4. Conclusion
The current investigation revealed that the mechanism of mixing cohesive materials in a bin blender changes with bin size. With smaller bins, convective mixing occurs only at the macro-scale. Commercial scale bins introduce a component of micro-scale mixing due to the increased shear provided by the higher drop heights.
Although the effectiveness of micro-scale mixing in a comil depends on the equipment and batch size, a subsequent convective mixing in a bin blender removes such dependency by continuing the micro-mixing concurrently with macro-mixing. These findings indicate that a combination of micro- and macro-scale mixing mechanism is required for homogeneous mixing of cohesive materials.