SUPPLY CHAIN AND PROCUREMENT OF COPPER

The usual commercial supplies of pure copper are used for the most critical electrical applications such as the production of fine and superfine enameled wires.

 

It is essential that purity is reproducibly maintained in order to ensure high conductivity, consistent annual ability, and freedom from breaks during rod production and subsequent wire drawing.

 

Since the applied enamel layers are thin but have to withstand voltage, they must have no surface flaws; consequently, the basis copper wire must have an excellent surface quality. Primary copper of the best grade is used for producing the rod for this work.

 

Uncontaminated recycled process scrap and other scraps that have been electrolytically refined back to grade 'A' quality may also be used.

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The copper used for power cables is also drawn from high conductivity rods but to a thicker size than fine wires.

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The quality requirements are therefore slightly less stringent. The presence of any undesirable impurities can cause problems such as hot shortness which gives expensive failures during casting and hot rolling. For the same reason, scrap containing such impurities can only be used for this purpose if well diluted with good-quality copper.

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For non-electrical purposes, copper is also used to make large quantities of plumbing tubes, roofing sheets, and heat exchangers. High electrical conductivity is not mandatory and other quality requirements are not so onerous.

 

Secondary copper can be used for the manufacture of these materials, though still within stipulated quality limits for impurities.