Tag: basics of metallurgy

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

Metals more reactive than carbon are usually extracted by_________.

  1. Pyrolysis

  2. Electrolysis

  3. Fractional distillation

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

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

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

  1. Electro-refining

  2. Electrowinning

  3. Both a and b

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

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

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

  1. Using sodium hydroxide

  2. Using electrolysis

  3. Froth flotation method

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

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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 $true$.
Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy 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

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

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

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

  4. (ii), (i), (iii)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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


Hence, the correct option is $(D)$

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

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

  1. Roasting

  2. Smelting

  3. Zone refining

  4. Ore dressing
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

The above process is:

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

  1. auto oxidation

  2. self reduction

  3. thermal reduction

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
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