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Development of carbon composite iron ore slime briquettes for using in ironmaking
No full textIron ore slime is a micro-fine of size below 20 µm in majority and rich in alumina and silica. It is
neither suitable for pelletization nor sintering. Jhama coal is not also used in the iron making because of its poor
caking property and thermal stability of lump. Therefore, the composite fluxed briquettes in a combination of
these two materials were made to use this in low shaft furnace or mini blast furnace wherein, Jhama coal will
be acting as a reducing agent and heat source, which may replace the use of costly metallurgical coke in the
subsequent iron making process. The present work develops a process for making composite briquettes with
slime and Jhama coal with a fluxing agent without any external binder or very little amount of binder to replace
the fluxing agent. The developed briquettes provide sufficient strength of up to 104 kg/cm2
, 70% reducibility index, 28% reduction degradation index, and good metallization after reduction which shows its suitability for low shaft furnace or mini blast furnac
Copper/manganese oxide catalyzed regioselective amination of quinoline N-oxides: An example of synergistic cooperative catalysis
No full textAn atom economical and efficient protocol for C-2 amination of quinoline N-oxides using our synthesized recyclable heterogeneous Cu–MnO catalyst has been reported here. Direct Csingle bondH aminations of heterocyclic N-oxides with secondary amine were carried out under base, and ligand-free conditions in good to excellent yields. The major advantage is that air is used as a sole oxidant and our catalyst is recycled several times
Feasibility study of iron ore fines beneficiation by shallow bed air fluidized separator
No full textMagnetic separation, dense media suspension fluidization techniques are tested for dry beneficiation of iron ore fines presently and found to have limitations. In the present study, the potential of shallow bed air fluidized separator (SBAFS), which does not have any suspension media and has high throughput is investigated for iron ore fines beneficiation. A set of experiments was designed by response surface methodology. Three parameters air flow rate, vibration frequency, and side tilt were considered for the experimentation. The individual effects of these factors and their interaction on yield and grade of concentrate products were studied. Experimental results show that grade of iron ore fines was enhanced by 5.5% in single stage operation with reasonable yield. Experimental results indicate that SBAFS has a huge potential for iron ore fines beneficiation with the added advantage of the reduction of water consumption during the beneficiation process. In order to understand the segregation of iron ore fines on SBAFS, mathematical equations were derived from the first principle of the force balance equation. Particle trajectories of different densities of mineral phases in iron ore fines were estimated by using the developed model. Simulation of particle trajectories was carried out by MATLAB software
Hydrometallurgical processing of waste integrated circuits (ICs) to recover Ag and generate mix concentrate of Au, Pd and Pt
No full textPresent research reports a novel and feasible process to recover Ag and generate concentrate of precious metals (Au, Pd and Pt) from waste ICs present in PCBs of computers. Initially, depopulated ICs were pulverized and beneficiated to obtain metallic concentrate, which contained (per ton) 7 Kg Ag, 5 Kg Au, 110 g Pd and 4 g Pt along with Cu, Pb, Fe and Ni. Leaching was carried out and found that at optimized
condition i.e. 3 M HNO3, temperature 80 C, pulp density 50 g/L and mixing time 1 h, >90% of Ag, Cu, Pb and Ni were leached leaving Au, Pt and Pd in the residue. From the leach liquor, Ag was precipitated using 1 M KCl in 30 min and other metals were recovered by precipitation, solvent extraction and cementation methods. All wastes (solid/ liquid) generated during process development could be treated using standard environmental procedure
Development of synthetic slag for desulphurisation of the steel during steelmaking in induction furnace
No full textCurrently, steel production through induction furnace is nearly 30% of total steel production in the world. However, steel produced through induction furnace routes contains high sulphur (0.06 to 0.1 wt %) which is not acceptable for the structural steels. Therefore, it is imperative to develop the synthetic slag for desulphurisation of the steel in the induction furnace. The slag properties such as sulphide capacity, sulphur partition ratio, viscosity, liquidus temperature, the solubility of components, basicity are considered to design synthetic slag for desulphurisation of the steel in the induction furnace. Developed synthetic slag is consist of 20-30 wt% SiO2, 5-20 wt% Al2O3, 40-60 wt% CaO, 5-10 wt% MgO. The evaluation of synthetic slag is performed in the induction furnace for desulphurisation of plain carbon and alloy steel. The maximum degree of desulphurisation is 84 % with the addition of 2-3 wt % synthetic slag in the induction furnace for Al killed steel while 32 % for non –killed steel is achieved. The desulphurisation time to achieve the sulphur level (0.03-0.04) is 10 minutes in the induction furnace using developed synthetic slag (2-3 wt % liquid metal). Sulphur partition (Ls, e) and sulphide capacity of synthetic slag increase with basicity of the developed synthetic slag
On the through-process texture evolution assessment in grain oriented Fe-3 wt% Si steel produced by a novel directional inoculation technique
No full textA novel directional inoculation technique has been designed to cast thin slab ingots containing Goss (or near Goss) oriented components in the as cast microstructure under the combined effect of oriented nucleation and oriented growth. The same has been targeted so as to retain Goss orientations and simultaneously develop gamma fiber components (ranging from {111}0>to {111}) during hot rolling. The designed scheme of directional inoculation achieved oriented nucleation by the effect of exogenously added soft magnetic inoculants under magnetic field and oriented growth by the effect of fast cooling rates prevailing in the mould. The choice of 65Fe-35Co (wt%) system as soft magnetic inoculants was made taking into account the similarity in crystal structure and lattice parameter. The chemically synthesized inoculants under the effect of external magnetic field during solidification were able to exhibit directional inoculation. Variation in the cast microstructure and microtexture by varying the extent of inoculant addition was studied by EBSD technique. The ingots cast under different conditions were subjected to a designed hot rolling schedule and the through process microstructural and microtextural evolution was assessed. It was observed that fine equiaxed grains with initial cube orientations in the as cast structure could lead to the most desirable microstructural as well as microtextural gradient in the hot band
Exploratory studies on beneficiation of low-grade Banded Iron ore Formations (BIF) of Karnataka, India
No full textIron ore is the basic raw material for production of metallic iron. With depletion of high-grade resources and fine dissemination of valuable minerals in the abundantly available low-grade banded iron ore formations (BIF), liberation is achieved at finer sizes. Hence, it necessitated all beneficiation techniques to be operated at this finer size. However, physical separation techniques have limitations in separation efficiency. A combination of pre-concentration technique such as magnetic separation followed by flotation of magnetic fraction proved to be promising in achieving the respectable grade. A low-grade iron ore sample (BIF) of Karnataka, India was subjected to high intensity magnetic separation followed by flotation for enhancing its grade and recovery. Laboratory scale studies on this ore assaying 39.80 Fe%, 39.62 SiO2% and 1.73 Al2O3% indicated that it could be improved to 63.78 Fe%, 3.10 SiO2% and 1.01 Al2O3% at an overall iron recovery of 24% only. However, attempts are being made to further improve the iron recovery
Recovery of Cobalt as Cobalt Sulfate from Discarded Lithium-Ion Batteries(LIBs) of Mobile Phones
Get PDFCobalt, an exceptional cathode material present in lithium-ion batteries(LIBs), is an essential element for the production of energy storage devices. But, the lifespan of rechargeable batteries is decreasing day by day, which becomes obsolete after reaching their end of life. Therefore, an enormous amount of discarded LIBs are
generated. Keeping in mind the above, a novel approach has been made to selectively recover cobalt from sulfate leach liquor of discarded LIBs containing 1.4 g/L Cu, 1.1 g/L Ni, 11.9 g/L Co, 6.9 g/L Mn, and 1.2 g/L Li. Initially, Cu and Ni were extracted by solvent extraction techniques using 10% LIX 84-IC. Almost complete precipitation of cobalt occurred from leach liquor at pH ~3 using ammonium sulfide solutions. Cobalt from the precipitated product was further dissolved in H2SO4 in the presence of H2O2 at elevated temperatures. The leach liquor obtained was evaporated to get the cobalt sulfate with a purity of more than 98%
Comparative life cycle assessment (LCA) of geopolymer cement manufacturing with Portland cement in Indian context
No full textIndia is the second-leading cement producer in the world after China. Cement causes huge carbon footprint during the production and transportation of materials. Various efforts are being made to reduce the environmental impacts. Among the notable developments are the use of by-product or secondary material to develop new binders such as geopolymer cement. This paper contains a cradle-to-gate life cycle impact assessment of two types of geopolymer cement produced from blending fly ash and slag, and blending fly ash and cement in an Indian scenario. As there is no standard data available for geopolymer cement production, the primary data used were collected by producing geopolymer cement at pilot scale (5 t/d). In an Indian context, the geopolymer cement significantly reduces the global warming potential (267 kg CO2-Equiv.), abiotic depletion potential fossil (3092 MJ), abiotic depletion potential element (1.18 e(-3) kg Sb-Equiv.), human toxicity potential (249 kg DCB-Equiv.), and terrestrial ecotoxicity potential (0.438 kg DCB-Equiv.) with blending fly ash and slag. The geopolymer cement produced from fly ash and slag reduces the global warming potential by 70%, abiotic depletion potential fossil by 49%, abiotic depletion potential element by 34%, and terrestrial ecotoxicity potential by 77% when compared with ordinary Portland cement of the building and construction industries. In case of geopolymer cement, the maximum impact on the environment is due to the use of an alkali solution. Based on the analysis, geopolymer cement appears more sustainable than traditional cement and thus has good potential as an alternate binder
Studies on Tensile Behaviour of Selective Laser Melted 316L Stainless Steel Using SEM Straining Stage
No full textMetallic components prepared by additive manufacturing are expected to exhibit microstructural anisotropy due to their
layer-by-layer architecture. This in-homogeneity in microstructure can result in variations in the deformation behaviour of materials in different directions, which may lead to premature failure of a component loaded in a particular orientation. Therefore, in the present study, an attempt has been made to investigate the microstructural characteristics and ensuing mechanical properties, in three different orientations with respect to the build direction in a 316L stainless steel, printed using selective
laser melting technique. Tensile tests were performed on micro-tensile specimens using a straining stage attached to scanning electron microscope (SEM) while observing crack initiation and propagation. The results were compared with that of conventionally processed AISI 316L stainless steel. Microstructural analysis of the SLM printed component revealed the presence of fine cellular structure within the clearly defined prior melt-pool boundaries. Furthermore, EBSD analysis revealed the presence of columnar grains, which were mostly oriented along the to direction in the build plane and along the direction in the long transverse plane. The favourable grain orientation for twinning in the samples drawn along the build plane led to a better accommodation of plastic strain during tensile deformation. Hence, the sample drawn from build plane showed an improved combination of strength and ductility, in comparison to the transverse orientations.
When compared with conventionally processed 316L stainless steel, the SLM printed samples showed a significant increase
in the strength in all the three orientations with a concurrent decrease in the ductility