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 (NH4)(2)SO4 and Mn with depth after leaching were fully investigated. Results indicated that some Mn-bearing soluble salts which covered on the surface of SiO2 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 (NH4)(2)SO4 and 71.57% of Mn and 65.40% of (NH4)(2)SO4 were recovered by intermittent leaching and continuous leaching, respectively. This work demonstrates a practical approach to recover valuable materials from industrial solid wastes.

Automated summary

A recovery method based on water column leaching under extremely low water consumption was reported for efficiently recovering manganese and ammonium sulfate from electrolytic manganese residue. The intermittent leaching method showed higher leaching efficiencies compared to continuous leaching, enabling the dissolution and transportation of manganese-bearing soluble salts for higher recovery rates.