Metallurgy

Question 1

What is Mineral? 3pts

Answer 1

Natural substance obtained by mining containing metal in free state or in form of compounds(sulphides , oxides)

All minerals are not ores

China clay is the ore of aluminium

Question 2

What is ore? 3pts

Answer 2

Ore is a substance from which the metal can be extracted economically and conveniently

All ores are minerals

Bauxite is the ore of aluminium

Question 3

What is Gangue ?

Answer 3

Non metallic impurity, Rocky material and siliceous matter

Question 4

Extraction of metal from Ore

Answer 4

Concentration of ore
Extraction of crude metal
Refining of crude metal

Question 5

Gravity separation or hydraulic wash?

Answer 5

Low specific gravity gangue
high specific gravity impurity
separated by washing with running water

Haematite(Fe2o3) and Tin stone(Sno2)

Question 6

Froth floatation? 5M

Question 7

Leaching types

Answer 7

Cyanide leaching 
Cementation 
Ammonia leaching 
Alkali leaching 
Acid leaching

Question 8

Define Leaching

Answer 8

Based on
Solubility of ore
Reaction with an aqueous solution

Forms complex and gangue settles down

Question 9

Cyanide leaching?

Answer 9

Gold ore forms a complex with aerated sodium hydroxide solution whereas the gangue aluminium silicate remains insoluble.

Equation

Question 10

Cementation

Answer 10

Gold is converted back into an elemental state by making it react with the deoxygenated leeched solution with zinc.

Equation

Question 11

Ammonia leaching?

Answer 11

Ore containing nickel, copper, and cobalt treated with an aqueous solution of ammonia under suitable pressure, it selectively leaches the elements whereas the gangue remains insoluble

Equation :

Question 12

What is Acid Leeching?

Answer 12

Leaching of sulphide ores like ZnS, PbS are done with this method.
Hot aqueous conc.sulphuric acid is used

Equation:

Question 13

Magnetic separation ? 5m …

Answer 13

Applicable to ferromagnetic ore
Tinstone can be removed from wolframite impurities by this method
Their process:

Question 14

What are the two methods used for Extraction of crude metal?

Answer 14

Roasting

Smelting

Question 15

Roasting ?

Answer 15

Roasting is a process where the ore is heated in a reverberatory furnace with excess air below the melting point of metal

Two equations:

Roasting also removes arsenic, antimony, sulfur etc…

Two equation:

Question 16

Smelting:

Answer 16

Smelting is a process where the ore is heated in the absence of metal.During this process, the water of crystallization present in the hydrated oxide removed as vapour.

Any other organic substance is also removed leaving behind a porous ore.