Flocs Properties and Flotation Performance of Fine Diaspore with Energy Input Pretreatment Induced Using Sodium Oleate

Liao Liao,Ou Ou

doi:10.3390/min9070433

Abstract

Energy input, an important factor affecting flocs properties and flotation performance, has rarely been studied in the field of diaspore flotation, which has severely limited our understanding of the flocculation flotation of fine diaspore. Therefore, in this study, the flocs properties and flotation performance of fine diaspore with energy input pretreatment were studied through flotation kinetics, flocs size measurements, and fractal dimension analysis. The results showed that the flocs size increased and the flocs structure became looser with the increasing energy input, while the flocs size decreased and the structure became compact when the energy input exceeded 10.93 kJ/m3. Meanwhile, there were significant differences in the flotation performance under different energy input pretreatment conditions, suggesting that the flotation performance of the fine diaspore was closely related with the flocs properties generated during the agitation process. In particular, the flotation performance was positively correlated with the flocculation degree of flocs, to a certain extent. The flocculation flotation of the fine diaspore benefited from a suitable energy input, and an excessive energy input was not conducive to flotation performance.

Highlights

The low aluminum oxide-to-silica mass ratio (A/S) of diaspore, typically ranging from 4 to 6, makes it uneconomical to feed the Bayer process directly because of the high energy and reagent consumption [1,2]
Energy input pretreatment is essential in order to allow the hydrophobic association to take place because of the electrostatic repulsion that acts as a barrier to the process, which means that the energy input is an important parameter in evaluating the flocculation process and flocs properties
Numerous papers about flocs properties and the flocculation process influenced by the energy input have been published, most of which were achieved by controlling the shear rate or agitation conditions; for example, the relation between the flocs size distribution and hydrodynamics [5], the transfer of mineral particles between flocs under various conditions of agitation [6], the temporal evolution of flocs size and structure in low-shear flow [7], and the fragmentation and erosion of aggregates in shear flow [8]

Summary

Introduction

The low aluminum oxide-to-silica mass ratio (A/S) of diaspore, typically ranging from 4 to 6, makes it uneconomical to feed the Bayer process directly because of the high energy and reagent consumption [1,2]. Energy input pretreatment is essential in order to allow the hydrophobic association to take place because of the electrostatic repulsion that acts as a barrier to the process, which means that the energy input is an important parameter in evaluating the flocculation process and flocs properties (i.e., flocs size, structure, density, shape, and porosity). Numerous papers about flocs properties and the flocculation process influenced by the energy input have been published, most of which were achieved by controlling the shear rate or agitation conditions; for example, the relation between the flocs size distribution and hydrodynamics [5], the transfer of mineral particles between flocs under various conditions of agitation [6], the temporal evolution of flocs size and structure in low-shear flow [7], and the fragmentation and erosion of aggregates in shear flow [8]

Objectives

Methods

Results