CaO-CaF₂-Fe₂O₃계 Slag에 의한 탄소포화 용철의 동시탈인, 탈황에 관한 연구

Abstract

실험적 규모로 CaO-CaF₂-Fe₂O₃계 Slag를 사용하여 1350℃에서 탈인 및 탈황에 대한 거동을 규명하였다.

실험조건 용선의 초기 ［Si］함량, Fe₂O₃첨가량 및 염기도를 변화시켜 결정하였다.

본 실험으로 얻어진 결과는 다음과 같다.

1) 용선중 초기 ［Si］함량이 적을수록 탈인 반응에는 유리하게 작용하나, 탈황반응에는 ［Si］함량이 높을수록 활발히 진행되었다.

2) 적정한 동시탈인, 탈황반응을 위하여 용선의 초기 ［Si］함량이 낮아야 효율적이다.

3) 용선중 ［P］의 농도는 Slag Feeding말기에 최저 수준으로 떨어졌으며, 그후 복인현상이 현저히 나타났다. 한편, 탈황반응은 복황현상이 나타나지 않았다.

4) 동시 탈인, 탈황반응에 미치는 염기도의 영향은 매우 크며, 적정염기도는 3이상이었다.

이상의 실험결과는 실제 제강조업과 일치하는 것이며, Bubbling법에 의한 CaO-CaF₂-Fe₂O₃계 Slag로부터 탄소 포화용철에 대한 탈인, 탈황율은 각각 85%와 80%를 얻을 수 있었다.

Laboratory-scale experiments using CaO-CaF₂-Fe₂O₃slags were carried out to clarify the behaviors of dephosphorization and desulfurization in carbon-saturated iron a 1350℃.

Experimental conditions were determined by varying initial silicon content in the molten metal, amount of Fe₂O₃and basicity of slag.

The results obtained in this study were as follows.

1) The beneficial effect of lower initial silicon content in liquid iron on dephosphorization was not applied to the desulfurization.

2) It was necessary to lower initial silicon content to the appropriate value for the purpose of simultaneous dephosphorization and desulfurization.

3) The phosphorous concentration fell to a minimum value soon after the end of slag feedding, and noticeable reversion of phosphorous follow thereafter.

On the other hand, substantial reversion of sulfur was not observed.

4) The influence of the slag basicity on the simultaneous dephophorization and desulfurization was great, then optimum basicity was more than 3.

The results of the experiment are corresponding to the steelmaking stage.

It was found that high dephosphorization and desulfurization (85% and 80%) were obtained by CaO-CaF₂-Fe₂O₃slag with N₂gas bubbling condition.

Laboratory-scale experiments using CaO-CaF₂-Fe₂O₃slags were carried out to clarify the behaviors of dephosphorization and desulfurization in carbon-saturated iron a 1350℃.

Experimental conditions were determined by varying initial silicon content in the molten metal, amount of Fe₂O₃and basicity of slag.

The results obtained in this study were as follows.

1) The beneficial effect of lower initial silicon content in liquid iron on dephosphorization was not applied to the desulfurization.

2) It was necessary to lower initial silicon content to the appropriate value for the purpose of simultaneous dephosphorization and desulfurization.

3) The phosphorous concentration fell to a minimum value soon after the end of slag feedding, and noticeable reversion of phosphorous follow thereafter.

On the other hand, substantial reversion of sulfur was not observed.

4) The influence of the slag basicity on the simultaneous dephophorization and desulfurization was great, then optimum basicity was more than 3.

The results of the experiment are corresponding to the steelmaking stage.

It was found that high dephosphorization and desulfurization (85% and 80%) were obtained by CaO-CaF₂-Fe₂O₃slag with N₂gas bubbling condition.