This set of Extractive Metallurgy Multiple Choice Questions & Answers (MCQs) focuses on “Advantages and Disadvantages of Hydrometallurgy”.
1. Which of the following does hydrometallurgy process use for the production of metals?
a) Organic solutions
b) Inorganic solutions
c) Electricity
d) Fire
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Explanation: Hydrometallurgy is a process that is used for the production of metals using reactions in aqueous and organic solutions. This process is usually carried out on low-grade ores. Hydrometallurgy processes are growing day by day.
2. Which of the following is not a step involved in a hydrometallurgical process?
a) Leaching
b) Separation of leach liquor
c) Electrowinning
d) Reagent recovery
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Explanation: The steps involved in a hydrometallurgical process are leaching, separation of leach liquor, recovery of metals from leach liquor and recycling of leach liquor. Electrowinning is an electrometallurgical process.
3. Which of the following may be the objective of a hydrometallurgical process?
a) To produce pure compounds
b) To produce impure compounds
c) To produce a non-metal directly from ore
d) To increase the speed of the process
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Explanation: The objectives of a hydrometallurgical process are to produce a pure compound which can be later used in pyrometallurgical processes. Other objectives are to produce a metal directly from the ore or metal compound or crude metal.
4. A hydrometallurgical process cannot be applied to complex ores.
a) True
b) False
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Explanation: A hydrometallurgical process is well suited for a complex ore because gangue in the ores remains unaffected by most of the leaching agents. It is difficult for pyrometallurgical processes because the gangue must be slagged and high temperature causes too much wastage of energy.
5. What is the reason behind obtaining metals directly in the pure form in hydrometallurgy?
a) Low temperature
b) High temperature
c) The high amount of leach liquor
d) Better control over every processing steps
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Explanation: In hydrometallurgy, we have greater control over every step involved in the process. This helps us to recover valuable by-products. We can also obtain metals directly in the pure form due to this advantage of hydrometallurgy.
6. How does hydrometallurgy help in reducing environmental pollution?
a) By not releasing SO2 gas in the air
b) By releasing SO2 gas in the air
c) By not using water for the processing steps
d) By saving heat energy
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Explanation: Hydrometallurgy helps in reducing environmental pollution by not releasing SO2 gas in the air. It keeps the sulphur in the solution after the leaching of ores. SO2 are not always used for the production of acid. It sometimes escapes in the air and causes environmental pollution. Pyrometallurgical processes release lots of SO2 gas during the processing of sulphide ores.
7. It is possible to design a hydrometallurgical process on a small scale.
a) True
b) False
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Explanation: It is possible to design and start a hydrometallurgical process on a small scale. It can be expanded further according to our need. A pyrometallurgical process has to be designed on a large scale. This is done for a better economic process.
8. Which of the following is not an advantage of a hydrometallurgy process?
a) Metal can be produced in various physical forms
b) Pure compounds can be obtained by hydrometallurgy
c) Reaction rates are very high at room temperature
d) Corrosion problem is comparatively less
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Explanation: Although there are so many advantages of a hydrometallurgy process, it has some disadvantages like reaction rate is lower at room temperature in for a hydrometallurgy process compared to processes at high temperature. Another disadvantage of a hydrometallurgy process is that some reagents are expensive and has to be recycled to make it economical.
9. Which of the following factors helps to meet the lower energy requirements of pyrometallurgical processes?
a) Endothermic nature of reactions
b) Low reaction rates
c) Increased residence time
d) Concentrated process streams
View Answer
Explanation: There are many factors which are beneficial for the lower energy requirements of pyrometallurgical processes over hydrometallurgy. Some of them are concentrated process streams, exothermic reactions, high reaction rates etc. In hydrometallurgy, heating and evaporation of aqueous solutions consume lot of energy even at room temperatures.
Sanfoundry Global Education & Learning Series – Extractive Metallurgy.
To practice all areas of Extractive Metallurgy, here is complete set of Multiple Choice Questions and Answers.
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