Effect of Dodecane-Oleic Acid Collector Mixture on the Evolution of Wetting Film between Air Bubble and Low-Rank Coal

Yinfei Liao,Xiaodong Hao,Maoyan An,Xingwei Song,Zhe Yang,Hourui Ren

doi:10.3390/min11010058

Abstract

The wetting film evolution process is essential for flotation, especially in bubble–particle attachment. A mixed collector has been proved effective in promoting flotation. In this paper, the effect of a mixed collector (MC) composed by n-dodecane (D) and oleic acid (OA) on wetting film evolution was investigated using the extended Derjagin–Landau–Verwey–Overbeek (EDLVO) theory, the Stefan–Reynolds model, induction time, and zeta potential measurement. The hydrophobic force constant between bubble and coal treated by different collectors was analyzed. The results showed that MC was superior in reducing the induction time and increasing the zeta potential. When bubbles interacted with coal treated by MC, they had relatively low interaction energy, high critical film thickness, and high drainage rate. The order of hydrophobic force constant was no reagent < D < OA < MC. It indicated that the hydrophobic interaction between bubbles and coal particles treated by MC was the strongest because of the synergistic effect of D and OA.

Highlights

Wetting film, i.e., thin liquid film, is a common phenomenon in nature, which often occurs when air bubbles and solid particles approach each other in a fluid medium
Theinduction inductiontime timeofofuntreated untreated coal interacting with air bubble is ms, while the induction time is coal interacting with air bubble is 1125 ms, while the induction time is 551ms, ms,92
It is obvious that the induction time decreases greatly after being treated by collectors, and mixed collector (MC) shortens the induction time most significantly

Summary

Introduction

I.e., thin liquid film, is a common phenomenon in nature, which often occurs when air bubbles and solid particles approach each other in a fluid medium. The evolution of wetting film experiences the process of drainage, thinning, and rupture. The three-phase contact line will form, expand, and relax, and the attachment occurs [1]. Froth flotation is a separation process based on the hydrophobicity difference between minerals. The hydrophobic particles will adhere to bubbles and rise, while the hydrophilic ones will remain in the pulp. The bubble–particle attachment that is dominated by the evolution of wetting film is a prerequisite for flotation [2]. The evolution of wetting film between air bubble and particle is closely related to flotation efficiency

Methods

Results

Conclusion