Synthetic slag

New required steel grades need the production of more alloyed, clean and desulphurized steels. This metallurgy demands the use of synthetic slags and slag additives more efficient and complex. According to that Aleastur has developed a wide range of products to get slags more actives.

Metallurgical applications

  • Homogeneous synthetic slags generation
  • Alternative flux to CaF2
  • Good protection against H2 /N2/O2 pick up
  • Capacity of S absorption
  • High capacity of absorption of steel inclusions
  • Free Fluorine slags
  • Addition of MgO in order to reduce refractory wearing
  • High melting speed

Typical compositions CaO/Al2O3/MgO

CaO 28-35 28-32 26-29 30-32
Al2O3 45-52 46-50 48-52 50-52
MgO 4-6 3-5 9-12 3-4
SiO2 <7 <7 <7 2.5-3.5
Fe2O3 <1,8 <1,8 <1,8 <0.8
TiO2 <0,5 <0,5 <0,5 0.08-0.10

Advantages against imported products

  • Local raw materials, out of abroad markets and currency exchanges.
  • Possibility to product a wide range of ratios CaO/Al2O3/MgO according to the process requirements.
  • Short delivery times, allowing reduce the customers stocks.
  • Product Presentation: cold agglomerated briquettes.
  • Technology protected under European Patent WO 2010/084219 A1.

Iron losses

  • Iron losses into desulphurization slag are one of the most important cost factor in hot metal desulphurization process.
  • Slags generation during desulphurization process and its stirring, causes iron droplets get caught into the slag if it has not fluidity enough.
  • Slag’s fluidity can be affected by the dissolved carbon incorporated during the process and high melting point slags generation.
  • The most efficient way to reduce slag’s melting points is by the use of fluxes in the process.


  • ALEASTUR is offering a wide range of Fluxes based in potassium cryolite.
  • Main Advantages of this Flux in comparison to sodium cryolite and fluorite:
    • Lower melting point: 650ºC vs 1100 and 1400ºC of Na3AlF6 and CaF2.
    • Lower cost due to: 1% Flux ST is equivalent to 1,3% of Na3AlF6 and 4% of CaF2.
    • Environmental issues due to lower fluorine content than CaF2 for the same fluxing results.

New applications and steel grades require lower sulfur content, so slags need to be more active in the desulphurization process. It means to have as low as possible oxygen activity. Carried slags form EAF and BOF during tapping process lead to more oxidized slags that expected. Aleastur offer different products to reduce oxygen activity in slags with variable Al metallic content and packing.

Typical compositions

 Deoxal 20P  Deoxal 50G
 Almet 20-25%  60-65%
 Al2O3 45-55%   25-35%
 SiO2 <8% <4%
MgO  <8% <2%

ALEASTUR offers the possibility of producing tailor-made slags according to customer needs.