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Effectiveness of sodium silicate as gangue depressants in iron ore slimes flotation

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International Journal of Minerals,Metallurgy and Materials 2011年第5期18卷 515-522页

作者： danda srinivas rao Tadiparthi Venkata VijayaKumar Sripada Subba rao Swarna Prabhakar Guntamadugu Bhaskar Raju National Metallurgical Laboratory-Madras Centre Council of Scientific and Industrial Research-Madras ComplexChennai 600 113India

The recovery of iron from the screw classifier overflow slimes by direct flotation was studied. The relative effectiveness of sodium silicates with different silica-to-soda mole ratios as depressants for silica and silicate bearing minerals was investigated. Silica-to-soda mole ratio and silicate dosage were found to have significant effect on the separation efficiency. The results show that an increase of Fe content in the concentrate is observed with concomitant reduction in SiO2 and A1203 levels when a particular type of sodium silicate at a proper dosage is used. The concentrate of 58.89wt% Fe, 4.68wt% SiO2, and 5.28wt% A1203 with the weight recovery of 38.74% and the metal recovery of 41.13% can be obtained from the iron ore slimes with 54.44wt% Fe, 6.72wt% SiO2, and 6.80wt% A1203, when NazSiO3 with a silica-to-soda mole ratio of 2.19 is used as a depressant at a feed rate of 0.2 kg/t.

关键词： iron ores sodium silicate depressants flotation

Characterization of dolochar wastes generated by the sponge iron industry

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International Journal of Minerals,Metallurgy and Materials 2012年第11期19卷 992-1003页

作者： Ranjan Kumar Dwari danda srinivas rao Akhila Kumar Swar Palli Sita Ram Reddy Barada Kanta Mishra CSIR-Institute of Minerals and Materials Technology Odisha State Pollution Control Board

Solid wastes generated by the metallurgical industry contribute significantly towards the enhancement of environmental pollution. The handling, utilization, and safe disposal of these solid wastes are major concerns for the world. Dolochar is such a solid waste generated by the sponge iron industry. Investigations were carried out on the physical, mineralogical, and chemical characteristics for the efficient utilization of dolochar. The detailed studies on physico-chemical properties and petrography were carded out by optical microscopy, X-ray diffraction （XRD）, and scanning electron microscopy （SEM）. Characterization studies revealed that the dolochar consists of quartz （free as well as locked）, free lime, Fe particles, and Ca or Mg and/or Ca＋Mg＋Fe oxide phases. The washability data of-300 ~m dolochar samples indicated that clean coal with 41wt% ash at 18% yield can be produced from dolochar with 78wt% ash. The studies further suggested that the liberation of the dolochar is hard to achieve for clear separation. The dolochar is observed to have high ash fusion temperature and the un- burned carbon can be best utilized for power generation.

关键词： solid wastes sponge iron dolochar characterization mineralogy trace elements

印度一水硬铝石样品中氧化铁相的矿物学、解离和浸出特性（英文）

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Transactions of Nonferrous Metals Society of China 2018年第8期28卷 1640-1651页

作者： danda srinivas rao Swagat S.RATH Nilima DASH Swagatika MOHANTY Surendra K.BISWAL Council of Scientific and Industrial Research Institute of Minerals and Materials Technology

利用磁选和浸出技术从印度一水硬铝石样品中除铁,采用扫描电镜、电子探针显微分析仪和X射线衍射等定量矿物学评价技术进行深入的矿物学表征研究。结果表明,极细的赤铁矿颗粒与其他几种矿物相以复杂的方式结合在一起;即使粒度小于38μm,... 详细信息

利用磁选和浸出技术从印度一水硬铝石样品中除铁,采用扫描电镜、电子探针显微分析仪和X射线衍射等定量矿物学评价技术进行深入的矿物学表征研究。结果表明,极细的赤铁矿颗粒与其他几种矿物相以复杂的方式结合在一起;即使粒度小于38μm,仍有约60%的赤铁矿未被解离出来;这个粒度也是物理分离过程去铁的极限。湿式强磁选研究表明,只有49%的铁可被除去。进一步的草酸浸出研究表明,在固液比0.05:1、温度90°C、时间120 min、酸浓度1 mol/L的条件下,可除去约76%的铁。铁在草酸中的溶解受化学反应控制,计算的活化能为35.15 k J/mol。

关键词：一水硬铝石解离矿物学浸出磁选

Ore petrography of low-grade siliceous manganese ores from the Bonai-Keonjhar belt, Orissa, India: The influence of mineral-fabric on their beneficiation

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Mining Science and Technology 2011年第6期21卷 803-808页

作者： Mishra Subrat Mohapatra Birendra Kumar Dash Nilima rao danda srinivas Institute of Minerals and Materials Technology Orissa Mining CorporationBhubaneswar751013India

Low grade siliceous manganese ores from the iron ore group of the Bonai-Keonjhar belt, Orissa, India are found mostly in shear zones. The ore characteristics of siliceous manganese ore samples from three differ- ent mines, viz. the Shankar (Barbil OMC lease hold area), the Sone-Patuli (Patmunda, OMM lease hold area), and the Musaghar (Roida, OMDC lease hold area), were studied. These siliceous manganese ores are of three types, respectively: (i) spongy-granular; (ii) massive-mosaic; and (iii) hard-mylonitized. The spongy-gran- ular type contains granular, saccharoidal quartz and the major manganese mineral present is pyrolusite. The second type contains well crystallized quartz and cryptomelane, while the third has cherty, fine grained quartz (mylonite) along with romanechite. All three ores were subjected to physical beneficiation under similar conditions. Both gravity and magnetic separation techniques were employed. The mineral-fabric of the ores has been correlated to the extent of their beneficiation using these physical techniques. Of these three ores only the spongy-granular type responded well to upgrading. The feed with 22% Mn content could be upgraded to 44% with a 28% yield and a 49% recovery. The good response to beneficiation of the spongy- granular sample could be due to the large euhedral crystals of pyrolusite and the friable nature of the sac- charoidal quartz. This study reveals the influence of mineral-fabric on beneficiation of low grade ore, siliceous Mn ore in particular.

关键词：物理选矿矿物结构低品位矿锰矿石铁矿石硅质印度岩石学

Magnetic separation studies for a low grade siliceous iron ore sample

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矿业科学技术学报：英文版 2013年第1期23卷 1-5页

作者： Dwari Ranjan Kumar rao danda srinivas Reddy Palli Sita Ram CSIR-Institute of Minerals and Materials Technology Council of Scientific and Industrial Research Bhubaneswar 751 013 India

Investigations were carried out, on a low grade siliceous iron ore sample by magnetic separation, to establish its amenability for physical beneficiation. Mineralogical studies revealed that the sample consists of magnetite, hematite and goethite as major opaque oxide minerals where as silicates as well as carbonates form the gangue minerals in the sample. Processes involving combination of classification, dry magnetic separation and wet magnetic separation were carried out to upgrade the low grade siliceous iron ore sample to make it suitable as a marketable product. The sample was first ground and each closed size sieve fractions were subjected to dry magnetic separation and it was observed that limited upgradation is possible. The ground sample was subjected to different finer sizes and separated by wet low intensity magnetic separator. It was possible to obtain a magnetic concentrate of 67% Fe by recovering 90% of iron values at below 200 lm size.

关键词：铁矿石磁铁矿描述干燥、湿的磁性的分离

Beneficiation of a low grade limestone sample

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Mining Science and Technology 2011年第5期21卷 631-636页

作者： rao danda srinivas Vijayakumar Tadiparthi Venkata Subba rao Sripada Bhaskar Raju Guntamadugu Prabhakar Swarna National Metallurgical Laboratory Madras Centre CSIR Madras Complex Chennai 600 113 India

Pilot scale column flotation studies were conducted on a low grade siliceous limestone ore. Silica content was reduced to less than 1% in the concentrate so that it became satisfactory for use in the paper or rub- ber industries. The limestone sample was crystalline and constituted primarily of calcite that contained quartz, feldspar, pyroxene, and biotite as gangue minerals. Quartz is the major silicate gangue whereas feldspar, pyroxene, and biotite exist in minor to trace quantities. Traces of pyrite were also observed within the sample. A reverse flotation process was adopted where the silicate gangue minerals were floated using two different commercial cationic collectors: Chem-750 F or Floatamine-D. The studies clearly suggest it is possible to produce a limestone concentrate assaying around 96-97% CaCO3 contain- ing less than 1% SiO2. The effect of feed flow rate, percent solids, froth depth, and wash water on the grade and recovery of the CaCO3 concentrate is discussed.

关键词：低品位石灰石样品选矿二氧化硅含量精矿品位脉石矿物反浮选工艺 CaC03

Inflammation and dry eye disease——where are we?

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International Journal of Ophthalmology(English edition) 2022年第5期15卷 820-827页

作者： srinivas K rao Rishi Mohan Nikhil Gokhale Himanshu Matalia Paras Mehta Darshan Eye Care&Surgical Centre ChennaiTamil NaduIndia MM Eyetech Institute of Ophthalmology New DelhiIndia Gokhale Eye Hospital MumbaiMaharashtraIndia Narayana Nethralaya Electronic CityBangaloreKarnatakaIndia Sameep Eye Hospital and Corneal Center VadodaraGujaratIndia

The presence of inflammation in dry eye disease(DED)results in increased patient symptomatology,ocular surface damage and worsening tear *** also affects the health of meibomian glands and their secretions which further aggravates ocular surface *** article reviews current knowledge regarding ocular surface inflammation in DED and explores the relationships between the vicious cycles of DED,inflammation and meibomian gland dysfunction(MGD).The clinical evaluation of eyes with such changes,markers that identify the presence of inflammation on the ocular surface and current treatment options are discussed.

关键词： dry eye disease inflammation meibomian gland dysfunction vicious cycle ocular surface disease

Hydro-elastic computational analysis of a marine propeller using two-way fluid structure interaction

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Journal of Ocean Engineering and Science 2022年第3期7卷 280-291页

作者： V.Rama Krishna srinivas Prasad Sanaka N.Pardhasaradhi B.Raghava rao Naval Science&Technological Laboratory Visakhapatnam532007India Department of Mechanical Engineering V.R.Siddhartha Engineering CollegeVijayawada520007India

Marine propellers have complex geometry and their performance is determined by costly and time consuming open water *** of numerical techniques helps researchers in effective design of *** approaches are used that predicted either hydrodynamic and acoustic response or structural ***-way fluid-structure interaction(FSI)analysis is a very useful approach providing all three responses which helps in the design,analysis and optimization of a *** objective of this paper is to predict the hydro-elastic response of a propeller using two-way FSI on a 0.2m diameter,DTMB-4119 propeller using ANSYS ***-way FSI analysis is carried out using system coupling approach that transfers the data between the structural and fluid *** turbulence effects are captured using the large-eddy simulation(LES)model and the Ffowcs Williams Hawkings(FWH)acoustic model is used for evaluating the sound pressure level(SPL)generated by *** is extended to evaluate the hydro-elastic and acoustic response of the propeller after validating the hydrodynamic performance with the experimental result in the *** results from Two-way FSI analysis are in close agreement when compared with the one-way FSI ***-way FSI can accommodate the peak value of stress and deformation developed during the initial part of the transient solution which is important in the design of *** study reveals that metallic(NAB)propeller can be replaced by a composite *** acoustic response from two-way FSI analysis will be more realistic due to the consideration of hydro-elastic effect of propeller.

关键词： Advance ratio Coupled analysis CFD Marine propeller Hydrodynamic parameters Two-way fluid structure interaction

Implications for the lithospheric structure of Cambay rift zone,western India:Inferences from a magnetotelluric study

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Geoscience Frontiers 2020年第5期11卷 1743-1754页

作者： Nagarjuna danda C.K.rao Amit Kumar P.Rama rao P.B.V.Subba rao Dr.K.S.Krishnan Geomagnetic Research Laboratory IIGAllahabad221505India Indian Institute of Geomagnetism New PanvelNavi Mumbai410218India Department of Geophysics Andhra UniversityVisakhapatnam530003India

Broad-band and long-period magnetotelluric(MT)data were acquired along an east-west trending traverse of nearly 200 km across the Kachchh,Cambay rift basins,and Aravalli-Delhi fold belt(ADFB),western *** regional strike analysis of MT data indicated an approximate N59°E geoelectric strike direction under the traverse and it is in fair agreement with the predominant geological strike in the study *** decomposed transverse electric(TE)-and transverse magnetic(TM)-data modes were inverted using a nonlinear conjugate gradient algorithm to image the electrical lithospheric structure across the Cambay rift basin and its surrounding *** studies show a thick(~1-5 km)layer of conductive Tertiary-Mesozoic sediments beneath the Kachchh and Cambay rift *** resistive blocks indicate presence of basic/ultrabasic volcanic intrusives,depleted mantle lithosphere,and different Precambrian structural *** crustal conductor delineated within the ADFB indicates the presence of fluids within the fault zones,sulfide mineralization within polyphase metamorphic rocks,and/or Aravalli-Delhi sediments/*** observed conductive anomalies beneath the Cambay rift basin indicate the presence of basaltic underplating,volatile(CO2,H2 O)enriched melts and channelization of melt fractions/fluids into crustal depths that occurred due to plume-lithosphere *** variations in electrical resistivity observed across the profile indicate that the impact of Reunion plume on lithospheric structures of the Cambay rift basin is more dominant at western continental margin of India(WCMI)and thus support the hypothesis proposed by Campbell&Griffiths about the plume-lithosphere interactions.

关键词： Cambay rift Deccan basalts Magnetotellurics Partial melt Reunion plume