Reductive-atmospheric leaching of manganese from pyrolusite ore using various reducing agents

Local pyrolusite ore from Waykanan regency (Lampung Province, Indonesia) has been treated by sulfuric acid leaching process using various reducing agents to produce manganese sulfate. The ore was detected as pyrolusite ore by XRD and contained Mn (36.8%), Fe (6.6%), and Si (4.1%). Various reducing agents such as molasses, glucosse, fructose, cane sugar, sodium sulfit, tannic acid, oxalic acid, citric acid, black tea, green tea, cellulose, sawdust of candlenut shell, sawdust of Acacia wood, sawdust of coconut shell, sawdust of Albizia chinensis wood, and H2O2 were used. From the experimental results, it can be found that tannic acid and oxalic acid were the most effective reducing agents for manganese leaching in sulfuric acid medium. The manganese recoveries were 100% when tannic acid and oxalic acid used as reducing agent, using 1 M of sulfuric acid and 5% of pulp density at 30°C of leaching temperature, 150 rpm of shaker speed, atmospheric pressure, and 8 hours of leaching period.