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Columbia River Magnetite Sands, Clatsop County, Oregon, and Pacific County, Washington, Hammond and McGowan Deposits

Description: Report issued by the U.S. Bureau of Mines on investigations of the magnetite-bearing sands near the Columbia River between Oregon and Washington. Properties of the sands and magnetite deposits are listed. This report includes tables, maps, and illustrations.
Date: February 1947
Creator: Kelly, James V.
Partner: UNT Libraries Government Documents Department

Corrosion Protection of Low Carbon Steel By Cation Substituted Magnetite

Description: Surfaces of low carbon steel sheet were modified by exposure to highly caustic aqueous solutions containing either chromium or aluminum cations. Corrosion resistances of such surfaces were compared with that of steel surfaces exposed to plain caustic aqueous solution. In all cases a highly uniform, black coating having a spinel structure similar to magnetite (Fe3O4) was obtained. The coated steel surfaces were characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectrophotometry (FTIR). Polarization resistances (Rp) of modified steel surfaces were measured and compared with that of bare steel surfaces. Results indicate that chromium (Fe2+ Fe3+x Cr3+1-x) or aluminum (Fe2+ Fe3+x Al3+1-x) substituted spinel phases formed on steel surfaces showed higher Rp values compared to only magnetite (Fe2+ 2Fe3+O4) phase formed in the absence of either chromium or aluminum cations. Average Rp values for steel surfaces with chromium containing spinel phase were much higher (21.8 k?) as compared to 1.7 k? for bare steel surfaces. Steel surfaces with aluminum containing spinel phase and steels with plain magnetite coated samples showed average Rp values of 3.3 k? and 2.5 k? respectively. XPS and EDS analysis confirmed presence of cations of chromium and aluminum in Fe3O4 in cation substituted samples. FTIR results showed all coating phases were of spinel form with major absorption bands centered at either 570 cm-1 or 600 cm-1 assigned to Fe3O4 and ?-Fe2O3 respectively.
Date: May 2013
Creator: Phadnis, Ameya
Partner: UNT Libraries

Iron Mountain Titaniferous Magnetite Deposits, Fremont County, Colorado

Description: Report issued by the Bureau of Mines over the Iron Mountain magnetite deposits. As stated in the introduction, "magnetic, gravity, and geologic surveys were made to permit an estimate of the extent and magnitude of the Iron Mountain, Colorado, titaniferous magnetite deposit" (p. 1). This report includes tables, maps, and illustrations.
Date: 1961
Creator: Becker, Robert M.; Shannon, S. S., Jr. & Rose, C. K.
Partner: UNT Libraries Government Documents Department

Magnetite and Ilmenite Resources, Iron Mountain Area, Albany County, Wyoming

Description: Report issued by the U.S. Bureau of Mines discussing magnetite and ilmenite mining methods and practices. As stated in the introduction, "this report summarizes the exploration of the titaniferous iron deposits in the Iron Mountain area, Albany County, Wyo." (p. 1). This report includes maps, tables, illustrations, and photographs.
Date: 1961
Creator: Dow, Vernon T.
Partner: UNT Libraries Government Documents Department

Study of lead sorption on magnetite at high temperatures.

Description: Lead's uptake on magnetite has been quantitatively evaluated in the present study at a temperature of 200°C and pH of 8.5 with lead concentrations ranging from 5 ppm to175 ppm by equilibrium adsorption isotherms. The pH independent sorption behavior suggested lead sorption due to pH independent permanent charge through weak electrostatic, non-specific attraction where cations are sorbed on the cation exchange sites. The permanent negative charge could be a consequence of lead substitution which is supported by increase in the lattice parameter values from the X-ray diffraction (XRD) results. Differential scanning calorimetry (DSC/TGA) results showed an increase of exothermic (magnetite to maghemite transformation) peak indicating substitution of lead ions due to which there is retardation in the phase transformation. Presence of outer sphere complexes and physical sorption is further supported by Fourier transformed infrared spectroscopy (FTIR). None of the results suggested chemisorption of lead on magnetite.
Date: December 2006
Creator: Paliwal, Vaishali
Partner: UNT Libraries

Remediation of Cr(VI) by biogenic magnetic nanoparticles: An x-ray magnetic circular dichroism study

Description: Biologically synthesized magnetite (Fe{sub 3}O{sub 4}) nanoparticles are studied using x-ray absorption and x-ray magnetic circular dichroism following exposure to hexavalent Cr solution. By examining their magnetic state, Cr cations are shown to exist in trivalent form on octahedral sites within the magnetite spinel surface. The possibility of reducing toxic Cr(VI) into a stable, non-toxic form, such as a Cr{sup 3+}-spinel layer, makes biogenic magnetite nanoparticles an attractive candidate for Cr remediation.
Date: September 4, 2009
Creator: Telling, N. D.; Coker, V. S.; Cutting, R. S.; van der Laan, G.; Pearce, C. I.; Pattrick, R. A. D. et al.
Partner: UNT Libraries Government Documents Department

Control of nanoparticle size, reactivity and magnetic properties during the bioproduction of magnetite by Geobacter sulfurreducens

Description: The bioproduction of nano-scale magnetite by Fe(III)-reducing bacteria offers a potentially tunable, environmentally benign route to magnetic nanoparticle synthesis. Here, we demonstrate that it is possible to control the size of magnetite nanoparticles produced by Geobacter sulfurreducens, by adjusting the total biomass introduced at the start of the process. The particles have a narrow size distribution and can be controlled within the range of 10-50 nm. X-ray diffraction analysis indicates that controlled production of a number of different biominerals is possible via this method including goethite, magnetite and siderite, but their formation is strongly dependent upon the rate of Fe(III) reduction and total concentration and rate of Fe(II) produced by the bacteria during the reduction process. Relative cation distributions within the structure of the nanoparticles has been investigated by X-ray magnetic circular dichroism and indicates the presence of a highly reduced surface layer which is not observed when magnetite is produced through abiotic methods. The enhanced Fe(II)-rich surface, combined with small particle size, has important environmental applications such as in the reductive bioremediation of organics, radionuclides and metals. In the case of Cr(VI), as a model high-valence toxic metal, optimised biogenic magnetite is able to reduce and sequester the toxic hexavalent chromium very efficiently in the less harmful trivalent form.
Date: August 2, 2011
Creator: Byrne, J. M.; Telling, N. D.; Coker, V. S.; Pattrick, R. A. D.; Laan, G. van der; Arenholz, E. et al.
Partner: UNT Libraries Government Documents Department

Radioactive Rare-Earth Deposit at Scrub Oaks Mine, Morris County, New Jersey

Description: From abstract: A deposit of rare-earth minerals in the Scrub Oaks iron mine, Morris County, N. J., was mapped and sampled in 1955. The rare-earth minerals are mainly in coarse-grained magnetite ore and in pegmatite adjacent to it. Discrete bodies of rare-earth-bearing magnetite ore apparently follow the plunge of the main magnetite ore body at the north end of the mine. Radioactivity of the ore containing rare earths is about 0.2 to 0.6 milliroentgens per hour.
Date: 1959
Creator: Klemic, Harry; Heyl, Allen V., Jr.; Taylor, A. R. & Stone, Jerome
Partner: UNT Libraries Government Documents Department

Magnetic Adsorption Method for the Treatment of Metal Contaminated Aqueous Waste

Description: There have been many recent developments in separation methods used for treating radioactive and non-radioactive metal bearing liquid wastes. These methods have included adsorption, ion exchange, solvent extraction and other chemical and physical techniques. To date very few, if any, of these processes can provide a low cost and environmentally benign solution. Recent research into the use of magnetite for wastewater treatment indicates the potential for magnetite both cost and environment drivers. A brief review of recent work in using magnetite as a sorbent is presented as well as recent work performed in our laboratory using supported magnetite in the presence of an external magnetic field. The application to groundwater and other aqueous waste streams is discussed. Recent research has focused on supporting magnetite in an economical (as compared to the magnetic polymine-epichlorohydrine resin) and inert (non-reactive, chemically or otherwise) environment that promotes both adsorption and satisfactory flow characteristics.
Date: March 1, 1999
Creator: Cotten, Gregory B.; Navratil, James D. & Eldredge, H. Bradley
Partner: UNT Libraries Government Documents Department

Geology of the North Bradfield River Iron Prospect, Southeastern Alaska

Description: From abstract: The North Bradfield River iron prospect is in southeastern Alaska in rugged terrain about 8 miles southwest of the Canadian boundary and about 15 miles northeast of the head of Bradfield Canal. The prospect includes several magnetite-rich ore bodies of pyrometasomatic origin that are localized in skarn. The skarn forms a small part of a northwestward-trending roof pendant that is enclosed in the composite Coast Range batholith. The dominant rocks of the roof pendant are gneiss, granulite, schist, and marble. The ore, which consists almost entirely of magnetite, contains subordinate amounts of hematite, hydrous iron sesquioxides, pyrrhotite, chalcopyrite, and malachite. The ore bodies are crudely stratiform and apparently discontinuous. The largest ore body exposed is traceable for about 350 feet along its strike and averages about 25 feet in thickness. An accurate appraisal of the economic potential of the prospect was precluded by poor outcrops, local snow cover, and inadequate subsurface data.
Date: 1963
Creator: MacKevett, E. M., Jr. & Blake, M. Clark, Jr.
Partner: UNT Libraries Government Documents Department

Optimizing Cr(VI) and Tc(VII) remediation through nano-scale biomineral engineering

Description: To optimize the production of biomagnetite for the bioremediation of metal oxyanion contaminated waters, the reduction of aqueous Cr(VI) to Cr(III) by two biogenic magnetites and a synthetic magnetite was evaluated under batch and continuous flow conditions. Results indicate that nano-scale biogenic magnetite produced by incubating synthetic schwertmannite powder in cell suspensions of Geobacter sulfurreducens is more efficient at reducing Cr(VI) than either biogenic nano-magnetite produced from a suspension of ferrihydrite 'gel' or synthetic nano-scale Fe{sub 3}O{sub 4} powder. Although X-ray Photoelectron Spectroscopy (XPS) measurements obtained from post-exposure magnetite samples reveal that both Cr(III) and Cr(VI) are associated with nanoparticle surfaces, X-ray Magnetic Circular Dichroism (XMCD) studies indicate that some Cr(III) has replaced octahedrally coordinated Fe in the lattice of the magnetite. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) measurements of total aqueous Cr in the associated solution phase indicated that, although the majority of Cr(III) was incorporated within or adsorbed to the magnetite samples, a proportion ({approx}10-15 %) was released back into solution. Studies of Tc(VII) uptake by magnetites produced via the different synthesis routes also revealed significant differences between them as regards effectiveness for remediation. In addition, column studies using a {gamma}-camera to obtain real time images of a {sup 99m}Tc(VII) radiotracer were performed to visualize directly the relative performances of the magnetite sorbents against ultra-trace concentrations of metal oxyanion contaminants. Again, the magnetite produced from schwertmannite proved capable of retaining more ({approx}20%) {sup 99m}Tc(VII) than the magnetite produced from ferrihydrite, confirming that biomagnetite production for efficient environmental remediation can be fine-tuned through careful selection of the initial Fe(III) mineral substrate supplied to Fe(III)-reducing bacteria.
Date: September 9, 2009
Creator: Cutting, R. S.; Coker, V. S.; Telling, N. D.; Kimber, R. L.; Pearce, C. I.; Ellis, B. et al.
Partner: UNT Libraries Government Documents Department

Stability of uranium incorporated into Fe(hydr)oxides under fluctuating redox conditions

Description: Reaction pathways resulting in uranium bearing solids that are stable (i.e., having limited solubility) under both aerobic and anaerobic conditions will limit dissolved concentrations and migration of this toxin. Here we examine the sorption mechanism and propensity for release of uranium reacted with Fe (hydr)oxides under cyclic oxidizing and reducing conditions. Upon reaction of ferrihydrite with Fe(II) under conditions where aqueous Ca-UO{sub 2}-CO{sub 3} species predominate (3 mM Ca and 3.8 mM CO{sub 3}-total), dissolved uranium concentrations decrease from 0.16 mM to below detection limit (BDL) after 5 to 15 d, depending on the Fe(II) concentration. In systems undergoing 3 successive redox cycles (15 d of reduction followed by 5 d of oxidation) and a pulsed decrease to 0.15 mM CO{sub 3}-total, dissolved uranium concentrations varied depending on the Fe(II) concentration during the initial and subsequent reduction phases - U concentrations resulting during the oxic 'rebound' varied inversely with the Fe(II) concentration during the reduction cycle. Uranium removed from solution remains in the oxidized form and is found both adsorbed on and incorporated into the structure of newly formed goethite and magnetite. Our 15 results reveal that the fate of uranium is dependent on anaerobic/aerobic conditions, aqueous uranium speciation, and the fate of iron.
Date: April 1, 2009
Creator: Stewart, B.D.; Nico, P.S. & Fendorf, S.
Partner: UNT Libraries Government Documents Department

Aggregate-scale heterogeneity in iron (hydr)oxide reductive transformations

Description: There is growing awareness of the complexity of potential reaction pathways and the associated solid-phase transformations during the reduction of Fe (hydr)oxides, especially ferrihydrite. An important observation in static and advective-dominated systems is that microbially produced Fe(II) accelerates Ostwald ripening of ferrihydrite, thus promoting the formation of thermodynamically more stable ferric phases (lepidocrocite and goethite) and, at higher Fe(II) surface loadings, the precipitation of magnetite; high Fe(II) levels can also lead to green rust formation, and with high carbonate levels siderite may also be formed. This study expands this emerging conceptual model to a diffusion-dominated system that mimics an idealized micropore of a ferrihydrite-coated soil aggregate undergoing reduction. Using a novel diffusion cell, coupled with micro-x-ray fluorescence and absorption spectroscopies, we determined that diffusion-controlled gradients in Fe{sup 2+}{sub (aq)} result in a complex array of spatially distributed secondary mineral phases. At the diffusive pore entrance, where Fe{sup 2+} concentrations are highest, green rust and magnetite are the dominant secondary Fe (hydr)oxides (30 mol% Fe each). At intermediate distances from the inlet, green rust is not observed and the proportion of magnetite decreases from approximately 30 to <10%. Across this same transect, the proportion of goethite increases from undetectable up to >50%. At greater distances from the advective-diffusive boundary, goethite is the dominant phase, comprising between 40 and 95% of the Fe. In the presence of magnetite, lepidocrocite forms as a transient-intermediate phase during ferrihydrite-to-goethite conversion; in the absence of magnetite, conversion to goethite is more limited. These experimental observations, coupled with results of reactive transport modeling, confirm the conceptual model and illustrate the potential importance of diffusion-generated concentration gradients in dissolved Fe{sup 2+} on the fate of ferrihydrite during reduction in structured soils.
Date: June 15, 2009
Creator: Tufano, K. J.; Benner, S. G.; Mayer, K. U.; Marcus, M. A.; Nico, P. S. & Fendorf, S.
Partner: UNT Libraries Government Documents Department

Formation of magnetite and iron-rich carbonates by thermophilic iron-reducing bacteria

Description: Laboratory experiments were performed to study the formation of iron minerals by a thermophilic (45 to 75 C) fermentative iron-reducing bacterial culture (TOR39) obtained from the deep subsurface. Using amorphous Fe(III) oxyhydroxide as an electron acceptor and glucose as an electron donor, TOR39 produced magnetite and iron-rich carbonates at conditions consistent, on a thermodynamic basis, with Eh ({minus}200 mV to {minus}415 mV) and pH (6.2 to 7.7) values determined for these experiments. Analyses of the precipitating solid phases by X-ray diffraction showed that the starting amorphous Fe(III) oxyhydroxide was nearly completely converted to magnetite and Fe-rich carbonate after 20 days of incubation. Increasing bicarbonate concentration in the chemical milieu resulted in increased proportions of siderite relative to magnetite and the addition of MgCl{sub 2} caused the formation of magnesium-rich carbonate in addition to siderite. The results suggest that the TOR39 bacterial culture may have the capacity to form magnetite and iron-rich carbonates in a variety of geochemical conditions. These results may have significant implications for studying the past biogenic activities in the Martian meteorite ALH84001.
Date: June 1, 1997
Creator: Zhang, C.; Liu, S.; Roh, Y.; Cole, D.; Phelps, T.; Vali, H. et al.
Partner: UNT Libraries Government Documents Department

Mechanisms of pyrite oxidation to non-slagging species. Quarterly report, January 1, 1995--March 31, 1995

Description: This document is the third quarterly status report on a project conducted at the High Temperature Gasdynamics Laboratory at Stanford University, Stanford, California and concerned with enhancing the transformation of iron pyrite to non-slagging species during staged, low-NO{sub x} pulverized coal (P.C.) combustion. The research project is intended to advance PETC`s efforts to improve our technical understanding of the high-temperature chemical and physical processes involved in the utilization of coal. The work focuses on the mechanistic description and rate quantification of the effects of fuel properties and combustion environment on the oxidation of iron pyrite to form the non-slagging species magnetite. The knowledge gained from this work is intended to be incorporated into numerical codes that can be used to formulate anti-slagging strategies involving minimal disturbance of coal combustor performance.
Date: August 1, 1995
Creator: Akan-Etuk, A.E.J. & Mitchell, R.E.
Partner: UNT Libraries Government Documents Department

Solubility and Reaction Rates of Aluminum Solid Phases Under Hydrothermal Conditions

Description: Experimental studies involving equilibrium solubility and dissolution/precipitation rates were initiated on boehmite (AIOOH) using a hydrogen-electrode concentration cell (HECC). This cell provides continuous, accurate in situ pH measurements of solid/solution mixtures to 295 C with provision for either removing solution samples for analysis of the metal content, or adding either of two titrants. This cell has been recently used to measure the solubility of minerals such as brucite; boehmite, zincite, arid magnetite. The ability to perturb pH, isothermally by addition of acidic or basic titrant opens the door for studies of the kinetics of dissolution/precipitation, even for relatively fast reactions. By monitoring the change in pH, with time, detailed kinetic information can be obtained without the need for sampling.
Date: November 14, 1999
Creator: Benezeth, P.; Palmer, D.A. & Wesolowski, D.
Partner: UNT Libraries Government Documents Department

A PURPOSE ORIENTED MAGNETIC SEPARATOR: SKIMMER

Description: A magnetic separator was designed to selectively separate fine-liberated magnetite. The conceptual design was simulated using CFD techniques. A separator tank was fabricated and a magnetic drum was used to capture magnetic particles. The initial tank design was modified to eliminate application oriented problems. The new separator was able to produce a fine product as a concentrate at relatively high feed rates. A plant simulation showed that such a device could lower circulating loads around ball mills by 16%, thereby creating room for a 5-8% increase in throughput at the same energy level. However, it was concluded that further improvements in terms of both size and mineral selectivity are needed to have a marketable product.
Date: August 9, 2005
Creator: Ersayin, Salih
Partner: UNT Libraries Government Documents Department

Studies of Particulates and Structural Transformations in Glass Using Synchrotron Radiation. Final Technical Report

Description: The initial study on nanoparticles of magnetite was carried out in an epoxy matrix. The formation of agglomerates of Fe3O4 nanoparticles was studied by mu-XRF, magnetic, TEM and SEM techniques. Because of the elevated viscosity of epoxy resin and its effect on particle agglomeration, this study was extended using less viscous polyvinyl alcohol and some sol gels as a matrix. Unlike the results found in epoxy resin, spherical agglomerates were found in a PVA matrix even at Fe3O4 concentration of up to 50%.
Date: April 13, 2001
Creator: Thorpe, Arthur
Partner: UNT Libraries Government Documents Department

Using Arrested Solid-Solid Multiphase Reactions in Geological Materials to Deduce the Rate of Crustal Uplift

Description: The history geological terrains experience can be traced as a series of temperature and pressure changes. Each change drives the system toward a new state of thermodynamic equilibrium. The resultant overprinted rock fabrics, textures and chemical heterogeneities can be difficult to interpret. However, if carefully chosen, features from the scale of kilometers to nanometers can be used to reconstruct the history of mountain systems. Uplift of the Sri Lankan Central Highlands was rapid enough to preserve well-developed symplectite textures, some of which represent arrested solid-state diffusion-controlled reactions of garnet + O{sub 2} to form orthopyroxene + plagioclase + magnetite, as the rocks were exhumed from over 30 km in the earth's crust. Our objective has been to determine the reaction mechanisms responsible for symplectite development, and to establish the time interval over which these reactions occurred, to constrain the rate of mountain uplift. Considering that the most rapid mechanism is solid state grain-boundary diffusion of oxygen, the reaction time can be constrained by bounding the rate of oxygen supply to the reaction site. The solid state grain boundary diffusion rate of oxygen has been inferred to be ca. 10{sup -14}m{sup 2}-sec (Farver and Yund, 1991), but is sensitive to inferred grain boundary width. The range of rates thus determined allows the distinction between rapid uplift similar to that of the Himalayan Mountains, and the slow and progressive erosion of a less dramatic terrain. Further constraints on diffusion control and energetic relationships are determined from crystallographic relationships between the reactant and product phases, and submicron scale microstructure.
Date: March 13, 2000
Creator: Glassley, W.E. & Meike, A.
Partner: UNT Libraries Government Documents Department