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Effect of high Blaine iron ore fines in hematite ore pelletization for blast furnace
No full textBlaine fineness is one of the most important parameters in pelletising. While the lower Blaine fineness does not provide sufficient strength to the both green pellet and indurated pellet, excessively high Blaine fineness causes problem in pellet making. Optimum Blaine fineness of iron ore in the range of 1700–2250 cm2/g is usually used for good quality pellet making. However, when a material of high Blaine fineness is produced after beneficiation and there is no option to control the fineness, the pellet making from high Blaine fineness ore becomes obligatory. In this work, the effect of high Blaine fineness (2700–3250 cm2/g) on the pellets properties has been studied and the optimum parameters to make it usable for blast furnace have been examined. 0.3 wt% bentonite and maximum 7 wt% initial moisture in the green mix with 45–50° disc angles have been found to be suitable for green pellet making with 2700 and 2986 cm2/g Blaine fineness. These pellets show very good CCS (260–290 kg/pellet), reducibility index (71–75%), reduction degradation index (12–13%) and swelling index(12–16%) at the optimum induration temperature of 1280°C for 10 min. However, very high Blaine fineness (say 3250 cm2/g) requires relatively lower initial moisture (5%), higher disc
angle and lower induration temperature (1250°C)
Vacuum based coatings for engineering applications
No full textIn the present modern age, vacuum based coatings are employed in every field of technology to reduce size and improve performance. The present paper briefly describes the physical concepts involved in vacuum coating for different applications along with technical details of necessary vacuum equipment
Spectroscopic changes in conventional magnetorheological fluid and graphene oxide based magnetorheological fluid with combustion method
No full textA comparative spectroscopic analysis of conventional Magnetorheological fluid and Graphene Oxide based Magnetorheological fluid. Raman spectra have been recorded using 532 nm laser excitation. The down shifted G-band of Graphene Oxide observed at 1576.42 cm-1 due to the doubly degenerate zone center E2g mode and 2D band at 2702.58 cm-1 confirms the presence of Graphene Oxide. UV - VIS Absorption spectrum of GO based MR fluid has been recorded of π-π plasmon peak at 233.82 cm-1 while a broad band is displayed in conventional Magnetorheological fluid. Here, Graphene Oxide used in Magnetorheological fluid is prepared by combustion method of separating Graphene layers by controlled oxidation. This analysis shows highly efficient, unequivocal, non-destructive identification of Graphene Oxide in Magnetorheological fluid
CSIR-NML NEWSLETTER SEPTEMBER- 2021
Get PDFSummary of significant activities
For the period September, 2021,
CSIR-National Metallurgical Laborator
CSIR Integrated Skill Initiative
No full textCSIR-NML has received funding support for the year 2018-2020 to conduct the skill training programmes under the CSIR flagship programme " CSIR Integrated Skill Initiative". This programme aims to train people of India in different skill areas. The mission is to generate quality human resources at various levels by providing and upgrading skills in various technical fields. Under this project, CSIR-NML provided skill trainings ranging from basic training for rural youths, summer/winter internship for undergraduate students, M.Tech/Ph.D dissertation guidance for post-graduate students, apprentice training programmes varied from 2 days to 1 year in duration. The main focus was to develop skills in the areas of metals, metallurgy, manufacturing, waste utilization, soft skills and entrepreneurship development. In the year 2018-20, CSIR-NML provided skill training to 1113 participants and 70% of them were from disadvantaged background
Microstructural evolution, recovery and recrystallization kinetics of isothermally annealed ultra low carbon steel
Get PDFThe recovery and recrystallization kinetics of 80%cold rolled ultra low carbon steel are investigated during isothermally annealing for temperature ranges 350–640 °C as a function of different annealing time. The recovery is assessed by magnetic coercivity (Hc),while the recrystallization is determined by mechanical hardness.At low temperature (350 to 520 °C) annealing, recovery dominates for long time (∼12 000 s),while the annealing at 550 °C/ 900s and 580 °C/ 300s causes the recrystallized nuclei formation . The recovery kinetics is introduced by differential rate equation, explaining the reduction in
coercivity with the recovery progress and the variation of an activation energy from41–113 kJmol−1. The recrystallization kinetics is found faster at high annealing temperature 640 °C than 550 and 580 °C based on hardness measurement, justifying by apparent activation energy within 114–190 kJ/mol. Furthermore, the recovery and recrystallization rate increase with different annealing time, consistent to the change of microstructures and grain boundary characteristics evaluated by the orientation imaging microscopy (OIM) of electron backscattered diffraction (EBSD)
A sustainable process for recovery of potash fertilizer from glauconite through simultaneous production of pigment grade red oxide
No full textA sustainable process is proposed and developed for the recovery of potash fertilizer from glauconitic clay with simultaneous production of pigment grade iron oxide. Potassium is a part of stable structure (dioctahedral T-O-T) in glauconite and locked in alumino-silicate matrix. In order to break this matrix and maximize potassium dissolution, the glauconite sample containing 5.6% K2O and 31.9% Fe2O3 was subjected to reduction with coke followed by oxidation cooling (redox roasting). The process simultaneously releases potash and convert iron in the matrix to ferric state. The redox roasted sample was leached in hydrochloric acid and the leach liquor containing 6.1 g/L of potassium and 30.2 g/L of iron was subjected to solvent extraction using mixed solvent system (20% Aliquat 336 and 15% TBP) to separate iron prior to recovery of potash. Based on McCabe-Thiele plot, two stage counter current extraction at O:A ratio of 1:0.75 and three stage stripping at O:A ratio of 0.4:1 are sufficient to remove >99% of iron from the leach solution. The strip solution was hydrothermally treated to produce red iron oxide suitable for pigment application and iron free raffinate was treated to produce fertilizer grade potassium chloride. (C) 2019 Elsevier B.V. All rights reserved
Prospects of utilization of waste dumped low-grade limestone for iron making: A case study
No full textLow grade dumped limestone sample having high silica of 8.1%, 36.8% CaO, and 3% Al2O3 has been studied with the aim to reduce the silica level to below 3% for its utilization in iron making. Beneficiation study of the sample was initiated with desliming of the feed sample of −100 µm to remove the siliceous ultrafine particles and to improve the feed quality. Flotation study was carried out by column flotation technique varying the collector dosage, superficial air flow velocity and froth depth to assess their effect on silica reduction and CaO recovery. It was observed that increased collector dosage and superficial air velocity increases the recovery of CaO, and increase in the froth depth reduces the mass flow and silica content in the concentrate. The best result was found at 1.25 cm/sec superficial air velocity, 25 cm froth depth, 1.25 kgpt collector dosage and concentrate assayed 47.3% CaO, 2.8% silica with 72% CaO recovery
Dissimilatory Iron-Reducing Bacteria: A Template for Iron Mineralization and Nanomaterial Synthesis
No full text5.1 Introduction
5.2 Types of DIRB
5.2.1 Fermentative Fe(III)-Reducing Bacteria
5.2.2 Sulfur-oxidizing Fe(III)-Reducing Bacteria
5.2.3 Organic Acid–Oxidizing Fe(III)-Reducing Bacteria
5.2.4 Hydrogen-Oxidizing Fe(III)-Reducing Bacteria
5.2.5 Aromatic Compound–Oxidizing Fe(III)-Reducing Bacteria
5.3 Microbe-Metal Interaction
5.4 The Mechanism for Crystal Formation
5.4.1 Magnetotactic Bacteria
5.4.2 Iron-Reducing Bacteria
5.5 The Diversity of Biominerals Formed
5.5.1 Oxides
5.5.2 Sulfides
5.5.3 Silicates
5.5.4 Phosphates
5.6 Molecular Mechanism of Microbial Fe(III) Reduction
5.7 Conclusions
Reference
Corrosion Behavior of Ti-Si-B-C Nanocomposite Hard Coating with Different Si Contents on 4130 Steel
No full textMicrostructural, mechanical and electrochemical properties of a Ti-Si-B-C nanocomposite coating with different Si percentages on 4130 steel were investigated. All the films with different SI contents in the range of 10 to 12 mu m thickness showed amorphous structures by X-ray diffraction. The hardness decreased with the increase of Si content in Ti-Si-B-C film. The particle size, pores, roughness and phases were responsible for the decrease of hardness with the increase of Si content. Electrochemical behavior is studied using open-circuit potential, impedance spectroscopy (EIS) and anodic polarization methods in 3.5 wt pct NaCl solution. The corrosion current density (icorr) was much lower, 0.45 to 2.34 mu A/cm(2), with varying Si content compared with uncoated steel (9.37 mu A/cm(2)), and passivation behavior was observed during the polarization study. The EIS fit model suggested the presence of a duplex oxide layer on the Ti-Si-B-C nanocomposite coatings. The Ti-Si-B-C coatings with lower Si (24 pct) content showed the best corrosion resistance compared with higher Si content (36 to 52 pct). Overall, the present study suggests that the hard Ti-Si-B-C nanocomposite coating significantly improved the corrosion resistance of 4130 steel