Effects of Minerals Type and Content on the Synthetic Graphitization of Coal: Insights from the Mixture of Minerals and Anthracite with Varied Rank

Abstract

The challenge of how to effectively treat minerals in coal before synthetic graphitization is a practical problem. It is unrealistic to remove minerals completely via physical or chemical methods. So, it is essential to clarify the role of minerals in the synthetic graphitization of coal. Based on the complex mineral composition, the mixture samples consisting of coal and mineral are used to obtain the effect of minerals type and content on the synthetic graphitization of coal. The role of minerals in synthetic graphitization is closely associated with the mineral content and type, as well as the rank. As to the lower-rank anthracite, quartz, kaolinite, and calcite have the role of inhibitor for the yields and defect degrees of corresponding samples after synthetic graphitization derived from the mixtures, but the role of catalyzer for their crystal structure (the degree of graphitization, stacking height, lateral size). The increasing content of quartz, kaolinite, and calcite is harmful for the yield, but useful for the crystal structure and defect degrees; the increasing content of pyrite is harmful for the yield, degree of graphitization, and stacking height, and it is useful for defect degrees. As to the higher-rank anthracite, quartz, kaolinite, and calcite have the role of inhibitor for the yield of corresponding samples after synthetic graphitization, catalyzer for their crystal sizes (stacking height, lateral size), and inertia for their degrees of graphitization. The increasing content of quartz, kaolinite, calcite, and pyrite is harmful for the yield and crystal size. A lower coal rank indicates being more prone to positive mineral effects on synthetic graphitization. The role of minerals in the synthetic graphitization of coal is complex and also represents a coupling relationship with the thermal transformation of anthracite.

Impact of Organic Sulfur on Coal Graphitization

“…According to the international classification of graphite, [80] the products prepared from BYH1, BYH2 BYH3, DLT2, CG1, and CG2 belong to semi‐graphite, and all others belong to graphite. From the equation of graphitization degree (G) in section 2.2.2, it can be seen that the graphitization degree is controlled by the interlayer spacing (d 002 ) of coal‐based graphite aromatic layers, and the graphitization degree of the coal‐based graphite products are all high and distributed between 76.02 % and 91.02 %, similar to the research results of other scholars [56,79] . It indicates that the graphitization treatment was relatively successful.…”

“…Table 5 shows the XRD parameters of coal‐based graphite, the diameter L a of coal‐based graphite cell is distributed from 10.14 nm to 25.48 nm, the stacking height L c of coal‐based graphite cell is distributed from 7.85 nm to 14.50 nm, the horizontal variation range of coal‐based graphite is larger than that of the vertical. Compared with previous research, the La and Lc of the produced products belong to the typical size of coal‐based graphite [56,79] . The ratio of horizontal‐to‐vertical of coal‐based graphite cells is distributed between 0.86 and 1.81.…”

Chemical Structure Evolution of Thermally Altered Coal during the Preparation of Coal-Based Graphene and Division of Thermally Altered Zone: Based on FTIR and Raman

“…To avoid the influence of minerals in the coal samples on the graphitization process and structural analysis of coal-based products, 45 the samples were demineralized in advance. Samples were crushed to 200 mesh.…”