Tag: basics of metallurgy

Questions Related to basics of metallurgy

Metals more reactive than carbon are usually extracted by_________.

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

  1. Pyrolysis

  2. Electrolysis

  3. Fractional distillation

  4. Filteration

Show answer
Correct Option: B
Explanation:

Metals more reactive than carbon are usually extracted by electrolysis. Electrolysis is the process of breaking down a compound using electrical energy and is needed to extract  the most reactive metals. 

What is the most common type of electrometallurgical processes to obtain pure metal?

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

  1. Electro-refining

  2. Electrowinning

  3. Both a and b

  4. Oxidation

Show answer
Correct Option: C
Explanation:

The most common types of electrometallurgical processes are electrowinning and electro-refining. Electrowinning is an electrolysis process used to recover metals in aqueous solution, usually as the result of an ore having undergone one or more hydrometallurgical processes. Electro-refining is used to dissolve an impure metallic anode and produce a high purity cathode. 

Which of the following is a physical mean for concentration of ore?

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

  1. Using sodium hydroxide

  2. Using electrolysis

  3. Froth flotation method

  4. None of above

Show answer
Correct Option: C
Explanation:

In many cases, it is possible to separate the metal compound from unwanted rocky material by physical means. A common example of this involves froth flotation. In this method, the unwanted object binds with air and comes on the surface as bubbles.

In electrolytic refining of any metal impure metal is taken as ...............

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

  1. anode

  2. cathode

  3. solution

  4. both B and C

Show answer
Correct Option: A
Explanation:

In electrolytic refining, impure metal is of positive charged anode and pure metal is of negative charged cathode.

Heating the ore is in the presence of air is ?

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

  1. roasting

  2. melting

  3. calcination

  4. none of these

Show answer
Correct Option: A
Explanation:

Heating of ore in the presence of oxygen is called roasting. It is a Pyrochemical Process. 

Eg: $2ZnS(s) + 3O _2 (g) \rightarrow 2ZnO (s) + 2SO _2 (g) $
      Zinc Blende 

State the given statement is true or false.
Statement: Mercuric oxide is reduced by thermal decomposition.
chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

  1. True

  2. False

Show answer
Correct Option: A
Explanation:
Mercury(II) oxide, a red solid, decomposes when heated to produce mercury and oxygen gas. A reaction is also considered to be a decomposition reaction even when one or more of the products are still compounds. A metal carbonate decomposes into a metal oxide and carbon dioxide gas.

$2HgO(s) \overset{\Delta}\longrightarrow 2Hg(l) + O _2(g)$

Hence, the given statement is $true$.

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