Chemistry · Science General

Metallurgical Processes

1,403 Questions

This section explores key metallurgical processes including ore concentration, pyrometallurgy, and metal refining. It also covers corrosion and the properties of refractory materials. These chemistry questions are relevant for engineering and science entrance tests.

Pyrometallurgy furnacesMetal refining techniquesCorrosion protection methodsOre concentrationAuto reduction process

Metallurgical Processes Questions

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

In the extraction of aluminium,
Process X: applied for red bauxite to remove iron oxide (chief impurity)
Process Y: applied for white bauxite to remove Z (chief impurity). 

Then, Process X and impurity Z are:

  1. X $=$ Hall - Heroults process & Y$=$ $SiO _{2}$
  2. X $=$ Bayers process and Z $=$ $SiO _{2}$
  3. X $=$ Serpecks process and Y $=$ iron oxide
  4. X $=$ Baeyers process and Y $=$ iron oxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bayer's process is used for beneficiation of red bauxite.
Serpeck's process is used for beneficiation of white bauxite. 
Reaction to remove impurity from white bauxite is:
$SiO _2+2C\rightarrow Si+2CO$ .

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

In electrtolysis of $Al _2O _3$ by Hall-Heroult process:

  1. Cryolite $Na _3[AIF _6]$ lowers the melting point of $Al _2O _3$ and increases its electrical conductivity.
  2. $Al$ is obtained at cathode and probably $CO _2$ at anode

  3. both (a) and (b) are correct

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

The electrolysis of alumina by Hall and Heroult's process is carried by using a fused mixture of alumina and cryolite  along with minor quantities of aluminum fluoride and fluorspar. The addition of cryolite and fluorspar increases the electrical conductivity of alumina and  lowers the fusion temperature. Thus, the option A is correct. Also at anode, alumina reacts with fluorine to give oxygen. The liberated oxygen reacts with carbon to form $CO$ and $CO _2$. These gases are liberated at anode.

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

Which one of the following statements is incorrect?

  1. In the aluminothermite process, aluminium acts as reducing agent.

  2. Lead is extracted from its chief ore by both carbon reduction and self-reduction.

  3. Zinc is extracted from its chief ore by carbon reduction.

  4. Extraction of gold involves the leaching of ore with cyanide solution followed by reduction with zinc.

  5. In Hall-Heroult process, the electrolyte used is a molten mixture of alumina, sodium hydroxide and cryolite.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation
(1) $Cr _{2}O _{3}+2Al\rightarrow Al _2O _3+2Cr^{3+}$
(2) $2PbS+2PbO\rightarrow 2PbO+2SO _{2}$
$PbS+2PbO\rightarrow 3Pb+SO _{2}$ (self reduction)
$PbO+C\rightarrow Pb+CO$ (carbon reduction)
(3) $ZnO+C\rightarrow Zn+CO$ (carbon reduction)
(4) $4Au(S)+8CN(aq)+2H _{2}O(aq)+O _{2}(g)\rightarrow 4[Au(CN) _{2}]^{-}(aq)+4OH^{-}(aq)$ - leaching
$2[Au(CN] _{2}]^{-}(aq)+Zn(S)\rightarrow 2Au(S)+[Zn(CN) _{4}]^{2-}(aq)$ - reduction
(5) It is molten mixture of alumina and cryolite
Multiple choice chemistry industrial inorganic chemistry extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

The following question is relevant to the extraction of Aluminium:
Along with cryolite and alumina, another substance is added to the electrolyte mixture. the substance is ___________.

  1. Fluorspar

  2. Mica

  3. NaCl

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

Fluorspar is the substance act as a solvent and it increases conductivity. (Pure alumina melts at about $2000^oC$ and is a bad conductor of electricity. If fused cryolite and fluorspar is added, the mixture melts at $900^oC$ and  $Al _2O _3$ becomes a good conductor of electricity.)

Multiple choice chemistry industrial inorganic chemistry extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

A compound added to lower the fusion temperature of the electrolytic bath in the extraction of Al is ___________.

  1. cryolite and fluorspar

  2. Bauxite

  3. Iron and fluorspar

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

Pure alumina melts at about $2000^oC$ and is a bad conductor of electricity. If fused cryolite and fluorspar is added, the mixture melts at $900^0C$ and $Al _2O _3$ becomes a good conductor of electricity.

Multiple choice geography crafts and industries development of industries in india traditional crafts and decline of indian industries impact of british rule on kerala

The method of obtaining Wootz by heating black magnetite ore in the presence of carbon in a sealed clay crucible inside a charcoal furnace is called ______.

  1. Tamilakam method

  2. Srilankan method

  3. Magadhan method

  4. Taxila method
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The specific process of producing high-quality Wootz steel in South India using crucibles and charcoal furnaces is historically associated with the Tamilakam region.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Mark the incorrect statement.
a) Alloys with required properties can be made.
b) Alloys have properties different from constituent metals.
c) Alloys can never have carbon in it.
d) Alloy is a heterogenous mixture.

  1. a, b

  2. c, d

  3. a, c

  4. b, d
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alloys have properties which can different from the constituent metals. In fact it is possible to make alloys having required properties.

Alloy is a homogeneous mixture. Steel is an alloy of iron and carbon.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Steel is heated to the very high temperature and then plunged into cold water. This process is called _______.

  1. tempering

  2. anodising

  3. regulating

  4. anealing
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Annealing is the process of heating the steel to high temperature to soften it and it undergoes three phases. Quenching involves heating the steel and tempering in water or oil. This rapid cooling results in hard and brittle steel.

Multiple choice metals alloys and crystals chemistry elements and compounds alloys and their properties chemical bonding and structure

Which of the following properties of elements can be modified by the formation of alloys?

  1. Resistance to corrosion

  2. Toughness

  3. Malleability & ductility

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Alloys are used in some applications, where their properties are superior to those of the pure component elements, for a given application. This can include improvement in corrosion resistance (like stainless steel), toughness (like carbon-iron alloys) and malleability-ductility (like wrought iron).

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Which of the following methods can be used for the preparation of alloys?

  1. Melting a mixture of metals

  2. Simultaneous eletrolytic deposition of metals

  3. By mixing the aqeous solutions of the metal salts

  4. Both 1 and 2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Alloys can either be produced by melting a mixture of metals or simultaneous eletrolytic deposition of metals. This is because alloys are interstitial compounds, and have one atom of a metal inside the solid structure of another atom. This requires mixing in an efficient way, and not just normal physical conditions. 

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Raney Nickel is finely divided nickel obtained by digesting alloys of $Ni/Al $ over $NaOH$.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Raney nickel is a fine-grained solid composed mostly of nickel derived from a nickel aluminum alloy
The alloy is treated with a concentrated solution of sodium hydroxide. The simplified leaching reaction is:
$2Al + 2NaOH + 6 H _2O \rightarrow  2 Na[Al{(OH)} _4] + 3 H _2$
After this process, leaching is done to form raney nickel which is powder and spongey.
Given statement is true.
Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Statement 1 : A mixture of pure metals is called an alloy. The melting point of an alloy will be lower than either of the component metal.
Statement 2 : The new bonds are weaker.

  1. <p>Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1</p>

  2. <p>Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1</p>

  3. <p>Statement 1 is correct but Statement 2 is not correct</p>

  4. <p>Statement 1 is not correct but Statement 2 is correct</p>

  5. <p>Both the Statement 1 and Statement 2 are not correct</p>
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Both Statement 1 and Statement 2 is correct and Statement 2 is the correct explanation of Statement 1.


A mixture of pure metals is called an alloy. The melting point of an alloy will be lower than either of the component metal because the new bonds are weaker.

Hence, the correct option is A.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Tinned iron sheets are used for making boxes for fruits, oils, vegetables etc.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Tinning is the process of thinly coating sheets of wroughtiron or steel with tin, and the resulting product is known as tinplate. While once more widely used, the primary use of tinplate now is the manufacture of tin cans. Formerly, tinplate was used for cheap pots, pans and other holloware. It has an extremely beautiful metallic luster as well as excellent properties in corrosion resistance, solderability, and weldability. 

So it's true.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Tin is used for making fusible alloys.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A fusible alloy is a metal alloy capable of being easily fused, i.e. easily meltable, at relatively low temperatures. The most widely used fusible alloys contain high percentages of bismuth, combined with lead, tin, cadmium, indium and other metals. Bismuth has an impact on the melting point, as well as the growth and shrinkage characteristics of the alloys.