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 refining of metals basics of metallurgy basic metallurgical processes

For alkali metals, only electrolytic reduction is employed.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Definition of electrolytic reduction: Removal of oxygen (or decrease of its active valency in the case of a positive element) by electrical means.

The highly electropositive metals, such as the alkali and alkaline earth metals are isolated by electrolytic reduction of their fused halides, since no suitable chemical reducing agent is available and aqueous solutions could not be used due to reactive nature of these metals.
For alkali metals, only electrolytic reduction is employed.

Multiple choice chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

Nickel metal is purified by the vapour phase refining process. This process is based on the fact that:

  1. nickel metal sublimes at high temperature

  2. nickel reacts with carbon monoxide to form nickel carbonyl which decomposes at high temperature to form nickel

  3. nickel reacts with chlorine to form nickel chloride which is volatile and decomposes easily to nickel

  4. nickel can be vapourized under vacuum leaving behind impurities
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nickel metal is purified by the vapour phase refining process. This process is based on the fact that nickel reacts with carbon monoxide to form highly volatile nickel tetracarbonyl which decomposes at high temperature to form pure nickel metal.
 $\displaystyle Ni+4CO \xrightarrow {\text {330-350 K}} Ni(CO) _4$
 $\displaystyle Ni(CO) _4 \xrightarrow { \text {450-470 K}}  \underset {\text {Pure metal }}{Ni}+ 4 CO$

Multiple choice chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

Which of the following statements is/are correct regarding metallurgy?

  1. Both calcination and roasting are generally carried out in the same furnace, i.e., reverberatory furnace.
  2. The slag formed during the extraction of Copper metal from Chalcopyrites ore is $CaSiO _3$.

  3. Mond's process involved in the extraction of nickel is related with formation and decomposition of a square planner complex of nickel metal.

  4. In case of electrolytic refining of extracted metals, generally impure metal rod is made the anode and pure metal rod is made the cathode.
Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation

Both calcination and roasting are generally carried out in the this furnace, one in absence of air and other in presence of air.
The slag formed during the extraction of Copper metal from Chalcopyrites ore is $FeSiO _3$.
Mond's process involved in the extraction of Nickel is related with formation and decomposition of a tetrahedral complex of nickel metal $[Ni(CO) _4]$. 

In case of electrolytic refining of extracted metals, generally impure metal rod is made the anode and pure metal rod is made the cathode. This is evident as at anode, we get impure slag and at cathode, we get pure metal.

Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

Silver can be separated from lead by:

  1. Distillation

  2. Amalgamation

  3. Filtration

  4. Cupellation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Cupellation is a process where ores are treated under high temperatures and controlled operations to separate noble metals like gold and silver from base metals like lead, copper, zinc, and others present in the ore or alloyed metal.

Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

Refining of silver is done by___________.

  1. liquidation

  2. poling

  3. cupellation

  4. van Arkel method
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cupellation is a process where ores are treated under high temperatures and controlled operations to separate noble metals like gold and silver, from base metals like led, copper, zinc, and others present in the ore or alloyed metal.

Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

Refining of silver is done by________.

  1. liquidation

  2. Poling

  3. cupellation

  4. van Aekel method
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cupellation is a process where ores are treated under high temperatures and controlled operations to separate noble metals like gold and silver, from base metals like led, copper, zinc, and others present in the ore or alloyed metal.

Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

Cupellation process is used in the metallurgy of:

  1. Copper

  2. Silver

  3. Aluminium

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

Cupellation is a process where ores are treated under high temperatures and controlled operations to separate noble metals like gold and silver, from base metals like led, copper, zinc, and others present in the ore or alloyed metal.

Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

When alloy of silver and lead is rich in silver:

  1. Cupellation process is used

  2. Parke's method is used

  3. Pattinson's method is used

  4. Any of the above methods can be used
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When alloy of silver and lead is rich in silver, cupellation process is used.
The silver metal can be obtained in when alloy of silver and lead is rich in lead is:
i) Parke's process
ii) Pattinson's process

Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

Softening of lead means:

  1. Melting pure lead at high temperature

  2. Removal of impurities, except silver, present in commercial lead

  3. Formation of lead alloy

  4. Formation of 100% pure lead
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We know the melting point of pure lead is very high. Softening of lead means removal of metallic impurities, except silver, present in the commercial lead. 


B  is the correct answer

Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

Tin is not refined by:

  1. Liquidation

  2. Zone refining

  3. Poling

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Poling is a [metallurgical] method employed in the purification of copper which contains copper oxide as an impurity and also in the purification of tin ("Sn") which contains tin oxide (stannic oxide or "$SnO _2$") as an impurity. It was the use of these greenwood poles gave rise to the term "poling."

Liquidation is suitable for metals with low melting points for example, tin. In this process, we heat the impure metal and then we let it flow on a sloped surface. The impurities will remain behind and the pure metal will collect at the bottom of the slope.


Zone refining is a special method we use to purify metals. It was the invention of William Pfann. It purifies metals to a very high degree. A rod of impure metal is placed in a container which we fill with inert gas. Then we place a circular heater around the rod at the top.

The melting point of tin is low. So zone refining is not suitable for Tin.

Hence, option B is correct.

Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

When alloy of silver and lead is rich in silver :

  1. CupelIation process is used

  2. Parke's method is used

  3. Bett's method is used

  4. All of the above method
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Cupellation: Pb impurities present in Ag are removed by this method. The impure metal is heated in a cupel or oval shaped crucible made of bone ash or cement and blast of air is passed over the molten mass. The impurities get oxidised and removed with the blast of air.
Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

Refining of tin can be done by :

  1. cupellation

  2. liquation

  3. poling

  4. electrorefining
Reveal answer Fill a bubble to check yourself
B,C,D Correct answer
Explanation
Poling is a method employed in the purification of copper which contains copper oxide as an impurity and also in the purification of tin ("Sn") which contains tin oxide (stannic oxide or "SnO2") as an impurity. It was the use of these greenwood poles gave rise to the term "poling."

Liquation is suitable for metals with low melting points, for example, tin. In this process, we heat the impure metal and then we let it flow on a sloped surface. The impurities will remain behind and the pure metal will collect at the bottom of the slope.

Electrorefining, producing pure tin from waste materials in cheap acid electrolytes can be effectively operated with parameters set to provide for the stability of the solution and high current efficiencies and the use of the periodical current reversal (PCR) technique.

Cupellation is a refining process in metallurgy where ores or alloyed metals are treated under very high temperatures and have controlled operations to separate noble metals, like gold and silver, from base metals, like lead, copper, zinc, arsenic, antimony, or bismuth, present in the ore.

Cupellation is used for purifying of metal under high temperature. so it is not suitable for tin(low melting point metal).
Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

Extraction of metal from the ore cassiterite involves

  1. carbon reduction of an oxide ore

  2. self- reduction of an sulphide ore

  3. removal of iron impurity

  4. both A and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Tin is obtained by reducing the ore cassiterite with coal in a reverberatory furnace; limestone is added to produce a slag with impurities, which can be removed.

$SnO _2  +  2C \longrightarrow Sn + 2 CO$.

Crude tin so obtained is contaminated with iron, lead, and other metals. It is, therefore, remelted on an inclined furnace. The process is called liquation. The easily fusible tin metals away and the less fusible impurities are left behind. Molten tin is finally stirred with green poles of wood in contact with air. In this process, any remaining metal impurities are oxidized forming a scum, which rises to the surface and is removed. This process is called polling.

Multiple choice chemistry principles and processes of isolation of elements refining of metals basics of metallurgy basic metallurgical processes

Which are correctly matched?

  1. Poling-refining of copper

  2. Cupellation- refining of silver

  3. Smelting-An oxidation process

  4. Roasting-An oxidation process
Reveal answer Fill a bubble to check yourself
A,B,D Correct answer
Explanation

A) Poling is a method employed in the purification of copper which contains cuprous oxide as an impurity.correct.
B) Cupellation is a refining process in metallurgy, where ores or alloyed metals are treated under high temperatures and controlled operations to separate gold and silver, from lead, copper, zinc, arsenic, antimony or bismuth.correct.
C) The process of extracting a metal from its oxide is known as 'smelting'. Most smelting processes involve direct reduction of the ore by carbon to metal and carbon dioxide. The production of primary aluminium is a good example of such a process. Its not oxidation.wrong
D) Roasting is a step of the processing of certain ores More specifically, roasting is a metallurgical process involving gassolid reactions at elevated temperatures with the goal of purifying the metal component(s). During roasting, the sulfide is converted to an oxide, and sulfur is released as sulfurdioxide, a gas.$2Cu _2S + 3O _2\rightarrow  2 Cu _2O + 2 SO _2$.correct.
options A,B & D are correct.