(431c) Suspension of Large and Dense Particles in Stirred Vessels: Further Application and Validation of Grenville-Mak-Brown (GMB) 2015 Approach

Stirred vessels are utilized for various chemical and hydrometallurgical processes involving two or more phases. As we know, most processes in the metallurgical industry involve the processing of solid particles in a liquid phase for the purpose of reaction, separation or transport. The design of these solid-liquid processes in stirred vessels operating in the turbulent flow regime with free-settling slurries requires the prediction of the Just Suspended condition N_JS, the impeller speed at which all particles are in motion [1]. Recently, Grenville et al. [2] [3] [4] presented experimental data measured at three different scales demonstrating success of an energy balance approach to modeling the suspension process. The particle size and density used in the experiments were less than 500µm and less than 2650 kg/m³ respectively. Literature was sourced to find additional datasets that could be used to improve the validity of the model, including transport of solids in pipelines [5] [6] [7] [8] [9]. New experiments including large and dense particles to sufficiently vary the Archimedes number have been conducted. Generally, the correlation has been validated for large and dense particles (2650-11340 kg/m³, 500 µm < d₄₃ < 10,000 µm). The GMB formulation has been generalized to account for local concentration effects due to the formation of a slurry cloud height. The effect of scale and scale up as well as vessel shape will also be discussed. The correlation when applied to slurry transport in pipelines has shown similar success in correlating the critical deposition velocity in pipelines.

References

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