Flotation Characteristics and Particle Size Distribution of Micro-fine Low Rank Coal

AbstractIn this work, attempts to float the micro-fine low rank coal and its particle size distribution in the flotation were made. Then, standard screening, FT-IR, XRD and SEM were adopted to characterize the size distribution and flotation of micro-fine Shendong low rank coal. The results indicated that the size fraction of -0.045mm was the dominant size fraction in raw coal with a yield of 91.65% and ash content of 46.25%. Flotation of Shendong low rank coal required a larger dosage of collector, 50kg/t of diesel oil, to achieve a higher combustible matter recovery (63.25%) and flotation efficiency index (40.70%) accompanied with a significant decrease in ash content (22.44 percentage points) due to the hydrophilicity of coal surface. Under this condition, concentrate contained 83.38% of -0.045mm size fraction (38.04% of total particles in feed) with ash content of 24.98%. In comparison, tailing was almost consisted of -0.045mm fraction (93.63%) with a higher ash content of 60.82%. It seems that the higher ash particles in feed were largely migrated in tailing at a proper collector dosage. The analysis of FT-IR, XRD and SEM would contribute to the understanding of the flotation and size distribution

Progress of the technique of coal microwave desulfurization

Abstract With the advantages of its fast speed, effective and moderate controllable conditions, desulfurization of coal by microwave has become research focus in the field of clean coal technology. Coal is a homogeneous mixture which consists of various components with different dielectric properties, so their abilities to absorb microwaves are different, and the sulfur-containing components are better absorbers of microwave, which makes them can be selectively heated and reacted under microwave irradiation. There still remain controversies on the principle of microwave desulfurization at present, thermal effects or non-thermal effects. The point of thermal effects of microwave is mainly base on its characters of rapidly and selectly heating. While, in view of non-thermal effect, direct interactions between the microwave electromagnetic field and sulfur containing components are proposed. It is a fundamental problem to determine the dielectric properties of coal and the sulfur-containing components to reveal the interaction of microwave and sulfur-containing compounds. However, the test of dielectric property of coal is affected by many factors, which makes it difficult to measure dielectric properties accurately. In order to achieve better desulfurization effect, the researchers employ methods of adding chemical additives such as acid, alkali, oxidant, reductant, or changing the reaction atmosphere, or combining with other methods such as magnetic separation, ultrasonic and microorganism. Researchers in this field have also put forward several processes, and have obtained a number of patents. Obscurity of microwave desulfurization mechanism, uncertainties in qualitative and quantitative analysis of sulfur-containing functional groups in coal, and the lack of special microwave equipment have limited further development of microwave desulfurization technology

Bioleaching Mercury from Coal with <i>Aspergillus flavus</i> M-3

This study focuses on the utilization of Aspergillus flavus(M-3) for the bioleaching mercury from coal, offering an alternative and environmentally to its clean utilization. The fungus was isolated from the soil near a high mercury coal mine in Lao Ying Shan (LYS), Guizhou. Utilizing direct mercury analysis, X-ray diffraction (XRD), and Fourier Transform-Infrared (FT-IR) analysis techniques, the transformation of mercury speciation, mineral components, and organic groups in the coal were analyzed before and after the bioleaching process. The findings of the study illustrated that the fungus M-3 exhibited a remarkable capacity for coal bioliquefaction and mercury leaching from LYS coal. Following a 15-day bioleaching process, a remarkable mercury leaching rate of 83.79% was achieved. Various forms of mercury speciation, including residue, organic matter, sulfide-bound, oxide-bound, exchangeable, and carbonate-bound forms, were released from the coal, with leaching rates ranging from 80.41% to 92.60%. XRD analysis indicated that the M-3 strain facilitated the dissolution of coal pyrite and the degradation of macromolecules, effectively loosening the coal structure. FT-IR analysis of raw and residual coal demonstrated the breakdown of the aromatic ring structure and introduced oxygen-containing functional groups by M-3. Overall, this study highlights the efficacy of bioliquefying coal using Aspergillus flavus (M-3) as a method for clean coal utilization while simultaneously bioleaching mercury

Species Delimitation in the Genus Moschus (Ruminantia: Moschidae) and Its High-Plateau Origin.

The authenticity of controversial species is a significant challenge for systematic biologists. Moschidae is a small family of musk deer in the Artiodactyla, composing only one genus, Moschus. Historically, the number of species in the Moschidae family has been debated. Presently, most musk deer species were restricted in the Tibetan Plateau and surrounding/adjacent areas, which implied that the evolution of Moschus might have been punctuated by the uplift of the Tibetan Plateau. In this study, we aimed to determine the evolutionary history and delimit the species in Moschus by exploring the complete mitochondrial genome (mtDNA) and other mitochondrial gene. Our study demonstrated that six species, M. leucogaster, M. fuscus, M. moschiferus, M. berezovskii, M. chrysogaster and M. anhuiensis, were authentic species in the genus Moschus. Phylogenetic analysis and molecular dating showed that the ancestor of the present Moschidae originates from Tibetan Plateau which suggested that the evolution of Moschus was prompted by the most intense orogenic movement of the Tibetan Plateau during the Pliocene age, and alternating glacial-interglacial geological eras

Investigation of the induction time of low-rank coal particles on rising bubble surfaces

<p>In this paper, the back-calculated induction times of low-rank coal particles on the rising bubble with mobile surfaces were back-calculated from the micro-flotation rate constants. The back-calculated induction times slightly increased with the flotation recovery increase or the surfactant concentration decrease. It is because the drainage time accounting for most of the induction time is affected by the force exerted on the wetting film. Moreover, the force exerted on the wetting film is characterized by the Reynolds number. Furthermore, the Reynolds number increased with increasing bubble rising velocity due to an increase in bubble size as a result of decreasing surfactant concentration. Therefore, the back-calculated induction times could reflect the difference in the flotation recoveries at the same surfactant concentration. Meanwhile, it indicated that the hydrodynamic condition in the flotation process had a significant effect on the back-calculated results of induction times. From this investigation, it can be speculated that the back-calculated induction time of particles sliding on the rising bubble with mobile bubble surfaces is greatly influenced by the Reynolds number.</p

Formation and preservation of ultra-deep liquid petroleum in the Ordovician sedimentary succession in Tarim Basin during the neotectonic phase

[Display omitted]•Neotectonism led to abnormally rapid subsidence and high temperatures.•Insufficient time at high temperatures controls the preservation of liquid petroleum.•The concentration ratios and isomerization ratios of diamondoid can be used for oil-source correlation.•Gas invasion affects the effectiveness of diamondoid proxies for maturity evaluation.The transformation of liquid petroleum to natural gases is accelerated at increasing depths and temperatures. Natural gas exploration predominantly focuses on deep layers. However, the ultra-deep petroleum (maximum burial depth of ∼ 7110 m and reservoir temperature of ∼ 166℃) in the Ordovician sedimentary succession in Tarim Basin has been found to remain in a liquid phase without cracking, and their mechanisms of formation and preservation are unclear. This study performed integrated high-resolution comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC–TOFMS), gas chromatography-mass spectrometry (GC–MS), stable carbon isotopes, and fluid inclusions. The similar molecular compositions and low δ13C values of n-alkanes (−36.0 ‰ to − 33.0 ‰) suggest that the oils are derived from the Cambrian Yuertusi Formation, with moderate thermal maturity (0.8–0.9 %) without distinct cracking. The low variety and abundance of diamondoids, narrow distribution of diamondoid proxies (concentration ratios and isomerization ratios) as well as lack of thiadiamondoids and ethanodiamondoids support this interpretation. The main charging period was the Late Hercynian orogeny, as evidenced by fluid inclusions and the burial model. Abnormally rapid subsidence during the neotectonic phase (age < 5 Ma) in Tarim Basin led to an abrupt temperature rise, reaching the cracking threshold for crude oils. The uncracked oil could be attributed to a limited time of burial at high temperatures. The neotectonism activated the earlier fault systems, connecting source rocks and reservoirs, and facilitating the migration of trace amounts of gas from deeper layers. Therefore, the ultra-deep strata still have high exploration potential for liquid petroleum

The species delimitation results based on the complete mt genome in <i>Moschus</i>.

<p><b>Note: (1)</b> Ml, Mf, Mc, Mm, Mb, Ma represents <i>M</i>. <i>leucogaster</i>, <i>M</i>. <i>fuscus</i>, <i>M</i>. <i>chrysogaster</i>, <i>M</i>. <i>moschiferus</i>, <i>M</i>. <i>berezovskii</i> and <i>M</i>. <i>anhuiensis</i>, respectively. <b>(2)</b> “Tree1”, “Tree 2”, “Tree 3”, “Tree 4”represents “(Mc, (Mm, (Mb, Ma))) or ((Ml, (Mc, Mf)), (Mm, (Mb, Ma)))”, “(Mm, (Mc, (Mb, Ma))) or (Mm, ((Ml, (Mc, Mf)), (Mb, Ma)))”, “((Mm, Mc), (Mb, Ma)) or ((Mm, (Ml, (Mc, Mf))), (Mb, Ma))”, “(Mc, (MbMa, Mm)) or ((McMf, Ml), (Mm, (Mb, Ma)))”, respectively.</p><p>The prior distributions were fixed on θ (1: 2000) and τ (1: 10).</p

Geographic distribution of <i>Moschus</i> species and consensus mitochondrial gene tree.

<p>Tree is equivalent to that of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134183#pone.0134183.g003" target="_blank">Fig 3</a>. All the information about geographic distribution of <i>Moschus</i> species were came from IUCN (<a href="http://www.iucnredlist.org/" target="_blank">http://www.iucnredlist.org/</a>), except a new distribution area of <i>M</i>. <i>berezovskii</i>, which was marked by a star [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134183#pone.0134183.ref039" target="_blank">39</a>].</p