Influence Factors Of Metallogenic Process On Graphite Quality

Graphite, a rare non-metallic mineral material, which is a new strategic resource widely used in the field of high-tech. There are three genetic types of regional metamorphic, contact metamorphic and magmatic hydrothermal types in our country,and the proportion of regional metamorphic crystalline graphite deposits is the highest.There are some differences between the graphite ore in the Wulatezhongqi area and the typical regional metamorphic graphite ore in some aspect, such as metallogenic epoch, ore-bearing strata, ore bearing lithology, the size of graphite scales, impurity composition, crystalline degree and degree of graphite mineralization, etc. The graphite deposits in the study area mainly occur in the low-grade metamorphic sedimentary rocks of the Jianshan formation of the Statherian group in the Middle Proterozoic Bayan Obo Group, such as Carbonaceous slate, schist, metamorphic quartz sandstone, metamorphic feldspar quartz sandstone, etc. The ore is mainly composed of andalusite mica graphite schist. The graphite of the Wulatezhongqi area is of medium-grade metamorphic amphibolite facies, which has the characteristics of contact metamorphic.Wulatezhongqi area owns abundant resources of graphite. In this paper, a series of mineralogical tests were carried out on the quality of the newly discovered graphite minerals in Wulatezhongqi area and typical metamorphic graphite minerals.(1) Graphite is crystalline and scaly, which is often exist in the form of disseminated or aggregates, in the graphite deposits of the Wulatezhongqi area. Scales of graphite are short, which diameter are generally less than 50 ?m. The thickness of graphite crystal plate is between 53nm and 8nm. The content of fixed carbon in ore is about 5%?10%. Only a small amount is more than 10%, or even close to 20%.Compared with typical metamorphic graphite, the fixed carbon content of the graphite minerals in the Wulatezhongqi area is high, but the mineralization of graphite is slightly lower than that of regional metamorphic graphite. Also, the graphite of the Wulatezhongqi area has directional distribution characteristics.(2) Most of the graphite's scales in the typical regional metamorphic type are large and thick. Directionality is not obvious. The scale (long axis) is usually between 0.05 and 3.5 mm. Individual larger scales can reach 5mm. The content of fixed carbon is lower, generally between 3% and 5%. The diameter of graphite is large, and the thickness of graphite crystal plate is thick. The crystal plate's thickness of graphite can reach 89nm. Graphite has a better shape, which is highly crystallized. The orderliness and integrity of graphite crystal are better. The content of C atom in graphite ore is relatively high, and the impurity atoms such as Si and Al are relatively few. The samples contain 3R graphite in varying degrees. The smaller the scale of the graphite was, the lower the mineralization of the graphite would be, and the more content of the 3R-type graphite. Contact metamorphic graphite ore in Wulatezhongqi area is with slightly higher impurities, lower metamorphic grade. The degree of crystallization,orderliness and integrity of graphite are slightly worse than those of typical metamorphic graphite deposits.