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FACTBOX-What are graphite electrodes and needle coke?
September 21, 2017 / 7:01 AM / a month ago

FACTBOX-What are graphite electrodes and needle coke?

    MANILA, Sept 21 (Reuters) - Graphite electrodes are the main
heating element used in an electric arc furnace, a steelmaking
process where scrap from old cars or appliances is melted to
produce new steel.
    Electric arc furnaces are cheaper to build than traditional
blast furnaces, which make steel from iron ore and are fuelled
by coking coal. But the cost of steelmaking is higher since they
use steel scrap and powered by electricity.
    The electrodes are part of the furnace lid and are assembled
into columns. Electricity then passes through the electrodes,
forming an arc of intense heat that melts the scrap steel.
Electrodes vary widely in size but can be up to 0.75 metres (2
and a half feet) in diameter and as much as 2.8 meters (9 feet)
long. The largest weigh more than two metric tons.
    It takes up to 3 kg (6.6 lb) of graphite electrodes to
produce one tonne of steel.   
    The tip of the electrode will reach 3,000 degrees Celsius,
half the temperature of the sun's surface. Electrodes are made
of graphite because only graphite can withstand such intense
heat. 
    The furnace is then tipped on its side to pour the molten
steel into giant buckets called ladles. The ladles then carry
the molten steel to the steel mill's caster, which makes new
products from the recycled scrap.
    The electricity needed for this process is enough to power a
town with a population of 100,000. Each melt in a modern
electric arc furnace typically takes about 90 minutes and makes
150 tonnes of steel, enough for about 125 cars. 
    Needle coke is the main raw material used in the electrodes
that producers say can take up to six months to make with
processes including baking and rebaking to convert the coke into
graphite.
    There is petroleum-based needle coke and coal-based needle
coke, and either can be used to produce graphite electrodes.
'Pet coke' is a by-product of the oil refining process, while
coal-based needle coke is made from coal tar which appears
during coke production.
    Below are the world's top producers of graphite electrodes
ranked by production capacity in 2016:    
    
 Company Name    Headquarters     Capacity        Shares
                                  (,000 tonnes)   YTD %
                                                                 
 GrafTech        U.S.                        191  Private
 International                                    
 Fangda Carbon   China                       165             +264
 *SGL Carbon     Germany                     150              +64
 *Showa Denko    Japan                       139              +98
 K.K.                                             
 Graphite India  India                        98             +416
 Ltd                                              
 HEG             India                        80             +562
 Tokai Carbon    Japan                        64             +137
 Co Ltd                                           
 Nippon Carbon   Japan                        30              +84
 Co Ltd                                           
 SEC Carbon      Japan                        30              +98
 
    *SGL Carbon in October 2016 said it will sell its graphite
electrode business to Showa Denko. 
    Sources: GrafTech International, UK Steel, Tokai Carbon Co
Ltd

    
 (Compiled by Manolo Serapio Jr.; Editing by Kenneth Maxwell and
Richard Pullin)
  

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