James Durrans Group
RecarburisersAufkohlungsmittelRecarburisers

Know-How seit 1863

James Durrans Group


Know-how since 1863

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Recarburisers

Recarburisers serve the purpose to adjust the required carbon content in liquid iron. There are various types of raw materials, differing in grain shapes, grain sizes, etc. The following table shows typical analytical results of the most common carbon sources.

Chemical composition (typical values)

Recarburising Material Carbon content Sulphur Nitrogen Ash content Volatile content Moisture
Low sulphur content LS            
High purity, synthetic graphite 99,00% 0,015% 0,003% 0,10% 0,10% 0,01%
Synthetic graphite 99,00% 0,040% 0,010% 0,50% 0,20% 0,30%
Low sulphur petroleum coke 99,55% 0,100% 0,07% 0,05% 0,20% 0,20%
Graphitised petroleum coke 98,90% 0,070% 0,040% 0,50% 0,40% 0,20%
Natural graphite 87,30% 0,100% 0,020% 11,00% 1,00% 0,70%
Acetylene coke pellets a. granule 99,25% 0,030% 0,030% 0,10% 0,40% 0,25%
Low sulphur pellets 98,10% 0,080% 0,050% 0,50% 1,30% 0,10%
Medium sulphur content MS            
Electrically calcined anthracite 95,57% 0,250% 0,400% 4,00% 0,23% 0,20%
Carbon pellets 98,80% 0,700% 0,500% 0,10% 1,00% 0,10%
Higher sulphur content HS            
High sulphur petroleum coke 99,30% 1,200% 1,000% 0,20% 0,30% 0,20%
High nitrogen petroleum coke 98,90% 1,100% 1,750% 0,40% 0,50% 0,20%
Metallurgical coke            
Metallurgical coke 85,20% 1,000% 1,500% 13,00% 1,50% 0,30%

Solubility of carbon

The solubility of carbon depends on the interaction of the saturation level, the temperature and the time. Furthermore the agitation of the furnace, the slag content of the melt, sulphur content of the iron alloy and of the recarburiser as well as the carbon structure influence the solubility.

Sulphur content of the recarburiser

With recarburisers special attention to the sulphur content is important. The basic rule is, the lower the sulphur content, the higher the raw material costs. It is often observed that excessively low sulphur levels are targeted in iron and steel melts, which does not provide a tangible added value for the production of the relevant alloy.

Under ideal circumstances and besides the solubility, also the sulphur content of the recarburiser should be adjusted according to the application.

The diagram and the sample chart below show the sulphurisation of the base iron through the recarburiser with <0,05% S,  0,15% S up to <0,5% S. It becomes clear that a recarburiser like Procarb LS with <0,15% S – i.e. a product in the middle price segment – offers a better value for money than the carburisation with i.e. Premco SG, 0,05% S, a product with higher raw material costs.

  Content in kg Content % S-Cont. % of charge kg-S of charge
GJS composition with recarburiser <0,05%S – i.e. Premco SG        
Scrap steel 5000 50,00% 0,010% 0,50
Returns 3500 35,00% 0,008% 0,28
Pig iron 1100 11,00% 0,010% 0,11
FeSi and other alloys 250 2,50% 0,000% 0,00
Recarburiser 150 1,50% 0,050% 0,08
Sum 10000 100% 0,0097% 0,97
GJS composition with recarburiser <0,15%S – i.e. Procarb LS        
Scrap steel 5000 50,00% 0,010% 0,50
Returns 3500 35,00% 0,008% 0,28
Pig iron 1100 11,00% 0,010% 0,11
FeSi and other alloys 250 2,50% 0,000% 0,00
Recarburiser 150 1,50% 0,150% 0,23
Sum 10000 100% 0,0112% 1,12
GJS composition with recarburiser <0,5%S – i.e. Procarb 99        
Scrap steel 5000 50,00% 0,010% 0,50
Returns 3500 35,00% 0,008% 0,28
Pig iron 1100 11,00% 0,010% 0,11
FeSi and other alloys 250 2,50% 0,000% 0,00
Recarburiser 150 1,50% 0,500% 0,75
Sum 10000 100% 0,0164% 1,64

Packaging

The material should be packed in a standard, convenient bag size. Usual package sizes are:

  • 12,5 kg bags
  • 25 kg bags
  • 500 kg Big Bags
  • 1.000 kg Big Bags