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A Study on the Pyrometallurgical Processing of Marmatite
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| 고창식 , 이정용 Chang Shik Koh , J . Y . Lee |
| KJMM 3(1) 1-10, 1965 |
ABSTRACT
In order to find out an optimum condition for the extraction of zinc from domestic marmatite, a series of pyrometallurgical tests were carried out using flue-solid roaster and horizontal distillation apparatus. It was confirmed that the roasted marmatite was magnetized at above 950℃ and the intensity of magnetism was increased during air colling after roasting. The normal reduction temperature was found 950℃∼1000℃ for the marmatite calcine which is approximatly 100℃ higher than that of zinc blende calcine. In this experiment, the reduction equation of marmatite calcine by solid carbon at the range from 950℃ to 1370℃ is assumed as follows; ZnO·Fe₂O₃＋2C = Zn＋2FeO＋2CO Carbon was sufficient with about two or three times of theoretical amount. Degree of reduction was 95% at 1300℃ after 10∼24 hrs treatment, and the purity of condensed zinc was 99%. It was also found the CaO is effective to increase the degree of reduction, ultimately up to 100%.
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Study on the Spheroidizing mechanism of Graphite in Cast Iron (3)
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| 최형섭H . S . Choi, 박원구W . K . Park, 이재선J . S . Lee |
| KJMM 3(1) 11-17, 1965 |
ABSTRACT
The melting of Fe·C, Fe·C·Zr and Fe·C·Ca alloys in graphite crucible placed in vacuum was carried out at 1540℃, and then cooled down with the rate of 35℃/sec or more. To eliminate from the problems as many composition variables as possible, the samples used in these experiments consisted simply of pure iron and reactor grade graphite with pure nodulizing element. The results show that under these relatively simple and limited conditions, nodular graphite is produced by the addition of strong deoxidizing agent such as Zr or Ca in the critical concentration. This suggests that the spheroidization of graphite in the cast iron may partially be attributed to the deoxidation of the iron which may induce the supercooling of the melt. The experimental results also indicate that the spheroidizing tendency of graphite in cast iron was increased by rapid cooling and thereby higher degree of supercooling or supersaturation of the carbon in the melt or both. These factors, however, were aidding the improvement of the spheroidization of graphite but not decisive in the formation of nodular graphite. The most favourable factor seemed to be the increase of the interfacial energy between the liquid iron and graphite surface due to the adsorbtion of nodulizing element on the graphite surface.
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