This document discusses the key steps in the metallurgy process: 1) Crushing and pulverization breaks down ore into powder. 2) Ore dressing or concentration removes gangue (waste rock) from powdered ore using methods like gravity separation or froth flotation. 3) Calcination or roasting heats the ore to convert compounds and evaporate impurities, preparing it for smelting. 4) Smelting uses heat and chemical reducing agents to extract the pure metal from the ore by melting it and separating it from the slag waste. 5) Refining further purifies the crude metal by removing remaining impurities.

1. Shri Shivaji Education Society Amravati’s
J.D.Patil Sangludkar Mahavidyalaya,
Daryapur.
Metallurgy
Rahul G sawarkar

2. Contents
Introduction
Steps in Metallurgy
Crushing and Pulverization
Ore Dressing or concentration of ore
Calcination
Roasting
Smelting
Refining
References

3. Introduction
Mineral
A "naturally occurring substance containing an element in free state”.
Or
A compound with “definite chemical composition and structure."
What is Metallurgy ?
An art and science of getting the metal in pure state economically from ore.

4. Steps in Metallurgy
4
Crushing and Pulverization.
Ore Dressing or Concentration.
Calcination.
Roasting.
Smelting.
Refining.

5. Crushing and pulverization
Crushes big lumps into small powdered in
mine by using mill and
send to next process.

6. Ore Dressing or Concentration
Removal of gangue from powdered ore is known as
ore dressing or concentration of ore.
The purified ore is known as concentrate.
Following are the methods for concentration of ore.
Gravity Separation
Froth Floatation
Electromagnetic separation

7. Gravity Separation
Principle
Gravity separation process is especially suitable for heavy ‘oxide’.
Process
This process is useful when the density ratio of ore and gangue is
more than 1.25, i.e. metallic part should be 1.25 (or more) times heavier
than gangue.
In this method the powdered ore is subjected to a stream of flowing
water so that lighter gangue particles are flown away leaving behind the
heavy metallic particles.

8. Principle:
Surface tension plays an important role in this method.
This method is usually employed for concentration of
sulphide ores.
Froath Flotation Process

9. Electro-Magnetic Separation
Principle:
Separation for magnetic impurities from non magnetic ore particles
(or vice-versa).

10. Calcination
What is Calcination ?
Heating an ore in absence of air below its melting point.
Calcination is usually done to carbonate ores.
It convert carbonates into oxide,
ZnCO3 ZnO + CO2
ii) Impurities evaporate on heating.

11. Roasting
The process of heating the ore in presence of air or oxygen
(or sometimes in presence of some other reagent) below its
melting point.
Roasting is usually done to sulphide ores.
i) To convert sulphides into oxide & suplhate resp.,
2 ZnS 2 ZnO + 2 SO2
2 ZnS ZnSO4
ii) Impurities are oxidized and then evaporated.
iii) Oxidation reactions take place in roasting.

12.  The roasted ore or calcined ore is heated to high
temperature along with reducing agent(generally coal or coke)
and another substance called as flux (generally lime CaO).
 The reducing agent converts the ore into molten metal,
while the flux removes the last traces of gangue in the form of
fusible mass, called slag (which floats on the molten metal)
and is removed separately.
Smelting

13. Fe2O3 + 3 C Δ 2 Fe + 3 CO
Ore Reducing Metal
agent (Molten)
SiO2 + CaO Δ CaSiO3
Impurity Flux slag
(Gangue) (Molten)

14. The purification of crude metals by removing metallic and non-metallic impurities
is known as refining of metals.
Refining