Optimizing Acid Mist Suppression: Unraveling Surfactant Effects on Bubble Formation and Bursting Dynamics in Copper Electrowinning

TL;DR

This study explores how surfactants reduce acid mist in copper electrowinning by examining bubble behavior, revealing that surfactant FC-1100 is particularly effective due to its impact on bubble dynamics.

Contribution

The study introduces a novel focus on bubble life cycle dynamics, including growth, propagation, and bursting, in the context of surfactant effects on acid mist suppression.

Findings

FC-1100 surfactant significantly reduces bubble terminal velocity and increases residence time in electrolyte.

FC-1100 generates bubbles with lower kinetic energy during rupture, enhancing acid mist suppression efficiency.

The study links bubble dynamics parameters like Weber and Ohnesorge numbers to surfactant effectiveness in mist suppression.

Abstract

The working mechanism of surfactant to reduce acid mist in copper electrowinning system is not well understood. Most of the studies are based on the surface tension reduction phenomenon but this is not the only function that causes acid mist reduction. In this paper, we investigated the effect of different surfactants on a bubble’s residence time, terminal velocity, flow regime, and bursting dynamics using a high-speed camera. We have evaluated five different surfactants and found that the presence of surfactants reduces the terminal velocity, bubble diameter, and increases the residence time of the bubble in electrolyte. Especially for FC-1100, the low terminal velocity and high residence time allowed the bubble to shift its flow regime to stokes flow and allow ample time for stabilization. This was dependent on the small Weber and Ohnesorge number when FC1100 was added, which means the bubbles had less deformation and better stabilization. Therefore, the addition of FC1100 generated bubbles with the lowest kinetic energy during rupture as compared to other surfactants. Most of the kinetic energy is used to elongate the bubble film and a little kinetic energy is used to burst the bubble. To validate our study, we have performed acid mist experiments in a chamber to measure different surfactants’ suppression efficiencies. The results of the study relate terminal velocity, residence time, kinetic energy and bubble diameter to suppression efficiencies that help the understanding of surfactant’s mechanism. Compared to previous studies our work has certain novelties in understanding of bubble growth, propagation and bursting mechanism in a copper electrowinning system in the absence and presence of surfactants with emphasis on surface tension, bubble terminal velocity, residence time and Kinetic energy. While previous research has primarily examined bubble size and its influence on mist generation, as well as the role of surfactants in altering bubble size and suppressing mist, this study expands the focus to include the dynamic behavior of bubbles throughout the life cycle of the bubble.

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