제강분진중의 철회수에 관한 연구 = A study on the Iron Recovery in the Steel-Making Dust

국문 초록 (Abstract)

製鋼過程에서 發生하는 粉鹿中에 含有된 鐵을 回收하고자 할 때, 鐵回收에 가장 큰 影響을 미치는 炭素使用比, 消石灰添加率 및 還元溫度 等을 所定의 範圍에서 變化시켜 還元實驗한 結果, 다음과 같은 結論을 얻었다.
1) 試料中에 消石灰를 添加하지 않고, 木炭만을 使用하여 還元하였을 때, 還元溫度가 1200℃ 및 1300℃에서는 luppe가 生成되지 않았으나, 還元溫度가 1400℃에서는 炭素使用量의 變化(炭素比:1.5∼3.0) 에 關係없이 半熔融狀의 slag와 luppe가 生成되었으며, 炭素使用量이 理論量의 2倍일 때 鐵回收率이 74%로서 가장 良好한 成績을 얻었다.
2) 鐵製鍊의 融劑로서 消石灰를 添加하여 末炭(炭素比:2.0)으로 還元實驗하였을 때, 還元溫度가 1200℃ 및 1300℃에서 消石灰添加率이 30±5% 範圍일 때는 鐵回收率이 60%以上 되었으나, 消石灰添加率이 그 以上과 以下에서는 luppe가 生成되지 않았다.
3) 還元實驗時 揮發率은 還元劑로 添加한 木炭의 炭素比가 增加할수록 揮發率도 增加하였고, 融劑로서 使用한 消石灰添加率이 增加할수록 揮發率은 대체로 減少하였다.
4) 融劑로서 消石灰를 30% 添加했을 때, 生成된 luppe의 顯微鏡組織은 1200℃의 還元溫度에서는 炭素比가 增加할수록 片狀黑鉛組織이 漸次 增大하였다. 그리고, 還元溫度가 1300℃에서 炭素比가 1.5 및 2.0일 때는 片狀黑鉛組織을 볼 수 없었으나 炭素比가 2.5 및 3.0일 때는 還元溫度가 1200℃의 同一條件에서 보다 片狀黑鉛組織이 크게 增大하였다.

다국어 초록 (Multilingual Abstract)

To recover the iron in the dust which produced in steel-making process, the reduction experiment was performed by means of varing the most effecting factors on the recovery of iron such as the carbon ratio (actual carbon required for reduction of pellets/theoretical carbon required for reduction of pellets), the lime addition ratio and the reduction temperature in a given range.
From this experiment, the following conclusions were summarized.
1) By the reduction with char-coal (carbon ratio: 1.5∼3.0, without addition of lime) the luppes were not produced at 1200℃ and 1300℃ but produced at 1400℃. And, at carbon ratio 2.0, the recovery of luppe produced at 1400℃ was optimum (74%).
2) By the addition of lime and the reduction with char-coal (carbon ratio: 2.0) the recovery of luppe was more than 60% at the reduction temperature 1200℃ and 1300℃, the lime addition ratio 30±5%. And in the case that the lime addition ratios were more or less than 30±5%, the luppes were not produced.
3) With the increase of the carbon ratio added with reducing reagent and the increase of the amount of addition of lime used by flux, the volatilization rates were increased and decreased, respectively.
4) In the case of addition of 30% lime the microstructure of graphite of luppes were coaser with increasing the carbon ratio at the reduction temperature 1200℃.
At 1300℃ and the carbon ratio 1.5 and 2.0 the graphite was not seen. But at 1300℃ and the carbon ratio 2.5 and 3.0, the graphite was coarser than that at 1200℃ .