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| Copper Metallurgical Operation |
Mineral
the form of soil or rocks
which contains different compounds of metals are called minerals.
Ores
Minerals which contains
sufficient quantity of metals are called ores. These minerals are consider to
be able for mining commercially to extract one or more metal. It is the raw
mineral which is found in earth crust where special metals are extracted. Such
as ores of copper is: chalcopyrite, bronite, covellite, chalcocite, azurite,
malachite and cuprite etc.
Metallurgy or metallurgical operations
The process or operation in which a metal is extracted from its ore is called
metallurgy or metallurgical operation. It is the study of structure and
properties of metals with special reference to their extraction from the
ground. The procedure of refining, alloying and making things form metals. And
there is no common process available for al metals extraction because all
metals are not same they are having different chemical and physical properties.
Thus each metal requires its own technique for separation and purification from
its own ores. The following metallurgical operation common for all metals are
as follow
Grinding and Crushing of ore (pulverization)
Crushing
the process of breaking
rocks and larger stones into smaller stones are called crushing.
Grinding
The smaller stones are
then ground into powder form is called grinding.
Concentration of ore
The grinded
ores are then concentrated by removing the major impurities present in this ore. This step is
called concentration. And the ores of different metals are extracted on
different ways.
Extraction of metal from oxide ore
the ores of metals are usually in the form of
oxides. Thus different techniques are used to separate different metals from
their ores.
Refining of crude metal
the process of refining
the crude metal is called refining. Crude metal is refined by various methods
which depends upon both physical and chemical properties. Such as distillation,
electrolytic refining and chromatography etc.
Metallurgy of copper or copper metallurgical operation
Copper is an important element or metal and has many usage in our daily
where it is used almost as electrical instrument due to an excellent conductor
of electricity and highly resistant to corrosion. Therefore almost in every
electrical instrument is made of copper. It is also used in utensils (barthan)
and alloys etc. such as brass and bronz are made of copper. The earth crust
contains 0.007% copper but remember that the earth concentration is not uniform
everywhere. There are many ores of
copper but copper is separated from its sulphide ore. The first step is to
concentrate the ore in copper content which is done by crushing the ore to
increase the surface are of the ore for subsequent process. And the second step
is extraction of pure copper from the concentrate. Such are as follow
1 . Concentration of the ore
The ores of copper are usually low grade and should be concentrated first to
make it economically useful. The methods used for concentration of copper is
forth (jhag) flotation process.
Forth flotation process
this process involves the
mixing of low grade ore with oils and water then hot air is introduced from the
bottom. The copper ore as it is lighter than the waste material sticks to the
forth and floats on water surface where the heavier impurities go to bottom and
settle down there and removed as waster. After the process of concentration the
copper sulphide ore contains 40% of copper which is termed as concentrate of
copper or concentrate.
Extraction of pure copper from concentrate
The other impurity like FeS are separated by treating it with SO2 at 1200°C.such as
Impurities
The impurities or slag floats on surface of the molten matte. Matte is the molten mixture of Cu2S and Fe+2S which contains 70% copper which is called copper matte. When air is blown through this molten copper matte at high temperature then the following reactions take place. Such as
The metallic copper is obtained in above reaction is 98% pure which is termed as blister copper because blister is formed due to evolution of SO2.
Refining of blister or electric refining of blister
Blister
copper is further purifies by electrolytic process therefore this process is
also called electro refining of blister. For this type of special type of
electrolytic cell are used. In these cells, the plates of impure copper
(blister copper) is as used as anode and the plate of pure copper is used as cathode.
This electrolytic cell is consists of an aqueous solution of 3 – 4 % of copper
sulfate and 10 – 16 % of sulphuric acid. A potential of only 0.2 to 0.4 is also
required to start this process. When current is passed through this solution
the plates of impure blister copper dissolves in solution gradually forming
Copper ion Cu+2 which
moves toward cathode where they gain electrons and deposits itself in atomic
form as metal of copper and making cathode as thicker because from anode all
electrons come to cathode or anode deposits it to cathode and as result cathode
gets thicker and anode gets thinner and thinner and anode become less in size
while cathode become large in size.
.
The following reaction that occurs are as follow
The following reaction that occurs are as follow
1 . At anode Oxidation takes place
Cu
è Cu+2 + 2e
2 . At cathode reduction takes place
Cu+2 + 2e
è Cu
After
electric refining the copper obtained is 99.9% is pure and can be used now in
any installation comfortably. Such a flow chart is as
follow
Mining è Concentration è Extraction è Chemical process è Electrolytic
refining è Pure copper
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