Synthesis and characterization of nano Mn3O4 and LiMn2O4 spinel from manganese ore and pure materials

Abstract

Extraction of nano materials form natural ores is considered as an interesting point of research. The present work focuses on preparation of nano Mn3O4 from two different sources, namely; manganese ore and pure chemicals. Mn3O4 leached from manganese ore or that prepared from pure chemicals were utilized for preparation of LiMn2O4 spinel by solid state method. The prepared oxide and spinel materials were investigated by XRF, XRD, TEM, SEM, BET and particle size distribution. The results revealed that the percentage of Mn3O4 reached 82% for that leached from manganese ore and 99.1% for that prepared from pure chemicals. Both of them exhibited needle-like particles with comparable size of several nanometers; at least in one dimension. The analysis of manganese oxide leached from manganese ore exhibited Mn3O4, iron oxide and some impurities while that prepared from pure chemical displayed only pure Mn3O4. LiMn2O4 spinel and excess manganese oxide were detected in the sample prepared using pure Mn3O4 while only LiMn2O4 spinel phase was detected in the sample prepared using oxide leached form manganese ore. The particle size of LiMn2O4 prepared from pure Mn3O4 (50 nm - <1 μm) was smaller than that prepared from oxide leached from manganese ore (100 nm - 2 μm). Consequently, the surface area of LiMn2O4 prepared from pure Mn3O4 was higher than (9.32 m2/g) that prepared form leached Mn3O4 (2.34 m2/g).