Carbon foams with open cell structure and high compressive strength were produced using three strongly caking bituminous coals without any pretreatment, by a proposed self-foaming technique under atmospheric pressure with the characteristics of simple operation, safety, and efficiency. The chemical composition, thermoplastic behavior, and pyrolysis characteristics of the raw coals were characterized by FT-IR, Raman, solid-state 13C NMR, Gieseler fluidity, Audibert-Arnu dilatation, and TG/DTG techniques. The results showed that the structure and mechanical properties of the carbon foams could be mainly controlled by fluidity and the chemical composition of the raw coals under the same initial foaming pressure. The carbon foams produced from DS coal with high fluidity and aliphatic carbon contents originated from the cyclic aliphatic structures presented open-cell structures, large cell size, andhigh porosity (78.43%) and showed a low compressive strength of 2.71 MPa. Carbon foam obtained from the TL coal with low fluidity, and large aromatic cluster structure presented thick ligaments, relatively uniform cell distribution and better crystalline structure, which showed the highest compressive strength of 18.13 MPa.

In the paper coal-based amorphous carbon was made by a simple method from anthracite raw material, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectrometer (XPS), and Raman spectra. Electrochemical behavior of coal-based amorphous carbon as Sodium ion battery anode has been investigated by charge/discharge testy and cyclic voltammetry (CV). The results showed that the ball to the raw coal ratio had a greater influence on the granularity of the coal-based amorphous carbon milled, and the HNO3 activation could improve its electrochemical performance. It was found that coal-based amorphous carbon had high rate capability and long cycling performance, providing a reversible capacity of 138 mAh/g at a current density of 50 mA/g after 80 cycles and delivering a capacity of 93 mAh/g at 500 mA/g after 1000 cycles.

In this work, magnetic properties of activated carbon coal, which is also named amorphous carbon, were investigated. Composition and structure analysis was performed by XRD, SEM and EDS techniques. Position and width of peaks on XRD pattern confirmed amorphous structure of coals with small degree of graphitization. Magnetic measurements were performed by SQUID magnetometer. According to thermomagnetic measurements, in part of the samples, antiferromagnetic transition was observed near 120 K. Nature of such phenomena, as well as effect of oxygen and magnetic contaminations on thermomagnetic measurements are discussed referring to similar results from previous researches and data from literature.

The nanostructure of amorphous carbon thin film is described in terms of a disordered conductive sp2 phase embedded in an electrically insulating sp3 matrix. The conductive sp2 phase is dominated by Drude type free-carries response, and the carrier conductive between sp2 clusters is hopping. The two conductivities are in a serial configuration under a percolation approximation. In view of this, we extend Shimakawa’s model for compact nanoparticles [14] to amorphous carbon thin films in order to provide understanding on its terahertz (THz) optical complex permittivity. Furthermore, the contribution of phonons for THz optical complex permittivity is included in the scope of Debye theorem phenomenologically. Considering the condition of ω<ωTO and the narrow frequency range, we interpret the complex phonon permittivity experimentally as ε̃phonon=Aωeiθ for amorphous carbon. Thus, the real and imaginary permittivity can be simultaneously explained by the above considerations. It is the first qualified analysis on the THz optical properties of amorphous carbon thin films experimentally.

This work examined some elemental composition and physico-chemical properties of coal deposits found in Lamza Village in Guyuk Local Government Area of Adamawa State. The major elements determined were carbon, hydrogen, nitrogen, oxygen, and sulphur, while some of the physico- chemical properties examined include; moisture content, ash content, volatile matter, fixed carbon, pH and calorific value. Also the elemental composition of the coal ash was determined using XRF. The proximate analysis showed that the moisture content, ash, volatile matter, fixed carbon and Calorific values of the coal are 2.38 %, 14.18%, 38.25%, 44.17% and 5126.74Kcal/Kg respectively. The ultimate analysis shows that the coal has 69.2621% Carbon, 4.7550% Hydrogen, 7.0679% Oxygen, 1.3350% Nitrogen and 0.7200% Sulphur. Based on the result of the proximate and ultimate analysis, the coal is of good quality if power and heat generation is to be considered. Coal-ash elemental analysis of Guyuk (Lamza) coal shows that due to the low heavy metals and ash content of the coal, utilization of the coal within a safe environment is feasible with just a little or no negative environmental impact Keywords: Analysis, Coal, Proximate, Oxides and Ultimate

Efficient separation and high-valued utilization of coal gasification ash or slag limit the clean and green development of coal chemical industry. In this paper, a coal-water slurry gasification fine slag (CWSFS) was studied by wet screening and classification. The relationship between the particle composition with different sizes and the structural characteristics was investigated by means of proximate analysis, XRF, XRD, BET and SEM. A classification method of CWSFS was proposed to guide the high-valued utilization of coal gasification slag. Then, dry separation of a coal-water slurry gasification fine slag was carried out using a combined treatment method of crushing and dissociation and airflow classification. The results show that the CWSFS particles of different sizes have obvious differences in fixed carbon content, ash composition and mineral types. For the CWSFS with the particle size above 74 μm, the fixed carbon content is more than 60%, the calorific value is more than 20 MJ/kg, the specific surface area is relatively high and the main component is the residual carbon that contains magnetite and brookite. For the CWSFS with particle sizes between 13–74 μm, the fixed carbon content is between 20%–60%, the calorific value is between 11–19 MJ/kg, the specific surface area is small and the main mineral types are pyroxene, marcasite and hematite, etc. For the CWSFS with a particle size between 0–13 μm, the fixed carbon content is less than 20% and the calorific value is less than 10 MJ/kg, which mainly includes the amorphous glass phase that was rich in aluminum, iron and calcium, quartz and a small amount of fayalite, muscovite and other minerals. According to the fixed carbon content of CWSFS with different particle sizes, the above three components with varying particle size ranges are defined as high-carbon component, medium-carbon component and low-carbon component, respectively. The dry separation test shows that the air flow crushing and classification process can achieve a higher product yield of 29.60% and a high ignition loss of 93.76%, compared to the traditional disc crushing-classification process. Airflow crushing was proved to be able to effectively increase the dissociation degree of residual carbon and greatly improve the separation and enrichment rate of residual carbon.

Materials keeping thickness in atomic scale but extending primarily in lateral dimensions offer properties attractive for many emerging applications. However, compared to crystalline counterparts, synthesis of atomically thin films in the highly disordered amorphous form, which avoids nonuniformity and defects associated with grain boundaries, is challenging due to their metastable nature. Here we present a scalable and solution-based strategy to prepare large-area, freestanding quasi-2D amorphous carbon nanomembranes with predominant sp2 bonding and thickness down to 1–2 atomic layers, from coal-derived carbon dots as precursors. These atomically thin amorphous carbon films are mechanically strong with modulus of 400 ± 100 GPa and demonstrate robust dielectric properties with high dielectric strength above 20 MV cm−1 and low leakage current density below 10−4 A cm−2 through a scaled thickness of three-atomic layers. They can be implemented as solution-deposited ultrathin gate dielectrics in transistors or ion-transport media in memristors, enabling exceptional device performance and spatiotemporal uniformity.

The macromolecule structural characteristics of thermally metamorphosed bituminous coals (TMBC) are very significant to understand the thermal evolution history of coal basin and coal organic maturation. However, the relevant information is still limited. Here, four TMBC, selected from Daxing coal mine, Liaoning province, China, were investigated by using varied modern tools including Fourier transform infrared spectroscopy, X-ray diffraction and Raman spectroscopy to expound the effect of igneous intrusions on their chemical structures. Results indicate that the studied TMBC are characterized as turbostratic structures, composing of crystalline carbon assorted with varying amounts of disordered amorphous carbon. An increase in agglomeration degree of molecular structure in TMBC was observed with the increase in coal ranks. In addition, the strong contact metamorphism imposed on indigenous coal has created new pores and fractures examined by scanning electron microscope, which facilitate the drainage of coal bed methane in coal mines.

Studying the pyrolysis and combustion properties of coal is advantageous for promoting the environmentally friendly and effective exploitation of this resource. To investigate the pyrolysis and combustion characteristics of coal with varying types and properties, a thermal gravimetric experiment was conducted. This experiment aimed to determine the characteristic index and comprehensive combustion index. The pyrolysis characteristics of pulverized coal in a nitrogen atmosphere and the rapid combustion characteristics in an oxygen atmosphere were examined separately. The obtained results provide insights into the governing principles of the carbon content effect on the pyrolysis and combustion processes of pulverized coal particles. The findings indicate a positive correlation between the carbon content of coal and the efficiency of pyrolysis and combustion processes for pulverized coal particles. Moreover, a notable enhancement in the performance of pyrolysis and combustion is seen with increased carbon content.

The influence of carbon additives with different texture on the thermal transformation of coal pitch is studied. The additives considered are Kemerit carbon nanomaterial, Taunit M nanotubes, AG-3 active coal, and graphite foam. All the additives increase the yield of solid residue and reduce the emissions of volatiles from pitch destruction, including carcinogens. The greatest increase in yield of the solid residue (up to 15%, rel.) is obtained with Kemerit carbon nanomaterial. However, the carbon material formed is more disordered than for individual pitch. Adding 5% of crystalline carbon (graphite foam) catalyzes the formation of graphite structures in the thermal destruction of pitch; their content in pitch carbonized at 900°C may be as much as 30%. At the same time, adding graphite foam reduces the content of carcinogens in the volatile destruction products of the pitch more effectively than adding amorphous carbon additives.