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      Kinetics and Recovery of Xanthate-Copper Compounds by Ion Flotation Techniques

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          Abstract

          The recovery of copper in aqueous media by ion flotation in a laboratory flotation cell was carried out. Hydrodynamics and gas dispersion parameters were obtained. The results show that the increase of potassium amyl xanthate concentration above the stoichiometric amount considerably affects the efficiency of the separation of copper. In a stage of flotation with recirculation, recoveries of 58% and 66 % were obtained with the flat and the cylindrical spargers respectively. The dispersion parameters and bubble surface area flux (Sb) show a good relation with the apparent flotation rate constant (k), even when the superficial gas velocity is 0.8 cm/s, where we can find the appropriate hydrodynamic conditions to carry out the ion flotation. The system subsequently changes from a homogeneous bubble flux to a turbulent flux. Gas dispersion results show that superficial gas velocity, superficial liquid velocity, dispersion system geometry and the simulated malfunction of spargers considerably affect the recovery of copper in a multi stage system of five flotation cells. The best recoveries were obtained at low superficial gas velocities, achieving efficiencies of 94%, 90% and 95 % with the flat, cylindrical and battery of four spargers respectively.

          Translated abstract

          Se llevó a cabo la recuperación de cobre contenido en medio acuoso por flotación iónica en una celda de flotación de laboratorio. Se obtuvieron los parámetros de la dispersión de gas e hidrodinámica del sistema. Los resultados muestran que el incremento de la concentración de xantato amílico de potasio por arriba de la cantidad estequiométrica afecta considerablemente la eficiencia de separación de cobre. En la flotación iónica en una etapa con recirculación se obtuvieron recuperaciones del 58 y 66 % para el dispersor plano y cilíndrico, respectivamente. Los parámetros de la dispersión, el flujo de superficie de burbujas Sb (s-1) tienen buena correlación con la constante cinética de flotación aparente k (min-1), esto hasta un valor de la velocidad superficial de gas de 0.8 cm/s, donde se tienen condiciones hidrodinámicas adecuadas, donde el sistema cambia de un flujo de burbujas homogéneo a uno turbulento. Los resultados de la dispersión de gas muestran que la velocidad superficial de gas, la velocidad superficial de líquido y la geometría del sistema de dispersión, afectan significativamente la recuperación de cobre acuoso en un sistema multi etapas de cinco celdas de flotación. Las mejores recuperaciones obtenidas se obtuvieron a bajas velocidades superficiales de gas, logrando eficiencia de 94, 90, y 95 % para el dispersor plano, cilíndrico y batería de cilíndricos, respectivamente.

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          Most cited references 21

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          Rapid planetesimal formation in turbulent circumstellar discs

          The initial stages of planet formation in circumstellar gas discs proceed via dust grains that collide and build up larger and larger bodies (Safronov 1969). How this process continues from metre-sized boulders to kilometre-scale planetesimals is a major unsolved problem (Dominik et al. 2007): boulders stick together poorly (Benz 2000), and spiral into the protostar in a few hundred orbits due to a head wind from the slower rotating gas (Weidenschilling 1977). Gravitational collapse of the solid component has been suggested to overcome this barrier (Safronov 1969, Goldreich & Ward 1973, Youdin & Shu 2002). Even low levels of turbulence, however, inhibit sedimentation of solids to a sufficiently dense midplane layer (Weidenschilling & Cuzzi 1993, Dominik et al. 2007), but turbulence must be present to explain observed gas accretion in protostellar discs (Hartmann 1998). Here we report the discovery of efficient gravitational collapse of boulders in locally overdense regions in the midplane. The boulders concentrate initially in transient high pressures in the turbulent gas (Johansen, Klahr, & Henning 2006), and these concentrations are augmented a further order of magnitude by a streaming instability (Youdin & Goodman 2005, Johansen, Henning, & Klahr 2006, Johansen & Youdin 2007) driven by the relative flow of gas and solids. We find that gravitationally bound clusters form with masses comparable to dwarf planets and containing a distribution of boulder sizes. Gravitational collapse happens much faster than radial drift, offering a possible path to planetesimal formation in accreting circumstellar discs.
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            The Dicke Quantum Phase Transition with a Superfluid Gas in an Optical Cavity

            A phase transition describes the sudden change of state in a physical system, such as the transition between a fluid and a solid. Quantum gases provide the opportunity to establish a direct link between experiment and generic models which capture the underlying physics. A fundamental concept to describe the collective matter-light interaction is the Dicke model which has been predicted to show an intriguing quantum phase transition. Here we realize the Dicke quantum phase transition in an open system formed by a Bose-Einstein condensate coupled to an optical cavity, and observe the emergence of a self-organized supersolid phase. The phase transition is driven by infinitely long-ranged interactions between the condensed atoms. These are induced by two-photon processes involving the cavity mode and a pump field. We show that the phase transition is described by the Dicke Hamiltonian, including counter-rotating coupling terms, and that the supersolid phase is associated with a spontaneously broken spatial symmetry. The boundary of the phase transition is mapped out in quantitative agreement with the Dicke model. The work opens the field of quantum gases with long-ranged interactions, and provides access to novel quantum phases.
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              Ion flotation

               F. Sebba (1962)
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                Author and article information

                Contributors
                Role: ND
                Role: ND
                Role: ND
                Role: ND
                Role: ND
                Role: ND
                Journal
                jmcs
                Journal of the Mexican Chemical Society
                J. Mex. Chem. Soc
                Sociedad Química de México A.C. (México )
                1870-249X
                March 2009
                : 53
                : 1
                : 15-22
                Affiliations
                [1 ] Universidad Autónoma del Estado de Hidalgo Mexico
                [2 ] Universidad Michoacana de San Nicolás de Hidalgo Mexico
                Article
                S1870-249X2009000100004

                http://creativecommons.org/licenses/by/4.0/

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                Categories
                Chemistry, Multidisciplinary

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