Cobalt is a lustrous, silvery-blue metallic chemical element, symbol Co, atomic
number of 27 and an atomic weight of 58.93. Cobalt is obtained primarily as a
by-product of the mining and processing of copper and nickel ores. Examples
of cobalt ores include cobaltite [(Co,Fe)AsS], erythrite
[(Co3(AsO4)2·8H2O)]. fukuchilite (
[(Co,Fe)AsS], linnaeite [(Co,Ni)3S4], skutterudite
and smaltite [(Co,Fe,Ni)As2]. Cobalt is extracted as a by-product of nickel and copper concentration through
pyrometallurgical, hydrometallurgical and electrolytic processes. Cobalt
contributes corrosion resistant and hardness
with other metals and when used in electroplating. The major uses of cobalt is
preparing metal alloys. Cobalt-60 with a half-life of 5.3 years
is a gamma ray source when used in radiotherapy and
It is used as a catalyst in the petroleum production and chemical synthesis.
catalyst is active in desulfurization
of petroleum. Cobalt is combined with many other elements including chlorine, sulfur, nitrogen
a common state +1, the most prevalent oxidation states of cobalt are +2 and +3.
Cobalt compounds are used as pigments in glass and ceramics. It is used as a
drying agent for paints, varnishes and
Cobalt sulfate is
any sulfate salt of either divalent or trivalent cobalt.
melts at 96.8 C; soluble in methanol. It is used in
pigments and other cobalt salts.
sulfate [called cobaltic sulfate,
Co2(SO4)3] contains trivalent cobalt
acts as an oxidizing agent;
soluble in sulfuric acid. Cobalt pigment is used in
porcelains and glass. Cobalt sulfate is used in storage batteries and electroplating baths. It is
used in sympathetic inks and as an additive to soils and animal feeds. It is
a raw material to make other
Cobalt oxide is a metallic pigment that provides blue
coloring in porcelains and glass. Various forms of cobalt
oxide are changes to CoO at 850 - 900 C. CoO is a grayish brown powder that decomposes at 1935
C, insoluble in water. It is also used as a drying agent in inks and varnishes
and as a feed and fertilizer additive. Cobalt carbonate has same coloring application
as it decomposes to cobalt oxide at high temperature.
Cobalt carbonate tends to disperse better in a glaze
but can produce blisters because of the CO2 gas presence
at high temperature. Commercial grades of cobalt carbonate are the
complex of carbonate and hydroxide such as cobalt carbonate hydroxide (1:1)
(CAS RN: 12069-68-0), Cobalt carbonate hydroxide (2:3)
(CAS RN: 12602-23-2), and cobalt carbonate hydroxide (2:3) monohydrate
Cobalt blue is
a green-blue inorganic
pigment consisting of alumina and cobalt oxide. Chemically it is a cobalt(II) oxide-aluminium oxide
It is also known as cobalt ultramarine
and king's blue.
It is the reaction product of
calcination at high tmeperature. Cobalt (II) oxide and aluminum oxide are homogeneously and ionically interdiffused with
trace amount of
modifiers (MgO, ZnO, Li2O, or TiO2) to form a crystalline
matrix of spinel. Cobalt blue pigment products are acid/alkalai resistant
and are extremely heat stable. They have excellent
weatherability and lightfastness. Cobalt oxide
is a pigment used in ceramics and glass. Artists use cobalt blue
for the high quality blue.
Cobalt blue is used as
a colorant and optical whitening agent for plastics, rubber,
inks, paints, cosmetics, detergents, cement, textile and paper.
Cobalt acetate [Co(C2H3O2)24H2O] is
a reddish-violet, deliquescent crystal;
soluble in water, alcohol, and acids. It is used as a dryer in paint and varnish.
Driers are substances put into paint to make dry
quickly. They are metallic salts of low-molecular-weight carboxylic acids. Hydrocarbon parts take oxygen in air and metals act as catalyst to
speed up the oxidative coating. Cobalt is the most useful. Cobalt acetate is a powerful
oxidation catalyst. It is used as a feed additive mineral supplement.