Season 2 Challenges

REWARD - RS 4,00,000 - 6,00,000
Ferous Oxide

We manufacture a compound/reagent (Desulphurising - DS) that is used to remove Sulphur from Liquid Iron (Hot Metal or Pig Iron). This compound is a mixture of CaC2(Calcium Carbide – dominant active ingredient) + CaO (Lime) + Slag Conditioner. The maximum utilization efficiency of CaC2 is 35% to 40% only.  We are exploring solutions which will enable us to improve the efficiency of utilization of CaC2 to 50% or more.

The CaC2 (Calcium Carbide) based compound will be used, for desulphurisation of Hot Metal (Liquid Iron) at temperatures ranging between 1280◦C to 1400 ◦C. The compound comprises of a mixture of Carbide based reagent (DS) (CaC2 + CaO + slag conditioner) and Magnesium (Mg) that are injected into the hot metal through a co-injection system. Both the reagents are kept separately in two different silos but are injected through same lance. The fineness of this compound is 90% below 63 microns. The injection is made through a ceramic Lance in Nitrogen (inert gas) pressure, into the hot metal. The exit end of Lance is 500 – 600mm above the base of the ladle. The rate of injection is 24 – 32 Kg/min. Typically for every Ton of hot metal 400 – 450 Kg of CaC2 and 40 – 50 Kg Mg is required to desulphurise hot metal having sulphur concentration of around 500 ppm.  The process takes about 14 to 15 minutes for completion. 

The basic reaction that takes place is CaC2 + S = CaS + 2C. 

The concentration of 'S' in the hot metal is typically 500ppm on an average (this varies between 400 to 600 typically. In some cases it is more than 800ppm or even higher). Use of CaC2 based reagent depends on the volume of hot metal and initial sulphur in the hot metal. As per existing practices, 35% to 40 % of CaC2 reacts with the 'S' in the hot metal and the remaining goes to the slag as un-reacted CaC2. We want to understand ways and means to improve the efficiency of utilization of CaC2 to 50% or more.

We believe that following factors may increase the CaC2 utilization:

  • Increase in retention time of CaC2 in hot metal (Liquid Iron or Pig Iron). As per existing studies this is about 1.33 s/m of metal depth. Total depth is typically 7-8 feet. Higher time for reaction will improve the efficiency
  • Improve the rate of reaction of CaC2 and Sulphur (S) i.e. CaC2 + S= CaS + 2C eg: use of catalyst 
  • Changing the fineness of the powder (reagent) which is currently at 90% below 63 micron. 

The solution should:

  1. Be economically feasible & there should be little or no modification in the equipment used for injecting Desulphurisation (DS) compound into the hot metal. 
  2. Not completely change the existing manufacturing facility of producing the Compound i.e. the mixture of CaC2 + CaO + Slag Conditioners 
  3. Should not increase the amount of slag generated in the process.  Ideally it should reduce it, which will ultimately reduce the metal (Fe) loss (slag is skimmed out (removed from the surface of hot metal) after DS treatment). The slag consists of CaS + CaC2 (Unreacted) + CaSiO2 (primarily)


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