Study On Microstructure Of Low-dimension Nano-micron Pyrite

Pyrite, the most important and widespread sulphide mineral on the Earth surface, usually occurs in the form of crystals displaying three main equilibrium faces, namely cube {100}, pentagonal dodecahedron{111}, octahedral{210} and poly-shaped. In the pyrite crystal growth experiments, cubic pyrite can grow into whisker, plate and sheet crystals in appropriate physical and chemical condition which is the multi-dimensional growth of pyrite specific performance in the nano-micro scale. Because the diversity of crystal morphology and the relationship between the crystal growth mechanism is unclear, so it’s difficult to achieve controllable preparation nano-micro pyrite crystals. From the microstructure study of micro-level and low-dimensional growth of pyrite, we can get crystal habit of pyrite to provide data and theoretical support in preparation of pyrite crystal morphology modulation.In order to identify the crystal habit of plate, sheet, whisker and linear-like pyrite crystal habit and the relationship between growth conditions, the phase of products were analyzed using PW3040/60X-ray diffractometer (XRD) and morphology of products were obtained by scanning electron microscopy (SSX-550). Then the microstructure of micro-level and low-dimensional growth of pyrite were taken with TEM (TECNAIG220).Structures of natural whisker in Gengzhuang were marcasite and pyrite. Part of the irregular shape of whiskers were mainly marcasite, and a large number of straight, smooth whiskers were pyrite crystals which structure was cubic (a=b=c=0.54176nm, α=β=γ=90°, Pa3).We discover numerous hydrothermal synthesis of pyrite morphologies such as square, rectangle, hexagon etc and crystals grow perfectly with few internal defects. Our measurement indicates that most growth crystal faces of quadrilateral pyrite are (001) and a few are (101). Growth crystal faces of rectangular pyrite are (001) and the long axis growth direction is<001>. Monocrystal along the{001}faces extend and polycrystalline aggregate are two modes of pyrite crystal growth. Combination of crystal growth theory, we discuss the crystallization and growth process of pyrite crystal.{210},{230},{111} whith large crystal surface energy and small spacing grow fastly.{100},{101} whith small crystal surface energy and large spacing grow slowly. The final morphologies of crystal are surrounded by the crystal surfaces which grow slowly. Sheet and flake crystals select{100} and extend along the<001> direction to constitute crystals in a relatively low temperature. Sheet and flake crystals’morphology is an intermediate crystal growth process of pyrite.