METALLURGY , CBSE , GRADE 12 ,CHEMISTRY ,ISOLATION OF ELEMENTS , CLASS 12, zone refining ,magnetic separation

1. ISOLATION OF ELEMENTS
Metallurgy , Concentration of ores, Refining

2. MINERALS AND ORES???

3. TYPES OF ORES!
• Cassiterite (tin)
• Chromite (chromium)
• Coltan (niobium and tantalum)
• Columbite (niobium)
• Hematite (iron)
• Ilmenite (titanium)
• Magnetite (iron)
• Pyrolusite (manganese)
Ores of reactive metals
are found
in combined state!!

4. CHEMICAL METHOD-LEACHING
• Leaching is the process in which the ore is concentrated by chemical reaction with a
suitable reagent which dissolves the ore but not the impurities,
• E.g., bauxite is leached with a hot concentrated solution of NaOH which dissolves
aluminium while other oxides (Fe2O3, TiO2, SiO2), remain undissolved and noble
metals (Ag and Au) are leached with a dilute aqueous solution of NaCN or KCN in
the presence of air.

6. LEACHING IS OFTEN USED IF THE ORE IS
SOLUBLE IN SOME SUITABLE SOLVENT. (CBSE
2014)

7. • A metal can be used to
reduce another metal. And
according to this diagram,
any metal will reduce the
oxide of another metal
lying above it .
• Eg: Mg can reduce Al till
1773k and after that Al will
reduce Mg.

8. • C is a good reducing
agent at higher
temperatures.(>983K)
• While CO is a good
reducing agent at low
temperatures.
• Since G is + at high
temp for CO. (VICE
VERSA)

9. ZONE REFINING

10. VAPOUR PHASE REFINING
• the metal is converted into its volatile compound and collected elsewhere. It is then
decomposed to give pure metal.