Split flotation of LVMC coal to generate multiple products for complete utilization

A low volatile medium coking coal from Jharia coal field, India was used for this investigation. The proximate analysis of the sample shows that it contains about 25% ash, 21.4% volatile matter and 52.4% fixed carbon. The sizewise ash analysis of -0.5 mm coal indicates that -0.5+0.15 mm fraction contains lower ash (21.9%) than -0.15 mm fraction (29.7%). The flotation characteristics of the -0.5 mm coal were determined by release analysis. The study reveals that recovery of combustible at 15% ash is about 27% and 43% at 17% ash level. The low recovery is due to the presence of high ash in finer fraction. In order to improve the recovery, the -0.5 mm feed was classified into -0.5+0.15 mm and -0.15 mm fractions, and subjected to flotation separately. The recoverable combustible obtained from the release analysis of -0.5+0.15 mm at 15% ash level is 46%. The effect of collector dosage, frother dosage and aeration rate on flotation was studied. The responses of these variables in collectorless flotation of the -0.5+0.15 mm fraction containing low ash were also studied. A lower aeration and frother dosage favored the generation of clean coal with low ash. The ash content in the tailing stream from -0.5+0.15 mm flotation circuit is close to that of the original -0.15 mm fraction. The former is ground to -0.15 mm and the two fractions are processed together. As -0.15 mm fraction contains relatively higher ash, collector aided flotation using sodium silicate was performed to recover the clean coal with 17% ash. The products of the overall flotation circuit having different ash levels were recommended for use in different applications. The reject from -0.15 mm flotation circuit contained 56.4% ash which can be used for fluidized bed combustion (FBC). This eventually leads to complete utilization of coal

Effective flotation of weathered coal using frother blend

Froth flotation of weathered coal is a challenging task in a conventional flotation cell using commonly used collector and frother. Generally weathered coal shows the erratic flotation behaviour due to the surface oxidation as it makes the coal surface hydrophilic. When the surface gets oxidized, surface modifier is employed to float the clean coal. Frothers play significant role in stabilizing the mineralized bubble. It reduces the bubble size by reducing the interfacial tension at the air water interface. During this investigation, the flotation was carried out with two types of frothers namely; methyl isobutyl carbinol (MIBC), a weak frother and a strong polyglycol type. The Factorial design matrix was used for carrying out the experiments with the different ratio of frother blend, collector and promoter dosage. The high concentration of MIBC is found to be not effective for recovering the significant amount of carbon value as it causes less reduction of the interfacial tension at the air-water interface. The presence of a correct dosage of strong frother with weak one dramatically improves the flotation behaviour as it stabilizes the air-water interface and also reduces the consumption of the frothers

Advanced Coal Cleaning Technology for Challenges in Near future

Beneficiation potential of a high ash (36%) medium coking coal to a low ash (12%) level is investigated. Characterization studies indicated that the coal must be processed after reducing the size to 1.18 mm in order to accomplish substantial yield of the clean coal. A gravity based flowsheet for the -1.18+0.5 mm fraction is developed to generate clean coal at 12% ash with 9.2% overall yield. Mechanical cell flotation circuit for the -0.5+0.15 mm size fraction resulted in additional 3.5% yield at the desired ash level. A flotation circuit for the fine fraction (-0.15 mm) is developed using Jameson Cell only that added further 3.0% yield in the overall mass recovery at 12% ash. Thus, a total of 15.7% yield of the clean coal with 12% ash is achieved by treating various size classes separately. Recycling of some of the intermediate product streams is recommended for continuous operation to enhance the overall yield of the clean coal significantly

Balance Your Work-Life: Personal Interactive Web-Interface

The term work-life balance can be described as a path to manage stresses and burnouts in the workplace. In this Covid-19 pandemic, work-from-home practice includes both personal and professional spaces as employees, more often, stay digitally connected. As a result, personal life hardly can be separated, which will potentially create imbalanced life, which creates problems regarding physical and mental health of the employees. In such unprecedented situations, we are required to maintain and/or integrate balanced work-life. A balanced work-life gives employees a stress-free environment to work and improves employees' mental and physical health conditions and relationships. In this study, we focus on maintaining a proper work-life balance through a monitoring tool, the ‘Wheel of Life.’ Considering the drastic changes in work culture (due to Covid-19, for example), we introduce an interactive interface based on ‘Wheel of life’ concept. Our interface helps tune various important factors, such as business, creative, social, love and life purpose, and provides multiple recommendations. The purpose of the study is to assist web users to balance their work-life, improve psychological well-being and quality of life in this unforeseen situation

Recovery of Iron Values from Waste Manganiferous Iron Ore Fines for Pellet Making

A large volume of overburden and mine wastes is generated during the extraction and beneficiation of the low grade ores. The waste low grade manganiferous iron ore fine from southern part of India was studied for recovery of iron values. The chemical assay of the sample is 52.36% Fe, 4.75% Mn, 8.5% SiO2 and 2.82% Al2O3. The characterization study of the sample indicates the presence of microplaty hematite, goethite, pyrolusite, cryptomelane with minor amount of quartz and kaolinite. The beneficiation study of the sample does not respond to the conventional route of desliming the ground feed followed by gravity separation and magnetic separation. Therefore, an alternative technique of reduction roasting using a producer gas was attempted at different conditions. The characterization of roasted product reveals the phase transformation to magnetite and microplaty magnetite. The low intensity magnetic separation conducted with the roasted products generated at optimal condition shows that 70% concentrate having 64.5% Fe and 1.87% Mn could be produced. The high manganese in the concentrate works as an additive for making pellet with enhancement in pellet strength and drop in reducibility. Utilization of mines waste has significant impact on mineral resources and environmental hazard

Characterisation of Residual Stress in Electron Beam Welded P91 Plates by Neutron Diffraction

Abstract This paper describes the characterisation of residual stress in electron beam welded P91 ferritic -martensitic steel plates (9 mm thick) by neutron diffract ion. The novelty of the work lies in revealing the residual stress profile at a fine length scale associated with a ~ 1 mm wide fusion zone. A characteristic 'M' shaped distribution of stresses across the weld line is observed with high tensile peaks situated just beyond the HAZ/parent material boundary. Measured stresses close to the weld centre-line are significantly less tensile than the adjacent peaks owing to martensitic phase transformat ion during cool-down of the weld region. The effect of applying a second smoothing electron beam weld pass is shown to be undesirable because it increases the tensile magnitude and spread of residual stress

Asymmetric rotations and dimerization driven by normal to modulated phase transition in 4-biphenylcarboxy coupled L-phenylalaninate

Amongst the derivatives of 4-biphenylcarboxylic acid and amino acid esters, the crystal structure of 4-biphenylcarboxy-(L)-phenylalaninate is unusual owing to its monoclinic symmetry within a pseudo-orthorhombic lattice. The distortion is described by disparate rotational property around the chiral centers ($\varphi_{\mathrm{chiral}}$ $\simeq$ -129 degrees and 58 degrees) of the two molecules in the asymmetric unit. Each of these molecules comprise of planar biphenyl moieties ($\varphi_{\mathrm{biphenyl}}$ = 0 degrees). Using temperature dependent single crystal X-ray diffraction experiments we show that the compound undergoes a phase transition below $T$ $\sim$ 124 K that is characterized by a commensurate modulation wave vector, $\mathbf{q}$ = $\delta(101)$, $\delta$ = $\frac{1}{2}$. The (3+1) dimensional modulated structure at $T$ = 100 K suggests that the phase transition drives the biphenyl moieties towards non coplanar conformations with significant variation of internal torsion ($\varphi^{\mathrm{max}}_{\mathrm{biphenyl}}$ $\leq$ $20$ degrees). These intramolecular rotations lead to dimerization of the molecular stacks that are described predominantly by intermolecular tilts and small variations in intermolecular distances. Atypical of modulated structures and superstructures of biphenyl and other polyphenyls, the rotations of individual molecules are asymmetric ($\Delta$$\varphi_{\mathrm{biphenyl}}$ $\approx$ 5 degrees) while $\varphi_{\mathrm{biphenyl}}$ of one independent molecule is two to four times larger than the other. Crystal-chemical analysis and phase relations in superspace suggest multiple competing factors involving intramolecular steric factors, intermolecular H--C${\cdot}{\cdot}{\cdot}$C--H contacts and weak C--H${\cdot}{\cdot}{\cdot}$O hydrogen bonds that govern the distinctively unequal torsional property of the molecules

Molecular heterogeneity of plpE gene in Indian isolates of Pasteurella multocida and expression of recombinant PlpE in vaccine strain of P. multocida serotype B: 2

Outer membrane proteins of Pasteurella (P.) multocida have been known to be protective immunogens. Pasteurella lipoprotein E (PlpE) has been reported to be an important cross reactive outer membrane protein in P. multocida. The gene encoding the PlpE of P. multocida serotypes A: 3, B: 2 and D: 1 was amplified from the genomic DNA. The amplified products were cloned and the nucleotide sequence was determined. Sequence analysis of the recombinant clones revealed a single open reading frame of 1,011 bp, 1,008 bp and 1,017 bp encoding a protein with a calculated molecular mass of 37.829 kDa, 37.389 kDa and 37.965 kDa for serotypes A: 3, B: 2 and D: 1 respectively. The comparison of the plpE sequence in different capsular types revealed a high degree (>90%) of homology. Furthermore, the plpE gene of Haemorhhagic septicaemia causing serotype (B: 2) was expressed in E. coli and recombinant PlpE was strongly immunostained by antiserum against whole cell antigen, indicating that the protein is expressed in vivo