METHOD FOR CARBURIZING HIGHLY CARBONATED FERROMANGAN OR HIGH-CARBONIZED FERROCHROM

摘要

1499049 Decarbonizing ferro chrome and ferro manganese GFE GES FUR ELEKTROMETALLURGIE mbH 7 July 1976 [11 July 1975 10 Sept 1975] 28172/76 Heading C7D High carbon ferro manganese or ferro chromium are decarbonized by blowing a superheated melt of the alloy with oxygen using jacketted nozzles. The alloy is heated to more than 100‹C above its melting range and blown, without the addition of cooling materials, to 1650-1900‹C for FeMn and 1750-2000‹C for FeCr to form high melting point Mn or Cr oxides which are reduced by lime and additions of reducing agents i.e. Si or Al and/or their alloys. The lime and reducing agents are added simultaneously, the lime being blown into the melt through the jacketted nozzles with an inert gas (Ar or Ar/H) and the reductants being added in solid or liquid form from above. Examples of reductants are FeSi, FeAl, SiCr and SiMn. The rate and amount of oxygen blown in is adjusted so that the decarburization reaction takes place in an area just above the gas nozzles, so that intensive mixing of the melt, oxygen and possibly, the jacket gas will occur there. The amount of oxygen required is 10-3 0NmSP3/SP for each 1%C to be removed per tonne of alloy, and it should be blown into the melt in 1-12.5 minutes. The protective jacket gas may be natural gas, propane &c., and up to 20% of the charge may be added in the form of solid material, provided the addition of the solid charge does not interfere with the decarbonization reaction above the nozzles.