Study on Separation of Manganese from Iron in High-Iron Pyrolusite Ore by Leaching with Simulated Flue Gas

Abstract

Due to the depletion of high-grade manganese ore, much attention has turned to recover manganese from low-grade ores; however, these are usually associated with high-iron content. Moreover, the conventional process of extracting Mn from iron-rich low grade manganese oxide ore focused on recovery of Mn, while ignoring the leaching characteristics of Fe. Hence, simultaneous investigations on leaching behavior and separation e ciency of both manganese and iron were carried out for attaining high recovery of manganese with low iron content from the high-iron low-grade pyrolusite ore using simulated ue gas as the reductant. The e ects of leaching parameters, ue gas components and initial particle size on the leaching e ciency of Mn and Fe were studied, and the results indicated that higher separation e ciency of Mn from iron was achieved at lower SO 2 concentration, O 2 concentration and suitable pulp density. The experimental validation revealed that 93.12% Mn and only 2.57% Fe were extracted under the optimal operating conditions: SO 2 percentage of 5%, O 2 percentage of 1%, reaction temperature of 35°C, solid-to-liquid ratio of 250 g/L, and more than 120 min. Kinetic modelling has indicated that the Mn leaching rate is controlled by the rate of di usion of SO 2 /O 2 from the gas phase to the liquid phase, and the rate of di usion of product or reactants to the ore surface through an inert product layer is the rate-limiting step for Fe dissolution.

Pre-reduction Behaviour of Manganese Ores in H₂ and CO Containing Gases

“…With an estimated world production of 17 million tons in 2018, 1) manganese ores have been widely used in many fields, such as the steel industry and in medicine. Most of manganese alloys produced globally is used in the steel industry, [2][3][4][5][6][7] while only about 6% of manganese ore is worldwide used to produce special metallurgical and chemical products. Management of the energy consumption in manganese alloys has become of primary importance to ensure the competitiveness of the industry as well as the minimization of environmental impacts, such as the greenhouse gas emissions.…”

Oxidation of SO2 by O2 and Its Effects on Dithionate Formation during Pyrolusite Leaching Process with Mixture Gas Containing SO2 and O2

“…Recently, recovery of manganese resources from low‐grade ores has drew much attentions, especially the low‐grade pyrolusite, which cannot react with sulfuric acid directly, caused that it could hardly be economically processed by conventional metallurgical treatment. Among those methods of recovery of pyrolusite, leaching with SO 2 is proved promising attributing to the advantages of fast leaching rate, high Mn extraction rate and selectivity leaching of Mn ,. However, along with the formation of MnSO 4 during pyrolusite leaching process with SO 2 , MnS 2 O 6 is also formed simultaneously as a byproduct,, which is quite inert in normal temperature and difficult to remove, thus affecting the quality and purify of MnSO 4 product .…”