Reductive leaching of manganese from manganese dioxide ores by bacterial-catalyzed two-ores method

• Bacteria catalysis (BC) greatly improved performance of two-ores method (TOM).
• Leaching time shorten up to 24 h for 97% of Mn release through optimum condition.
• Test amplification up to 30 L reactor had no negative effect on Mn flow by BC-TOM.
• The diffusion controlled model described well release of Mn from MnO2 by BC-TOM.
• Leaching liquor from bioleaching in 30 L-reactor was eligible to make EMM.

The two-ores method (TOM) has been well established for reductive leaching of MnO2 under high reaction temperature and oxygen pressure. In this work, the TOM was carried out under ambient condition via biological catalysis. The results showed that the bacterial catalysis (BC) evidently improved the performance of TOM, especially the mixed culture consisting of Acidithiobacillus thiooxidans (A.t) and Leptospirillum ferriphilum (L.f) achieved an increase of 39% from 60% to 99% in Mn extraction. The leaching period was greatly shortened from 96 to 24 h for 97% of Mn release by the mixed culture under optimum conditions of 12 g/L pyrite concentration, 100 g/L pyrolusite content, 40 °C of temperature and 180 rpm of shaking speed. 96% of Mn dissolution was still obtained in a 30 L reactor within 24 h. The diffusion controlled model described well dissolution of MnO2 ore by the BC-TOM. The bioleaching liquor was competent for preparing high purity electrolytic manganese metal.