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Zhou C.-C.,China University of Mining and Technology | Zhou C.-C.,Key Laboratory of Coal Processing and Efficient Utilization | Zhang N.-N.,China University of Mining and Technology | Peng C.-B.,China University of Mining and Technology | And 3 more authors.
Energy and Fuels | Year: 2016

The content and modes of occurrence of arsenic and its distribution in Yunnan coal of China as well as its partitioning behavior during the coal separation process were investigated. The following laboratory equipment such as proximate analyzer, ultimate analyzer, sulfur analyzer, inductively coupled plasma mass spectrometer and the methods including sequential chemical extraction process, screening analysis, float-and-sink analysis, heavy liquid separation, and progressive release flotation were frequently used during the research process. The coal sample has a high sulfur content of 8.21%, and its arsenic content is 15.1 μg/g, which is within the range of the mild enrichment level. Content relationship among the various modes of occurrence in order is sulfide-associated form (47.38%) > organically bounded form (18.09%) > silicate-associated form (17.51%) > carbonate-associated form (12.04%) > ion-exchangeable form (3.84%) > water-soluble form (1.14%). The sulfide-associated form is the dominant mode of occurrence of arsenic in the raw coal, which means arsenic has an affinity to sulfur. Arsenic in the sulfide-associated form mainly occurs in the inorganic sulfide minerals (especially in pyrite). Besides, the arsenic content increases with the decrease of coal particle size, and arsenic is concentrated in high-density products. There is a good correlation between the removal rate of arsenic and clean coal ash in either gravity separation or flotation, and arsenic removal rate of 57.96% and 70.77% could be obtained through gravity separation and flotation, respectively. In order to ensure arsenic removal rate and clean coal yield, a combined approach of physics and chemistry should be developed. © 2016 American Chemical Society.

Li X.-C.,China University of Mining and Technology | Li X.-C.,Key Laboratory of Coal Processing and Efficient Utilization | Hu Y.-F.,China University of Mining and Technology | Jiang Y.-Y.,China University of Mining and Technology | Xiong J.-J.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2011

Study object is the throttle-type self-excitation dust collection. Through the measurement of time-averaged value of pulsatile pressure on turbulence flow, gas-liquid coupling status in dust separator was studied. The primary conclusions are made as follows: the dedusting effect is influenced by the height of the catch-cavity because the gas-liquid coupling status is changed with the height of the catch-cavity. And the suitable height of catch-cavity is 300 mm. Pressure of catch-cavity reduce gradually along with the direction of flown line. As the throttle strength value α aggrandizing, the whole pressure value of catch-cavity drops, and the vortex intensity produced in whirlpool area is also reduced. As the changing of α value, the water injected in the catch-cavity will influence the gas-liquid coupling of catch-cavity. There are several influence formats which are increasing throttle resistance, exciting dust removal drip, transferring the airflow direction and the interaction of all. If it has the size of 400 mm × 300 mm, the dust collection has the third influence format and with good dedusting effect when the α value between 250/300~235/300.

Yao J.,China University of Mining and Technology | Yao J.,Key Laboratory of Coal Processing and Efficient Utilization | Xiao L.,China University of Mining and Technology | Xiao L.,Key Laboratory of Coal Processing and Efficient Utilization | Wang L.,China University of Mining and Technology
International Journal of Mining Science and Technology | Year: 2012

The bioconversion of coal at ambient conditions is a promising technology for coal processing, although the mechanisms of coal degradation are still not understood fully. In this work, the bioconversion of lignite was studied using a fungus isolated from decaying wood. The lignite samples were oxidized with nitric acid under moderate conditions and then the oxidized samples were placed on a potato medium with isolated fungus for lignite bioconversion. Lignite, oxidized lignite and residual products after bioconversion of lignite were sequentially extracted with petroleum ether, CS 2, methanol, acetone and tetrahydrofuran (THF), and then each extract was characterized by gas chromatography-mass spectrometry (GC/MS). The differences in composition and structure among the samples were inferred by comparing the differences between the extracts. The results show that aromatics with one or several benzene rings and their derivatives; and some long-chain alkanes containing oxygen decreased in the methanol-, acetone-, and THF-soluble fraction from residual lignite, whereas long chain or a few branched alkanes and small quantities of aromatic compounds increased in petroleum ether and CS 2 soluble fractions. © 2012 Published by Elsevier B.V. on behalf of China University of Mining and Technology.

Zheng X.,Key Laboratory of Deep Coal Resource Mining | Feng X.,Key Laboratory of Deep Coal Resource Mining | Zhang N.,Key Laboratory of Deep Coal Resource Mining | Zhang N.,Hunan University of Science and Technology | And 2 more authors.
Arabian Journal of Geosciences | Year: 2015

Bolt supports within stratified strata in coal mines contribute to the unique characteristics of low-buried engineering structures such as tunnels or subways. Failure at the bolt interface is the main trigger of support failure in such settings. This paper comprehensively investigates the serial decoupling mechanism at a resin–rock interface, which is a process that occurs frequently in stratified strata. There are, however, different evolutionary processes that exist at the interface, from a total bonding stage to a plastic bonding stage, a slippage plastic bonding stage, a slippage plastic stage and a total slippage stage, sequentially. These processes accelerate the shortening speed of anchor life, whereupon axial force will fluctuate at each stage and corresponding equations can be derived successfully. Finally, a long-term field monitoring test which verifies the theoretical results and effective measures, such as pregrouting, can be used to prevent serial decoupling. The service life of the bolt system also can be prolonged. © 2014, Saudi Society for Geosciences.

Zhou L.,Key Laboratory of Coal Processing and Efficient Utilization | Zong Z.-M.,Key Laboratory of Coal Processing and Efficient Utilization | Tang S.-R.,Key Laboratory of Coal Processing and Efficient Utilization | Zong Y.,Key Laboratory of Coal Processing and Efficient Utilization | And 8 more authors.
Energy Sources, Part A: Recovery, Utilization and Environmental Effects | Year: 2010

Bio-oil prepared from flash pyrolysis of rice stalk around 500C was upgraded by filtration and catalytic esterification. Both raw and upgraded bio-oils were observed with an optical microscope. The upgraded bio-oil was extracted with benzene, carbon disulfide, hexane, and carbon tetrachloride, respectively, and the soluble fractions were analyzed with FTIR and GC/MS. In addition, ion trap mass spectrometer was used for analysis of the benzene-soluble fraction. The results show that the upgrading substantially improved the dispersity of organic droplets in the bio-oil and completely removed char particles from the bio-oil, but heavy species are still the main components in the upgraded bio-oil; the soluble fractions contain aliphatic, benzene-ring-containing, ester, and bonded hydroxyl moieties, and methoxy-containing species are the most abundant GC/MS-detectable compounds.

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