Fundamental properties of flotation frothers and their effect on flotation

Abstract

In the present work, five different flotation frothers were tested in order to evaluate their performance in the flotation of two coal samples in terms of their effect on the entrainment of fine particles. The experimental program included the characterization of the investigated frothers by means of surface tension measurements, dynamic foamability index (DFI), critical coalescence concentration (CCC) and water recovery tests in aqueous solutions. The experiments also included both forward and reverse batch flotation tests in the presence of the tested reagents. The results indicate that, while there is a clear relationship between water recovery in a two-phase system and the fundamental properties of the frothers, expressed in terms of DFI, the trend observed in the batch flotation tests in the presence of coal for the same frothers is different. This indicates that characterization of flotation frothers in a two-phase experiment is not adequate since the water transport results obtained in the two-phase and three-phase experiments were different. The reverse flotation tests revealed that dodecyl trimethyl ammonium bromide (DTAB), which is used as a collector for mineral matter and as a frother, generates froths characterized by low water contents and high stability, which promote the entrainment of unwanted particles to the froth collection zone. It was also observed that when polyacrylamide (PAM) was used in addition to the coal depressant (dextrin) and DTAB, the selectivity of the process slightly improved. However, in the presence of PAM, the rates of transfer of water and solids to the froth also increased, which translated into a higher degree of entrainment of coal particles in the froth product. The selectivity of the coal reverse flotation process and the reagent consumption, at this point of the development of this technology, constitute a problem which remains unsolved. ii 1. INTRODUCTION

Effect of frothers and solid particles on the rate of water transfer to froth

“…As surface tension measurements for the tested frothers (Melo and Laskowski, 2006) revealed, DF-1012 frother is the most surface active of the four tested frothers, MIBC and DF-200 are the least surface active with α-terpineol being somewhere in between them. In agreement with these measurements, the two-phase measurements of the "water transfer rates" for DF-1012 frother turned out to be the highest.…”

Flotation Frothers: Review of Their Classifications, Properties and Preparation

“…Polyglycol ether and aldehyde molecules are more surface active and produce more stable and viscous froth compared to alcohol frothers, which leads the recovery of coarse particle size fraction of flotation feed. Therefore, it is difficult to use a single frother that will effectively give good overall flotation performance for wide particle size distributed flotation feed [35][36][37]. This suggests potential benefits of blending frothers for improved overall valuable recovery.…”

Collectorless flotation of marmatite with pine oil

“…Froth flotation is widely used to recover marmatite by adding various reagents, such as collectors, frothers, and depressants. Frothers are important additives in flotation with a major influence on bubble size, stability [2][3][4], potential [5,6], and froth phase [7][8][9][10]. Moreover, synergistic adsorption occurs between frother and collector in the mineral flotation.…”