Balling and granulation kinetics revisited

Balling of finely comminuted solids by random coalescence and granulation of iron ore fines and other minerals by autolayering are two major size enlargement processes. The existing kinetic model for random coalescence does not take into account the strong dependence of coordination number on the size distribution of agglomerating entities. We present a coordination number based coalescence model, which mimics the underlying physical process more realistically. Simulations show that in spite of highly diverse model structures, random and coordination coalescence models give remarkably similar results. Only static models of autolayering are available presently. These map the input size distribution of feed solids into steady state or terminal size distribution of granules, with little or no information on the path traversed by the process. We propose a continuous-time dynamic model of autolayering within the population balance framework. The model, which is based on the proportionate growth postulate of autolayering, agrees reasonably well with experimental data

Data for: A Coupled CFD-PBM and Thermodynamic Analysis of Continuous Supercritical Hydrothermal Synthesis of Nanoparticles

We have provided the detailed boundary conditions for all the variables, model parameters, and user-defined functions for mass averaged density, nucleation rate, diffusional growth rate, and coagulation kernels etc

Thermodynamic analysis of hydrothermal synthesis of nanoparticles

The hydrothermal method is one of the most commonly employed techniques for synthesis of metal oxides, metals, and metal composites with different crystalline structures and morphologies, that are in the form of fine particles. The hydrothermal synthesis of nanoparticles involves hydrolysis of metal salt and condensation of metal hydroxide to produce ultrafine metal or metal oxide particles. We propose a Thermodynamic Modeling Framework for predicting the stability of the chemical species under the hydrothermal conditions. This can help in identifying the feasible regions for the hydrothermal synthesis of materials. The method is based on the integration of the Gibbs free energy equation, modified Bromley model for predicting activity coefficients, and the revised Helgeson-Kirkham-Flowers (HKF) model for estimating the standard-state thermodynamic properties of the species. The framework is tested with published experimental data for the synthesis of boehmite under subcritical temperature and supercritical conditions. The stability diagrams are generated for ceria and boehmite. The effect of pressure on the stability of the ceria species is studied. The proposed thermodynamic framework is useful for determining and identifying the process conditions under which the metal complex of interest is thermodynamically stable. (C) 2017 Elsevier B.V. All rights reserved