ハロゲン化合物を含むCaO系混合フラックスによる4%C-Fe溶融合金の脱燐,脱硫

抄録

Liquid 4% C-Fe alloy at 1 350°C was refined with CaO-based fluxes (CaO-SiO₂-Fe₂O₃) containing chloride and/or fluoride compound of metals (Li, Na, K, Mg, Ca, Ba, Al and Fe), in order to study the effect of halide addition on the refining power of CaO-based flux. A rotating crucible containing 1 kg alloy was used to avoid the reaction between the molten flux and the crucible. Weight ratios of the flux to the alloy and the halide compound to CaO were 0.030-0.037 and 0.4-0.6, respectively. The refining power of Na₂CO₃-based flux (Na₂CO₃-SiO₂) without an addition of halide compound was also studied in comparison with that of CaO-based fluxes.
The experimental results showed that the addition of the halide compounds enhanced both the rate and the degree of phosphorus removal except the cases of KCl and NaCl addition. Na₂CO₃-based flux showed the excellent dephosphorizing power in the whole range of basicity studied. In a limited range of basicity from 4 to 6, however, CaO-based fluxes containing LiF, LiCl, CaCl₂ and CaCl₂-CaF₂ revealed the dephosphorizing power comparable to that of Na₂CO₃-based flux; the degree of phosphorus removal was nearly 90%. The degree of sulfur removal attained by CaO-based fluxes (0-80%) was lower than that of Na₂CO₃-based flux (85% or more).