Tag: extraction of metals from ore

Questions Related to extraction of metals from ore

The order of processes involved in the dressing of an ore are :
(i) grinding and crushing           (ii) hand picking                (iii) pulverization

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

  1. (i), (ii), (iii)

  2. (i), (iii), (ii)

  3. (ii), (iii), (i)

  4. (ii), (i), (iii)

Show answer
Correct Option: D
Explanation:

Dressing of ore can be carried out by first handpicking followed by crushing and grinding and then pulverization.


Hence, the correct option is $(D)$

Identify the oxide ore among the following :

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

  1. Copper pyrites

  2. Copper glance

  3. Siderite

  4. Limonite

Show answer
Correct Option: D
Explanation:

Formula of Limonite is $F _eO(OH)\cdot nH _2O$. It is an oxide ore.

The process of carrying out the reduction of metal oxides by heating with coke is termed as :

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

  1. Roasting

  2. Smelting

  3. Zone refining

  4. Ore dressing

Show answer
Correct Option: B
Explanation:

Smelting is the process where heat is applied to ore to extract the base metal, using a reducing agent. So, it is used to carry out reduction of metal oxides to metal by heating with coke.

The above process is:

$HgS\xrightarrow{O _2}HgS.HgO$
                         $\downarrow\Delta$
                        $Hg$ 

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

  1. auto oxidation

  2. self reduction

  3. thermal reduction

  4. none of the above

Show answer
Correct Option: B
Explanation:

Cinnabar ($HgS$), when heated with a current of $O _2$ gets reduced to $Hg$ without the need of any additional reducing agent. The process involved is known as self reduction

Which of the following metal oxides are reduced by CO?

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

  1. ZnO

  2. Fe$ _2$O$ _3$

  3. CaO

  4. Al$ _2$O$ _3$

Show answer
Correct Option: A,B
Explanation:

Oxides of highly reactive metals cannot be reduced by $CO$. Hence $CaO$ and $Al _2O _3$ are not reduced by $CO$ and both $ZnO $ and $Fe _2O _3$ are reduced by $CO$

In which of the following chemical leaching is used either in the extraction of metal or in the concentration of ore?

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

  1. Argentite

  2. Bauxite

  3. Alluvial sand containing gold

  4. All of these

Show answer
Correct Option: A

Which one of the following statements is incorrect about rock salt type?

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

  1. It has fcc arrangement of $\mathrm { Na } ^ { + }$

  2. Nat and Cl-ions have a co-ordination number of $6:6$

  3. A unit cell of $NaCl$ consists of four $NaCl$ units

  4. All halides of alkali metals have rock-salt type structure

Show answer
Correct Option: D
Explanation:

The alkali halides crystallize in the NaCl structure also known as rock-salt structure (rock salt is the mineral form of sodium chloride); exceptions being CsCl, CsBr, and CsI, which crystallize in the CsCl structure. In the NaCl structure (face-centered cubic lattice), each cation is surrounding by six anions, and vice versa (coordination number of 6). In the CsCl structure, each cation is surrounded by eight anions and vice versa (coordination number of 8).

Option D is incorrect

The extraction of metals from oxide ores may involve:

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

  1. reduction with carbon

  2. reduction with aluminium

  3. electrolyte reduction

  4. reduction with CO

Show answer
Correct Option: A,B,C,D
Explanation:

These are the methods for extraction of metals from oxide ores:
Carbon reduction, involving reduction with CO or C
Self reduction
Thermite reduction, which employs Al
Electrolytic reduction.

The advantage(s) of using carbon to reduced a number of oxides and other compounds are :

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

  1. easy availability of coke.

  2. low cost of carbon.

  3. tendency of carbon to show catenation..

  4. presence of carbon lowers the melting point of the oxide.

Show answer
Correct Option: A,B
Explanation:

The advantage(s) of using carbon to reduced a number of oxides and other compounds are
 (i) easy availability of coke.
 (ii) low cost of carbon.
 (iii) exothermic nature of reaction which requires less energy to keep the furnace hot.


Hence, A and B are the correct options. 

The extraction of metals from oxide ores involve :

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

  1. reduction with carbon

  2. reduction with aluminium

  3. electrolyte reduction

  4. reduction with $CO$

Show answer
Correct Option: A,B,C,D
Explanation:

During extraction of metals from oxide ores, the reduction of metal ore to crude metal can be carried out by using several methods such as pyrometallurgy, hydrometallurgy and electrometallurgy. Various reducing agents such as carbon, hydrogen, aluminum or other metals can be used. CO also reduces metal ores to crude metals.