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The recovery of cathode materials using deep eutectic solvents (DESs) still requires a long leaching time and relatively high temperatures. The poor selectivity of the leaching process leads to the low purity of the precipitate. Herein, a microwave-assisted choline chlorine–oxalate–water system was designed to selectively leach Li and recover high-purity cobalt oxalate simultaneously, which could greatly shorten the extraction time and decrease the leaching temperature. Fourier transform infrared spectroscopy, X-ray diffraction, inductively coupled plasma–mass spectrometry, and X-ray photoelectron spectroscopy methods were used to explore the mechanism of microwave-assisted DES leaching of valuable metals from lithium cobalt oxide (LCO). It was found that 99.05% of Li could be selectively leached and 99.21% of Co could be precipitated as cobalt oxalate at 100 °C in 10 min simultaneously. The purity of cobalt oxalate precipitated was 95.36% without any purification procedures. A new polymer compound Co2+­[(Ch+) x ­(Cl–) y ­(HC2O4 –) z ] was formed during the microwave-assisted leaching process. The compound could be hydrolyzed, and the cobalt oxalate precipitate appeared by increasing the water content in the DES. Finally, the DES for the recovery of LCO could be cycled four times with favorable selectivity. A low-pollution, efficient, process-simple, and precipitant-free technology using a microwave-assisted DES for selective recovery of LCO was proposed, which provided an important reference method for large-scale recovery of valuable metals from spent lithium-ion batteries.

To handle the increasing environmental issues caused by red mud and municipal solid waste incineration (MSWI) fly ash, an integrated technology for its comprehensive utilization was developed through the activation of red mud followed by synthesis of 4A‐zeolite. Three influencing factors on the thermal‐alkali activation effect of red mud were investigated. Afterwards, activated red mud was combined with fly ash to synthesize 4A‐zeolite and solidify heavy metal simultaneously. The results indicated that the maximum extraction ratios of Si (57.77%) and Al (76.34%) from red mud were achieved at the NaOH/red mud mass ratio of 1.8, alkali fusion temperature of 800°C, and alkali fusion time of 120 min. Furthermore, the mixture of activated red mud and MSWI fly ash could be served as low‐costing raw materials to synthesize zeolite products with a compact structure. The solidification effect of typical heavy metals could meet GB 16889–2008 and HJ/300–2007 completely. Especially, the solidification efficiency for Cu, Zn, Pb, and Cd could reach 98.23%, 99.09%, 99.72%, and 98.21%, respectively. This paper not only solved the red mud accumulation and heavy metal pollution caused by fly ash under a relatively low‐temperature environment but also synthesized zeolite products containing huge economic benefits.