This document provides an overview of principles of extractive metallurgy. It outlines the course objectives which are to understand extractive metallurgy processes, identify extraction types, learn thermodynamics of extraction, and understand various metal production flow sheets. The syllabus covers topics like extraction processes, pyrometallurgy versus hydrometallurgy, calcination, roasting, smelting, thermodynamics principles, and electrometallurgy. Key extraction concepts like comminution, classification, separation methods, and kinetics are also mentioned.

1. Principles
of
Extractive Metallurgy
Prepared By
Dr. M. Kalyan Phani
Sr Assistant Professor,
Dept. of Metallurgical Materials Engineering
OP Jindal University
Raigarh, Chhattisgarh
kalyan.makkuva@opju.ac.in

2. Course Objectives
• Understand what is Extractive metallurgy
• Identify various types of Extraction process
• Learn to understand the thermodynamics behind
extraction
• Learn various flow sheets of extraction of various
metals

3. Syllabus
UNIT- 1
Introduction, type, advantages and limitations of different extraction processes. Beneficiation steps in
ore processing like comminution, classification, separation methods, comparison of pyro-metallurgy
and hydrometallurgy.
UNIT- 2
Calcination, roasting, sintering, pelletisation, smelting, converting, refining, pyro-metallurgical process
using vacuum. Thermodynamic principle and stability diagram (Ellingham diagram in pyro-metallurgy),
limitation of Ellingham diagram, metallic reduction by C, CO, Hydrogen and metals, principle of
metallothermic reduction and halide metallurgy.
UNIT- 3
Principle, general considerations kinetics, leaching, reagent kinetics, role of oxygen, pressure
leaching, bacterial leaching, solvent extraction, ion exchange. gaseous reduction of aqueous solution.
UNIT- 4
Eletro-winning, and electro-refining of metal from aqueous anode fused salt system, Physico-chemical
principle of fused salt electrolysis.
UNIT- 5
Simplified flow sheet for the production of aluminum copper, zinc lead, tin and magnesium. Order of
reactions, theories of reaction kinetics, role of activation energy, theory of absolute reaction rate.

4. Text Books/Reference Books
• Principles of Extractive Metallurgy, Terkel Rosenqvist,
McGraw-Hill Book Company.
• Principles of Extractive Metallurgy, H.S. Ray and A.
Ghosh, New Age Publication.
• Extractive Metallurgy of Copper, W.G. Davenport, A.K.
Biswas, PERGAMON publishing company.
• Handbook of Extractive Metallurgy, Fathi Habashi; Wiley-
VCH.

5. Topics at glimpse
• Compound
• Ores
• Minerals
• Metals
• Material
• Alloys
• Why metal has to be extracted?
• Which metal will get oxidized?
• Which metal will get reduced?
• What is reaction? And why does it happen?

6. What is Metallurgy?
Physical
Metallurgy
 It is a branch of Metal science and
technology where we study exaction
of metals from their ores production
of alloys by mixing these metals,
generate required properties in the
final product which is being delivered
for a good cause for the mankind.
 Apart from this metallurgy consists
also of the generation of a product
with minimized defects.
Extractive
Metallurgy
Mineral
Processing

11. Metals with high chemical reactivity tend to form relatively unstable complex compounds.
Those with lower reactivity tend to form relatively unstable associations.
Noble metals may be found in native state.

13. Sources of metals
• Earths Crust
• Ocean waters
• Metal Scrap – Urban Ore Concept

20. Resources of metal
containing minerals in
India
• Abundant: Al, Be, Cr,
Fe, Mn, Mg, Ti, Zr, Th,
Pb and Zn, raw earth
metals
• Very small: Co,
Ni,Cu,Sn, Au, V, Ni,
Cd and U.
• Poor or not found:
Sb, Bi, Co, Hg, Mo,
Nb, Ta, Sr, Se, Ag, W,
Pt

21. • Tonnage production of metals will depend on:
– Accessibility of ore deposits
– Richness of ore deposits
– Nature of extraction and refining process
– Physical and chemical properties of metals
– Demand for metals – governed by its physical and chemical properties.
• Two types of EM:
– Ferrous
– NonFerrous
• Steps required of extraction
– Electrolysis – Al, Cu, Zn etc.
– Smelting-Pb, Fe, Cu etc.
The above mentioned steps are called unit steps and these are classified into unit
operations and unit processes.
Unit operations: Comminution, filtration, casting, distillation etc.
Unit processes: leaching, smelting etc.

22. • Separation process is divided into 2 stages:
– Concentration: separation of ore minerals from other gangue
minerals (Mineral Engineering)
– Extraction or refining: separation of desired metals rom other
constituents ( Extractive metallurgy)
• For Chemical Engineers:
– Mechanical separation process: Gravity separation, filtration,
magnetic separation
– Diffusional separation process: distillation, precipitation,
extraction etc.
• Separation based on phase equilibria and kinetics:
Solvent extraction, slag metal reactions, distillation
• Separation methods based on rate process: gaseous diffusion
and electrophoeresis
• These seperation process accounts for the main cost of the individual metal:
Lower the concentration of metal in ore higher the cost of metal extracted.
• Radium costlier than gold costlier than copper and so on.

23. Extractive Metallurgy

24. Principles in EM!!
• Heat and mass balance: to know the material requirement
• Thermodynamics: Feasibility criteria • Kinetics and rate of
process: How long it take to complete the process
• Heat transfer: For improving the thermal efficiency of the
process
• Fluid dynamics: To know the mixing of the reactor
• High temperature properties of metals/slag: To know the
physical properties of various phases, their mobility and role in
metal refining processes.
• Electrochemistry: To estimate, overpotential, current efficiency
• Hydrometallurgy: Eh-pH diagram, rate estmation of leaching
process

25. Types of Extractive Metallurgy
• Pyrometallurgy
• Hydrometallurgy
• Electrometallurgy
Or
• Solid state processing
• Liquid state processing
Extractive metallurgy is multi-disciplinary-it talks
about reduction

27. Pyrometallurgy
• Heat is the main source
• Three types: Calcination, Roasting, Smelting
• Advantages:
– Cheap and used for large scale productions
– High temperature provide good reaction rates
and make some reactions thermodynamically
possible.
– Easy metal slag separation due to melt state.
• Pb, Zn, Cu, Al, Fe, Mg, Na, Sb etc. are produced
using this method

28. Calcination
• It is a process in which the ore is heated in a limited
supply of air at a temperature insufficient to melt it.
• Organic matter, volatile impurities and moisture present
in the ore are expelled and remaining mass becomes
porous.
• Used for carbonate ores
• Generally done in reverberatory furnace, Rotary kiln or
fluidized bed reactor to render the porous and easily
workable in subsequent stages.
• CaCo3 CaO (Quick Lime) + Co2(g) at 850-950 0C
• Al2O3.2H2O Al2O3 + 2H2O
• 2Fe2O3.3H2O 2Fe2O3+3H2O

29. • Calcination is a thermal treatment process and applied to
ores and other solid materials to bring
a) thermal decomposition b) phase transition and c)
to remove volatile fractions such as CO2, H2O
Applications:
• To produce cement from CaCO3
• To cause decomposition of hydrated minerals as in
calcination of bauxite to produce refractory grade Al2O3.
• To cause decomposition of volatile matter contained in
petroleum Coke.
• To heat treat to effect phase transformation as in
devitrification of glass materials.
• To produce anhydrous Al2O3 for electrolysis of Al2O3to Al
in Hall‐Heroult cell

30. Roasting
• It is a Chemical conversion process
• Usually used to convert one form of the ores to
other form
– Eg. Sulphide to Oxide
• It involves not only heating but reaction with gas
• 2ZnS+3O22ZnO+2SO2
• TiO2+C+2Cl2TiCl4+CO2
• When ΔH is negative Autogeneous roasting
possible

31. Steps in Roasting
• Heating of particles
• Reactive gas such as air, O2 and Cl2)
contacts the particles
• Particles react with gas
• Gaseous reaction product are carried
away

32. Roasting Terms
Dead Roast: ore is completely reacted and
leaves the process cold
Sweet Roast: Ore is completely reacted ,
but leaves the furnace still hot
Sour Roast: Roasting reaction not run to
completion

33. Roasting Calcination
Chemical Conversion process Chemical decomposition
process and volatile removal
process
Happens at 550 0C Happens at 850 – 950 0C
Is a pyrometallurgy process Is a pyrometallurgy process
Involve heating ore before
fusion temperature
Involve heating ore before
fusion temperature
Involves removing of volatile
matter
Involves removing of volatile
matter
Used for sulphide ores Used for Carbonate ores
Happens in presence or
absence of air
Happens a presence of air

34. Smelting
• Smelting: It is a process for the production of
metal/metal rich phase known as ‘matte’
along with gangue known as ‘slag’
• Reduction of metal oxide ore is done by
smelting process:
• MO (s,l) + C (s) = M (s,l) + CO (g)
• MO (s,l) + CO (g) = M (s,l) + CO2 (g)
• Example: Blast furnace

35. Blast Furnace – Iron Maker