A comparative study on the mineralogy, chemical speciation, and combustion behavior of toxic elements of coal beneficiation products

The huge demand for high-quality coal in China has resulted in increased generation of preparation plant wastes of various properties. A series of beneficiation products collected from a preparation plant were characterized to understand their petrographic and mineralogical characteristics, as well as thermochemical and trace element behavior during combustion. The minerals in the Luling preparation plant wastes from Huaibei coalfield mainly included kaolinite and quartz, with minor calcite, ankerite, pyrite, illite, chalcopyrite, albite, K-feldspar, anatase/rutile, and iron-oxide minerals. Massive clay lumps of terrigenous origin, cleat-infilling carbonate, and pyrite of epigenetic origin were prone to be enriched in the middlings and coal gangue. Minor or trace heavy minerals also reported to the preparation plant wastes. The contents of low-density density vitrinite and liptinite were enhanced in the clean coal, while inertinite-maceral group were enriched in the middlings. The modes of occurrences of toxic elements differed between raw coal and the waste products; and their transformation behavior during heavy medium separation is largely controlled by clay minerals (V, Cr, Co, Sb, and Pb), carbonate minerals (Co and Pb), sulfide minerals (As, Cu, Ni, Cd, and Zn) and organic matters (V, Cr, Se, and Cu). Three groups were classified based on the volatile ratio (Vr) of toxic elements. Group 1 includes the highly volatile element Se with Vr &gt; 85%; Group 2 contained elements As, Pb, Zn, Cd and Sb, with the Vr in the range of 20&ndash;85% and V, Cr, Co, Ni and Cu with Vr less than 20% were placed into Group 3. Thermal reactivity of coal inferred from the combustion profiles could be significantly improved after coal beneficiation, whereas the increased inorganic components probably inhibited the thermal chemical reaction of wastes.<br style="line-height: normal; text-align: -webkit-auto; text-size-adjust: auto;" /

Genome-wide meta-analysis of 158,000 individuals of European ancestry identifies three loci associated with chronic back pain

Back pain is the #1 cause of years lived with disability worldwide, yet surprisingly little is known regarding the biology underlying this symptom. We conducted a genome-wide association study (GWAS) meta-analysis of ch

Consensus Paper: Cerebellum and Social Cognition.

The traditional view on the cerebellum is that it controls motor behavior. Although recent work has revealed that the cerebellum supports also nonmotor functions such as cognition and affect, only during the last 5 years it has become evident that the cerebellum also plays an important social role. This role is evident in social cognition based on interpreting goal-directed actions through the movements of individuals (social "mirroring") which is very close to its original role in motor learning, as well as in social understanding of other individuals' mental state, such as their intentions, beliefs, past behaviors, future aspirations, and personality traits (social "mentalizing"). Most of this mentalizing role is supported by the posterior cerebellum (e.g., Crus I and II). The most dominant hypothesis is that the cerebellum assists in learning and understanding social action sequences, and so facilitates social cognition by supporting optimal predictions about imminent or future social interaction and cooperation. This consensus paper brings together experts from different fields to discuss recent efforts in understanding the role of the cerebellum in social cognition, and the understanding of social behaviors and mental states by others, its effect on clinical impairments such as cerebellar ataxia and autism spectrum disorder, and how the cerebellum can become a potential target for noninvasive brain stimulation as a therapeutic intervention. We report on the most recent empirical findings and techniques for understanding and manipulating cerebellar circuits in humans. Cerebellar circuitry appears now as a key structure to elucidate social interactions

Investigation on Structural and Thermodynamic Characteristics of Perhydrous Bituminous Coal by Fourier Transform Infrared Spectroscopy and Thermogravimetry/Mass Spectrometry

Perhydrous bituminous coal has multi-purpose industrial applications determined mainly by its structural and thermodynamic parameters. The Huainan coalfield in China has a large reserve of perhydrous bituminous coal resource. However, little information is available concerning its physicochemical characteristics. In this study, perhydrous bituminous coal samples from number 13-1 and 8 coal seams were selected from 11 Huainan coal mines. The Fourier transform infrared spectroscopy (FTIR) showed that the chemical structures of perhydrous coal were characterized by relatively low aromaticity, implying that the process of hydrogen enrichment during coalification influenced the reactivity of aromatization and condensation of coal macromolecules. The thermogravimetry/mass spectrometry (TG/MS) experiments were conducted at different heating rates (10, 20, and 30 degrees C/min). At the heating rate of 20 degrees C/min, number 13-1 coal seam had similar pyrolysis characteristics as number 8 coal seam. Three pyrolysis stages could be divided at this heating rate, and the main pyrolysis temperature range is 300-600 degrees C. Variation in heating rates mainly affected the primary pyrolysis stage (450-550 degrees C) of perhydrous coals. With the increase of heating rates, the maximum weight loss rate of coal and the releasing rates of gaseous species increased. The second- and third-order reaction parameters fitted better representations of the non-isothermal pyrolysis processes of perhydrous coals from the Pan4 coal mine. The apparent activation energy was calculated with values ranging from 78 to 307 kJ/mol.</p

Thermal behavior and Raman spectral characteristics of step-heatingperhydrous coal: Implications for thermal maturity process

Perhydrous coal (PHC) had been widely investigated; however, a systematic research on the relationship between the structure of PHC and its thermal reactivity was rarely reported in the previous studies. The PHC was widely developed in the Carboniferous-Permian coal-bearing strata in the northern and eastern regions of the Huainan coalfield. In this study, we chose No. 13-1 PHC as the research object. Based on the macroscopic observation of No. 13-1 PHC of the borehole #9-3 and its logging response, a typical PHC sample was selected and pyrolyzed using a thermogravimetric analyzer (TGA) to acquire a set of coal samples after pyrolysis with wide range of random vitrinite reflectance (% VRo) from 0.86 to 7.79%. The thermal evolution process of PHC before and after pyrolysis was investigated by atomic force microscopy (AFM) and Raman spectroscopy. Research results show that: 1) in the experimental temperature range, the reflectance (VRo) range of PHC varied greatly; 2) with the increase of pyrolysis temperature, the Raman spectra of PHC changed significantly in the D band of disordered structure and the G band of ordered structure and the orderliness of its macromolecule particle arrangement was increasing gradually; 3) the relationship between the thermal reactivity of PHC and its Raman structure parameters was established, the FWHM of G-band can be used as indicators of the degree of thermal evolution of PHC; 4) compared with the G FWHM of normal coal with different rank, the thermal reaction temperature of PHC was advanced. Under the premise of comparable reaction temperature, the thermal maturity of PHC was gradually higher than that of bituminous coal, and slightly lower than anthracite, indicating that the actual PHC thermal maturity was suppressed by a higher amount of hydrogen

Comparative study on geochemical characterization of the Carboniferousaluminous argillites from the Huainan Coal Basin, China

Aluminous argillites were widely deposited in the Taiyuan Formation at the Huainan Coalfield at the southeast margin of the North China Plate. However, knowledge about their formation conditions and geochemical characterizations is not presently known. We recovered underground aluminous argillites at depths of 485-610 m from a borehole in the Zhangji Coal Mine and characterized their geochemical parameters, including major and trace elements, by X-ray fluorescence, inductively coupled plasma optical emission spectrometry, and inductively coupled plasma mass spectrometry. The provenance, climatic conditions during the weathering process of parent rocks, weathering extent, and depositional environments of Huainan aluminous argillites were investigated. Results show that Huainan aluminous argillites are depleted in alkalis and alkaline earth elements and enriched in Al, Fe, and Ti. The ratios of immobile trace elements such as Nb/Ta and Zr/Hf are similar in all the argillite samples. The NASC-normalized rare earth element (REE) patterns of the argillites show an enrichment of heavy REEs and depletion of light REEs, with positive Ce and negative Eu anomalies. The provenance analysis indicates that the studied aluminous argillites probably derived from the common parent rocks composed of felsic to intermediate igneous rocks. These argillites were presumably deposited under anoxic environments.</p