6 Metallurgy Flashcards
Basis of differentiation for Metals and Non metals are?
Atomic Structure
What are physical differences depended on?
What are chemical differences depende on?
- Arrangement of Atoms
- a. Number of valence shell
b. Their behaviour during chemical reaction (ability to redox)
Quality of the metals can be improved by?
- Alloying (mixing with other metals)
2. Protecting by electroplating
What is Metallurgy?
The large scale process of involved in extraction of pure metals from their respective ores.
Give the properties of metals and their exceptions for each.
- Exist in solid state: Mercury
- MP and BP: Na, K, Hg
- Density: Na, K, Ca
- Ductility: Hg, Zn
- Malleability: Zn
- Amphoteric oxides: ZAP
Give the properties of Non-metals and exception for each:
- Non Lustruous: Iodine and Graphite
- MP and BP: Carbon and Silicon
- Density: Diamond
- Ductility: Carbon Fibre
- Malleability: Carbon Fibre
- Acidic or Neutral oxides (CO, N2O, NO, H2O)
Occurance of metals can be:
- Free or Naitive
2. Combined
What is free or Native state?
- Occuring in freee metallic form
- Not acted upon by natural elements
- Like constituents of air and Water
- Example Gold and Platinum
What is Combined state?
Metals occuring in the form of Compounds.
What is a mineral?
- Compounds of various metals
- Found in nature
- Assosciated with their earthly impurities
What is an Ore?
- Naturally occuring mineral
- From which metals can be extracted
- Profitably and Conveniently
What is Metallurgy?
- Large scale process
- Involved in the extraction of pure metals
- From their respective ores
What is a matrix?
- Rocking impurities (including silica, mud)
- Assosciated with the ore
- Also called Gangue
What is a Flux?
- Substance added to the ore
- To get rid of matrix
- Resulting in the formation of a fusible compound -> SLAG
What are the steps involved in the extraction of Aluminium?
- Dressing of the ore (Concentration of the ore and seperating ore from Gangue) -> Baeyer’s Process.
- Conversion of Ore to Oxide Ore (not necesary)
- Reduction of metallic oxide to metal (Hall Heroult’s Process)
- Electrorefining -> Hoope’s Process
What is the most abundant metal in the earth’s crust? Give its %
Which is the 2nd most abundant metal in the earth’s crust? Give its %
Aluminium (7.4%)
Iron(4.7%)
Why doesnt aluminium occur in free state?
Because it is a reactive metal
What is the main ore of Aluminium?
What kind of oxide is it?
Bauxite (Al2O3.2H2O)
It is an amphoteric Oxide.
Give the three equation of Dressing of the ore.1
- Converting impure bauxite to Sodium Aluminate:
Al2O3. 2H2O + 2NaOH —> (150 to 200*) NaAlO2 + 3H2O - Converting Sodium Aluminate to Aluminium Hydroxide:
NaAlO2 + 2H2O —> (50 to 60*) Al(OH)3 + NaOH - Converting of Al(OH)3 to Pure Alumina:
Al(OH)3 —->(1100*) Al2O3 + 3H2O
Give the points of first step of the first step in extraction of aluminium:
- Bauxite (amphoteric) reacted with conc. Soln. of NaOH (base)(FOR 2 HRS UNDER PRESSURE) —> Gives salt and water.
- Impurities dont react -> Not amphoteric
- Impurities are seperated out AS RESIDUE
What are the two main impuries assoscitated with the bauxite ore?
- Fe2O3 and SiO2
Give the points of fsecond step of the dressing in extraction of aluminium:
- NaAlO2 diluted with water + Crystals of Al(OH)3 —> Further precipitates Al(OH)3. This is called Seeding
- After Agitation insoluble Al(OH)3 is filtered out and dried.
THIS IS HYDROLYSIS