Leaching of manganese ores using sawdust as a reductant

Abstract:The extraction of manganese from a semi-oxidized manganese ore was investigated with sucrose as the reducing agent in dilute sulfuric acid medium. The kinetics of leaching manganese from the complex ore containing MnCO 3 and MnO 2 was also investigated. The effects of sucrose and sulfuric acid concentrations, leaching temperature and reaction time on the total Mn (TMn), MnO 2 and MnCO 3 leaching were investigated. Results showed that MnCO 3 could more easily react with hydrogen ions than MnO 2 in ores, and MnO 2 decomposition could be advantageous for MnCO 3 leaching. The leaching efficiencies of 91.8% for total Mn, 91.4% for MnO 2 and 96.9% for MnCO 3 were obtained under the following optimized conditions: 0.035 mol/L sucrose concentration, 5 mol/L sulfuric acid concentration, 60 min of reaction time and 363.2 K of leaching temperature. In addition, it was found that the leaching process of semi-oxidized manganese ore follows the shrinking core model and the leaching rate was controlled by chemical reaction and diffusion. The apparent activation energy of the total manganese, MnO 2 , and MnCO 3 leaching were 40.83, 40.59, and 53.33 kJ·mol −1 , respectively.

Section: Characterization Of Semi-oxidized Manganese Ore and Leachingsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Hydrometallurgical Process and Kinetics of Leaching Manganese from Semi-Oxidized Manganese Ores with Sucrose

Wang

Sheng-long

et al. 2017

“…Several authors have evaluated the use of cellulose as a reductant in manganese leaching [11][12][13]15]. Tang et al [12] reported that the leaching efficiency of Xiangxi manganese oxide ore reached 99.8% under the optimal conditions: mass ratio of manganese ore to waste tea 10:1, 1.7 mol/L sulfuric acid, a liquid/solid ratio of 7.5:1, and a leaching temperature of 368 K for 8 h. However, when using biomass as a reducing agent, the process often requires long reaction times, high temperature, and acid strength.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Study of the Leaching of Low-Grade Manganese Ores by Using Pretreated Sawdust as Reductant

Sun

Jiang

2017

Abstract:The reductive leaching of manganese from a low-grade manganese oxide ore was investigated by using pretreated sawdust as the reductant in a sulfuric acid medium. The effects of stirring speed, liquid/solid ratio, sawdust/ore mass ratio, sulfuric acid concentration, reaction temperature, and time on the manganese extraction were examined. It was found that the leaching efficiency is strongly dependent on temperature and acid concentration. The leaching efficiency of manganese reached 94.1% under the optimal conditions: stirring speed of 300 rpm, liquid/solid ratio of 8:1, mass ratio of sawdust to ore 0.25, sulfuric acid concentration of 1 mol/L and a temperature of 363 K for 180 min. The kinetic analysis was carried out based on the shrinking core model, which indicated that the reductive leaching process was controlled by the chemical reaction. The reaction orders with respect to the sulfuric acid concentration and mass ratio of sawdust are 1.66 and 0.57, respectively. The apparent activation energy for the leaching process has been calculated using the Arrhenius expression and was found to be 51.7 kJ/mol.

“…Only poor targets could be achieved for the high similarity in density and magnetic susceptibility of manganese and iron minerals. Additionally, their extremely fine, but intergrowth occurrence state, also obstructs the effective beneficiation [10][11][12]. Reduction-leaching processes are proposed to recover manganese from manganese oxide ores [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Carbothermic Reduction of Ferruginous Manganese Ore for Mn/Fe Beneficiation: Morphology Evolution and Separation Characteristic

Huang

Jiang

et al. 2017

Abstract:In the present paper, beneficiation of Fe and Mn elements from a ferruginous manganese ore via carbothermic reduction followed by magnetic separation process was investigated in detail. The effects of the experimental parameters were systematically discussed. Iron-rich products with an Fe grade of 62.3% and 88.2% of Fe recovery, and manganese-rich product with a Mn grade of 63.7% of and 70.4% of Mn recovery were obtained, respectively, at an optimal temperature of 1100 • C, with a roasting time of 100 min, anthracite addition of 25%, milling fineness of 90% passing 0.074 mm, and a magnetic intensity of 140 A/m. Furthermore, the morphology evolution and phase transformation laws along with reduction process were revealed by optical microscope, scanning electron microscope equipped with energy dispersive X-ray detector (SEM-EDX), X-ray diffraction (XRD), and chemical phase analysis. The results demonstrated that the ferruginous manganese ore reduction can be described as follows: plate-like Fe-Mn symbiotic phase decomposition → granular MnO phase formation → fine metallic iron formation → aggregation of metallic iron → boundary development between Fe and Mn phases.