Water column leaching recovery manganese and ammonium sulfate from electrolytic manganese residue: extremely low water consumption toward practical applications.

Regional contamination by electrolytic manganese residue (EMR) not only composes a serious environmental problem but also leads to severe valuable resources waste. Directly recovering manganese and ammonium sulfate is a promising way, but it is still challenging to efficiently recover without high water consumption. Herein, a recovery method based on water column leaching under extremely low water consumption was firstly reported. The effect of continuous leaching and intermittent leaching on leaching behaviors, leaching trends, and spatial variations of (NH)SO and Mn with depth after leaching were fully investigated. Results indicated that some Mn-bearing soluble salts which covered on the surface of SiO in the micropores could be fully dissolved and transported out of the micropores in the EMR with the help of rest periods in the method of intermittent leaching, resulting in higher leaching efficiencies with comparison to continuous leaching, 73.50% of Mn and 67.71% of (NH)SO and 71.57% of Mn and 65.40% of (NH)SO were recovered by intermittent leaching and continuous leaching, respectively. This work demonstrates a practical approach to recover valuable materials from industrial solid wastes.