The treatment of coal fly ash for the recycling as ceramic raw materials : I. The effect of calcination and elutriation

요업원료로 재활용하기 위한 석탄회의 처리 : I. 하소 및 수비의 영향

Coal fly ash was calcined and elutriated for recycling as ceramic raw materials. C Crystal phases, morphologies, chemical components, particle size distributions and Ig. loss of as-received, calcined and elutriated coal fly ash were investigated to study the effects of the calci nation and elutriation on the coal fly ash classification. The experimental equations, which were used in elutriation of clay, were examined in order to find out which equation is appropriated for coal fly ash classification. It turned out that Rittinger's equation is relatively well matched for the fly ash. Having nothing to do with the treatment conditions, the crystal phases of coal f fly ash were mullite, quartz. Calcite peak was detected in as - received and elutriated coal fly a ash; however, it disappeared in calcined coal fly ash. As - received coal fly ash consists of various type of particles such as a cenosphere, coke type, silicate type, whisker type and aggregat e ed type. In case of calcined coal fly ash, coke type particles were eliminated and agglomerated type particles were relatively increased. Most of the particles that were relatively spherical cenosphere in the 4th step of elutriator. Particle size distribution was narrowed by calcination a and elutriation. Especially, in elutriation, particle size distribution was very narrow.

석탄회를 요업원료로 재활용하기 위하여 하소 및 수비에 의하여 선별화 하였으며, 선별화의 영향을 고찰하기 위하여 비처리 석탄회와 하소 및 수비 처리한 석탄회의 결정상, morphology, 화학성분, 입도분포, 강열감량을 측정하였다. 또한, 기존의 점토 수비 실험식이 석탄회의 수비에도 적용될 수 있는지 여부를 조사하였다. 점토에 대한 수비 실험식을 석탄회의 수비에 적용한 결과 Rittinger의 실험식과 비교적 잘 일치하였다. 처리조건에 관계없이, 석탄회는 mullite와 quartz가 주결정을 이루고, 비처리 및 수비 처리한 석탄회에서는 calcite 결정이 관찰되었으나 하소한 경우 calcite의 결정 peak가 나타나지 않았다. 입자의 형태는 비처리 석탄회의 경우 cenosphere, coke type, silicate type, whisker type, aggregate type 입자로 이루어져 있고 하소한 경우에는 coke type 입자가 제거되고 상대적으로 aggregated type 입자가 많이 관찰되었다. 특히 수비 4단계의 경우에는 비교적 구형의 cenosphere가 많이 얻어졌다. 하소에 의해 입도분포가 좁아졌으며, 특히 수비에 의해서 매우 좁은 입도분포를 얻었다.