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Artificial neural network approach to assess selective flocculation on hematite and kaolinite

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International Journal of Minerals,Metallurgy and Materials 2014年第7期21卷 637-646页

作者： Lopamudra Panda P.K.Banerjee Surendra Kumar Biswal R.Venugopal N.R.Mandre R&D tata steel limited Institute of Minerals and Materials Technology(Council of Scientific and Industrial Research) Department of Fuel & Minerals Engineering Indian School of Mines University

Because of the current depletion of high grade reserves, beneficiation of low grade ore, tailings produced and tailings stored in tailing ponds is needed to fulfill the market demand. Selective flocculation is one alternative process that could be used for the beneficiation of ultra-fine material. This process has not been extensively used commercially because of its complex dependency on process parameters. In this paper, a selective flocculation process, using synthetic mixtures of hematite and kaolinite in different ratios, was attempted, and the ad-sorption mechanism was investigated by Fourier transform infrared （FTIR） spectroscopy. A three-layer artificial neural network （ANN） model （4？4？3） was used to predict the separation performance of the process in terms of grade, Fe recovery, and separation efficiency. The model values were in good agreement with experimental values.

关键词： hematite kaolinite flocculation artificial neural networks back propagation algorithm Fourier transform infrared spectroscopy separation efficiency

Application of High Tension Roll Separator for the Separation of Titanium Bearing Minerals: Process Modeling and Optimization

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Journal of Minerals and Materials Characterization and Engineering 2012年第10期11卷 1005-1011页

作者： Srijith Mohanan Sunil Kumar Tripathy Y. Ramamurthy C. Raghu Kumar tata steel limited Jamshedpur India

The High Tension Roll Separator (HTRS) is one of the main electrostatic unit operations employed to separate titanium minerals like ilmenite, rutile and leucoxene which behave as conducting from zircon, sillimanite, garnet and monazite which behave as non-conducting minerals when a high potential difference is applied. Three process inputs, namely roll speed, feed material temperature and roll speed have been optimized. Experiments were conducted based on the Box- Behnken factorial design;the results were analyzed using response surface methodology (RSM). A new term, called Operational Quality Index (OQI) has been defined as a process output, which is maximized by quadratic programming, to obtain the optimum operating conditions. The maximum value of OQI obtained under the constraints of grade >96% and recovery >98% is 195.53, at the following operating conditions—Temperature: 102°C, Feed Rate: 1.75 tph and Roll Speed: 132 rpm. Under these conditions, the grade and recovery obtained are 96.6% and 98.9% respectively.

关键词： High Tension Roll Separator Response Surface Methodology Titanium Box-Behnken Design

Extensive Analysis of Multi Strand Billet Caster Tundish Using Numerical Technique

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World Journal of Mechanics 2019年第2期9卷 29-51页

作者： Rohit Agarwal Mrityunjay K. Singh Ram Bachchan Kumar Biswajit Ghosh Sudhansu Pathak tata steel limited Jamshedpur India

Continuous casting of steel involving different grades in the same casting sequence remains a challenge to billet caster operators. The intermixed composition obtained during the grade change does not meet the specification of either grade and must be downgraded. Incorrect identification of this intermixed region may result in non-conforming products reaching the customer. In this study, a numerical model based on CFD (computational fluid dynamics approach) has been developed which predicts the start and end of the intermixed composition and the tonnage to be downgraded under different casting conditions. This model was validated and the results were in good agreement with the actual plant data for a 6-strand billet caster at LD-1 of tata steel, India. This model is used to calculate transition tonnage for different scenarios, e.g. when one of the outermost strands is not functional or some combinations are not functional and varying casting speed during operation. Furthermore, impact of different design of baffles on performance of Tundish has been evaluated to find a way to reduce transition or intermixed composition.

关键词： Continuous Casting CFD Billet Tundish Grade Change Modelling Quality Control Fluid Flow Heat Transfer

Reconciliation of size-density bivariate distributions over a separating node

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Particuology 2008年第3期6卷 167-175页

作者： Bidarahalli Venkoba Rao Vivek Ganvir Sirigeri Jois Gopalakrishna Engineering and Industrial Services Tata Consultancy Services Limited 1Mangaldas RoadPune 411001India tata Research Development and Design Centre Tata Consultancy Services Limited 54BHadapsar Industrial EstatePune 411013India Department of Mineral Processing Post Graduate CenterSandurKarnataka 583119India

Data reconciliation considers the restoration of mass balance among the noise prone measured data by way of component adjustments for the various particle size or particle density classes or assays over the separating node. In this paper, the method of Lagrange multipliers has been extended to balance bivariate feed and product size-density distributions of coal particles split from a settling column. The settling suspension in the column was split into two product fractions at 40% height from the bottom after a minute settling of homogenized suspension at start. Reconciliation of data assists to estimate solid flow split of particles to the settled stream as well as helps to calculate the profiles of partition curves of the marginal particle size or particle density distributions. In general, Lagrange multiplier method with uniform weighting of its components may not guarantee a smooth partition surface and thus the reconciled data needs further refinement to establish the nature of the surface. In order to overcome this difficulty, a simple alternative method of reconciling bivariate size-density data using partition surface concept is explored in this paper.

关键词： Data reconciliation Size-density partition surface Settling test

Magnetic separation studies on ferruginous chromite fine to enhance Cr:Fe ratio

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International Journal of Minerals,Metallurgy and Materials 2015年第3期22卷 217-224页

作者： Sunil Kumar Tripathy P.K.Banerjee Nikkam Suresh Research and Development Division Tata Steel Ltd. Fuel and Mineral Engineering Dept. Indian School of Mines

The Cr：Fe ratio （chromium-to-iron mass ratio） of chromite affects the production of chrome-based ferroalloys. Although the lit- erature contains numerous reports related to the magnetic separation of different minerals, limited work concerning the application of mag- netic separation to fine chromite from the Sukinda region of India to enhance its Cr：Fe ratio has been reported. In the present investigation, magnetic separation and mineralogical characterization studies of chromite fines were conducted to enhance the Cr：Fe ratio. Characterization studies included particle size and chemical analyses, X-ray diffraction analysis, automated mineral analysis, sink-and-float studies, and mag- netic susceptibility measurements, whereas magnetic separation was investigated using a rare earth drum magnetic separator, a rare earth roll magnetic separator, an induced roll magnetic separator, and a wet high-intensity magnetic separator. The fine chromite was observed to be upgraded to a Cr：Fe ratio of 2.2 with a yield of 55.7% through the use of an induced roll magnetic separator and a feed material with a Cr：Fe ratio of 1.6.

关键词： chromite ore treatment magnetic separation characterizafion mineral processing industry

微合金化和余热处理热轧带肋钢筋高低周疲劳性能对比研究

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钢铁钒钛 2015年第2期36卷 39-48页

作者： Surajit Kumar Paul Pritam Kumar Rana Debdulal Das Sanjay Chandra Saurabh Kundu 杨雄飞 R & D Tata Steel Limited Department of Metallurgy and Materials Engineering Bengal Engineering and Science University

通过试验研究,对比分析了微合金化和余热处理带肋钢筋的高周疲劳和低周疲劳性能。研究表明,微合金化钢筋比余热处理钢筋具有更好的疲劳性能。在微合金化和余热处理带肋钢筋的高低周疲劳试验中,观察到在横肋根部裂纹萌生并沿该区域扩展... 详细信息

通过试验研究,对比分析了微合金化和余热处理带肋钢筋的高周疲劳和低周疲劳性能。研究表明,微合金化钢筋比余热处理钢筋具有更好的疲劳性能。在微合金化和余热处理带肋钢筋的高低周疲劳试验中,观察到在横肋根部裂纹萌生并沿该区域扩展。有限元模拟结果显示在横肋根部出现应力集中,应力三轴度变大。模拟过程中也发现在横肋根部拉应变累积。有限元模拟结果有助于解释试验观察结果,即疲劳裂纹沿热轧带肋钢筋的横肋根部萌生及扩展。

关键词：余热处理钢筋微合金化钢筋高周疲劳低周疲劳抗震性能应力集中应力三轴度横肋

Emitter Quality Optimization Using Lightly Doped Phosphorus Diffusion and Thermal Oxide Anneal for Cell Efficiency Improvement in Multi-Crystalline Black Silicon Solar Cells

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Journal of Power and Energy Engineering 2022年第3期10卷 35-47页

作者： Kishan Shetty Yudhbir Kaushal Nagesh Chikkaiah Chandra Mauli Kumar tata Power Solar Systems limited Bangalore India

Improving solar cell performance by increasing solar cell efficiency by various process optimization had always been a simple straight-forward methodology followed in a R&D or in a solar cell manufacturing company. This is also the most cost-effective practice to improve a product performance using the same technology without the need to procure alternative or expensive raw materials or by adopting advanced solar cell processing techniques. Aluminium Back Surface Field (Al-BSF) technology using multi-crystalline wafers (mc-Si) had been a well-established and a dominant product in the solar industry for more than two decades. However, as the industry progresses, the demand for high efficiency solar cells and modules started going up and full area Aluminium BSF based cells suffers from a lot of inherent limitations on cell efficiency. This is primarily due to the intrinsic high density of crystal lattice defects or otherwise called as grain boundary defects present dominantly only in mc-Si wafers. These grain boundaries tends to accumulate several defects and become trap centres which cause high recombination for minority carriers thereby exhibiting lower conversion efficiency and higher dispersion in electrical parameters in batches of tested cells. Years of research using this material have helped to derive the maximum benefits using this mc-Si wafer in producing industrial full area BSF cells and we can say with certainty that the efficiency potential has reached the saturation point with this technology. An interesting development that happened in the area of improving the final product performance using mc-Si wafers at both cell and module level, is by replacing the conventional acid texturing process with an introduction of a nano-texturing process called Metal Catalysed Chemical Etching (MCCE) using specialized chemicals which improves the light trapping capabilities by creation of inverted pyramid texture on the silicon wafer surface and thereby enabling the w

关键词： Lightly Doped Emitter Oxidation Annealing Metal Catalyst Chemical Etching Phosphorus Silicate Glass Diffusion

Challenges in Processing Diamond Wire Cut and Black Silicon Wafers in Large-Scale Manufacturing of High Efficiency Solar Cells

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Journal of Power and Energy Engineering 2020年第2期8卷 65-77页

作者： Kishan Shetty Yudhbir Kaushal Nagesh Chikkan D. S. Murthy Chandra Mauli Kumar tata Power Solar Systems limited Bangalore India

Texturing of diamond wire cut wafers using a standard wafer etch process chemistry has always been a challenge in solar cell manufacturing industry. This is due to the change in surface morphology of diamond wire cut wafers and the abundant presence of amorphous silicon content, which are introduced from wafer manufacturing industry during sawing of multi-crystalline wafers using ultra-thin diamond wires. The industry standard texturing process for multi-crystalline wafers cannot deliver a homogeneous etched silicon surface, thereby requiring an additive compound, which acts like a surfactant in the acidic etch bath to enhance the texturing quality on diamond wire cut wafers. Black silicon wafers on the other hand require completely a different process chemistry and are normally textured using a metal catalyst assisted etching technique or by plasma reactive ion etching technique. In this paper, various challenges associated with cell processing steps using diamond wire cut and black silicon wafers along with cell electrical results using each of these wafer types are discussed.

关键词： Diamond Wire Cut Black Silicon Slurry Wafers Amorphous Silicon Additives Etching and Texturization

Kinetic analysis of iron ore powder reaction with hydrogen-carbon monoxide

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International Journal of Minerals,Metallurgy and Materials 2022年第10期29卷 1882-1890页

作者： Xudong Mao Pritesh Garg Xiaojun Hu Yuan Li Samik Nag Saurabh Kundu Jianliang Zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China R&D Tata Steel Ltd.JamshedpurJharkhand 831001India School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Iron ore powder was isothermally reduced at 1023-1373 Kwith hydrogen/carbon monoxide gas mixture(from 0vol%H_(2)/100vol%CO to 100vol%H_(2)/0vol%CO).Results indicated that the whole reduction process could be divided into two parts that proceed in *** first part represents a double-step reduction(Fe_(2)O_(3)→Fe_(3)O_(4)→FeO),in which the kinetic condition is more feasible compared with that in the second part representing a single-step reduction(FeO→Fe).The influence of hydrogen partial pressure on the reduction rate gradually increases as the reaction *** average reduction rate of hematite ore with pure hydrogen is about three and four times higher than that with pure carbon monoxide at 1173 and 1373 K,*** addition,the logarithm of the average rate is linear to the composition of the gas *** can prominently promote carbon deposition to about 30%at 1023 *** apparent activation energy of the reduction stage increases from about 35.0 to 45.4 kJ/mol with the increase in hydrogen content from 20vol%to 100vol%.This finding reveals that the possible rate-controlling step at this stage is the combined gas diffusion and interfacial chemical reaction.

关键词： reduction carbon monoxide hydrogen kinetics mechanism