| Air-enhanced hydrocyclones (AEHCs) are gaining popularity as mineral separators. These devices strive to increase the recovery of valuable minerals by combining the selectivity of flotation with the capacity and simplicity of hydrocyclones. Despite promising improvements in the recovery of fine particles via AEHCs, the performance of these separating devices, particularly the air-injected hydrocyclone, can be improved through detailed analysis.; In this dissertation, improved performance of an air-injected hydrocyclone is sought through modeling and optimization. This improvement is accomplished by completing three research tasks: (1) Produce an accurate model of froth flotation in a centrifugal field; (2) Incorporate an existing hydrocyclone model into the flotation model to predict the behavior of an AEHC; (3) Optimize the design and operation of a specific AEHC, an air-injected hydrocyclone, using a genetic algorithm.; Initially, the equations of motion for a single bubble, single particle system are numerically integrated, providing an estimate of P{dollar}sb{lcub}rm c{rcub}{dollar}, the probability of a bubble-particle collision. This probability is found as a function of two non-dimensional parameters, the Stokes' number and a non-dimensional representation of the centrifugal force in the AEHC. P{dollar}sb{lcub}rm c{rcub}{dollar} forms the cornerstone of the AEHC model.; Next, an existing model of a conventional hydrocyclone is incorporated into the flotation model. This coupling yields a model of an AEHC. AEHC model predictions are compared to experimental results to verify the accuracy of the AEHC model.; Finally, the AEHC model is used to optimize the design and operation of an air-injected hydrocyclone. This optimization is completed by utilizing a genetic algorithm. Specifically, the performance of the genetic algorithm is compared to a conventional optimization technique, the Nelder-Mead method. To improve the convergence characteristics of the genetic algorithm, a small population reproduction scheme, simplex reproduction, is employed. |
