Platinum
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Chemical formula | Pt |
---|---|
Atomic Number | 78 |
OTP appearance | silvery solid |
Molar Mass(g/mol) | 195 |
Density(g/cc) | 21.45 |
Melting Point(°C) | 1769 |
Boiling Point(°C) | 4825 |
Coefficient of Thermal Expansion(×10-6 °C-1) | 8 |
NFPA 704 |
Along with gold, Platinum is classed as a noble metal because it is extremely unreactive. Platinum also has a very high melting point. This and its nonreactive nature make it an excellent catalyst and electrode. Platinum is exceedingly rare in the earth's crust, approximate 30 times rarer than gold.
Uses
Primary
- Catalysts, particularly for Ostwald production of nitric acid
- Feedstock for WHO LEM chemotheraputics including Cisplatin, Oxaliplatin, and Carboplatin, .
Other
- As an electrode
- As a catalyst
- As platinum black
Natural Sources
- Elemental platinum does occur naturally
- Elemental platinum occurs as an impurity in silver and gold
- Platinum exists in virtually all placer gold, but in ppm quantities:
- ... One dredging company, which recovered about 50,000 ounces of gold from 10,000,000 cubic yards of gravel, sold about 110 ounces of crude platinum metals; these contained 70 ounces of platinum (~1400ppm) and 6 or 8 (~140ppm) ounces each of iridium and osmium.[1]
- Platinum exists in virtually all placer gold, but in ppm quantities:
- Platinum appears as a minute impurity (3-6ppm, g/ton) in chalcopyrite and pentlandite.
Production
Extraction
From gold-platinum alloy
- Dissolve gold-platinum in aqua regia
- Slowly add enough iron (III) sulfate to precipitate all the gold
- Separate gold from solution and wash gold with hydrochloric acid
- Neutralize platinum solution, precipitating platinum.
See Also
- Lee, George E. (1920) "Recovering Precious Metals from Waste Liquid Residues".
SPON & CHAMBERLAIN, 120 LIBERTY STREET
Chapter XXXIV Separating Platinum from Gold
References
- ↑ Gardner, E. D.; Johnson, C. H. (1934) "Placer Mining in the Western United States"
United States Bureau of Mines Information Circular(6786)