Composition Structure Of Pyrite Raw Materials

The chemical composition of pyrite raw material is Fe[S2] (of which the mass fraction of iron is 46.67% and the mass fraction of sulfur is 53.33%). Common elements such as Co and Ni in the composition are isomorphously substituted for Fe to form CoS2-FeS2 and FeS2-NiS2 series. Contains Au, Ag, Cu, Pb, Zn, etc. as mechanical admixtures. [4]
Crystal structure
Isometric crystal system; -Pa3; a0=0.542nm, Z=4. Main powder crystal lines: 1.632 (100), 2.709 (85), 2.423 (65). The pyrite raw material is a derivative structure of the NaCI type structure, with Fe2+ occupying the corner vertices and face centers, and dumbbell-shaped sulfur ions [S2]2- distributed in the diagonal direction equivalent to one-eighth of a cube. The distance between sulfur SS is 0.210nm, which correspondingly shortens the distance between the cation Fe2+ and the sulfur. The radius of S2- is 0.185nm, the radius of Fe2+ is 0.07nm, and the sum of the two is 0.259nm. In fact, the distance between S-Fe is 0.226nm, indicating that they tend to be close. Because the extension direction of the dumbbell-shaped sulfide ions is staggered in the structure, the bond forces in each direction are similar, the cleavage of pyrite is extremely incomplete, and the hardness increases. [4]
Morphology: Trapezoidal complex dodecahedron crystal type, Th-m3 (3L24L33PC). The crystal is intact. Main single forms: cube a{100}, pentagonal dodecahedron e{210}, octahedron {111}, and trapezoidal complex dodecahedron {321}. Three groups of mutually perpendicular stripes (polymorphic stripes of {100} and {210}) are seen on the cubic crystal face, and they are iron cross interlaced twins according to (110). The aggregate is usually granular, dense block, spherical, strawberry-shaped, etc. The cryptocrystalline alternating pyrite raw material is called pyrite raw material.