Preparation of Monoclinic Pyrrhotite by Thermal Decomposition of Jarosite Residues and Its Heavy Metal Removal Performance

Minerals

Shuchuan Peng¹  Qiaoqin Xie¹  Fan Xu¹  Tianhu Chen¹  Yuefei Zhou¹  Cuimin Xu¹  Hanlin Wang¹ 

[1] Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China;

关键词: jarosite residues;    hazardous solid waste;    sulfidation;    pyrrhotite;    adsorption;   

DOI  :  10.3390/min11030267

来源: DOAJ

【 摘 要 】

Jarosite residues produced by zinc hydrometallurgical processing are hazardous solid wastes. In this study, monoclinic pyrrhotite (M­Po) was prepared by the pyrolysis of jarosite residues in H₂S atmosphere. The influence of gas speed, reaction temperature, and time was considered. The mineral phase, microstructure, and elemental valence of the solids before and after pyrolysis were analyzed using X­ray diffraction, scanning electron microscopy, and X­ray photoelectron spectroscopy, respectively. The performances of the prepared M­Po on the removal of Zn and Pb from aqueous solution were evaluated. The results show M­Po to be the sole product at the reaction temperatures of 550 to 575 °C. Most of the M­Po particles are at the nanometer scale and display xenomorphic morphology. The phase evolution process during pyrolysis is suggested as jarosite → hematite/magnetite → pyrite → pyrite+M­Po → M­Po+hexagonal pyrrhotite (H­Po) → H­Po. The formation rate, crystallinity, and surface microtexture of M­Po are controlled by reaction temperature and time. Incomplete sulfidation may produce coarse particles with core–shell (where the core is oxide and the shell is sulfide) and triple-layer (where the core is sulfate, the interlayer is oxide, and the shell is sulfide) structures. M­Po produced at 575 °C exhibits an excellent heavy metal removal ability, which has adsorption capacities of 25 mg/g for Zn and 100 mg/g for Pb at 25 °C and pH ranges from 5 to 6. This study indicates that high-temperature sulfidation is a novel and efficient method for the treatment and utilization of jarosite residues.

【 授权许可】

Unknown