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Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Blister copper is refined by stirring molten impure metal with green logs of wood because such a wood liberate hydrocarbon gases (like $CH {4}$). This process $X$ is called _____ and the metal contains impurities of $Y$ is ___________ .

  1. $X$= cupellation, $Y$= $CuO _{2}$
  2. $X$= polling, $Y$= $Cu _{2}O$
  3. $X$= polling, $Y$= $CuO$
  4. $X$= cupellation, $Y$= $CuO$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The refining process of blister copper is known as polling.
The $Cu _2O$ impurities are present in the copper metal.
In presence of heat of molten metals, the green logs liberate hydrocarbon gases which reduce copper oxide into copper.

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Roasting of copper pyrites is done:

  1. to remove moisture and volatile impurities

  2. to oxidise free sulphur
  3. to decompose pyrites into ${Cu} _{2}S$ and $FeS$
  4. to decompose ${Cu} _{2}S$ into blister copper
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

During roasting of copper pyrite ore: 

(A) moisture is removed and sulphur, arsenic and antimony are removed in the form of their volatile oxides.
(B) Free sulphur is oxidized to sulphur dioxide.
(C) Coppr pyrite decomposes into cuprous sulphide and ferrous sulphide.

Thus options A, B and C are correct.
(D) Cuprous sulphide is decomposed into blister copper during bessemerisation. 
Thus option D is incorrect.

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Name the process  used for the formation of blister $Cu$ by following reaction :(unbalanced reactions)

$2Cu _2S\, +\, 3O _2\, \rightarrow\, Cu _2O\, +\, SO _2$

$Cu _2O\, +\, Cu _2S\, \rightarrow\, Cu\, +\, SO _2$ 

  1. Bessemerisation

  2. Parkes or Pattinson process

  3. Forth flotation

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

The process is called bessemerisation.  $Cu$ produced by Bessemerisation is known as blister $Cu$ which is $95 $%  pure. The balanced chemical reactions are as shown.

$2Cu _2S\, +\, 3O _2\, \rightarrow\, 2Cu _2O\, +\, 2SO _2$

$2Cu _2O\, +\, Cu _2S\, \rightarrow\, 6Cu\, +\, SO _2$

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

In the extraction of Cu, the reaction takes place in bessemer converter is:

  1. $2Cu _2O\, +\, Cu _2S\, \rightarrow\, 6Cu\, +\, SO _2$
  2. $2CuFeS _2\, +\, O _2\, \rightarrow\, Cu _2S\, +\, FeS\, +\, SO _2$
  3. $2Cu _2S\, +\, 3O _2\, \rightarrow\, 2Cu _2O\, +\,2SO _2$
  4. $2FeS\, +\, 3O _2\, \rightarrow\, 2FeO\, +\, 2SO _2$
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

The sulphide ore of copper is heated in the air until a part is converted to oxide and then further heating in the absence of air to let the oxide react with unchanged sulphide.


Self-reduction of CuS to Cu can be carried out in either Bessemer converter or Pierce-Smith converter.

$2Cu _2S+3O _2 \rightarrow 2Cu _2O + 2SO _2$
$2Cu _2O+Cu _2S \rightarrow 6Cu+SO _2$

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

The final step for the extraction of copper pyrites in Bessemer converter involves the reaction__________.

  1. $Cu _2S\,+\,2FeO\,\rightarrow\,2Cu\,+\,2Fe\,+\,SO _2$
  2. $Cu _2S\,+\,2Cu _2O\,\rightarrow\,6Cu\,+\,SO _2$
  3. $4Cu _2O\,+\,FeS\,\rightarrow\,8Cu\,+\,2FeSO _4$
  4. $2Cu _2O\,+\,FeS\,\rightarrow\,4Cu\,+\,Fe\,+\,SO _2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sulphide ore of copper is heated in air until a part is converted to oxide and then further heating in the absence of air to let the oxide react with unchanged sulphide.
Self-reduction of CuS to Cu can be carried out in either Bessemer converter or Pierce-Smith converter.
$2Cu _2S+3O-2 \rightarrow 2Cu _2O + 2SO _2$
$2Cu _2O+Cu _2S \rightarrow 6Cu+SO _2$
This is the final step in Bessemer converter.

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Self-reduction of CuS to Cu can be carried out in :

  1. Bessemer converter

  2. Blast furnace

  3. Both (A) and (B)

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

The following reaction takes place in Bessemer converter :


$ Cu _2S + \dfrac{3}{2}O _2 \rightarrow Cu _2O + SO _2$

$2Cu _2O + Cu _2S \longrightarrow 6Cu + SO _2$

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Which of the following statement is correct regarding Cu-extraction ?

  1. In the smelting step, carbon reduction takes places
  2. During roasting, $Cu _2S$ remains almost unaffected

  3. In Bessemer converter, only self reduction occurs, not slag formation
  4. Blister formed in the blister Cu is due to dissolved $CO _2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
In the extraction of copper, metal is formed in the Bessemer converter due to self reduction as

${ Cu } _{ 2 }S+2{ Cu } _{ 2 }O\rightarrow 6Cu+S{ O } _{ 2 }$
So Option C is correct
Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Extraction of zinc from zinc blende is achieved by:

  1. electrolytic reduction

  2. roasting followed by reduction with carbon

  3. roasting followed by reduction with another metal

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

Zinc blende (ZnS) is first roasted to form zinc oxide (ZnO), which is then reduced to zinc metal using carbon (coke).