NCM계 폐리튬이온 배터리에서 회수한 Black Mass의 CH4 가스에 의한 환원배소

초록

In this study, the effect of temperature on the reduction roasting by CH4(g) of the black mass (B/M) recovered from NCM (LiNixCoyMn1–x–yO2)-based spent lithium-ion batteries was investigated through thermogravimetric analysis, exhaust gas analysis, and X-ray diffraction analysis of the products. When the B/M sample was subjected to thermogravimetric analysis up to 1,100 °C in a 50 vol.% CH4(g)+Ar atmosphere, the sample weight decreased rapidly from about 760 °C and then increased again from about 1,020 °C. At this time, CO(g) reached its maximum value and then decreased rapidly. This rapid decrease in sample weight is thought to be largely due to the contribution of C solution loss caused by the Boudouard reaction. In the isothermal reduction 713 ℃~1,000 ℃), CO2(g) and CO(g) were generated before CH4(g) supply, and the sample weight began to decrease. With the supply of CH4(g), the sample weight further decreased, reaching the minimum value before increasing significantly again, and at 1,000°C, it showed a value much higher than the weight of the original sample weight. Regardless of the reduction roasting temperature, oxides such as Ni and Co were reduced, and the Li recovery rate was approximately 87% or higher, independent of the isothermal roasting temperature. At 802 °C and 908 °C, LiOH was also detected, suggesting that the cathode material was reduced by H2(g) through the thermal decomposition of CH4(g).

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