PRECIOUS METALS... Aluminum and other metals

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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


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