A comparative study on the mineralogy, chemical speciation, and combustion behavior of toxic elements of coal beneficiation products

Biao Fu, Guijian Liu, Mei Sun, James C. Hower, Guangqing Hu, Dun Wu

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

The huge demand for high-quality coal in China has resulted in increased generation of preparation plant wastes of various properties. A series of beneficiation products collected from a preparation plant were characterized to understand their petrographic and mineralogical characteristics, as well as thermochemical and trace element behavior during combustion. The minerals in the Luling preparation plant wastes from Huaibei coalfield mainly included kaolinite and quartz, with minor calcite, ankerite, pyrite, illite, chalcopyrite, albite, K-feldspar, anatase/rutile, and iron-oxide minerals. Massive clay lumps of terrigenous origin, cleat-infilling carbonate, and pyrite of epigenetic origin were prone to be enriched in the middlings and coal gangue. Minor or trace heavy minerals also reported to the preparation plant wastes. The contents of low-density density vitrinite and liptinite were enhanced in the clean coal, while inertinite-maceral group were enriched in the middlings. The modes of occurrences of toxic elements differed between raw coal and the waste products; and their transformation behavior during heavy medium separation is largely controlled by clay minerals (V, Cr, Co, Sb, and Pb), carbonate minerals (Co and Pb), sulfide minerals (As, Cu, Ni, Cd, and Zn) and organic matters (V, Cr, Se, and Cu). Three groups were classified based on the volatile ratio (Vr) of toxic elements. Group 1 includes the highly volatile element Se with Vr & gt; 85%; Group 2 contained elements As, Pb, Zn, Cd and Sb, with the Vr in the range of 20-85% and V, Cr, Co, Ni and Cu with Vr less than 20% were placed into Group 3. Thermal reactivity of coal inferred from the combustion profiles could be significantly improved after coal beneficiation, whereas the increased inorganic components probably inhibited the thermal chemical reaction of wastes.

Original languageEnglish
Pages (from-to)297-308
Number of pages12
JournalFuel
Volume228
DOIs
StatePublished - Sep 15 2018

Bibliographical note

Funding Information:
This work was supported by the National Natural Science Foundation of China ( 41672144 ), the Nature Science research project of Anhui Province, China ( 1408085MB29 ), the Research Projects of Department of Land and Resources of Anhui Province, China ( 2016-K-2 ), and the National Key R&D Program of China ( 2016YFC0201600 ). Biao Fu thanked Chinese Scholarship Council for his joint-PhD scholarship studying at the University of Kentucky. We acknowledge editors and reviewers for polishing the language of the paper and for in-depth discussion. Appendix A

Publisher Copyright:
© 2018 Elsevier Ltd

Keywords

  • Mineralogy
  • Modes of occurrences
  • Preparation plant wastes
  • Toxic elements
  • Volatility

ASJC Scopus subject areas

  • Chemical Engineering (all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Organic Chemistry

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