Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.40, No.4, 498-506, 2002
매체교반형 미분쇄기에 의한 무기분말의 초미분쇄 기구에 관한 연구
The Ultra-fine Grinding Mechanism of Inorganic Powders in a Stirred Ball Mill
최근 신소재 개발과 관련하여 분쇄실험을 행하는데 있어서, 서브미크론(submicron) 영역의 초미분쇄가 주목을 받고 있다. 특히, 미분쇄에서 초미분쇄 영역까지 널리 사용되고, 상업적으로도 많이 이용되는 매체형 교반밀에 의한 연구가 많이 발표되고 있다. 본 연구에서는 방해석, 납석, 활석 같은 무기분말의 시료와 수직형 교반볼밀을 사용한 일련의 실험에서 교반볼밀의 분쇄메커니즘(mechanism)을 밝히는 것을 목적으로 하였다. 에너지특성을 조사하기 위해 실험조작조건과 관련지어 분쇄와 에너지투입과의 상관관계를 해석하기 위해 분쇄기의 소비 동력을 측정하였고, 각 실험조작인자에 대한 상관관계를 통계적으로 해석하여 모델식을 제안하였다. 그리고, 각 실험조건에서 분쇄에너지 효율을 검토하여 분쇄조제가 분쇄효율의 개선에 미치는 영향을 조사하여, 분쇄조제를 사용하였을 때, 분쇄조제를 사용하지 않고 최적의 효율을 나타내었던 실험조작조건 보다 분쇄효율이 약 13.1% 개선된 것을 알 수 있었다. 또한, 얻어진 데이터에 분쇄속도론을 적용, 분쇄속도상수에 미치는 회전속도, 슬러리 농도 및 분쇄조제 첨가의 영향을 실험적으로 검토하여, 실험재료의 물성이 달라지거나 실험조작조건을 달리했을 경우에 실험조작인자가 분쇄속도에 미치는 영향을 분쇄속도상수의 변화를 통해 알 수 있었고, 분쇄조제를 사용하지 않았을 때에 비해 최대 25.6%의 분쇄속도가 빨라짐을 알았다.
Recently in various industrial processes, the need for fine particles especially submicron particles has been increased in preparation field of raw powders such as fine ceramics and high technical products. The grinding by a stirred ball mill to submicron range has been achieved commercially in many cases. A series of grinding experiments using a vertical stirred grinding media mill and inorganic powders such as calcite, pyrophyllite and talc as test samples were carried out to clarify the grinding mechanism of the stirred grinding media mill. The effect of experimental conditions such rotation speed of stirrer, ball filling ratio, ball diameter and slurry concentration on the power inputted in the stirred media mill were measured and the quantitative relationship between them was proposed with multiple regression analysis. The relationship between the experimental factors and the comminution consumption power could also be regressed as a power-law and effect of grinding aids on particle size distribution and on grinding efficiency defined as the increase of specific surface area per the specific grinding consumed energy was investigated. In this study it can be concluded that the grinding energy efficiency using grinding aids was improved about 13.1% than no aids experiment. And the effect of grinding aids on grinding rate constant K was investigated. Also the relationship between grinding rate constant K and experimental conditions including the effect of grinding aids was examined and it is confirm that the grinding rate can be improved in the degree of the maximum of 25.6% compared with without grinding aids.
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