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

Yang Sun,Gaofeng Fu,Lan Jiang

doi:10.3390/min7050083

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.

Highlights

Manganese, one of the important strategic metals, is widely used in metallurgy, the chemical industry, batteries, electronics, and many other fields
(1) It is possible to carry out the leaching process by using pretreated sawdust as a reducing been obtained: agent
Many factors influencing the manganese extraction are studied, and the results indicate that

Summary

Introduction

One of the important strategic metals, is widely used in metallurgy, the chemical industry, batteries, electronics, and many other fields. With the rapidly growing demand for manganese and the continuous mining of high-grade manganese ore, considerable research attention has been directed at the recovery of manganese from low-grade ores [2,3,4,5]. These low-grade ores are mainly high-valence oxides, such as pyrolusite, which are stable in both acid and alkaline media, so the extraction of manganese from such sources must be carried out under reductive conditions [1,2].

Methods

Results

Conclusion