Structural characterization of carbonized briquette obtained from anthracite powder

The structural characteristics of carbonized anthracite briquettes (CAB) obtained at different pyrolysis temperatures were studied by surface area measurements, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results indicated that the pyrolysis of the anthracite briquette mainly included the following three processes: drying, decomposition and bonding-repolymerization. The total pore volumes and surface areas of the CAB reached maximum values at 500 degrees C and decreased at higher temperatures. The side chains were removed during pyrolysis, leaving the CAB enriched with polyaromatics. The original oriented anthracite crystallites were deposed, and the microcrystalline planar size L-a underwent a prominent decrease before 700 degrees C. When the pyrolysis temperature rose to 900 degrees C, the higher pyrolysis temperature and more open structure of the briquette promoted the repolymerization of free radicals, and the value of L-a increased from 9.03 to 14.60. The variation of L-a correlated well with the mechanical strength of the CAB. The major change in L-a in the bonding-repolymerization process revealed stronger interactions between the binder and the anthracite, which improved the quality of the CAB. (C) 2015 Elsevier B.V. All rights reserved.