Influence Of Acidification And Oxidization On The Structural Characterization Of Anthracite

Elementary compositions, minerals and structural characteristics of Anyang, Taixi, Jincheng and Yongcheng anthracite were investigated by industrial analysis, elemental analysis, SEM, X-ray diffraction, Raman and FT-IR spectroscopy. The Anyang anthracite was selected as the raw coal used in oxidization and acidization. The effect of acid concentration, acidizing time, oxidant species, oxidizing time and the combination of acidification and oxidization(or calcination) on the structural characteristics of the anthracite was discussed. The results show that the minerals are effectively removed, the content of oxygen-containing groups and ordered crystalline carbon increases when Anyang anthracite is acidized by 60% H2SO4 around 2h; after oxidized by 30% H2O2 around 24 h at 60℃, the hydroxyls resulted from the phenol, alcohols and fatty acid and the aromaticity are improved obviously due to the oxidation of the aliphatic-CH3; after calcinated at 800℃ and acidized by HF around 72 h, the side alkyl chains of the aromatic carbon layer are broken, the intensity of aliphatic C-H decreases, the content of the aromatic C-H and the crystalline carbon shows a significant increase, and the orientation of aromatic layer is improved; after oxidized by H2O2 around 72 h and acidized by HF, the covalent cross-linking bonds in derived coals are further broken, the crystalline layers become much thinner and the particle size in width decreases significantly from 1μm to less than 100 nm, and the layers have better dispersibility. The comparison of microstructure characteristics of different derived coals reveals that the combination of 30% H2O2 oxidization around 24 h at 60℃ and HF acidification around 72 h is more effective to obtain the superfine crystalline carbon materials like graphite structure.