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| Anodes |
Positively polarised electrodes in an electrolytic cell; copper content about 99.5%. |
| Anode furnace |
A furnace used in pyrometallurgical copper refining in which copper
is cleaned in a combined rinsing and reduction process (known as
poling) and anode copper produced by reducing the copper’s oxygen
content. |
| Anode slimes |
A product of the copper tankhouse which settles on the bottom of an
electrolytic cell as the copper anodes dissolve and which also adheres
to the remains of the anodes. The precious and non-soluble components
of the anode are enriched in the anode slimes (e.g. silver, gold,
selenium, lead). |
| Backwardation |
"The apples at the market are more expensive than the apples on the
tree." Specific price circumstances on the metal exchanges (LME, COMEX)
created by a shortage of copper on the spot markets. In contrast to
contango, during a period of backwardation, the short-term prices of
metals (spot rate, rate of the day) exceed the long-term prices thereof
(three months, futures price). |
| BE Copper |
Best electrolytic copper; features particular electrical
conductivity, good brazing properties and excellent hydrogen resistance. |
| Blister copper |
Unrefined porous copper. Molten copper absorbs gases more easily
than copper in solid form. During solidification, dissolved gases in
such copper form small blisters in the copper. |
| Cakes |
Square bars produced in the continuous casting process with
variable lengths and a weight of up to 25 tonnes. Cakes are the raw
material for the production of copper sheet and foil. |
| Catalysts |
Catalysts are substances which through their presence influence
(increase) the process rates of chemical reactions and after completion
of the reaction are still in an unchanged form. In theory, a catalyst
is not consumed. |
| Cathodes |
Negatively polarised electrodes in an electrolytic cell. |
| COMEX |
Together with the LME, one of the two most important metal exchanges. It is of particular importance to the American market. |
| Contango |
"The apples on the tree are more expensive than the apples at the
market". The normal status of metal price quotations on the metal
exchanges in which the rate of the day is lower than the long-term
price for a metal. |
| Contimelt plant |
A continuous and thus highly energy-saving process developed by NA
and Union Minière (Belgium) for the processing of blister copper,
copper scrap and anode scrap into copper anodes. |
| Continuous cast wire rod |
Semi-finished product produced using the Southwire process for
further processing into wire. The wire rod diameter ranges from 8 to 25
mm. |
| Continuous casting |
Continuous casting is a process during which - in contrast to mould
casting - a continuous strand is produced. During the casting process,
sizes of various lengths are separated from the casting billet by a
flying saw. A variety of profiles (billets and cakes) and lengths can
be created as required by the customer. The square bars (cakes) are
processed by rolling into sheets, strips and foil, the round bars
(billets) are mainly reformed into profiles or tubes.
|
| Converter |
A furnace in which metal production or refining processes are
typically carried out through oxidation. Copper matte from the flash
smelter is treated in the converter to blister copper. |
| Copper anodes |
End product of a metallurgical process (copper content
99.6%). They are further processed in the tankhouse to copper cathodes. |
| Copper cathodes |
Product of the copper tankhouse (copper content > 999.99%) and NA’s main product (first basic product). |
| Copper concentrate |
A product resulting from the processing (enriching) of copper ore,
NA’s main raw material. Since copper is found principally only in ores
in compound form and in low concentrations (0.5 to 4% copper content),
the ores, after extraction from the mine, are enriched in processing
facilities into concentrates (copper content of 25 to 40%). In addition
to its main components of copper, iron and sulphur (each about 30%),
the copper concentrates processed by NA may also contain precious
metals, arsenic, bismuth, lead, nickel, selenium and tellurium. |
| Copper electrolysis |
Copper tankhouse |
| Copper matte |
A mixed phase of copper sulphide and iron sulphide (nCu2S
x FeS) arising during the pyrometallurgical processing of sulphide
copper concentrate. The copper (crude) matte produced in NA’s flash
smelter with a copper content of about 65 % is initially processed in
the converter by selective oxidation to white metal (Cu2S) and then to blister copper. |
| Copper tankhouse |
The copper tankhouse, a hydrometallurgical process for the
electrochemical refining of copper, is the last refining stage in
copper recovery. Anodes and cathodes are hung in a cell containing a
sulphuric acid solution (electrolyte) and connected to an electric
current. During the process the copper contained in the anodes is
dissolved in the electrolyte together with the soluble impurities
(arsenic, nickel, etc.). Precious metals and the non-soluble impurities
(e.g. lead, selenium) sink to the cell bottom and form the anode
slimes. Copper from the solution is deposited on the cathode with a
purity of more than 99.99%. |
Double absorption
contact acid plant |
During the production of sulphuric acid, the sulphur dioxide (SO2) contained in exhaust gas is converted by catalysts into sulphur trioxide (SO3) and absorbed into sulphuric acid (H2SO4).
In a single absorption contact acid plant, the conversion rate of the
sulphur dioxide to trioxide reaches 97.5 %. The efficiency of SO2
conversion in a double absorption contact plant is significantly higher
(approximately 99.6 %) due to a second catalytic step and subsequent
absorption. |
| DOWA Tower |
A facility used at NA to remove mercury before producing sulphuric acid from the SO2
containing off-gases in the RWO. The offgases are channelled through a
tower filled with pumice pellets. DOWA is the name of the Japanese firm
which developed the process and holds the patent. |
| Electrolyte |
A material (or its solution) which, due to the existence of free
ions, has electric conductivity. In the copper tankhouse, the
electrolyte consists of a sulphuric acid copper sulphate solution which
acts as an electric conductor to form the connection between anode and
cathode. During the electrolytic process, copper and other soluble
materials (e.g. arsenic, nickel) are enriched in the electrolyte. After
decopperisation, enriched materials, such as arsenic in the form of
arsenic trioxide (As2O3) and nickel in the form of nickel sulphate (NiSO4) are also recovered. The electrolyte is thereafter recycled and used again in the electrolytic process (closed circle). |
| Flash smelter |
The first pyrometallurgical phase in the processing of copper
concentrates. The concentrates suspended in the reaction shaft react
with oxygen. The concentrates are melted by the heat released. Sulphur
and iron are separated into intermediate products. The copper is then
enriched in the copper matte to a copper content of about 65 %. |
| Iron silicate stone |
A byproduct of the (primary) copper concentrate smelting process.
During such process the iron contained in the copper concentrate is
combined with silicate flux (SiO2) to yield iron silicate (2FeO x SiO2).
Although its structure is similar to natural rock, this artificially
produced stone has a substantially higher density and hardness. |
| LME (London Metal Exchange) |
The most important metal exchange in the world with the greatest turnover. |
| Metal exchange |
Commodity futures exchange, where generally accepted metal prices
are fixed by the comparison of supply and demand and form the basis for
the global trade in metals and commodity futures contracts. |
| Metallurgy |
The production of metals from raw materials such as ore
concentrates, residues and recycling materials. There are two
processes: pyrometallurgical (where high temperatures are used to
extract metals) and hydrometallurgical (where chemical reactions in
water are used to extract metals). |
| Moulds |
Casting moulds made of copper, graphite, cast iron or steel for
casting metal ingots. Water-cooled moulds made of graphite with copper
coating, which are open at the top and the bottom, are used for the
production of continuous cast copper shapes. |
| OF copper |
Oxygen-free copper. |
| Outokumpu process |
Outukumpu Oy is the name of a Finnish smelter which has developed
this smelting technology for the processing of copper and nickel ore
concentrate. The core unit of this process is the flash smelter. |
| Oxidation |
In metallurgy, this term includes chemical reactions in which
oxygen is absorbed (consumed). The product of this reaction is often an
oxide. In general chemistry, this term comprises all reactions in which
atoms, molecules or ions release electrons. |
| Production standstill |
Regularly recurring production standstill in order that all
furnaces and connected plant can be overhauled, maintained and repaired
(new refractory for the furnaces, burners exchanged, etc.). |
| Red gun metal (red brass) |
Copper alloys with 4-10% tin, 2-7% zinc and up to 7% lead belonging to the bronze group. |
| Reduction |
In metallurgy, this term includes chemical reactions in which
oxygen is released. In general chemistry, this means the absorption of
electrons. Reduction procedures are of major importance in metallurgy
for the production of metals from their compounds (oxides). |
| Silver doré |
Crude silver with a silver content of more than 90% which also
contains gold and platinum. It is further refined in the silver
electrolysis. |
| Smelter |
A part of a works or company, in which crude metal or bullion are
recovered, is called a smelter. Typical products are lead bullion,
blister and black copper and red gun metal (red brass). |
| Southwire process |
In this process, which is also used at NA, the casting of wire bars
which was previously performed discontinuously and in separate process
steps is combined with the subsequent hot rolling into single wire
sections in a continuous process. In so doing, the molten copper is
initially cast via a casting wheel into an endless strand. Using the
melting heat in a multi-stage hot-rolling process, this is reformed
directly into continuous cast wire rod which is the starting product at
our customers for the production of cable, strands and ultra-fine wire. |
| Spot market |
Daily-business-market for prompt supplies. |
Top blown rotary
converter (TBRC) |
A single-stage pyrometallurgical facility for the recovery of precious metals from the anode slimes in the copper tankhouse. |
Treatment and refining
charges (TC/RCs) |
Compensation which NA receives from the mines for the processing of copper concentrates and copper scrap to copper. |
German
Kupferinstitut
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