Physical analysis and modeling of the Falcon concentrator for beneficiation of ultrafine particles

Abstract

International audienceA predictive model of the Falcon enhanced gravity separator has been derived from a physical analysis of its separation principle, and validated against experimental data. After summarizing the previous works that led to this model and the hypotheses on which they rely, the model is extended to cover a wide range of operating conditions and particle properties. The most significant development presented here is the extension of the analytical law to concentrated suspensions, which makes it applicable to actual plant operating conditions. Two examples of industrial use cases are described and studied by interrogation of the model: dredged sediment waste reduction and coal recovery from fine tailings. Comparisons with empirical studies available in the literature show a good agreement between model predictions and industrial data. The model is then used to identify separation efficiency limitations as well as possible solutions to overcome them. These two examples serve to show how this predictive model can be used to obtain valuable information to improve physical separation processes using a Falcon concentrator, or to evaluate Falcon separator's abilities for new applications

Rare earths (La, Ce, Nd) and rare metals (Sn, Nb, W) as by-products of kaolin production – Part 3: Processing of fines using gravity and flotation

“…This may appear consistent as desliming prior to gravity concentration is a well-proven technique for devices operating in normal gravitational field condition (1G). In addition, the presence of slimes is known to increase the pulp viscosity (Ndlovu et al, 2013;Sivamohan, 1990) which has a negative effect on Falcon UF separation efficiency as illustrated by recent studies on Falcon UF fluid dynamics based model by Kroll-Rabotin et al (2013. On the contrary some works have shown that slimes can improve centrifugal separation by acting as a quasi-heavy medium as illustrated by better performance obtained when treating cyclone feeds rather than cyclone underflows for gold and precious metals (Sprake and Mcalister, 2003).…”

Application of Falcon Centrifuge as a Cleaner Alternative for Complex Tungsten Ore Processing

“…The bowl can be fluidized to avoid compaction and to remove light particles from the concentration zone (Falcon SB), while the Falcon UltraFine (UF) bowl, specifically designed to recover very fine particles, is not fluidized. Rotary speed, pulp density, feed flowrate, and fluidization pressure (for the Falcon SB only) are the main operating parameters involved in the separation [27,28,[31][32][33][34]. Falcon concentrators are operated in semi-batch mode but, at industrial scale, continuous Falcon concentrators (Falcon C) can process continuously up to 100 t/h of ore with high feed pulp density (up to 45 wt %) [24].…”

“…The intercept is high (87.52), which indicates a high WO 3 recovery at the center of the experimental domain. As the entrapment of a particle is directly linked to its settling length in the bed [33,34,39,40], scheelite settles probably very fast at the considered operating conditions. The gangue minerals recoveries (proportional to K 2 O, P 2 O 5 , and Fe 2 O 3 recoveries) show similar trends: as the WO 3 recovery, they are all affected by a significant negative effect of the rotary speed whereas the pulp density displays a high positive coefficient.…”

A review of cassiterite beneficiation fundamentals and plant practices

“…Falcon Ultra-Fine (UF) separator is used for the concentration of heavy minerals present in the ultra-fine (up to 3 lm) particles (Kroll-Rabotin et al, 2013). Generally, the heavy mineral content in the fines should be above 0.1% by weight.…”