Precious Metals

A Dilbert Cartoon

Also known as Noble Metals

Gold and Silver

Platinum Group Elements

All are rare and very costly to recover

World Locations of Precious Metals

Price of Gold for the past 30 years

Gold Production: From textbook

Total amount of Au mined to 2000 is estimated to be 130,000 metric Ton

Total World production post 1900 128,833 ton (data from USGS historical tables)

Gold Production

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1900 1950 2000

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Gold Production: A thought

What is the volume of a metric ton of gold?

1000 kg of water=103 liters of water=106 cm3

1000 kg of gold=1000/19.3=51,813 cm3

Or a cube 37.28 cm on each side Or a cube 14.67 in on each side!

Gold: Geological Occurrence

Hydrothermal Veins (many of these) E.g. Gold rush of 1849 in California

Invisible gold (Carlin type) Placers Paleoplacer

Witwatersrand in South Africa Discovered in 1886 20 times larger than any other Au district in the

world

http://www.wrc.org.za/downloads/watersa/2006/Oct%2006/2020.pdf

Grasberg: Cu and Ag porphyry http://faculty.kutztown.edu/friehauf/indonesia/grasberg.html

Gold uses:

Electronic Products Aerospace Industry Special Alloys Dentistry Jewelry

Carat 24k is pure gold

Gold extraction:

Mercury Amalgam (the old way) Panned for gold Used Hg, Au grains wetted by Hg Separated by squeezing out the Hg, or

vaporizing it Cyanide (CN)

Au is soluble in CN solutions Heap leaching with 0.05% NaCN, pH > 10

Sebastião SalgadoFull view of the Serra Pelada gold mineBrazil, 1986

© Sebastiao Salgado

Chilkoot Pass, 1898

Silver: The not so precious

Occurs as a native element and as Ag bearing sulfides

Athens—mines at Laurium Romans brought Ag into coinage What year did we stop using Ag in coins in

the U.S.? 1965 In Canada? 1967

Major Silver Producers in 2006

Mexico Peru Australia China

For a total of 19,500 metric Tons on reserves of 270,000 tons (570000 reserve base)

Uses of silver

Photography (AgI) Jewelry and silverware (check your grandma’s) Industrial

Ag: Geological Occurrence

By product of Cu mining By product of Pb mining About 25% silver veins where Ag is the main

metal

Ag: Substitutes

Al and Rh in mirrors Ta in surgical plates, pins, sutures Stainless steel in flatware

Ag prices: 1792 to 1999

Ag Price: going up

Platinum Group Elements

The really precious metals

Pt, Pd, Os, Rh, Ir, Ru Named after Platinum

Platinum

Pre-Incan Adornments100 BC - Ancient South American civilizations, the most famous being the Incas - gifted metal workers and craftsmen, use platinum and gold to create nose rings and other items of  ceremonial jewelry. Platinum is then lost to mankind for two millennia, forgotten for thousands of years, only to briefly re-appear when European explorers discover the new world.

Platina

Confused Conquistadores1590 - Platinum is next encountered by the Spanish conquistadores, who give it the derogatory name 'platina', meaning 'little silver'. Spanish naval officer don Antonio de Ulloa y Garcia de la torre was one of the conquistadores to misunderstand the value of platinum. Thirsty for gold, and unimpressed by platinum's appearance, the Spanish mistakenly dismiss it as an inferior metal and throw it back into the rivers of Ecuador to 'ripen'. Once again, platinum mysteriously disappears from history.

Uses: Platinum (Web Elements)

jewellry wire and vessels for laboratory use thermocouple elements electrical contacts corrosion-resistant apparatus in dentistry platinum-cobalt alloys have magnetic properties coating missile nose cones, jet engine fuel nozzles the metal, like palladium, absorbs large volumes of hydrogen, giving it up at red heat in the finely divided state platinum is an excellent catalyst (such as the contact process for producing

sulphuric acid). Also as a catalyst for cracking oil and as a catalyst in fuel cells and in catalytic converters for cars

platinum anodes are extensively used in cathodic protection systems for large ships and ocean-going vessels, pipelines, steel piers

platinum wire glows red hot when placed in the vapor of methanol - acting as a catalyst to convert the alcohol into formaldehyde. This phenomenon has been used commercially to produce cigarette lighters and hand warmers

sealed electrodes in glass systems laboratory vessels, corrosion-resistant equipment dentistry currently fashionable use in antipollution devices in cars cis-platin, [PtCl2(NH3)2], is an effective drug for certain types of cancer such as leukaemia or testicular

cancer platinum/osmium 90/10 alloy is used in implants such as pacemakers and replacement valves

Geologic Occurrence

Chromite seams:

Geologic Occurrence Cont’d

By Product of Cu-Ni Mining Sudbury Ontario

Canada Noril’sk Russia

Placer Deposits

PGE Production

Dominated by Russia and South Africa

PGE

PGE substitutions

Platinum price

Palladium Price

Rh Price

Data are in kilograms!