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Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

(a) In smelting process carried out in blast furnace for the exgtraction of iron, lower region of the furnace has the highest temperature.
(b) Formation of $CO$ from ${CO} _{2}$ and coke reduces the temperature of the middle region of blase furnace.
(c) Limestone is taken blast furnace as flux.
(d) Silica present in the ore as gangue is converted to fusible slag by the process of reduction
Which of the following regarding the process of smelting is correct?

  1. a, b and c

  2. b and c

  3. only a

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

The extraction of metal in the fused state is termed smelting. The ore is reduced by carbon to the free metal. A hot blast of air (sometimes with oxygen enrichment) is blown into the lower section of the furnace through a series of pipes . Formation of $CO$ from $CO _2$ and coke reduces the temperature of the middle region of blase furnace. Flux is a chemical substance which combines with gangue at higher temperaturesto form easily fusible material called slag which is not soluble in the molten metal. Limestone is taken blast furnace as basic flux. Silica present in the ore as gangue is converted to fusible slag by the process of oxidation  in flux.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

The manufacture of iron from iron ore involves the process of :

  1. oxidation

  2. reduction

  3. fractional distillation

  4. electrolysis

  5. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The manufacture of iron from iron ore (like haematite) involves the reduction of iron oxide using a reducing agent such as carbon monoxide in a blast furnace.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Nitriding is a process of heating steel in atmosphere of:

  1. $NH _3$
  2. $N _2$
  3. $O _2$
  4. $CO _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nitriding is the surface hardening process where nitrogen is added to the surface of steel parts using dissociated ammonia as the source. Gas nitriding develops a very hard case in a component at relatively low temperature. It is carried out at temperature below the transformation temperature of alloy steels and parts to be nitrided are heat treated to proper strength level and finally machined.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

(a) Thermite welding process exploits the difference in reactivity of different metals.
(b) Zinc spelter is used as cathode in electrolyte refining process of zinc.
(c) Iron is generally refined by electrolytic reduction process
(d) Iron is alloyed with other metals and carbon, only to prevent corrosion.
Which of the following options regarding the above statements is correct?

  1. a and d

  2. b and c

  3. only a

  4. a, b and c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Thermite welding process exploits the difference in reactivity of different metals. Pure zinc rod is used as cathode while a block of impure zinc spelter is used as anode. Iron is generally refined by smelting process.Iron is alloyed with other metals and carbon prevents the oxidation of iron and formation of rust.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Which of the following processes involves the smelting process?

  1. $ZnCO _3 \rightarrow ZnO + CO _2$
  2. $2PbS +3O _2 \rightarrow 2PbO + 2SO _2$
  3. $Fe _2O _3 + 3C \rightarrow 2Fe + 3CO$
  4. $Al _2O _3.2H _2O \rightarrow Al _2O _3 + 2H _2O$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In smelting, Iron ore is reduced to iron.

$Fe _{2}O _{3}+3C{\rightarrow}Fe+3CO$