Nickel

 

Nickel

Chemical formula	Ni
Atomic Number	28
OTP appearance	silver solid
Molar Mass(g/mol)	58.7
Density(g/cc)	8.9
Melting Point(°C)	1455
Boiling Point(°C)	2730
Coefficient of Thermal Expansion(×10-6 °C-1)	13.3
NFPA 704	4 2 1

Uses

Primary

• Production of Urushibara nickel catalysts
• As a primary component in many steels

Secondary

• As an alloy with chrome (nichrome) for electrical heating elements
• -carbonyl can be used to nickel-plate metals

Natural Occurrence

• Elemental nickel occurs in meteorites, but rarely.
• -sulfide in pentlandite
• minority constituent (1-3%) goethite

Hazards

• -carbonyl is toxic
• Many nickel salts are carcinogenic

Production

Extraction

Elemental Nickel

• from -sulfide via calcining and carbothermic reduction

  2 NiS + 3 O₂ → NiO + 2 SO₂

  NiO + C → Ni + CO

Purification

Typically, Nickel occurs with problematic amounts of iron and/or cobalt.

1. Repeat
   1. Treat powdered impure nickel oxides with hydrogen at 200°C to reduce the oxides to nickel.

      NiO(s) + H₂(g) → Ni(s) + H₂O(v)

   2. Expose the impure metal to carbon monoxide forming -carbonyl gas

      FeCoNi(s) + 4 CO(g)

      {

      →

      60-220°C}

      Ni(CO)₄(g) + FeCo(s)

   3. Separate the -carbonyl gas from the solid impurities
   4. Decompose the -carbonyl at 250°C, leaving carbon monoxide to be reused

      Ni(CO)₄(g)

      {

      →

      ≥250°C}

      Ni(s) + 4 CO(g)

2. Until the powder is no longer yielding -carbonyl