This presentation is purely academic for undergraduate and postgraduate students

1. Metallurgy of Palladium and Platinum
Dr. Julekha. A. Shaikh
Maharashtra College of Arts, Science and Commerce

2. • Minerals:
• The naturally occurring chemical substances in the earth’s crust which are
obtained by mining are known as minerals. Metals may or may not be
extracted profitably from them.
• Ores :
• The rocky materials which contain sufficient quantity of mineral so that the
metal can be extracted profitably or economically are known as ores.
• Gangue:
• The earthy or undesirable materials present in ore are known as gangue.
• Metallurgy:
• Process involving physical and Chemical steps by which a metal is extracted
economically from its source is known as metallurgy /
• The entire scientific and technological process used for isolation of the metal
from its ores is known as metallurgy.
Dr. Julekha Shaikh, Maharashtra College 1

3. Dr. Julekha Shaikh, Maharashtra College 2

4. Palladium
Atomic No : 46 (Group 10, Period 5)
Atomic Weight : 106.7
Electronic Configuration : [Kr] 4d10
Discoverer– William Hyde Wollaston in 1803
Palladium is named after the asteroid Pallas, in turn named
after the Greek goddess of wisdom, Pallas. 3

5. • Braggite ( Pt, Pd, Ni) S ------ 20% Pd
• Stibiopalladinite Pd3Sb
• Potarite PdHg
• Porpazite or Palladium gold
• ( 85 - 90% Au & 6 - 7% Pd)
Palladium has been found uncombined in nature, in Brazil,
but most is found in sulfide minerals such as Braggite.
It is extracted commercially as a by-product of nickel
refining. It is also extracted as a by-product of copper and
zinc refining.
Dr. Julekha Shaikh, Maharashtra College 4

6. • From Sudbury Nickel Ore
• Ore is Concentrated & digested with aqua regia  sol of PdCl2 +
PtCl4
• Filtrate + NH4Cl  yellow ppt of Amm. Chloroplatinate & PdCl2
PtCl4 + 2 NH4Cl (NH4)2 [PtCl6]
(ammonium chloroplatinate)
Solution is treated with NH3 & concentrated by heating
PdCl2 + 4 NH3 + H2O [Pd(NH3)4 ] Cl2 H2O
(Tetrammine Palladium (II) chloride
monohydrate)
[Pd(NH3)4 ] Cl2 H2O Pd + 4NH3 + Cl2 + H2ODr. Julekha Shaikh, Maharashtra College
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7. Filtrate Insol. residue
NH4Cl/ C2H5OH
(NH4)2 [PtCl6] Filtrate
(NH4)2 [IrCl6] ppt (NH4)2 PdCl4
NH4Cl/ C2H5OH
(NH4)2 [PtCl6]
(NH4)2 [IrCl6]
ppt
Filtrate
(NH4)2 PdCl4
Hg(CN)2
Pd(CN)2 ppt
Pd Pure metalDr. Julekha Shaikh, Maharashtra College
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Palladiferous ores
Aqua regia
Ignited

8. • Metallic Pd – igniting Pd(NH3)2Cl2 /(NH4)2 PdCl4
Pd(NH3)2Cl2  Pd + 2NH3 + Cl2
(NH4)2 PdCl4  Pd + 2NH3 + HCl + Cl2
• Spongy Pd – reduction of PdCl2 with sodium formate
PdCl4 + HCOONa  Pd + HCl + NaCl + H2O
• Palladised asbestos –soaking asbestos with hydrochloro palladous salt
H2 PdCl6  Pd + 2HCl + 2Cl2
• Colloidal Pd – reduction – sparkling Pd electrodes under ice water or
– reduction of PdCl2 with TiCl3 / hydrazine HCl
PdCl2 + TiCl3  Pd + TiCl4
PdCl2 + NH2-NH2  Pd + HCl + N2 + H2
• Palladium black – precipitation of Pd salt sol. with sodium formate
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9. 
Dr. Julekha Shaikh, Maharashtra College 8

10.  Pd used in jewellery and some dental fillings and crowns. White gold is an alloy of gold that
has been decolourised by alloying with another metal, sometimes palladium.
 It is used in the electronics industry in ceramic capacitors, found in laptop computers and
mobile phones. These consist of layers of palladium sandwiched between layers of ceramic.
 Pd has adsorptive capacity of for many gases especially for Hydrogen. It adsorbs 700 or
more times its volume of H2. The adsorbed H2 is very active hence has good catalytic activity.
Finely divided palladium is a good catalyst and is used for hydrogenation and dehydrogenation
reactions. Palladium does however have a genuine use in 'green' energy, as a catalyst in
hydrogen fuel cells. Palladium is one of a number of metals starting to be used in the fuel cells to
power a host of things including cars and buses.
 The main use of palladium, along with rhodium and platinum, is in the three-way catalytic
converters in car exhaust systems. They are called three-way converters as they reduce three
types of harmful emissions. Converting toxic carbon monoxide into carbon dioxide; the
hydrocarbons in unburned fuel into carbon dioxide and water; and toxic oxides of nitrogen (which
can contribute to smog and acid rain) into harmless nitrogen gas.
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11. • +1 – Pd2O, PdCl
• +2 – PdO, PdF2, PdCl2 (linear polymer)
• +4 – PdO2
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12. • Atomic No : 78 (Group 10, Period 6)
• Atomic Weight : 195
• Electronic Configuration : [Xe] 4f14 5d9 6s1
• Discoverer – Antonio de Ulloa (name derived from spanish term
Platina meaning little silver)
• Platinum is a soft, silver-white metal. Malleable & ductile
• Density = 22.4
• M.P = 1769°C
• B.P = 4530°C
• Occurrence
• Braggite ( Pt, Pd, Ni) S
• Sperrylite – PtAs2
• Cooperite - Pt (AsS)2 11

13. Step 1 – Preparation of Concentrate (2 process)
1) From Mond’s Process
Non volatile residue (obtained from Mond’s Process from Sudbury ore)
Contains Ru, Rh, Pd, Os, Ir, Pt, Cu, Ag,Au)
Roasted residue
undissolved portion
(Pt metals concentrate)Dr. Julekha Shaikh, Maharashtra College 12
roasted in air (Cu  CuO)
H2SO4 (CuO dissolves forming CuSO4)

14. 2) From Native metal
Platiniferrous sands & gravels present in river bed
(Ru, Rh, Pd, Os, Ir, Pt, Cu, Ag, Au Ni)
Stream of water
Gangue (Lighter) Heavier metals
Sand particles (washed away) left behind
Ni  Ni(CO)4 Non volatile residue
(Volatile) (Pt metals concentrate)
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CO gas

15. Step 2 – Separation of Pt metal from concentrate
• Ore is Concentrated & digested with aqua regia  sol of Pd , Pt & Au along
with some Ir, Rh chloro complexes
• Filtrate + FeSO4 --- sol chlorides & Au metal
H2 PdCl6 + Fe+2  PdCl2 + 2Fe+3 + 2HCl
RuCl4 + Fe+2  RuCl2 + 2Fe+3 + 2Cl-
H2 AuCl4 + Fe+2  Au (solid) + 3Fe+3 + 4Cl- + H+
• Filtrate + NH4Cl  yellow ppt of Amm. Chloroplatinate & PdCl2 Remains
Unaffected
PtCl4 + 2 NH4Cl  (NH4)2 [PtCl6]
(ammonium chloroplatinate)
(residue ignited --- spongy Pt as greyish black porous mass
(NH4)2 [PtCl6]  Pt + 2NH4Cl + 2Cl2
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16. • Spongy Pt – igniting (NH4)2 [PtCl6 ] greyish black porous mass
(NH4)2 [PtCl6]  Pt + 2NH4Cl + Cl2
• Pt black – precipitate obtained by adding Zn / HCOOH to Pd salt in
aqua regia
• H2 [PtCl6] + 2HCOOH  Pt (black) + 6HCl + 2CO2
• Platinised asbestos –soaking asbestos with hydro platinic chloric acid
H2 [PtCl6]  Pt + 2HCl + 2Cl2
• Colloidal Pt – reduction – sparkling Pt electrodes under ice water or
– reduction of H2 [PtCl6] with TiCl3 / hydrazine HCl
H2 [PtCl6] + NH2-NH2  Pt + 6HCl + N2
Colloidal
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17. • Noble metal -Not affected by air, O2 even on heating
• Not attacked by single acid, hot aqua regia dissolves Pt forming
H2 [PtCl6]. HF has no action on Pt.
• Dissolves in nitric acid producing PtN
• Combines with many elements
F2,Cl2, P, S, As  PtF4, PtCl4, Pt3F5 PtS, Pt3As3
• Combines with metals like Sn, Pb, Ag, Zn  alloys
Hence these metals cannot be heated in Pt crucibles
• attacked by fused alkali, oxides & peroxides
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18. • Catalyst – Ostwalds process (NH3  NO), Contact process (SO2  SO3),
decomposition of H2O2, oxidation of CH3OH  HCHO, etc.
• Finely divided Pt adsorbs several hundred times its volume of H2 --- catalyst in
hydrogenation, dehydrogenation in petroleum & glass industry.
• Scientific instruments & laboratory apparatus – (high M.P & Corrosion resistance)
crucibles, dishes, spatula, Pt wires, electrodes etc.
• Jewellery - setting of diamonds, Pt – Ir alloy as pen points, standard weights, coins.
• Dental fillings, artificial teeth, support for dentures.
• Pt salt --- printing 7 toning of photography
• Medical field – X – ray tubes, lypodermic needles, radium applications.
• Compounds – +2 PtO, PtS, PtCl2,
+4 PtCl4, PtS2, H2 [PtCl6]
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19. Dr. Julekha Shaikh, Maharashtra College 18