JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II Year PRINCIPLES OF EXTRACTIVE METALLURGY Previous Question Paper (May - 2019 - R16)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
List out the important ores of iron and aluminium.
Answer
Important ores of iron include Hematite (Fe2O3), Magnetite (Fe3O4), Limonite (FeO(OH)·nH2O), and Siderite (FeCO3). Important ores of aluminium include Bauxite (Al2O3·nH2O), Cryolite (Na3AlF6), and Corundum (Al2O3).
Classify different roasting methods.
Answer
Roasting methods are classified based on the atmosphere and purpose:
- Oxidizing Roasting: Heating in excess air to convert sulfides to oxides.
- Sulfating Roasting: Controlled oxidation to convert metal sulfides into soluble sulfates.
- Chloridizing Roasting: Heating with chlorinating agents to convert metals into volatile or soluble chlorides.
- Volatilizing Roasting: Heating to convert impurities into volatile oxides.
- Dead Roasting: Complete removal of sulfur from sulfide ores.
What is basicity of slag?
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What are the objectives of sintering?
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Explain the principle of cementation process.
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Why pressure leaching is carried out in autoclave.
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What are the basic conditions that should be met by an electrolyte?
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Define faraday’s laws of electrolysis.
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Give the necessity of zone refining.
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What are the basic approaches to the refining of pure metals?
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Part B
List different pyrometallurgical processes and explain each one of them.
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Write a note on chloride free energy diagrams and their limitations.
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Draw Standard free energy diagram for different metal oxides? Explain use of O2, CO/CO2 and H2/H2O scale.
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Discuss different steps of fluidized bed roasting process? Mention the importance of fluidization curve?
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Define smelting. Explain flash smelting process with a neat diagram.
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Explain the process of pelletisation? Discuss theory of bonding in palletization.
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What is Slag? How is it formed? Explain its importance in metal extraction process.
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Differentiate between Matte smelting and Reduction smelting.
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List out the advantages of pressure leaching.
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Describe microbial leaching process? Explain the effect of bacteria on leaching rate and extent of recovery.
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What is Hydrometallurgy? Compare Hydrometallurgy with Pyrometallurgy in terms of advantages limitations and applications?
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Name various leaching methods and explain them in brief.
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How electro winning is different from electro refining? Explain in detail.
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Discuss the principle involved in electrorefining of metals using molten salts? Explain the principle in reference to refining of aluminum.
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What are the factors causing lowered current efficiency in the electrolysis of fused salts? Describe the methods to overcome lower current efficiency.
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Write a note on Electrowinning? Explain its applications.
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Explain in detail about the fire refining process during copper extraction process?
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Is it possible to produce 100 percent pure metals? Justify your answer.
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What is meant by selective distillation? Explain with the help of a suitable example.
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What is the principle involved in refining by liquation? Explain with a suitable example.
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