Modelling of residence time distribution of liquid and solid in mechanical flotation cells

Yianatos, J.; Bergh, L.; Vinnett, L.; Panire, I.; Díaz, Francisco Javier Llorca

doi:10.1016/j.mineng.2015.04.011

Cited by 27 publications

(13 citation statements)

References 9 publications

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“…If we assume that the cell is well mixed (Yianatos et al, 2015), then the ratio of the mass of slurry to that of air in a given volume will remain constant. This means that the slurry density will also be constant in a well-mixed system given its assumed incompressibility:…”

Section: Discussionmentioning

confidence: 99%

“…The shape of the response in the experimental system here suggests that the well-mixed assumption has some limitations. Hydrodynamic characterisation of industrial flotation cells carried out by Yianatos et al (2015) showed that the mixing in most single cells was adequately described by a perfect mixing model plus dead time. The lag exhibited here in the gas phase by the experimental system may be attributed to dead time, however this dead time will be determined by the rise time of the existing bubbles, and by the size distribution of those existing bubbles.…”

Section: Mean Bubble Sizementioning

confidence: 99%

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A dynamic model for level prediction in aerated tanks

Shean

Hadler

Neethling

et al. 2018

Minerals Engineering

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Section: Discussionmentioning

confidence: 99%

Section: Mean Bubble Sizementioning

confidence: 99%

A dynamic model for level prediction in aerated tanks

Shean

Hadler

Neethling

et al. 2018

Minerals Engineering

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“…The residence time distributions were estimated by a parametric deconvolution methodology (Yianatos et al, 2015). Given measured inlet [x(t)] and outlet [y(t)] tracer concentrations and a model structure for the RTDs [h(t)], Eq.…”

Section: Modelling Residence Time Distributionsmentioning

confidence: 99%

A sensitivity analysis of kinetic characterizations in continuous flotation circuits under moderate deviations with respect to perfect mixing

Vinnett¹,

Pino-Muñoz²,

Yianatos³

et al. 2022

Physicochem. Probl. Miner. Process.

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This paper studies the effect of moderate deviations with respect to perfect mixing on the estimated kinetic parameters in industrial flotation banks. Radioactive tracer tests and mass balance surveys were performed to characterize the mixing regimes and Cu kinetic responses. For three models (Single Rate Constant, Rectangular and Gamma), two approaches to incorporate the residence time distributions (RTD) in the kinetic characterizations of rougher banks were compared: (i) RTDs measured from the radioactive tracer tests; and (ii) pure perfect mixing in each flotation machine. The measured RTDs did not present significant bypass in the evaluated banks. In all cases, comparable model fitting was obtained with both RTD approaches, which indicates that the kinetic models add sufficient flexibility to compensate for moderate biases in the mixing regime. The studied kinetic models showed non-significant differences in the estimated maximum recoveries (R∞), mean (kmean) and median (k50) rate constants when comparing the process modelling from measured RTDs and pure perfect mixing. However, the Gamma model was more sensitive to the RTD assumption in terms of the shapes of the flotation rate distributions. From the results, kinetic characterizations focused only on model fitting, or on R∞ and kmean (or k50) estimations have low sensitivity to the assumption of perfect mixing when the RTDs present moderate deviations with respect to this regime. Special attention must be paid when characterizing floating components as the perfect mixing assumption may bias the shapes of the flotation rate distributions.

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“…It can also be seen that the Elgeti's equation had a good agreement with the experimental data (Pe versus N), mainly for N greater than 8. Special attention is drawn to the fact that this liquid-phase RTD study can be applied to the solid phase when it is composed of fine particles because, in this case, the differences of flow between these phases are small (Yianatos et al, 2001;Yianatos et al, 2015). However, in RTD studies involving mineral pulps constituted by a significant amount of coarser particles (mainly > 150 μm), specific tests using proper tracers for the solid phase should be performed to obtain better results (Yianatos et al, 2001).…”

Section: Axial Dispersion Modelmentioning

confidence: 99%

Liquid-phase RTD studies in a flotation column: an analysis between tanks-in-series and axial dispersion models

2021

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The objective of the present study is to evaluate the fluid dynamics of a flotation column (2" in diameter and 6 m in height) based on gas hold-up measurements and, in particular, by applying the liquid-phase RTD (residence time distribution) technique. Additionally, a comparative study is performed between different methodologies used to determine RTD hydrodynamic parameters such as fitting of tanks-in-series and axial dispersion models to the experimental data.The evidence indicates that the axial dispersion and tanks-in-series models agreed well with the experimental data, with a slight advantage of the first model, in terms of obtaining the fluid dynamic parameters. It was proven that the axial dispersion model parameters (Pe or N d ) can be obtained with good precision (R 2 > 0.99) within the evaluated ranges from correlations that use the number of tanks in series (N) values estimated by the tanks-in-series model.

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Modelling of residence time distribution of liquid and solid in mechanical flotation cells

Cited by 27 publications

References 9 publications

A dynamic model for level prediction in aerated tanks

A dynamic model for level prediction in aerated tanks

A sensitivity analysis of kinetic characterizations in continuous flotation circuits under moderate deviations with respect to perfect mixing

Liquid-phase RTD studies in a flotation column: an analysis between tanks-in-series and axial dispersion models

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