XIAN Hai-yang1，PENG Tong-jiang1,2，SUN Hong-juan1，WU Xiao1
(1. Institute of Mineral Materials & Application, Southwest University of Science and Technology, Mianyang 621010, China;
2. Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010, China)
Abstract: To investigate the mineralogical characteristics of some typical graphite samples in China, the structure, composition, physical and chemical properties were characterized by XRD, FESEM-EDS, TEM and Raman etc analysis methods. The results show that the phaneritic and adiagnostic graphite are both consist of graphite flakes, the main difference is the crystallite size of the former is lager; both kinds of graphite are in 2H-structure, and a certain degree of 3R-structure, a is from 0.243 nm to 0.249 nm, c is from 0.672 nm to 0.677nm, the unit cell volume (V) is from 0.0347 nm3 to 0.0362 nm3 and V increases with the O content of the crystalline structure. The graphitization degree (r) of the samples is very high which can reach 1. Because of the later transformation by geological or artificial process, the secondary defect was introduced into the structure, lead to the decrease of r and increase of disorder degree. The initial oxidation temperature (T) of both kinds of graphite samples are from 700 ℃ to 800 ℃ and from 600 ℃ to 650 ℃, respectively, and smaller the particle size leads to lower T. The surface of the graphite is charged in negative electricity in water, and the maximum charge value is at pH10.5. The hydrophobic property and electro conductivity of phaneritic graphite are better than those of adiagnostic graphite.
Keywords: phaneritic graphite; adiagnostic graphite; mineral; composition; structure; mineralogical characteristics
Email: tjpeng@swust.edu.cn
ACTA MINERALOGICA SINICA Vol. 35, No. 3, 2015, Page 395-405
