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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

When copper ore is mixed with silica, in a reverberatory furnace copper matte is produced. The copper matte contains:

  1. Sulphides of copper (II) and iron (II)

  2. Sulphides of copper (II) and iron (III)

  3. Sulphides of copper (I) and iron (II)

  4. Sulphides of copper (I) and iron (III).
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Copper matte is a mixture of cuprous sulphide (Cu2S) and ferrous sulphide (FeS). These are sulphides of copper (I) and iron (II).

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

The balance reaction involved during extraction of zinc from its ore, by calcination of zinc ore, is:

  1. $2ZnCO _{3} (s) \xrightarrow{Heat} 2ZnO(s) + CO _{2}(g)$
  2. $ZnCO _{3} (s) \xrightarrow{Heat} ZnO(s) + CO _{2}(g)$
  3. $ZnCO _{3} (s) \xrightarrow{Heat} 2ZnO(s) + CO _{2}(g)$

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

Calcination is defined as heating to high temperatures in the presence of air or oxygen. Heating the metal carbonates result in the formation of metal oxides and carbon dioxide.
$ZnC{ O } _{ 3 }(s)\xrightarrow { heat } ZnO(s)+C{ O } _{ 2 }(g)$

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

$Cu _{2}S+2Cu _{2}O \rightarrow 6Cu+SO _{2}$
In which process of metallurgy of copper, above equation is involved -

  1. roasting

  2. self reduction

  3. refining

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

During the Bessemerisation process, the sulphide ores of less electropositive metals are heated in air to convert part of the ore into oxide or sulphate which then react with the remaining sulphide ore to give the metal and sulphur dioxide.
Copper sulphide is partially oxidised to cuprous oxide which futher can react with remaining copper sulphide to form copper and sulphur dioxide.
$2Cu _{2}S+3O _{2} \rightarrow 2Cu _{2}O+2SO _{2}$
$Cu _{2}S+2Cu _{2}O \rightarrow 6Cu+SO _{2}$
This process is also called  autoreduction process or air reduction process. 

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 two substances react to produce blister copper?

  1. $Cu _{2}S _{(s)}$ and $Cu _{2}O _{(s)}$
  2. $Cu _{2}O _{(s)}$ and $FeS _{(s)}$
  3. $Cu _{2}S _{(s)}$ and $O _{2(g)}$
  4. $Cu _{2}S _{(s)}$ and $FeS _{2(s)}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Blast of air converts $Cu _2S$ partly into $Cu _2O$ which reacts with remaining $Cu _2S$ to give molten copper. The copper so obtained is called "Blister copper" because, as it solidifies, $SO _2$ hidden in it escapes out producing blister on its surface

option A 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

In the extraction of copper, the copper matte is a mixture of:

  1. copper (II) sulphide and iron (II) sulphide

  2. copper (II) sulphide and iron (III) sulphide

  3. copper (I) sulphide and iron (II) sulphide

  4. copper (I) sulphide and iron (III) sulphide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • The chemical formula of copper matte is $Cu _2S+FeS$. It is a combination of copper sulphide and iron sulphide.
  • It is a phase in which extracted metal is converted into crude metal which is a final product.
  • $80-70\%$ of copper matte is used $80-95\%$. $5- 17\%$ metallic copper, $Fe-Co$ alloy etc are used.
Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Metallurgical process of zinc involves roasting of zinc sulphide followed by reduction. Metallic zinc distills over as it is volatile and impurities like Cu, Pd and Fe gets condensed. The crude metal obtained is called spelter, which may be purified by:

  1. electrolysis process

  2. fractional distillation

  3. polling

  4. heating with iodine
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

Spelter Zn is purified by both distillation and electro fining process(here we get more pure Zn).

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 wood liberates hydrocarbon gases (like $CH _{4}$). Name the process involved.

  1. Cupellation

  2. Poling

  3. Scaling

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

Blister copper contain $Cu _2O$ as impurity and is refined by poling process. 


In this process, the molten impure metal is stirred with green logs of wood because such a wood liberates hydrocarbon gases (like  $CH _{4}$), and hence, act as a reducing agent to reduce copper oxide to metal.


Option B 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

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

  1. Bessemer converter

  2. Pierce-Smith converter

  3. both (a) and (b)

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

Self-reduction of CuS to Cu can be carried out in either Bessemer converter or Pierce-Smith converter.
$2Cu _2S+3O-2 \rightarrow 2Cu _2O + 2SO _2$
$2Cu _2O+Cu _2S \rightarrow 6Cu+SO _2$