Coke is one of the important materials for ironmaking process such as blast furnace as it plays multiple roles by providing heat energy, performing the role of reducing agent and spacer for maintaining the blast furnace permeability. Due to increasing economic and environmental concerns, there is growing interest in reducing coke consumption by using innovative blast furnace operations such as accelerating coke reactions at relatively lower reactions. In an operating blast furnace, coke carbon structure is continuously modified as it descends towards lower parts of a blast furnace. Evolution coke carbon structure is well known to influence its reactions in a blast furnace such as solution loss reaction and graphitisation. Coke quality issues are becoming increasingly pertinent as less coke would be available to supply sufficient reducing gases under proposed innovative low temperature BF operations. On the hand, graphitisation behaviour could influence its fines generation behaviour in high temperature regions of an operating blast furnace. Therefore, understanding of evolution coke carbon structure at increasing temperatures is very important for the success of any new innovative blast furnace operations.Carbon structure of carbonaceous materials is often characterized by maceral analysis or reflectance measurements which are often subjective in nature and do not distinguish atomic level differences of different carbon types. Recently, advanced analytical tools such as the X-ray Diffraction or Raman Spectroscopy are being developed to characterize carbon structure of different carbonaceous materials includ-1165

Mixing of fine particles is an important operation to obtain products with controlled properties in the pharmaceutical as well as many other industries. Here, the Discrete Element Method (DEM) is used to simulate the mixing behavior of monosized fine particles in a vertically shafted cylindrical bladed mixer. The mixer impeller consists of two rotating blades of rake angle ϕ fitted to a vertical shaft. The particle cohesion is considered to be due to the van der Waals forces and is changed by varying the Hamaker constant Ha for particles of a given size. The aim is to examine the effects of interparticle cohesion, rake angle, and particle-wall cohesion on the flow and mixing behavior of fine particles. The results suggest that all these factors should be carefully selected for obtaining a good mixing performance. In particular, it is shown that the particle bed may be lifted up and remains above the rotating blades without mixing if the interactions between particles and walls are highly cohesive. At a high shaft speed, blades of 90°rake angle can result in a high mixing rate and a small shaft torque, with mixing mechanisms different from those at other rake angles.

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