Ultrasonically-enhanced leaching: correlating acoustic spectra and solid particle properties in NMC cathode...

Area of Science:

• Chemical Engineering
• Materials Science
• Acoustics

Background:

• Acoustic cavitation is a powerful technique for intensifying industrial dissolution processes.
• Its application in hydrometallurgical recycling of battery cathode materials offers a sustainable alternative using organic acids.

Purpose of the Study:

• To map cavitation activity during the leaching of NMC (lithium nickel manganese cobalt oxide) cathode particles.
• To understand the relationship between acoustic cavitation and acid-leaching interactions with particles.

Main Methods:

• Leaching of NMC cathode particles as a model system.
• Quantification of cavitation activity using hydrophone measurements and acoustic spectra analysis.
• Characterization of solid particles via scanning electron microscopy (SEM) and gas adsorption surface area analysis.

Main Results:

• Leaching reduced particle size from 10 μm to 1.5 μm, with 85% mass reduction in 10 min.
• Cavitation intensity decreased by three orders of magnitude during leaching, correlating with particle surface area.
• A cushioning effect from oxygen release during the reaction was identified as a cause for cavitation attenuation.

Conclusions:

• Cavitation activity is dependent on the total surface area of solid particles during leaching.
• Understanding these interactions is key for designing and controlling intensified leaching reactors.
• Findings facilitate improved hydrometallurgical recycling processes for battery materials.