Ultrasonic-enhanced flocculation and sedimentation of lead-zinc tailings: mechanisms and efficiency improvements

As global mining activities continue to increase, the accumulation of tailings presents significant environmental and social challenges. Traditional tailings treatment methods often struggle with efficiency and cost-effectiveness. Recently, ultrasonic technology has emerged as a novel and efficient approach, showing the potential to enhance the flocculation and sedimentation processes of mineral tailings. This study aims to investigate the mechanisms by which ultrasonic treatment enhances the flocculation of lead-zinc tailings. The research examines changes in particle properties, floc structure, and filter cake filtration performance of lead-zinc tailings under different flocculant systems before and after ultrasonic treatment. The results demonstrate that ultrasonic treatment significantly increases the contact angle of tailing particles, indicating enhanced surface hydrophobicity. Specifically, the contact angle increased from 52.0° in untreated tailings to a maximum of 66.5° after ultrasonic treatment with the addition of flocculants. Furthermore, zeta potential measurements reveal that the absolute value of the zeta potential decreased from -31.31 mV to -28.69 mV, -21.23 mV, and -14.59 mV after ultrasonic treatment with flocculants 02, 06, and 10 s, respectively, facilitating particle aggregation. Adsorption tests show increased flocculant adsorption on particle surfaces after ultrasonic treatment, promoting better flocculation. The ultrasonic treatment reduces the viscosity and surface tension of the filtrate, forming a more stable flocculation system and improving filtration efficiency. Moreover, the study found that ultrasonic treatment significantly increases the size and strength of flocs. These findings provide a comprehensive understanding of the interactions between tailing particles under ultrasonic action and offer valuable insights into the efficient treatment of tailings in mining operations.