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Journal articles on the topic 'Gibbsite Scale'

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Published: 4 June 2021
Last updated: 1 February 2022

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1

Golubev, Vladimir, and Tatyana Litvinova. "Dynamic simulation of industrial-scale gibbsite crystallization circuit." Journal of Mining Institute 247 (March 16, 2021): 88–101. http://dx.doi.org/10.31897/pmi.2021.1.10.

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Population balance model is crucial for improving the method of aluminum hydroxide massive crystallization and enhancing the quality of control over industrial precipitation trains. This paper presents the updated population balance model, which can be used for simulation of industrial-scale precipitation. Processes of birth-and-spread and particle breakage are considered integral parts of the precipitation process along with secondary nucleation, growth and agglomeration of particles. The conceptual difference of the proposed system of equations is its ability to reproduce the oscillatory process that occurs in precipitation circuits as a result of cyclic changes in the quality of the seed surface. It is demonstrated that self-oscillations can occur in the system without any external influence. The updated model is adjusted and verified using historical industrial data. The simulation of seed-recycle precipitation circuit showed an exact correspondence between the calculated dynamic pattern of changes in particle size distribution of aluminum hydroxide and the actual data.
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2

Bekker, A. V., T. S. Li, and I. Livk. "Dynamic response of a plant-scale gibbsite precipitation circuit." Hydrometallurgy 170 (July 2017): 24–33. http://dx.doi.org/10.1016/j.hydromet.2016.06.002.

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3

Webster, Nathan A. S., Ian C. Madsen, Melissa J. Loan, Robert B. Knott, Fatima Naim, Kia S. Wallwork, and Justin A. Kimpton. "An investigation of goethite-seeded Al(OH)3precipitation usingin situX-ray diffraction and Rietveld-based quantitative phase analysis." Journal of Applied Crystallography 43, no. 3 (April 15, 2010): 466–72. http://dx.doi.org/10.1107/s0021889810008484.

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Anin situX-ray diffraction investigation of goethite-seeded Al(OH)3precipitation from synthetic Bayer liquor at 343 K has been performed. The presence of iron oxides and oxyhydroxides in the Bayer process has implications for alumina reversion, which causes significant process losses through unwanted gibbsite precipitation, and is also relevant for the nucleation and growth of scale on mild steel process equipment. The gibbsite, bayerite and nordstrandite polymorphs of Al(OH)3precipitated from the liquor; gibbsite appeared to precipitate first, with subsequent formation of bayerite and nordstrandite. A Rietveld-based approach to quantitative phase analysis was implemented for the determination of absolute phase abundances as a function of time, from which kinetic information for the formation of the Al(OH)3phases was determined.
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Hai, Chunxi, Yuan Zhou, Lijuan Zhang, Yanxia Sun, Xiang Li, Yue Shen, Huaijin Zhan, Qier Han, Jianghua Liu, and Hongbo Ren. "Large-scale synthesis of uniformly dispersed hexagram-like gibbsite by a controlled replacement reaction." CrystEngComm 19, no. 27 (2017): 3850–55. http://dx.doi.org/10.1039/c7ce00822h.

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A facile, convenient and mild method has been developed for synthesis of uniformly dispersed 2D six-pointed star-like gibbsite micro-nano crystals with lateral size around 2.5 μm and thickness around 100 nm.
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5

Enright, E., T. Curtin, J. Haines, and K. T. Stanton. "The influence of surface roughness on gibbsite scale development on steel." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 226, no. 1 (September 23, 2011): 61–71. http://dx.doi.org/10.1177/1464420711421269.

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6

Fernandes, Kathleen, José Marques Júnior, Angélica Santos Rabelo de Souza Bahia, José A. M. Demattê, and Adriana Aparecida Ribon. "Landscape-scale spatial variability of kaolinite-gibbsite ratio in tropical soils detected by diffuse reflectance spectroscopy." CATENA 195 (December 2020): 104795. http://dx.doi.org/10.1016/j.catena.2020.104795.

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Kiani, Sajad, Abdolreza Samimi, and Alimorad Rashidi. "Novel one-pot dry method for large-scale production of nano γ-Al2O3 from gibbsite under dry conditions." Monatshefte für Chemie - Chemical Monthly 147, no. 7 (February 1, 2016): 1153–59. http://dx.doi.org/10.1007/s00706-015-1642-1.

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8

Reatto, Adriana, Ary Bruand, Eder de Souza Martins, Fabrice Muller, Euzebio Medrado da Silva, Osmar Abílio de Carvalho, and Michel Brossard. "Variation of the kaolinite and gibbsite content at regional and local scale in Latosols of the Brazilian Central Plateau." Comptes Rendus Geoscience 340, no. 11 (November 2008): 741–48. http://dx.doi.org/10.1016/j.crte.2008.07.006.

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9

Dong, Jie Ji, Guang Wang, Mao Fang Zuo, Hua Li, and Qing Guo Xue. "Characteristics of the Sierra Leone High Alumina Iron Ore and Utilization in Sintering." Advanced Materials Research 881-883 (January 2014): 1515–21. http://dx.doi.org/10.4028/www.scientific.net/amr.881-883.1515.

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The characteristics of the Sierra Leone iron ore were studied at laboratory scale by chemical analysis, XRD, SEM-EDS and TG-DSC methods. The Sierra Leone iron ore was a kind of limonite, which was mainly consisted of hematite, goethite and gibbsite. The iron ore lost its crystal water at a fast speed ranging from 200°C to 400°C and the total content of the crystal water was about 8.2 wt.%. The initial melt formation temperature of the iron ore with CaO was stably kept at around 1209°C and the amount of liquid increased with the increasing of CaO content. Its melt formation temperature is higher than Australian limonite. The sintering pot test showed that the yield of sinter decreases from 78.37wt.% to 73.36wt.% and the drum index decreases from 60.5wt.% to 49.63wt.% when the blending ratio of Sierra Leone iron ore increases from 7wt.% to 27.3wt.%.
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10

Aristide Zé, Parfait, Cornelius Tsamo, and Richard Kamga. "Characterization of Minim-Martap Bauxite and Its Extracted Alumina." Journal of Advanced Chemical Sciences 4, no. 4 (December 6, 2018): 598–600. http://dx.doi.org/10.30799/jacs.198.18040402.

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Due to their chemical and mineralogical properties bauxites are composites with multiple applications. In this work, the properties of bauxite collected from Minim-Martap and its extracted alumina were evaluated. Alumina was extracted by adapting the Bayer process at laboratory scale while the characteristics of bauxite and alumina were variably characterized by determining the particle size distribution, relative humidity, loss on ignition, pH, EC, CEC, PZC, XRD, IR, and DSC-TGA. These results show that Minim-Martap bauxite gray bauxite with easily extractable alumina. This bauxite is acidic with a pH of 6.05, PZC of 6.91 and CEC of 15 Meq/100 g which is closer to that of kaolinite clays. This result was confirm by XRD which shows two types of kaolinites: Al2Si2O5(OH)4 with 83.24% and H4Al2Si2O9 with 42.47%, mullite Al2.25Si0.75O4.875 with 67.32%, gibbsite (H2SiO4) with 83.92%. The bauxite is hydroscopic as evident from its humidity results. The IR spectroscopy of bauxite and alumina shows the presence of Al-OH and Si-OH which increase with acid treatment. Minim-martap bauxite and its extracted alumina can be used as raw materials for many industrial processes because of the different properties they possess as revealed by this study.
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11

Mugele, Frieder, Igor Siretanu, Naveen Kumar, Bijoy Bera, Lei Wang, Riëlle de Ruiter, Armando Maestro, Michel Duits, Dirk van den Ende, and Ian Collins. "Insights From Ion Adsorption and Contact-Angle Alteration at Mineral Surfaces for Low-Salinity Waterflooding." SPE Journal 21, no. 04 (August 15, 2016): 1204–13. http://dx.doi.org/10.2118/169143-pa.

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Summary Most solid surfaces acquire a finite surface charge after exposure to aqueous environments caused by desorption and/or adsorption of ionic species. The resulting electrostatic forces play a crucial role in many fields of science and technology, including colloidal stability, self-assembly, wetting, and biophysics. Enhanced oil recovery (EOR) is an example of a large-scale industrial process that hinges in many respects on these phenomena. In this paper, we present a series of experiments illustrating fundamental aspects of low-salinity waterflooding in well-defined model systems. We show how pH and ion content of the water phase as well as the presence of model polar components (fatty acids) in the oil phase affect the wettability (i.e., contact-angle distribution) of oil/water/rock systems. Specifically, we discuss high-resolution atomic-force microscopy (AFM) experiments demonstrating the preferential adsorption of multivalent cations to mineral surfaces such as mica and gibbsite. Cation adsorption leads to increased and, in some cases, reversed surface charge at the solid/liquid interface. In particular, the adsorption of divalent cations gives rise to charge reversal and thereby induces a transition from complete water-wetting in the absence to finite contact angles in the presence of such ions. Although already dramatic for pure alkanes as base oil, adding fatty acids to the oil phase enhances the effect of divalent ions on the oil/water/rock wettability even more. In this case, contact-angle variations of more than 70 ° can be observed as a function of the salt concentration. This enhancement is caused by the deposition of a thin film of fatty acid on the solid surface. AFM as well as surface plasmon-resonance spectroscopy measurement in a microfluidic continuous flow cell directly demonstrate that adsorbed Ca2+ ions promote secondary adsorption of acidic components from the oil phase. The combination of the effects discussed provides a rational scenario explaining many aspects of the success of low-salinity waterflooding.
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12

Grotto, Francesco, and Umberto Pappalettera. "Equilibrium statistical mechanics of barotropic quasi-geostrophic equations." Infinite Dimensional Analysis, Quantum Probability and Related Topics 24, no. 01 (March 2021): 2150007. http://dx.doi.org/10.1142/s0219025721500077.

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We consider equations describing a barotropic inviscid flow in a channel with topography effects and beta-plane approximation of Coriolis force, in which a large-scale mean flow interacts with smaller scales. Gibbsian measures associated to the first integrals energy and enstrophy are Gaussian measures supported by distributional spaces. We define a suitable weak formulation for barotropic equations, and prove existence of a solution preserving Gibbsian measures, thus providing a rigorous infinite-dimensional framework for the equilibrium statistical mechanics of the model.
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13

Krakauer, Bruce W., and David N. Seidman. "Absolute atomic-scale measurements of the Gibbsian interfacial excess of solute at internal interfaces." Physical Review B 48, no. 9 (September 1, 1993): 6724–27. http://dx.doi.org/10.1103/physrevb.48.6724.

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14

Rüsing, Järg, Jason T. Sebastian, Olof C. Hellman, and David N. Seidman. "Three-dimensional Investigation of Ceramic/Metal Heterophase Interfaces by Atom-probe Microscopy." Microscopy and Microanalysis 6, no. 5 (September 2000): 445–51. http://dx.doi.org/10.1007/s100050010050.

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AbstractThe results of a three-dimensional atom probe (3DAP) analysis, on a subnanometer scale, of a ceramic/metal heterophase interface, MgO/Cu, are presented. Segregation of Ag, from the Cu (Ag) matrix, at MgO/Cu interfaces is investigated and the Gibbsian interfacial excess of silver is determined; the range is 2.33 × 1018 to 5.81 × 1018 m−2. Also, silver segregation at the same MgO/Cu interfaces is analyzed employing a new approach that utilizes a proximity histogram or proxigram.
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15

Merkl, Franz. "Quenched asymptotics of the ground state energy of random Schrödinger operators with scaled Gibbsian potentials." Probability Theory and Related Fields 126, no. 3 (June 2003): 307–38. http://dx.doi.org/10.1007/s00440-003-0266-2.

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16

Isheim, Dieter, Olof C. Hellman, David N. Seidman, Frédéric Danoix, Alain Bostel, and Didier Blavette. "Atomic-scale Study of a Transition Phase Precipitate and Its Interfacial Chemistry in an Fe−15 at.% Mo−5 at.% V Alloy." Microscopy and Microanalysis 7, no. 5 (September 2001): 424–34. http://dx.doi.org/10.1007/s10005-001-0017-z.

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AbstractA Mo-rich precipitate in an Fe-rich matrix and the heterophase interface bounding the precipitate have been examined on an atomic scale by three-dimensional atom-probe (3DAP) microscopy and transmission electron microscopy (TEM). The Mo-rich precipitate was generated by isothermal solid-state decomposition at 500°C of an Fe-15 at.% Mo-5 at.% V alloy. After this heat treatment, TEM reveals a characteristic modulated strain contrast structure. The precipitate has a composition of Mo-13.0 at.% Fe-4.9 at.% V as measured by 3DAP microscopy. The alloy decomposes at a nearly constant 5 at.% V, constituting a metastable tie-line between Fe-rich and Mo-rich bcc solid solutions. The formation of the equilibrium intermetallic phases is kinetically impeded. A local vanadium enrichment of 21 at.% is detected at the interface of the precipitate in a matrix region about 0.27 nm or 1–2 atomic layers in thickness. The corresponding value of the Gibbsian interfacial excess of vanadium is 3.3 ± 1.3 nm−2.
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17

Krakauer, B. W., and David N. Seidman. "Absolute Atomic Scale Measurements of the Gibbsian Interfacial Excess of Solute at Grain Boundaries in an Iron (Silicon) Alloy." Materials Science Forum 155-156 (May 1994): 393–96. http://dx.doi.org/10.4028/www.scientific.net/msf.155-156.393.

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18

Williams, D. B., and A. D. Romig. "Measurement of solute segregation to grain boundaries in the AEM: A review." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 606–7. http://dx.doi.org/10.1017/s0424820100105096.

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The segregation of solute or imparity elements to grain boundaries can occur by three well-defined processes. The first is Gibbsian segregation in which an element of minimal matrix solubility confines itself to a monolayer at the grain boundary. Classical examples include Bi in Cu and S or P in Fe. The second process involves the depletion of excess matrix solute by volume diffusion to the boundary. In the boundary, the solute atoms diffuse rapidly to precipitates, causing them to grow by the ‘collector-plate mechanism.’ Such grain boundary diffusion is thought to initiate “Diffusion-Induced Grain Boundary Migration,” (DIGM). This process has been proposed as the origin of eutectoid transformations or discontinuous grain boundary reactions. The third segregation process is non-equilibrium segregation which result in a solute build-up around the boundary because of solute-vacancy interactions.All of these segregation phenomena usually occur on a sub-micron scale and are often affected by the nature of the grain boundary (misorientation, defect structure, boundary plane).
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19

Kuśmierz, Łukasz, Bartłomiej Dybiec, and Ewa Gudowska-Nowak. "Thermodynamics of Superdiffusion Generated by Lévy–Wiener Fluctuating Forces." Entropy 20, no. 9 (August 31, 2018): 658. http://dx.doi.org/10.3390/e20090658.

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Scale free Lévy motion is a generalized analogue of the Wiener process. Its time derivative extends the notion of “white noise” to non-Gaussian noise sources, and as such, it has been widely used to model natural signal variations described by an overdamped Langevin stochastic differential equation. Here, we consider the dynamics of an archetypal model: a Brownian-like particle is driven by external forces, and noise is represented by uncorrelated Lévy fluctuations. An unperturbed system of that form eventually attains a steady state which is uniquely determined by the set of parameter values. We show that the analyzed Markov process with the stability index α < 2 violates the detailed balance, i.e., its stationary state is quantified by a stationary probability density and nonvanishing current. We discuss consequences of the non-Gibbsian character of the stationary state of the system and its impact on the general form of the fluctuation–dissipation theorem derived for weak external forcing.
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20

Rogankov, V., M. Shvets, and O. Rogankov. "New Non-Stationary Gradient Model of Heat-Mass-Electric Charge Transfer in Thin Porous Media." Refrigeration Engineering and Technology 53, no. 5 (November 2, 2017): 33–46. http://dx.doi.org/10.15673/ret.v53i5.850.

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The well-known complicated system of non-equilibrium balance equations for a continuous fluid (f) medium needs the new non-Gibbsian model of f-phase to be applicable for description of the heterogeneous porous media (PMs). It should be supplemented by the respective coupled thermal and caloric equations of state (EOS) developed specially for PMs to become adequate and solvable for the irreversible transport f-processes. The set of standard assumptions adopted by the linear (or quasi-linear) non-equilibrium thermodynamics are based on the empirical gradient-caused correlations between flows and forces. It leads, in particular, to the oversimplified stationary solutions for PMs. The most questionable but typical modeling suppositions of the stationary gradient (SG) theory are: 1) the assumption of incompressibility accepted, as a rule, for f-flows; 2) the ignorance of distinctions between the hydrophilic and hydrophobic influence of a porous matrix on the properties; 3) the omission of effects arising due to the concomitant phase intra-porous transitions between the neighboring f-fragments with the sharp differences in densities; 4) the use of exclusively Gibbsian (i.e. homogeneous and everywhere differentiable) description of any f-phase in PM; 5) the very restrictive reduction of the mechanical velocity field to its specific potential form in the balance equation of f-motion as well as of the heat velocity field in the balance equation of internal energy; 6) the neglect of the new specific peculiarities arising due to the study of any non-equilibrium PM in the meso- and nano-scales of a finite-size macroscopic (N,V)-system of discrete particles. This work is an attempt to develop the alternative non-stationary gradient (NSG) model of real irreversible processes in PM. Another aim is to apply it without the above restrictions 1)-6) to the description of f-flows through the obviously non-Gibbsian thin porous medium (TPM). We will suppose that it is composed by two inter-penetrable fractal sf-structures of f-phase (formed by the “mixture” of g- and l-phases termed, in total, interphase) and solid (s) porous matrix termed below s-phase. The permanent influence of humidity and the respective increase of the moisture content in TPM including the unavoidable phenomenon of capillary condensation are the main factors to occur the non-stationary transport f-flows through its texture.
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21

Thiry, Médard, Florence Quesnel, Johan Yans, Robert Wyns, Anne Vergari, Hervé Theveniaut, Régine Simon-Coinçon, et al. "Continental France and Belgium during the early Cretaceous: paleoweatherings and paleolandforms." Bulletin de la Société Géologique de France 177, no. 3 (May 1, 2006): 155–75. http://dx.doi.org/10.2113/gssgfbull.177.3.155.

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Abstract During the early Cretaceous, successive tectonic phases and several sea level falls resulted in the emersion of the main part of western Europe and the development of thick “lateritic” weathering. This long period of continental evolution ended with the Upper Cretaceous transgressions. During this period, the exposed lands displayed a mosaic of diverse morphologies and weathered landscapes. Bauxites are the most spectacular paleoweathering features, known for long in southern France. Recently, new residual outcrops have been identified, trapped in the karstic depressions of the Grands Causses. Other bauxitic formations, containing gibbsite, have also been recognised, occurring with the Clay-with-Jurassic-cherts in the southeastern border of the Paris Basin. These bauxitic formations overlay Jurassic limestone and are buried beneath Upper Cretaceous marine deposits. The recognition of bauxites up north into the southern Paris Basin significantly widens the extension of the Lower Cretaceous bauxitic paleolandscapes. On the Hercynian basements thick kaolinitic weathering mantles occur. They have been classically ascribed to the Tertiary. The first datings of these in situ paleosoils, by means of paleomagnetism and/or radiogenic isotopes, record especially early Cretaceous ages. This is the case for the “Siderolithic” formations on the edges of the French Massif Central, but also for the kaolinitic profiles in the Belgian Ardennes. In the Flanders, the Brabant basement is deeply kaolinised beneath the Upper Cretaceous cover. These paleosoils show polygenetic evolutions. The relief of these basement paleolandscapes may have been significant. There where probably high scarps (often of tectonic origin) reaching 200 m in elevation or beyond, as well as wide surfaces with inselbergs, as in the present day landscapes of tropical Africa and South America. On the Jurassic limestone platforms occur diverse kaolinitic and ferruginous weathering products. Around the Paris Basin they show various facies, ranging from kaolinitic saprolites to ferricretes. Due to the lack of sedimentary cover, the age of these ferruginous and kaolinitic weathering products has been debated for long, most often allocated to the Siderolithic sensu lato (Eocene-Oligocene). Recent datings by paleomagnetism have enabled to date them (Borne de Fer in eastern Paris Basin) back also to the early Cretaceous (130 ± 10 Ma). These wide limestone plateaus show karstified paleolandforms, such as vast closed and flat depressions broken by conical buttes, but also deep sinkholes in the higher areas of the plateaus and piedmonts. The depth of the karst hollows may be indicative of the range of relative paleoelevations. Dissolution holes display seldom contemporaneous karst fillings, thus implying that the karstland had not a thick weathering cover or that this cover had been stripped off before or by the late Cretaceous transgression. Nevertheless, some areas, especially above chert-bearing Jurassic limestone or marl, show weathering products trapped in the karst features or as a thick weathering mantle. In the Paris Basin, the Wealden gutter looked like a wide floodplain in which fluvio-deltaic sands and clays were deposited and on which paleosoils developed during times of non-deposition. The edges of the gutter were shaped as piedmonts linked up with the upstream basement areas. The rivers flowing down to the plain deposited lobes of coarse fluvial sands and conglomerates. The intensity of the weathering, the thickness of the profiles and their maturation are directly dependent on the duration of the emersion and the topographic location relative to the gutter. Near the axis of the gutter, where emersion was of limited duration, the paleoweathering features are restricted to rubefaction and argillization of the Lower Cretaceous marine formations. On the other hand, on the borders of the basin and on the Hercynian basement, where emersion was of longer duration, the weathering profiles are thicker and more intensively developed. The inventory of the Lower Cretaceous paleoweathering features shows the complexity of the continental history of this period. Moreover, the preserved weathering products are only a part of this long lasting period, all the aspects relative to erosion phases are still more difficult to prove and to quantify. In this domain, apatite fission tracks thermochronology (AFTT) can be helpful to estimate the order of magnitude of denudation. Residual testimonies and subsequent transgressions may enable to estimate relative elevations, but in return, we presently have no reliable tool to estimate absolute paleoelevations. In the work presented here, the inventory enabled to draw a continental paleogeographic map showing the nature of the weathering mantles and the paleolandscape features, just as paleoenvironments and paleobathymetry presently appear on marine paleogeographic maps. For the future, the challenge is to make progress in dating the paleoweathering profiles and especially in the resolution of these datings, in order to correlate precisely the continental records with the different events which trigger them (eustatism, climate, regional and global geodynamics). The final goal will be to build up a stratigraphic scale of the “continental geodynamic and climatic events” in parallel with “sequential stratigraphy” in the marine realm.
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22

Trotignon, L., H. Peycelon, M. Cranga, and F. Adenot. "Modelling of the Interaction Between an Engineered Clay Barrier and Concrete Structures in a Deep Storage Vault." MRS Proceedings 556 (1999). http://dx.doi.org/10.1557/proc-556-607.

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AbstractThe degradation of concrete structures in a storage vault will release an alkaline plume influencing the geochemical evolution of clay engineered barriers or plugs. The studied configuration has a representative scale and is composed of a rectangular clay barrier interfaced on one side with a cement block and on the other side with an external granitic field. A clay model including major and accessory minerals is used; cement material is supposed to be made of portlandite and CSH minerals. The clay barrier and the cement block are assumed to be initially saturated and in equilibrium with their respective interstitial water. Diffusive transport of aqueous species coupled to chemistry is simulated in a one dimension space up to 10000 y. The feed-back of the porosity evolution on the transport properties is not taken into account. The temperature is supposed to be constant (25°C). Calculations are performed with the TRIO-EF coupled transport-chemistry code.The main results deal with the evolution of the pH profile across the clay barrier, the dissolution of clay minerals and the precipitation of new solid phases in the clay such as albite, gibbsite and CSH. These simulations show that the pH excursion includes only a minor part of the clay barrier at 10 000 y and that the CSH precipitation retards the alkaline plume progression. The appearance of local accumulations of newly precipitated minerals might reduce strongly the porosity. Future developpements of this work include: (i) the completion of the geochemical model by introducing other minerals in concrete (other CSH phases and sulfo-aluminates) and ion exchange sites within the clay, (ii) the implementation of a precipitation/dissolution model in order to describe on a realistic way the porosity profile evolution and possible clogging phenomena.
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