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Demineralization of high ash non-coking coal fines of Indian origin using Castor oil: Implications of wet milling
No full textThe high-ash low-grade coals of Indian origin are relatively more challenging to demineralize due to their unfavorable hydrophilic surface chemistry. Herein, we report castor oil as a potential bridging liquid, which efficiently agglomerated high-ash low-grade coals by 55-60% at lower concentration (10 wt%) compared to literature (20-25 wt%), without inclusion of surfactants. A blend of castor oil and turpentine oil proved further beneficial. Wet milling of coal was a crucial prerequisite for efficient agglomeration. Three low-grade coals, Bhubaneshwari (35.8% ash), Kaniha (35% ash), and Hingula (26% ash), were beneficiated in the present study. A detailed analysis of process parameters validated with structural characterization using FTIR, Petrography, zeta potential, and SEM analysis was performed. The chemistry between ricinoleic acid in castor oil with that of surface functionality of coal is speculated to be the reason behind the obtained agglomeration results. Castor oil, being non-edible, bio-based, non-toxic, and non-polluting in nature, provides a greener alternative to mineral oils toward the production of clean fuel
Microstructure and Mechanical Properties of Al/Cu-p/SiCp/TiCp-Based Hybrid Composites Fabricated by Spark Plasma Sintering
No full textAluminum-based hybrid composites with new combinations of both hard ceramic particulates (5-10 wt.% SiC and 5-10 wt.% TiC) and ductile metallic (27 wt.% Cu) reinforcements are successfully synthesized via spark plasma sintering route to achieve significantly high specific hardness and specific modulus. The synthesized hybrid composites exhibit an adequate consolidation with marginal porosity and a clean particle-matrix interface, ensuring better particle-matrix bonding. Detailed microstructural characterization by electron microscopy and X-ray diffraction analysis further reveals that metallic copper particles could be successfully incorporated with marginal intermetallic formation by the interfacial reaction. Mechanical properties have been evaluated by macro-hardness and depth-sensing nano-indentation measurements. Among the fabricated ones, the Al-27wt.% Cu-p-5wt.%SiCp-5wt.% TiCp hybrid composite exhibits impressively high specific hardness (35 VHN/gcm(-3)), specific Young's modulus (33.9 GPa/gcm(-3)), and very high bulk modulus (28.2 GPa/gcm(-3)) when compared with the Al-based composites reported in the literature. This is attributed to the evolution of a novel microstructure consisting of SiC, TiC, and Cu particulates in a highly sub-structured aluminum-based matrix with a significant amount of dislocation density (6.6x10(14) m(-2)). The elasto-plastic characteristics of the matrix are further explored through the depth-sensing nano-indentation technique
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A review on characteristics of silico-manganese slag and its utilization into construction materials
No full textThis paper reviews the potential use of silico-manganese slag (SiMnS) as binder and aggregate in Portland cement and geopolymer concrete. SiMnS is a byproduct of alloy steel production. Depending on the process of solidification, the slag is available in crystalline hard stone type and granulated glassy form. The latter one is more reactive due to the presence of amorphous phases. Therefore, granulated slag has been mostly used as supplementary cementitious material, either blending with clinker or as a precursor for alkali activated binder. Whereas the former is less reactive, and has been mostly used as aggregate, which can enhance the properties of the concrete. The reactive component such as CaO and SiO2 improve the binding capability of the cement gel. The leaching of toxic and heavy metals from the SiMnS reacted binder matrix is not reported. This paper also highlights the future potential of this slag by a process called slag engineering to modify its chemistry similar to granulated blast furnace slag (GBFS), to be utilized more effectively
Membrane distillation crystallization for simultaneous recovery of water and salt from tannery industry wastewater using TiO2 modified poly (vinylidene fluoride-co-hexafluoropropylene) nanocomposite membranes
No full textMembrane distillation crystallization (MDCr) is a promising technology for simultaneous water recovery and salt crystallization from tannery industry wastewater. We synthesized TiO2 modified poly(vinylidene fluoride-cohexafluoropropylene) (PVDF-HFP) nanocomposite flat sheet membranes to treat tannery industry wastewater by MDCr. The influence of TiO2 nanoparticles morphologies on membrane performance (salt rejection and water flux) was investigated. The nanocomposite membranes were analyzed for surface morphology, thermal stability, porosity, water flux, and salt rejection. It was demonstrated that the TiO2 modified PVDF-HFP nanocomposite membrane showed improved hydrophobicity, porosity and number of pores; thus, water flux significantly increased without any deterioration in salt rejection. Among different membranes, decanoic acid-modified TiO2 nanoparticles (bipyramidal morphology) nanocomposite membrane (M-1B) showed 6.1 kg m(-2) h(-1) water flux with similar to 100% salt rejection with mixed synthetic salt solution (1% NaCl and Na2SO4, each) feed. Using real tannery industry wastewater, the M-1B membrane showed 5.9 kg m(-2) h(-1) water flux and 99.97% salt rejection. The crystallization of salts revealed cubic NaCl crystals and monoclinic Na2SO4 crystals in the wastewater. The XRD spectra revealed a high purity of salts and ruled out any co-crystallization. These findings suggested the potential candidature of the M-1B membrane for the treatment of tannery industry wastewater by the MDCr process. The recovered salt and water can also be re-used in the tannery industry
Effect of Lead and Antimony on Sulfuric Acid Leaching of Copper in Speiss from Top Submerged Lance Furnaces
No full textCu-Pb and Cu-Sb alloys were prepared at various ratios, from 10:90 to 90:10, and leaching tests with sulfuric acid were conducted to investigate the effect of Pb and Sb on the leaching of Cu from speiss, which is obtained from the top submerged lance furnace process. The Cu leaching efficiency increased as the amount of Cu increased in both alloys, but the leaching efficiencies were lower in the Cu-Sb alloy than in the Cu-Pb alloy. For example, in alloys with 70% Pb and Sb ratio, the leaching efficiency of Cu from the Cu-Pb alloy increased to 95%. The leaching efficiency of the Cu-Sb alloy was 67% in 2 mol/L sulfuric acid solution with 1% pulp density and 1000 cc/min O2 at 90 °C, 400 rpm, and 6 hours. When the leaching residues were examined with SEM (scanning electron microscopy)-EDS (Energy-dispersive X-ray spectroscopy), it was found that in all Cu-Pb alloys, Cu and Pb exist as independent metal phases, while, in Cu-Sb alloys, Cu formed intermetallic compounds with Sb such as Cu2Sb, because the Cu-Sb alloy has a lower melting point than the Cu-Pb alloy. These results suggest that Sb may retard the leaching rate of Cu from the alloy. When the leaching residue of speiss obtained from a top submerged lance furnace, intermetallic alloys of Cu-Sb were also observed, having a net structure. The net structure contains Cu metal in the center of the speiss particle, while the intermetallic alloys of Cu-Sb were present in the outer layer of the particle, in good agreement with the results using the alloys in this study. This suggests the intermetallic alloys of Cu-Sb can prevent copper from leaching
Aligning Individual and Organizational R&D Goals for Self-Sustainability: Investigating Preferences of Researchers in Selected CSIR-Laboratories, India
Get PDFThis paper intends to explore the measure for aligning the goals of researchers towards achieving organizational R&D targets. The paper also explores the significance and ordering of R&D outputs and the factors that influence generation of R&D outputs, from the perspective of researchers working in the Indian public sector organizations.
Data was collected in five Indian R&D laboratories and Weighted Average Method; Spearman Correlation Coefficient and Rank Regression were utilized for the analysis.
The findings indicated that various groups of researchers prefer to target different R&D outputs and not all the factors are considered as equally significant in influencing the generation of R&D outputs. Further, the R&D organization should include preferred real factors while policy making for achieving collaborative efforts towards fulfilling organizational objectives. The set of selected R&D outputs and influencing factors were also ordered according to the average rankings given by the researchers.
The findings can help R&D managers to identify the expectations of the researchers and include their preferences in R&D Planning. The study could be extended to a larger dataset of researchers working in other government as well as private R&D organizations.
Hardly any studies were found that explored the preferences of researchers with respect to R&D outputs and influencing factors with respect to the Indian public sector R&D laboratories.
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Final Published Version is available at: DOI (10.1108/IJPPM-12-2019-0556)
Citation
Kumari, B., Sahney, S. and Madhukar, A. (2021), "Aligning individual and organizational R&D goals for self-sustainability: investigating preferences of researchers in selected CSIR laboratories, India", International Journal of Productivity and Performance Management, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/IJPPM-12-2019-055
Green process for recovery of vanadium from hazardous spent contact process catalyst by oxalic acid: kinetics and mechanism
No full textThis work aims to develop a green method for the recovery of vanadium from spent contact process catalyst (SVC) with 6–7% V2O5. The efficiency of leaching was evaluated using oxalic acid by varying pulp density, time, particle size, and temperature. It is found that with 0.25 M of oxalic acid, almost 98% V, 42% Fe and 24% Al was recovered in 2 h at 323 K and pulp density of 20% using <50 µm particle size. The leaching kinetics and mechanism was further established by characterizing the feed and residues by XRD and SEM. Separation of vanadium was performed using ion-exchange and precipitation
A comparative study on environmental impact analysis of synthetic and ESR flux used for refining of steel
No full textas to improve the mechanical property and performance of steel during critical applications. Similarly, Electro Slag Remelting (ESR) fluxes are
used during the remelting of steel ingots in the ESR process for refining purpose. These fluxes have been manufactured by mixing the various
slag components or fusing them at a high temperature. Both of these manufacturing methods have pros and cons during refining of steel. This
investigation focuses on the life cycle assessment of different manufacturing processes of fluxes for steel refining. The major objective of this
investigation is to perform an analysis of environmental impact assessment of the processes. A detailed comparison of the environmental
impact has been carried out and discussed relative to the contribution of different unit steps involved in the manufacturing stage for the cradle to-
gate analysis. The results indicate that energy consumption as well as environmental impact is significant for the mixer and furnace heating
step during production of refining fluxes for the steel industry
The Pros and Cons of an Energy-Efficient Q&P Approach to Develop Advanced Steels
No full textThe development of steels with increasing strength levels, while retaining a sufficient ductility and toughness, has been the major focus area of research in recent times. These property combinations can be achieved by (i) tailoring and enriching the composition, e.g. TWIP and austenitic stainless steels, (ii) optimization of processing parameters and (iii) employment of novel processing route, etc. The higher alloying additions to steel lead to increased cost and pose difficulty in casting, rolling, welding, fabrication, etc. Therefore, it is of significant importance to achieve higher strength levels in low alloy steel compositions with the help of novel processing routes. One such approach is quenching and partitioning (Q&P) process, which leads to the stabilization of retained austenite in a martensitic matrix. Some of the recent studies have also shown the presence of bainite and carbides, in addition to the retained austenite and martensite, leading to a multiphase microstructure at room temperature. The Q&P process involves austenitization, hot rolling, quenching in the Ms–Mf range, followed by isothermal holding and cooling to room temperature. The isothermal holding helps in the partitioning of supersaturated carbon in the martensite to the remaining austenite, which leads to the stabilization of austenite and its retention at room temperature. As an alternative, the extremely slow cooling of a hot-rolled coil, after the quenching at the run-out table, can also be used for this purpose, eliminating the need for an extra arrangement for isothermal holding. In view of the above, the present paper describes the pros and cons of the application of this energy-efficient Q&P approach to low alloy steels