DETERMINATION OF HOMOGENEITY SCALE IN ORDERED AND PARTIALLY ORDERED MIXTURES

The scale of homogeneity in solid particulate mixtures is critical to diverse sets of applications ranging from fertilizers to pharmaceutica ls and advanced ceramics. In the past, probability-based models have b een used to describe random particulate mixtures. However, such models are not generally applicable to ordered mixtures such as those obtain ed by various particle coating techniques. The current work presents a concentric-shell model for the simulation of particle distributions i n a spatial framework. The model is applicable to mixtures of multiple components with a variety of particle coating configurations and part icle size distributions. For each component, the calculated results in clude mean, variance and percentile distributions. For random particle mixtures, the compositional variances predicted by the concentric-she ll and probability-based models converged with increasing sample size; however, the concentric-shelf model was more appropriate for the eval uation of close-range mixing distributions. In addition, the concentri c-shell model is useful in evaluating component distributions over a r ange of mixture types, including random, partially ordered and ordered mixtures. A substantial decrease in mixing Variance was predicted for ordered mixtures achieved by particle coating.