A novel recovery process of metal values from the cathode active materials of the lithium-ion secondary batteries

摘要

A novel process was conducted with experiments which separated and recovered metal values such as Co, Mn, Ni and Li from the cathode active materials of the lithium-ion secondary batteries. A leaching efficiency of more than 99 percent of Co, Mn, Ni and Li could be achieved with a 4 M hydrochloric acid solution, 80 deg C leaching temperature, 1 hour leaching time and 0.02 gml~(-1) solid-to-liquid ratio. For the recovery process of the mixture, firstly the Mn in the leaching liquor was selectively reacted and nearly completed with a KMnO_4 reagent, the Mn was recovered as MnO_2 and manganese hydroxide. Secondly, the Ni in the leaching liquor was selectively extracted and nearly completed with dimethylglyoxime. Thirdly, the aqueous solution in addition to the 1 M sodium hydroxide solution to reach pH = 11 allowed the selective precipitation of the cobalt hydroxide. The remaining Li in the aqueous solution was readily recovered as Li_2CO_3 precipitated by the addition of a saturated Na_2CO_3 solution. The purity of the recovery powder of lithium, manganese, cobalt and nickel was 96.97, 98.23, 96.94 and 97.43 wt. percent, respectively.