Danda Rao | Institute of Minerals and Materials Technology (CSIR) (original) (raw)

Papers by Danda Rao

Chromite resources of Orissa are mostly confined to Second ultramafic belt and Boula Nausahi igne... more Chromite resources of Orissa are mostly confined to Second ultramafic belt and Boula Nausahi igneous complex. In these deposits, chromite is mainly present as layers in ultramafic rocks (high magnesian). These high magnesian ultramafic chromite overburden rocks are dumped as waste materials during chromite mining operations. These rocks are classified as dunite, peridotite and their altered products (Serpentinite), pyroxenite and saxonite depending on their mineral assemblage. Petrological, chemical and thermal characterization of these high magnesian rocks have been studied in light of their utilization as a flux substitute for the iron and steel industry in place of conventional fluxes. The study reveals that the chromite overburden materials being rich in magnesium and silica have advantage over the conventional flux combination.

Transactions of Nonferrous Metals Society of China, 2014

Ammonia leaching kinetics of a complex Cu-ore assaying 8.8% Cu and 36.1% Fe was examined. Mineral... more Ammonia leaching kinetics of a complex Cu-ore assaying 8.8% Cu and 36.1% Fe was examined. Mineralogical characterization indicated that the major phase of the ore was siderite with chalcopyrite as the major sulfide mineral. The effects of parameters such as agitation, temperature, NH 3 concentration, particle size and oxygen partial pressure (p O 2 ) were investigated. Under the standard leaching conditions of 125−212 µm particle size, 120 °C, 1.29 mol/L NH 3 and 202 kPa of p O 2 , about 83% Cu could be selectively extracted in 2.5 h. However, when using higher NH 3 concentration and lower particle size, more than 95% extraction was achieved. The leaching process was found to be surface reaction controlling. The estimated activation energy was (37.6±1.9) kJ/mol and empirical orders of reaction with respect to p O 2 and [NH 3 ] were about 0.2 and 1, respectively.

International Journal of Mining Science and Technology, 2013

ABSTRACT This paper deals with the recovery of ilmenite mineral from red sediments of badlands to... more ABSTRACT This paper deals with the recovery of ilmenite mineral from red sediments of badlands topography and suggested flowsheet with material balance. The results of these investigations reveal that the red sediment samples contain 33.2% total heavy mineral, in which ilmenite mineral concentrate is 28.71% (by weight). The ilmenite concentrate recovered from red sediment sample by physical beneficiation process, which included scrubbing, desliming, gravity concentration, magnetic and electrostatic separation, contains 99.41% grade with 97.3% recovery. The ilmenite mineral concentrate recovered from red sediments is also suitable for industrial applications. The characterization studies on ilmenite reveal that the TiO2 percentage is marginally increasing from 46.69% to 47.86% with increasing magnetic intensity from 0.46 to 1.55 T.

Journal of Mining and …, 2011

International Journal of Mineral Processing, 2016

Zusammenfassung: Eine Probe von minderwertigem Kieselkalkstein mit weißer Färbung und einem Gehal... more Zusammenfassung: Eine Probe von minderwertigem Kieselkalkstein mit weißer Färbung und einem Gehalt von 45,10 % CaO und 15,60 % SiO 2 aus der Abbaustätte Jayantipuram im Bundesstaat Andrha Pradesh/Indien, wurde bezüglich ihrer Eignung durch Flotation untersucht. Die Kalksteinprobe war kristallin und bestand vorwiegend aus Calcit und Quarz. Es wurden Experimente mit direkter Flotation durchgeführt, wobei Natriumsilicat und Natriumoleat als Drücker bzw. Sammler eingesetzt wurden. Es wurde das Verfahren der reversen Flotation eingesetzt, wobei das Siliciumdioxid (Quarz) enthaltende taube Gestein mit Hilfe des kationischen Sammlers SOMU Sokem 565C flotiert. Im Ergebnis konnte der Gehalt an CaO im Kalkstein gesteigert und der von SiO 2 reduziert werden, so dass der Kalkstein für die Zementherstellung verwendet werden kann. Summary: White colored low grade siliceous limestone sample containing 45.10 % CaO and 15.60 % SiO 2 from the Jayantipuram mine of Andhra Pradesh/India has been investigated for amenability to beneficiation by flotation. The limestone sample was crystalline and consisted mainly of calcite and quartz. Direct flotation experiments were carried out using sodium silicate and sodium oleate as depressant and collector respectively. The reverse flotation process was used where in the gangue minerals containing silica (quartz) are floated using a cationic collector SOMU Sokem 565C. The results are highly encouraging in enhancing the CaO and reducing the SiO 2 content in the limestone and thus to make it suitable for cement manufacture.

Goa state in India is endowed with large deposits of low-grade iron ores, geologically formed fro... more Goa state in India is endowed with large deposits of low-grade iron ores, geologically formed from the lower Dharwar super group of Archaean rocks. Petrological studies have revealed that silica and alumina are the main gangue minerals. where alumina exists as fine clay and adherent material interspersed in ore body and in some cases both silica and alumina are interlocked with iron ore particles. The amenability of Column flotation and Dual Extraction Column to remove such gangue was studied by installing test units at the Greater Ferromet beneficiation plant of Mis. Sociedade De Fomento Industrial Ltd., Goa. A reverse flotation process was adopted wherein gangue minerals containing silica and alumina are floated using cationic collector. Sodium hydroxide and starch were used to regulate the slurry pH and depress the iron ore, respectively. Iron ores of different mines and their mixtures were studied using different cationic collectors. The effect of both process and column parameters on grade and recovery were established. The results clearly suggest that iron ore concentrate assaying 67% Fe and 2% Si02 and Ah03 could be obtained with a recovery of 85-90% by single stage column operation. The better performance offlotation column over Dual Extraction Column in terms of reduction of gangue was also brought out in these studies.

The Open Mineral Processing Journal, 2011

The recovery of fine hematite particles from banded hematite quartzite (BHQ) ore with potato star... more The recovery of fine hematite particles from banded hematite quartzite (BHQ) ore with potato starch has been investigated using selective flocculation. Microscopic features, coupled with x-ray diffraction (XRD), and Fourier transforms infrared (FTIR) spectroscopic data provide evidences for adsorption of starch molecules on hematite surface. The starch molecules show good selectivity for hematite particles in the pH range of 8.5-9.5 and in the reagent concentration range of 20-40 mg/l. The Scanning electron microscope (SEM) studies show that flocs of hematite particles are larger and appear to be denser than that of quartz. Initial results with 1:1 hematite-quartz mixture indicated that it is possible to achieve an iron concentrate of 64.5% Fe with 92.0% of iron recovery from a feed of 34% Fe. However under optical conditions of pH and reagent concentration, the BHQ ore could be upgraded from an initial grade of 38.9% Fe to 57.2% Fe with 71% recovery. The overall results indicate that separation of very fine grained hematite present in the BHQ iron ore is feasible by selective flocculation.

Malanjkhand Copper Project (MCP), India is designed for excavating 2 million tons (MT)/annum of c... more Malanjkhand Copper Project (MCP), India is designed for excavating 2 million tons (MT)/annum of copper ore. The beneficiation plant of MCP utilizes Cu -0.45 % and above for production of concentrates thereby generating reject (mill spillage) from its ball mill unit. This waste contains mainly chalcopyrite which is recalcitrant to hydrometallurgical process. Economic and eco-friendly extraction of copper from such waste will definitely contribute to country's copper output. A novel technique using activation of the surface by thermal means aims on efficient copper recovery which is dealt in the present investigation. This process of activation modifies the surface morphology developing cracks, micro pores helping bacterial solution to penetrate and leach out copper efficiently. In the present work, the leaching ability of mesophillic acidophiles consortium consisting predominantly At. ferrooxidans towards this waste was studied in columns at 1 Kg scale. It was found that copper c...

Aufbereitungs-Technik/Mineral Processing

Ferrochrome industry waste, such as flue dust, contains chromite minerals that are considered to ... more Ferrochrome industry waste, such as flue dust, contains chromite minerals that are considered to be hazardous materials if left untreated, stockpiled or landfilled. Recovery of chromite values, by physical beneficiation techniques, can be applied to support recycling, the remaining waste being transformed into non-toxic materials for safe disposal. It is beneficial both with regard to saving raw material resources as well as reducing chromium pollution. To understand the nature of this waste and to develop a process for recovery of the chromium values, studies were conducted, with closer examination of the methods and equipment used, e.g. optical microscopy, XRD, Mozley mineral separator and magnetic separation.

Combustion Science and Technology

Mineralium Deposita

Manganese ores of Nishikhal occur as distinctly conformable bands in the khondalite suite of rock... more Manganese ores of Nishikhal occur as distinctly conformable bands in the khondalite suite of rocks belonging to the Precambrian Eastern Ghats complex of south Orissa, India. Manganese minerals recorded are cryptomelane, romanechite, pyrolusite, with minor amounts of jacobsite, hausmannite, braunite, lithiophorite, birnessite and pyrophanite. Goethite, graphite, hematite and magnetite are the other opaque minerals and quartz, orthoclase, garnet, kaolinite, apatite, collophane, fibrolite, zircon, biotite and muscovite are the gangue minerals associated with these ores. The mineral chemistry of some of the phases, as well as the modes of association of phosphorous in these ores have been established. The occurrence of well-defined bands of manganese ore; co-folding of manganese ore bands and associated metasedimentary country rocks; the mineral assemblage of spessartite-sillimanite-braunite-jacobsite-hausmannite; the geochemical association of Mn-Ba-Co-Ni-Zn together with the Si versus Al and Na versus Mg plots of the manganese ores suggest that the Nishikhal deposit is a metamorphosed Precambrian lacustrine deposit. Continental weathering appears to be the source for manganese and iron. After deposition and probable diagenesis, the manganese-rich sediments were metamorphosed along with conformable psammitic and pelitic sediments under granulite facies conditions, and subsequently underwent supergene enrichment to produce the present deposit.

The Open Mineral Processing Journal

The present investigation deals with the recovery of iron values from the screw classifier overfl... more The present investigation deals with the recovery of iron values from the screw classifier overflow slimes from an iron ore washing plant by means of reverse cationic flotation as an alternate to direct anionic flotation. Selectivity index, an indicator of separation efficiency, was chosen as the response parameter for optimizing thequantity and evaluating a series of generically same but chemically different cationic collectors used in reverse flotation and for further optimization of other flotation process parameters. In the optimization, the main variables investigated were percent solids, collector and depressant dosage. An increase in the iron content ofthe concentrates is obtained with concomitant reduction in SiO2 and Al2O3 levels.

Journal of Minerals and Materials Characterization and Engineering, 2005

Two different placer samples from the Navaladi and Surungudi area of Teri, Tamilnadu, in southern... more Two different placer samples from the Navaladi and Surungudi area of Teri, Tamilnadu, in southern India, were collected and characterized in terms of their heavy mineral content. Mineralogical analysis on both the samples revealed the presence of high amounts of garnet and ilmenite. The alteration characteristics of ilmenite from these deposits were investigated by optical and electron probe microanalysis. Optical microscopic studies revealed that the alteration of ilmenite was seen to proceed along grain boundaries and/or fractures resulting in an amorphous to crypto-or microcrystalline mass resembling leucoxene. The alteration is in the nascent stage.