Microwave-ultrasound enhanced lithium extraction and lithium carbonate preparation from α-spodumene

This is the authors' abstract. We don't add key points for this paper.

Achieving efficient and sustainable lithium extraction from silicate ores remains a major challenge due to the high temperatures and complex phase transformations required in conventional processes. Here, we report a microwave-assisted alkali roasting strategy that enables near-complete lithium recovery under mild conditions (~250 °C and 1 atm). Microwave irradiation selectively couples with alkali and α-spodumene, activating the roasting reaction to form soluble lithium-bearing phases without the energy-intensive phase transition in conventional routes. Subsequent ultrasound-enhanced leaching achieves nearly 100% lithium extraction, markedly higher than the 57.5% obtained via conventional roasting under identical conditions, while minimizing solid residue generation. The leachate undergoes gradient precipitation purification in ultrasonic field, removing over 99% of impurity elements (Si, Al etc.) with minimal lithium loss, yielding industrial-grade Li 2 CO 3 with an overall recovery of 98.86%. This integrated microwave-ultrasound process reduces solid waste generation by ~20%–35% relative to traditional acid-based routes. Beyond spodumene, this approach is readily extendable to other lithium-bearing minerals, offering a green and energy-efficient pathway for sustainable lithium production.