PRESENTATION ON ELLINGHAM DIAGRAMS.

1. TOPIC:-ELLINGHAM DIAGRAM
Presented by:- B Sagar Naik
17265A1802
MME 3/4

2. Definition of Ellingham diagram:-
• An Ellingham diagram is a graph showing the
temperature dependency for compounds, this
analysis is used to evaluate the case of reduction of
metal oxides and sulphides
• Thermodynamic feasibility of a reduction depends
on
∆G=∆H-T∆S
∆G=Gibbs free energy change
∆H=Enthalpy change
∆S=Entropy change

4. CONSTRUCTION:-
• An Ellingham diagram is a plot of ∆G verses
temperature since ∆H and ∆s are essentially constant
with temperature unless a phase change occurs
• Where ∆S is the slope ∆H is the Y-intercept
• Free energy of formation is –ve for mass metal oxides,
so ∆G=0 at the top of the diagram and values of ∆G
shown are all –ve
• The solid reacting with a mole of gas to produce a
mole of gas, and so there is little change in entropy
and the line is nearly horizontal
C+O2CO2
2C+O22CO

5. • Reactions closes to the top of the diagram are noble
metals and these oxides are unstable and easily
reduced
• Since 2co line is sloping downward it cuts almost all
the lines in the diagram
• The carbon can then reduce the metal oxide to metal
FEO+COFE+CO2

6. FEATURES:-
• The majority of lines slope upwards with an
approximately same slope
• The slope of a line changes when there is a phase
change
• Under standard state all metals with –ve value of ∆G
may oxidized simultaneously, the oxides with +ve ∆G
is not stable
• A metal can reduce the oxides of other metal where
lines lie above them

7. LIMITATIONS:-
• It is only applicable to one atmospheric
presure
• It is not applicable to alloy metals
• It is not applicable to compound
formation of the elements

8. APPLICATION:-
• The main application of Ellingham diagram in the
extractive metallurgy industry
• Aluminum oxide is more stable than chromium oxide
since is –ve, aluminum can reduce chromium oxide
• Knowing the value of ∆G at any temperature the
partial pressure of o2 a metal oxide formation can be
calculated
• Entropy change of any metal oxide can be known
∆G=∆H-T∆S
• Suitable reducing agent for any metal can be chosen

9. Disadvantages:-
• The free energy changes shown refer to standard
state only
• Do not give any information regarding the rate of the
process
• The possibilities of the formation of intermetallic
compounds between the product and reactants are
not considered

10. THANK YOU