Elkem Elgraph® recarburisers
Elkem has created a special production unit to make very high purity recarburisers for the manufacture of cast irons. Grades are available for both grey cast iron and ductile/compacted graphite iron. These graphites are particularly efficient and dissolve rapidly into the iron, making them particularly suited for trim additions.
Advantages of the Elgraph® recarburisers are
- high carbon recoveries
- easily rapid solubility even at low agitation
- cost effective (Value added)
- carbon trimming just prior to casting
- low nitrogen level for grey iron production
For full specification, please contact us.
General information about Elkem's recarburiser products
Trends in the iron foundry industry towards electric melting and higher steel scrap charges mean that more carbon units have to be added to the furnace.
Economy and cost effectiveness are key words in the foundry and steel industries, and apply as well to the selection of recarburisers. Some key requirements are high carbon yields ("value for money"), less slag (economy, power costs and better working conditions), dissolution rate (energy costs and tap-to-tap times ), reproducibility (planning, automation and fewer rejects), lining life (economy and down-time).
Recarburisers are either natural materials or most commonly by-products from the manufacture of graphite electrodes, the refining of crude oil or other manufacturing processes.
Elkem has been a producer of electrode paste since 1917 in specially designed calciners, for use in the Søderberg process ( Dr. Søderberg was an Elkem employee) and these are recognised and sold all over the world. Recent technology changes have meant that Elkem’s calcining furnaces are able to produce recarburisers which have been given the trade name Elgraph®. The new calcining technology allows the production of recarburisers with very low levels of sulphur, nitrogen, hydrogen, volatile matters and ash. Elgraph® recarburisers products are widely used in the manufacture of cast irons and in steel production.
Elgraph® recarburisers are produced at Elkem Carbon's plant in Kristiansand, on the southern coast of Norway.
Elgraph® recarburiser is especially formulated as a carbon raiser for grey iron, with high purity and particular emphasis on low content of nitrogen and hydrogen. Its high dissolution rate makes it very suitable in the carbon adjustment phase of metal preparation.
Elgraph® recarburisers are carbon additives formulated and manufactured at high temperatures from selected raw materials specifically for use as recarburisers during cast iron and steel manufacture. Extensive research has resulted in the development of a new generation continuous electric calciner, operating at very high temperatures (up to 3000ºC) to manufacture the Elgraph® recarburisers.
The high calcining temperature alows us to produce a purer product and a more graphitised product. It is generally found that the more graphitised the recarburiser, the better the carbon recovery and solubitity.
As a measurement for the degree of graphitisation the electical resistance can be used. Practical foundry experience has shown that solubility can be related to the degree of graphitisation, which is related to the resistivity of the recarburisers.
Typically a good solubility recarburiser should have a resistivity of less than 270 µOhm.