Diminished segregation in continuous powder mixing

- Continuous mixers are superior to batch blenders for mixing of segregating mixtures.
- Segregation index of mixtures is related to d50∗ρ1d50∗ρ2.
- RSD (equipotent mixture from a batch blender) ∝ segregation index
- RSD (equipotent mixture from a batch blender) ∝ d50∗ρ1d50∗ρ2

Binary powder mixtures with variable segregation tendencies were “mixed” in a tumbling batch blender and in a continuous convective tubular blender. The degree of homogeneity of the final blend obtained from the continuous blender was found to be much higher than that from the batch V-blender, for mixtures and blender process parameters examined in this study. A direct relationship was observed between the segregation index of mixtures and a new material property metric defined as the ratio of the median particle size and bulk density of the ingredients that constitute the mixture. Moreover, for freely flowing materials, the extent of non-homogeneity at the end of a batch blending process was found to be proportional to the segregation index of the mixture and thus consequently in relation to the material property metric. Results demonstrate the superior capability of continuous blenders compared to batch blenders in their ability to homogenize segregating mixtures.

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