溶銑処理温度における石灰系スラグと炭素飽和溶鉄間のりんの分配平衡(脱りん・脱硫 : 石灰系スラグ)(<特集>溶銑処理の発展)

概要

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In order to thermodynamically understand the dephosphorization behavior of hot metals, the equilibrium distribution of phosphorus between a solid iron strip and CaO-bearing slag was measured in the temperature from 1200℃ to 1400℃ as a function of slag composition, avoiding the possible violent CO evolution if carbon-saturated iron were used. The obtained result was then converted to the value for the hot metal system using available thermodynamic data of phosphorus in solid and liquid irons. The results are summarized as follows : 1) The CaO-SiO_2-FeO system has very high dephosphorizing capacity when it is saturated with 2CaO・SiO_2. 2) The CaO-CaF_2-FeO system containing a large amount of CaO and CaF_2 has high L_p values, where L_p denotes the distribution ratio of phosphorus between slag and carbon-saturated iron. 3) When FeO content is low, the CaO-SiO_2-CaF_2-FeO system containing a large amount of CaO has very high phosphate capacity. 4) Iron oxide decreases the phosphate capacity of basic slags. 5) From the laboratory equilibration test of the CaO-bearing slags used in the practical hot-metal treatment, the partial pressure of oxygen at the slag-metal interface is estimated at 10^<-14>∿10^<-15> atm, which is ten times as high as that in the soda-ash treatment. This lies between the one determined by the reaction Fe+1/2O_2=FeO and the one by C+1/2O_2=CO.
社団法人日本鉄鋼協会の論文
1983-11-01