PRECIOUS METALS... Aluminum and other metals
melting point of silver
1,761 degrees Fahrenheit
melting point of gold
1,945 degrees Fahrenheit
Bauxite
A mineral used in making aluminum
thermite
A very exothermic reaction between aluminum powder and another metal oxide, sometimes used in welding.
Aluminum Oxide
Al₂O₃
cyanide process
a method of producing gold or silver from ores, using sodium cyanide and warm air
catalyst
causes a chemical reaction to occur without being used up in the process
silver uses
mirrors before mirrors, photo film, coins, silver solders, jewelry, bearings, tableware
gold
most malleable of all metals
Iridium
s one of the densest metals. It also has one of the highest melting points and is the most corrosion-resistant element. Uses: Pen nibs, watches, jewelry, compasses, electronics, medicine, automotive industry
platinum
softness, ductility, corrosion resistance, good electrical conductivity, ability to function as a chemical catalyst
Aluminum
third most abundant element in the earth's crust
melting point of platinum
3,215° degrees Fahrenheit
melting point of zirconium
3,371 degrees Fahrenheit
melting point of osmium
5,491 degrees Fahrenheit
The Hall-Heroult process for the production of aluminum involves the electrolysis of ?
Al₁O₃
iridium uses
Pen nibs, watches, jewelry, compasses, electronics, medicine, automotive industry
amalgam
a mixture or blend of different elements
catalytic converter
a platinum, coated device that oxidizes most of the VOCs and some of the CO that would otherwise be emitted in exhaust, converting them to CO2.
Thermite reaction
a reaction where aluminum displaces iron from iron oxide
malleability
able to be hammered or pressed permanently out of shape without breaking or cracking
Alumina
aluminum oxide
precious metals
can be mined in almost pure form but most are obtained as by products during production of copper, zinc, tin and lead, most are refined by electrolytic
reduction of aluminum oxide
done by electrolysis
osmium
element with greatest density, member of platinum family
silver
excellent electrical conductivity, high thermal conductivity, resistance to corrosion, high reflective, photo-sensitive
zirconium
gray-white, ductile, strong, corrosion-resistant, rapidly attacked by hydrofluoric acid, spontaneously ignites in the air as a powder, nuclear energy applications, poor absorbing neutrons, surgical tools, superconducting magnets.
Platinum Group Metals
includes palladium, rhodium, iridium, and osmium
uses for platinum
jewelry, chemical catalyst, electrical components,
titanium aluminide
powder alloy: low density, weight reduction, turbo impellors
Copper
sometimes is listed as a precious metal because it is used in currency and jewelry, but copper is plentiful and readily oxidizes in moist air, so it is not particularly common to see it considered "precious."
Osmium
the densest of all elements, twice as dense as lead
Cryolite
the substance added to aluminum oxide to lower its melting point in the purification of aluminum
Palladium
used as automotive catalyst
gold uses
used as currency and jewelry, extreme corrosion resistance, high work ability, ductility, malleability and excellent electrical conductivity
