is easier to obtain a metal from its oxide as compared to its sulphides and carbonates

  3. it is easy to heat oxide compared to sulphides and carbonates
  4. both $A$ and $B$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

It is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates. Therefore, prior to reduction, the metal sulphides and carbonates must be converted to metal oxides.

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
C Correct answer
Explanation

The given roasting and auto-reduction reactions are classic steps in the extraction of lead (Pb) from galena (PbS). Lead sulfide reacts with oxygen to form lead sulfate and lead oxide, which then react further with remaining sulfide to yield molten lead and sulfur dioxide.