Market Survey on Copper - Indian Bureau of Mines

eaction is identical to that in electro-refining but the anode reaction is different
i.e. formation of oxygen gas takes place at anode. The electrowinning reaction
is
Cu 2+ SO4 2- + H2O � Cu + O2 + 2H + + SO4 2-
For which standard cell potential is 0.89 V. The regenerated sulphuric
acid is cycled to the leaching or solvent extraction stripping circuits.
The purity of electrowon cathodes (99.75 - 99.9% Cu) is inferior to that
of electro-refined copper. However, they are suitable for all non-electrical uses.
Lead is an especially difficult impurity to avoid because it originates from the
anodes and affects annealing properties of copper wire.
3.2.5 Copper Segregation Process
The copper segregation process is designed to concentrate oxidized
copper ores or mixed sulphide-oxide copper ores which are refractory to normal
and cheaper beneficiation and hydrometallurgical (leaching) operations. Such
ores contain copper minerals in dolomitic/calcitic gangue. Under these
circumstances, neither flotation is possible nor leaching is economically viable.
A high temperature treatment (700-800 0 C) of the ore in presence of
small amounts of sodium chloride and finely divided carbon ensures transfer of
metallic copper from the copper minerals to the carbon particles and copper is
thereafter recovered by flotation. The reactions involved are :
Sodium chloride reacts with water vapours and acid gangue produces
hydrogen chloride which reacts with copper leading to formation and
volatilisation of cuprous chloride which is immediately reduced on coal
particles by hydrogen emanating from the volatile matter of coal and from water
gas reaction. Hydrogen chloride is regenerated and a new cycle of reaction
begins. The sulphides, if present, are oxidised on heating and then react like
oxides in segregation process. Silver, bismuth, arsenic and antimony can also
be subjected to same reactions. Gold is usually recovered with copper as it
floats well along with copper.
3.2.6 Copper Ore Processing in India (Concentrator plants)
Indian Copper industry was dominated by Hindustan Copper Ltd. (HCL)
since 1967. It was incorporated as Indian Copper Corporation Ltd. in 1972 and
in 1982 HCL expanded its operations in Madhya Pradesh by developing the
Malanjkhand Copper Project. The activities relating to mining, processing of
copper ore and production of copper metal was solely carried out by HCL. In
the year 1992, the Indian Copper Industry was thrown open for private sector
investment. Sterlite Industries Ltd. (SIL) and Indo Gulf Corporation set up
plants at Tuticorin, Tamil Nadu at Dahej, Gujarat. The Dahej plant was
subsequently taken over by Hindalco Industries Ltd. However, HCL is the only
vertically integrated copper producer in India engaged in wide spectrum of
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