固体CaO化合物で飽和したCaO-CaF2-SiO2系スラグと炭素飽和溶鉄間のりんの分配平衡
1985 年 71 巻 6 号 p. 693-699
詳細
1985 年 71 巻 6 号 p. 693-699
The information of thermodynamic properties of phosphorus in lime bearing slags at low temperatures is required in connection with the recent progress of hot metal treatment.
In the present study, the equilibrium distribution ratio of phosphorus (LP) between CaO-CaF2-SiO2 melts saturated with CaO, 3CaO·SiO2 and/or 2CaO·SiO2 and carbon-saturated iron was measured under CO atmosphere at temperatures ranging from 1 200 to 1 400°C, keeping in mind that the industrial flux always contains some undissolved solids.
The results are summerized as follows :
(1) LP increases with increasing CaO content and has a maximum when the slag is saturated simultaneously with CaO and 3CaO·SiO2.
(2) Phosphate capacity was confirmed to be independent of the oxygen partial pressure by using ironcarbon melts equilibrated with austenite and CO at 1 300°C. The phosphate capacity in basic regions of this system is much greater than other lime bearing slags.
(3) CaF2 is more effective for dephosphorization than CaCl2, probably because the interactions between fluorine and phosphorus and between fluorine and calcium are stronger than those between chlorine and phosphorus and between chlorine and calcium, respectively.
(4) LP increases significantly with a small Na2O addition to the CaO-CaF2-SiO2 system. This result indicates that the costly soda ash treatment can be replaced by using lime based fluxes containing a little soda ash.
