Tag: thermodynamic principles of metallurgy

Questions Related to thermodynamic principles of metallurgy

Which of the following process involves smelting?

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

  1. ${2PbS+3O _2\rightarrow 2PbO+2SO _2}$

  2. ${Al _2O _3.2H _2O \rightarrow Al _2O _3+2H _2O}$

  3. ${Fe _2O _3+CO\rightarrow 2Fe+2CO _2}$

  4. ${Cr _2O _3+2Al\rightarrow Al _2O _3+2Cr+Heat}$

Show answer
Correct Option: C
Explanation:
Smelting : The process of extraction of metal in its molten state by any reducing agent in presence of flux is called smelting. 
For example : oxides of less electro - positive metals like Pb, Zn, Fe, Cu are reduced by any other reducing agents.
Reactions:
${Fe _2O _3+3CO\rightarrow  2Fe+3CO _2}$

During the extraction of copper, the impurity (FeS) is removed as slag by mixing the contaminated copper ore with silica and coke. The molecular formula of slag is:

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

  1. $FeSiO _3$

  2. $Fe _2O _3$

  3. $FeSi\ (solid)$

  4. $FeSi\ (vapour)$

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Correct Option: A

Aluminum metal is frequently used as a reducing agent for the extraction of metal such as chromium or manganese from their respective _______

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

  1. zinc

  2. oxides

  3. reduction

  4. none of these

Show answer
Correct Option: B
Explanation:

Aluminium is more electropositive than Cr or Mn.
Hence, aluminum metal is frequently used as reducing agent for the extraction of metal such as chromium or manganese from their respective oxides.
The process of reduction is known as Aluminothermy. Thermite mixture $Fe _2O _3 + Al$ in 3:1 ratio is used.
$Cr _2 O _3 + 2Al       \rightarrow      Al _2O _3 + 2Cr$
$3 Mn _3 O _4 + 8 Al    \rightarrow     4 Al _2 O _3 + 9 Mn$

The metallurgical process in which a metal is obtained in a fused state is called:

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

  1. Smelting

  2. Roasting

  3. Calcination

  4. Froth floatation

Show answer
Correct Option: A
Explanation:
The process of extraction of metal in its molten state by any reducing agent in the presence of flux is called smelting. 

For example oxides of less electropositive metals like $Pb, Zn, Fe, Cu$ are reduced by any other reducing agents.

So, the correct option is $A$

Which one is mismatched ?

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

  1. Poling - refining of copper

  2. Cupellation - refining of silver

  3. Smelting - An oxidation process

  4. Roasting - An oxidation process

Show answer
Correct Option: C
Explanation:
Poling: The molten impure metal (Cu) containing oxides as impurities is stirred with green poles of wood which releases hydrocarbon gases. The hydrocarbon gases reduces oxide to metal. It is used in refining of copper.

Cupellation: Pb present in Ag is 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. It is used in refining of silver.

Smelting: The process of extraction of metal in its molten state by any reducing agent in presence of flux is called smelting. For example: oxides of less electropositive metals like Pb, Zn, Fe, Cu are reduced by any other reducing agents. Thus, smelting is a reduction process and not an oxidation process.

Roasting: The process in which the concentrated ore is heated in blast of air and ore gets converted into oxide and impurities like sulphur, arsenic are also oxidised to their oxides and is removed is called Roasting. It requires very high temperature and specialized furnace like Bessemer or reverberatory furnace. Thus, it is an ixidation process.



Haematite is an ore of :

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

  1. Fe

  2. Zn

  3. Cu

  4. Al

Show answer
Correct Option: A
Explanation:

Hematite is the most important ore of iron.

It is an iron oxide with a chemical composition of $Fe _2O _3$.
So answer is A.

$Fe _3O _4$ is the chemical formula of :

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

  1. monazite

  2. magnetite

  3. haematite

  4. bauxite

Show answer
Correct Option: B
Explanation:

$Fe _3O _4$ is the chemical formula of magnetite.

Magnetite is the mineral of Iron.
Magnetite is the most magnetic of all the naturally-occurring minerals on Earth.
The chemical IUPAC name is Iron(ll,lll) oxide and the common chemical name is ferrous-ferric oxide.
So answer is B.

Reduction to free metal: some of the methods commonly used to get free metal from the concentrates ore are below.
Smelting: The process of extracting a metal in the state of fusions is called smelting. In this process the ore is mixed with carbon and heated in suitable furnace
Electrolytic reduction process: This process is used in the extraction of the alkali and alkaline earth metals, zinc and aluminium.
Self reduction process: The sulphide ores of less electropositive metals like Hg, Pb, Cu etc., are heated in air so asto convert part of the ore into oxide or sulphate which then reacts with the remaining sulphide ore to give the metal.

After partial roasting, the sulphide of copper is reduced by :
thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. Reduction by carbon

  2. Electrolysis

  3. Self-reduction

  4. Cyanide process

Show answer
Correct Option: C
Explanation:
In the extraction of copper, metal is formed in the Bessemer converter due to self reduction as

${ Cu } _{ 2 }S+2{ Cu } _{ 2 }O\rightarrow 6Cu+S{ O } _{ 2 }$

Which metal among the following is present in human blood?

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

  1. Titanium

  2. Mercury

  3. Gold

  4. Iron

Show answer
Correct Option: D
Explanation:

Iron is present in human blood.

Reduction to free metal: some of the methods commonly used to get free metal from the concentrates ore are below.
Smelting: The process of extracting a metal in the state of fusions is called smelting. In this process, the ore is mixed with carbon and heated in a suitable furnace
Electrolytic reduction process: This process is used in the extraction of the alkali and alkaline earth metals, zinc and aluminium.
Self-reduction process: The sulphide ores of less electropositive metals like Hg, Pb, Cu etc., are heated in the air so as to convert part of the ore into oxide or sulphate which then reacts with the remaining sulphide ore to give the metal.

In the metallurgical extraction of zinc from ZnO, the reducing agent used is :
thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

  1. $CO$

  2. $SO _{2}$

  3. $CO _{2}$

  4. $NO$

Show answer
Correct Option: A
Explanation:
In the metallurgical extraction of zinc from ZnO, the reducing agent used is C/CO.

$ZnO + C \rightarrow   Zn + CO$
$ ZnO + CO \rightarrow  Zn + CO _2$