Desulfurization of microwave pretreated fine coal by magnetic separation

ABSTRACT

The production of pyrite extraction by the conventional magnetic separation method was effectively improved by increasing the magnetic susceptibility of pyrite. The electromagnetic characteristics and the absorption response of fine high-sulfur coal were studied for their improving effect on the magnetic susceptibility of pyrite. In this study, the complex dielectric constant and the loss tangents of fine coal samples obtained from Weinan Co. were investigated in the frequency of 0.5 ∼ 6.5 GHz. The complex dielectric constant of raw coal was small, indicating comparatively less loss of microwave energy during the magnetization process, essentially acting against the microwave energy absorption. The microwave energy absorption and electromagnetic parameters of coal samples depend on the thickness of the coal sample. When the microwave treatment time of the fine coal was 240 s, the sulfur content of the clean coal reached as low as 2.92%, and the optimum desulfurization degree and yield were 32.01% and 91.97%, respectively.

KEYWORDS:

• Desulfurization mechanism
• dielectric properties
• fine coal
• microwave response
• reflection coefficient

Acknowledgments

The authors acknowledge the financial support by the Jiangsu Natural Science Fund-Youth Fund (BK20160263), the Fundamental Research Funds for the Central Universities (No. 2015XKZD10), the National Natural Science Foundation of China (No. U1508210), the Research Fund for the Postdoctoral Program (No.2015M581898) and the Priority Academic Program Development of Jiangsu Higher Education Institutions.