Investigation Of Manganese Removal from Acidic Mineral Wastewater (AMD) by Combining Precipitation and Oxidation Methods

Document Type : Original Article

Authors
Amirabbas Mahmoudzadeh 1
Marzieh Sadeghizadeh 2
Ali Ahmadi 2
1 Faculty of Mining Engineering, Isfahan University of Technology
2 Faculty of Mining Engineering, Isfahan University of Technology, Isfahan, Iran
Abstract
This study evaluates a cost-effective and efficient combined process for manganese removal from acidic copper mine wastewater. Because Mn²⁺ remains highly soluble even at neutral pH, conventional alkaline precipitation alone requires very high pH (~10) and large chemical consumption. In this work, real mine wastewater was first pretreated to remove iron at pH 4, followed by alkaline precipitation using sodium hydroxide and sodium carbonate at different pH levels, and finally ozonation at neutral pH. The results showed that sodium carbonate alone achieved a maximum manganese removal of about 60% at pH 9, whereas the combined alkaline precipitation–ozonation process increased the removal efficiency to 79.5%, reducing manganese concentration from 8.92 to 3.19 mg/L. In addition, sodium carbonate consumption was significantly lower than that of sodium hydroxide. Overall, the combined ozonation–precipitation approach is demonstrated to be a promising, sustainable, and cost-effective method for manganese removal from acidic mine wastewater, offering higher efficiency and lower chemical demand compared to conventional alkaline precipitation alone.
Keywords
Acidic wastewaters
manganese
precipitation
oxidation
ozone
Subjects