Metal extraction from ores and waste materials by ultrasound-assisted leaching -an overview

ABSTRACT

The traditional leaching process is characterized by extensive reaction time, low efficiency, and considerable leaching reagent consumption. It was well demonstrated that using ultrasound could effectively enhance the leaching reaction rate by removing the passivating layer and increasing the mass transfer rates. This improvement would result from bubble cavitation and other mechanical-chemical mechanisms that ultrasounds can generate during ultrasound-assisted leaching (UAL). Thus, these days using UAL for the recovery and recycling of various valuable metals has markedly received attention as an environmentally friendly process. However, surprisingly no comprehensive overview has been provided to focus on various reaction mechanisms through the applications of UAL and deliberate them for nearly two decades. This work has explored various applications of UAL applied for ore and waste processing by a systematic approach to fill this gap. An overview of different mechanisms (mechanical, thermal, sonochemical) based on main ultrasound operating variables (frequency, power, and time) and their level of leaching effectiveness on the leaching metallurgical responses in varied conditions was discussed in detail. It was indicated that the common approach for conducting UAL investigation mainly focuses on improving the leaching efficiency of metals by using single-frequency ultrasound. While analyzing the correlation between ultrasonic cavitation theory and assisted leaching process and exploring the systematic effect of multi-frequency ultrasonic system need to be further clarified in future research. In general, the present work is going to potentially pave the path for understanding UAL and further its development in the future.

KEYWORDS:

• Ultrasonic treatment
• ecofriendly leaching
• cavitation
• kinetics

Acknowledgments

The Fundamental Research Funds support this work for the Central Universities (No. 2019XKQYMS18). The authors gratefully acknowledge financial support from the Project funded by the National Nature Science Foundation of China (Grant No. 52204296).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Credit authorship contribution statement

Investigation, Literature research, Formal analysis, Roles/Writing – original draft: Xiangning Bu; Supervising, writing – revising & editing: Saeed Chehreh Chelgani; Engineering and writing guidance: Ahmad Hassanzadeh, Ali Behrad Vakylabad, and January Kadenge Danstan.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/08827508.2022.2117173

Additional information

Funding

The work was supported by the Fundamental Research Funds for the Central Universities [2019XKQYMS18].