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A project aims at determining the water footprint of various metals using life-cycle analysis and developing technologies that reduce water consumption. Mathematical models were developed to establish the relationship between ore grade and water use. Ni, Cu and Au were initially chosen for their relatively high water intensity. Life-cycle based inventory data on water consumption at various stages were collected from the open literature, and some embodied water footprints of materials and processes were compiled from the Ecoinvent database. Processes considered were the mining, beneficiation, smelting and refining of Cu sulphide ore grading 0.75% Cu; mining, heap leaching and solvent extraction-electrowinning of Cu oxide ore grading 0.75% Cu; mining, cyanidation, carbon-in-pulp, electrowinning, smelting and refining of non-refractory Au ore grading 3.5 g/t Au; mining, integrated flotation-pressure oxidation, cyanidation, carbon-in-pulp, electrowinning, smelting and refining of a refractory Au ore grading 3.5 g/t Au; mining, beneficiation, smelting, ammonia leaching and hydrogen reduction of a Ni sulphide ore containing 1.3% Ni; and mining, high-pressure acid leaching, sulphide precipitation, ammonia leaching and hydrogen reduction of a Ni limonite ore grading 1.3%Ni. The results showed that the main process variable affecting the direct water footprint is the grade of the ore being mined, while another key factor was the degree of water recycling that occurs in the concentrator and tailings storage facility. The main opportunity to recover and reuse/recycle water is from the tailings dewatering processes. In general dewatering to higher tailings solids densities will result in lower direct water consumption and as ore grades decline the differences are exacerbated. The indirect water consumption was estimated to be less than the direct water consumption for Au production, Cu pyrometallurgy and Ni pyrometallurgy but higher than direct consumption for Cu and Ni hydrom, A project aims at determining the water footprint of various metals using life-cycle analysis and developing technologies that reduce water consumption. Mathematical models were developed to establish the relationship between ore grade and water use. Ni, Cu and Au were initially chosen for their relatively high water intensity. Life-cycle based inventory data on water consumption at various stages were collected from the open literature, and some embodied water footprints of materials and processes were compiled from the Ecoinvent database. Processes considered were the mining, beneficiation, smelting and refining of Cu sulphide ore grading 0.75% Cu; mining, heap leaching and solvent extraction-electrowinning of Cu oxide ore grading 0.75% Cu; mining, cyanidation, carbon-in-pulp, electrowinning, smelting and refining of non-refractory Au ore grading 3.5 g/t Au; mining, integrated flotation-pressure oxidation, cyanidation, carbon-in-pulp, electrowinning, smelting and refining of a refractory Au ore grading 3.5 g/t Au; mining, beneficiation, smelting, ammonia leaching and hydrogen reduction of a Ni sulphide ore containing 1.3% Ni; and mining, high-pressure acid leaching, sulphide precipitation, ammonia leaching and hydrogen reduction of a Ni limonite ore grading 1.3%Ni. The results showed that the main process variable affecting the direct water footprint is the grade of the ore being mined, while another key factor was the degree of water recycling that occurs in the concentrator and tailings storage facility. The main opportunity to recover and reuse/recycle water is from the tailings dewatering processes. In general dewatering to higher tailings solids densities will result in lower direct water consumption and as ore grades decline the differences are exacerbated. The indirect water consumption was estimated to be less than the direct water consumption for Au production, Cu pyrometallurgy and Ni pyrometallurgy but higher than direct consumption for Cu and Ni hydrom

The MagSonicTM process involves the carbothermal reduction of magnesia directly with carbon in the high-temperature gas-solid reaction. This process achieves minimal reversion by cooling the reaction product gases at up to 1 000 000 degrees C/second by supersonic acceleration through a Laval nozzle. Energy intensity is just 56 GJ per tonne Mg, less than a quarter that of the next best technology, and global warming potential 14 t CO2-eq/t Mg, slightly better than for the electrolytic process and less than half that of the silicothermic Pidgeon process. Operating cost compares favourably, only 6 person hours/t Mg, half that of electrolysis and one fifteenth that of the Pidgeon process. However, the capital cost is estimated at US, The MagSonicTM process involves the carbothermal reduction of magnesia directly with carbon in the high-temperature gas-solid reaction. This process achieves minimal reversion by cooling the reaction product gases at up to 1 000 000 degrees C/second by supersonic acceleration through a Laval nozzle. Energy intensity is just 56 GJ per tonne Mg, less than a quarter that of the next best technology, and global warming potential 14 t CO2-eq/t Mg, slightly better than for the electrolytic process and less than half that of the silicothermic Pidgeon process. Operating cost compares favourably, only 6 person hours/t Mg, half that of electrolysis and one fifteenth that of the Pidgeon process. However, the capital cost is estimated at US

Data from 12 different Cluster orbits containing banded chorus emissions, with observations from 22 different events spread across the four Cluster spacecraft, are used to show the spatial dependence of banded chorus intensity near the magnetic equator under conditions of moderate magnetic disturbance (K-p <= 5). The intensities for upper band (UB) and lower band (LB) chorus were manually determined from frequency-time spectrograms generated from WBD data. Out of the 22 events, 5 of the spacecraft observations showed a complete absence of chorus emissions within 0.5 degrees of the magnetic equator. The intensity, I, of the chorus emissions generally increased exponentially with distance, z, away from the magnetic equator according to the relation I = I(o)e(az), where alpha is the spatial growth factor. The exponential distribution of alpha provides a new boundary condition for consideration in current and future chorus generation models. Citation: Haque, N., U. S. Inan, T. F. Bell, and J. S. Pickett (2012), Spatial dependence of banded chorus intensity near the magnetic equator, Geophys. Res. Lett., 39, L17103, doi:10.1029/2012GL052929., ONR; NASA GSFC

Bell et al. (2009) proposed that the source region for banded chorus consists of whistler mode ducts of depleted electron density (N-e) for upper band (UB) chorus for all wave normal angles (theta) and ducts of either enhanced or depleted N-e for lower band (LB) chorus for small theta and theta near or greater than the Gendrin angle, respectively. This paper provides support for this model using new high resolution (17 km) N-e observations from the Cluster WHISPER and EFW instruments. Data is examined from January 20, 2004, when strong banded chorus was observed over 3000 km of the Cluster 2 orbit, ending at the magnetic equator. Previous analysis of LB chorus on this day indicated the wave normal angles were larger than the Gendrin angle. Using the N-e data, we show that the LB chorus is generated within depletion ducts in the source region and that the half-width of these ducts (similar to 70 km) is comparable to the transverse scale (similar to 100 km) of the chorus source region. Making use of the fact that the group velocity of the LB chorus waves has a significant cross-L component, we show that the source region extends over 500 km near the magnetic equator., NASA; ONR

A technical and economic study was made of the value generated by CSIRO's newly developed process for the treatment of high arsenic copper ores, which uses flotation to separate off the arsenic-bearing minerals. Both the conventional and arsenic-removal flowsheets were modelled using the METSIM software package. Based on a series of price and consumable/labour assumptions, the study indicated that the cost of the new process was 17% higher (Aus, A technical and economic study was made of the value generated by CSIRO's newly developed process for the treatment of high arsenic copper ores, which uses flotation to separate off the arsenic-bearing minerals. Both the conventional and arsenic-removal flowsheets were modelled using the METSIM software package. Based on a series of price and consumable/labour assumptions, the study indicated that the cost of the new process was 17% higher (Aus

Opportunities for reducing energy and water consumption in the processing of copper, and to a lesser extent nickel, have been identified through the use of life cycle assessment. One major area of energy consumption was that of comminution, while the greatest consumption of water occurred during mineral processing stage. Among the alternative technologies outlined are the use of high-pressure grinding and heap leaching. The implications for downstream operations of lowering the concentrate grade, and the use of dry processes at the mineral processing stage, are also considered., Opportunities for reducing energy and water consumption in the processing of copper, and to a lesser extent nickel, have been identified through the use of life cycle assessment. One major area of energy consumption was that of comminution, while the greatest consumption of water occurred during mineral processing stage. Among the alternative technologies outlined are the use of high-pressure grinding and heap leaching. The implications for downstream operations of lowering the concentrate grade, and the use of dry processes at the mineral processing stage, are also considered.

Using data from the High Frequency Waveform Receiver on board the Polar spacecraft, 1,765 and 993 wave normal angles have been analyzed for 13 orbits containing upper band magnetospheric chorus emissions and 15 orbits containing lower band emissions, respectively. The purpose of this study is to characterize the distribution of the polar wave normal angle, theta, for chorus emissions as a function of magnetic latitude, l. Understanding wave normal angles is an important step in evaluating resonant wave particle interactions. For upper band chorus, wave normal angles tend to remain at or rise toward the resonance cone angle for low latitudes and midlatitudes but move away from the resonance cone angle at higher latitudes. For lower band chorus, wave normal angles with values theta < 20 degrees have the highest probability of occurrence in the latitude range of 10 degrees-50 degrees. Just off the equator, 10 degrees <= lambda < 25 degrees, there exists a secondary occurrence peak in the range of 50 degrees <= theta < 70 degrees. The probability of observing these higher wave normal angles decreases with increasing latitude. The time-averaged Poynting flux, S, is much larger for lower band chorus waves, which have a mean value of 8.5 x 10(-8) W/m(2), than for upper band chorus waves, which have a mean value of 1.4 x 10(-9) W/m(2). S is fairly evenly distributed about its median value, 3.1 x 10(-10) W/m(2), for all wave normal angles for upper band chorus but deceases as theta increases for lower band chorus., Office of Naval Research; NASA; NSF; GAAV

Iron modified materials have been proposed as a filter medium to remove arsenic compounds from groundwater. This research investigated the removal of arsenate, As(V) from aqueous solutions by iron-coated light expanded clay aggregates (Fe-LECA). Arsenic is effectively adsorbed by Fe-LECA in the optimum pH range 6-7 by using a 10 mg mL- 1 adsorbent dose. Kinetics experiments were performed to investigate the adsorption mechanisms. Electrostatic attraction and surface complexation were proposed to be the major arsenic removal mechanisms. The experimental data fitted the pseudo-first-order equation of Lagergren. For an arsenic concentration of 1 mg L- 1, the rate constant (k1) of pseudo-first-order was 0.098 min- 1, representing a rapid adsorption in order to reach equilibrium early. Equilibrium sorption isotherms were constructed from batch sorption experiments and the data was best described by the Langmuir isotherm model. Large scale column experiments were conducted under different bed depths, flow rates, coating duration and initial iron salts concentration to determine the optimal arsenic removal efficiency by Fe-LECA column. Volumetric design as well as higher hydraulic detention time was proposed to optimize the efficiency of the column to remove arsenic. In addition, concentrated iron salts and longer coating duration were also found to be crucial parameters for arsenic removal. The maximum arsenic accumulation was 3.31 mg of As g- 1 of Fe-LECA when the column was operated at a flow rate of 10 mL min- 1 and the LECA was coated with 0.1 M FeCl3 suspension for a 24 h coating duration. © 2007 Elsevier B.V. All rights reserved.

Two decades ago, it was predicted [Y S. Kim et al., Phys. Rev. Lett. 46, 1326 (1981)] that relativistic effects should alter the dynamics of the photoionization process in. the vicinity of Cooper minima. The present experimental and theoretical study of t, Addresses: Wang H, Univ Nevada, Dept Chem, Las Vegas, NV 89154 USA. Univ Nevada, Dept Chem, Las Vegas, NV 89154 USA. Univ Uppsala, Dept Phys, S-75121 Uppsala, Sweden. Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. Univ Calif Berkeley, Lawrence