Dissolution Behavior Of Metals Research Articles

Comprehensive insights into the gallic acid assisted bioleaching process for spent LIBs: Relationships among bacterial functional genes, Co(III) reduction and metal dissolution behavior

Despite the growing demand for resource recovery from spent lithium-ion batteries (LIBs) by bioleaching, low Co leaching efficiency has hindered the development and application of this technology. Therefore, a novel process was designed, combining gallic acid (GA) and mixed culture bioleaching (MCB), to enhance the removal of metals from spent LIBs. Results indicated that the GA + MCB process achieved 98.03% Co and 98.02% Li leaching from spent LIBs, simultaneously reducing the biotoxicity, phytotoxicity and leaching toxicity of spent LIBs under optimal conditions. The results of mechanism analysis demonstrated that functional microorganisms adapted to the leaching system through various strategies, including oxidative stress reduction, DNA damage repair, heavy metal resistance and biofilm formation, maintaining normal physiological activities and the continuous production of biological acid. The biological acid erodes the surface of waste LIBs, causing some Co and a large amount of Li to be released, while also increasing the contact area between GA and Co(III). Therefore, GA is beneficial for reducing insoluble Co(III), forming soluble Co(II). Finally, biological acid can effectively promote Co(II) leaching. Collectively, the results of this study provide valuable insight into the simultaneous enhancement of metal extraction and the mitigation of environmental pollution from spent LIBs.

Analysis of Wafer Cleaning Solution Characteristics and Metal Dissolution Behavior according to the Addition of Chelating Agent

Analysis of Wafer Cleaning Solution Characteristics and Metal Dissolution Behavior according to the Addition of Chelating Agent

Pressure leaching of chalcopyrite with oxalic acid and hydrogen peroxide

This study investigated the dissolution behavior of metals from chalcopyrite concentrate in a pressure reactor system in the presence of hydrogen peroxide by oxalic acid leaching. The fact that the compounds formed by copper and iron with oxalic acid had different dissolution coefficients showed that metals could be selectively extracted based on the leaching temperature. The effects of various leaching parameters on metal extraction in the autoclave system were investigated at different H2O2 concentrations (1–5 M), H2C2O4 concentrations (25–125 g/L), leaching temperatures (318–443 K) and leaching times (15–180 min). While iron and copper extraction as a result of 180 min of leaching with 5 M H2O2, 318 K and 100 g/L H2C2O4 was respectively 90.6% and 1.73%, 88.5% of copper and 2.11% of iron could be extracted as a result of 180 min of leaching with 3 M H2O2, 443 K and 100 g/L H2C2O4. The reversal of the copper and iron extraction dissolution behavior started after the leaching temperature of 378 K. In the XRD analysis of leach residues obtained at low leaching temperatures, CuC2O4 peaks were dominant, while at high temperature conditions, Fe2O3 peaks were dominant.

Metal dissolution behavior from deep-sea hydrothermal sulfide samples; Impact assessment for seafloor massive sulfide mining

Metal dissolution behavior from deep-sea hydrothermal sulfide samples; Impact assessment for seafloor massive sulfide mining

Effective leaching and extraction of valuable metals from electrode material of spent lithium-ion batteries using mixed organic acids leachant

The present work focuses on simultaneous recycling of Li and Co from crushed products of mixed electrode materials using mixed organic acids, in which benzenesulfonic acid and formic acid were cooperatively used as the leaching reagents. Results show that the optimal leaching efficiency of 97% Co and 99% Li were obtained under the conditions of 1.3mol/L benzenesulfonic acid, 1.5mol/L formic acid, a solid to liquid (S/L) ratio of 30g/L, and 40min reaction time at 50°C. Meanwhile, the leaching of Li and Co fits well to logarithmic rate model with apparent activation energy of 32.7 and 47.0kJ/mol in this given leaching system, respectively. Besides, cobalt was directly recovered from the leach liquor as pure cobalt benzene sulfonic with the recovery efficiency of 99%, and lithium can be entirely precipitated by adding phosphoric acid. Further, the reaction mechanism involves the leaching-hydrating-complexing model of LiCoO2 particles was proposed based on the dissolution behavior of metals and then verified by morphological and phase characterization (i.e. FT-IR, XRD and SEM-EDS) of the recycling product. The whole process is found to be effective and sustainable for recovery of Li, Co and graphite from mixed industrial crushing product of spent LIBs.

First-principles modeling of anisotropic anodic dissolution of metals and alloys in corrosive environments

There have been extensive experimental observations of the anisotropic corrosion behavior of metals and alloys, and their mechanisms were assumed to be correlated with the so-called surface energy or the work function. However, to date, a specified mechanism or theory to interpret anisotropic corrosion behavior remains unclear. Here, we determine the anisotropic anodic dissolution of metals and alloys in corrosive environments by developing a formula to specify the relationship between the electrode potential (U) and the current density (I) by considering the basic parameters of our defined surface energy density (Esurf/ρ) and the work function (Φ). Therefore, we build an ab initio model to evaluate the anisotropic anodic dissolution behavior of metals and alloys using the inputs obtained within density functional theory. This theory is further validated in the case of variations in the crystallographic planes of Mg. Moreover, some selected alloying additions such as Ga, Cd, Hg, In, As, and Cr are theoretically elucidated to effectively reduce the anodic dissolution rates of the Mg matrix to some extent, in close agreement with available experimental observations. This model is capable of predicting the anisotropic anodic dissolution behavior, providing a promising perspective for designing better corrosion-resistant alloys.

Rapid and gradual modes of aerosol trace metal dissolution in seawater.

Atmospheric deposition is a major source of trace metals in marine surface waters and supplies vital micronutrients to phytoplankton, yet measured aerosol trace metal solubility values are operationally defined, and there are relatively few multi-element studies on aerosol-metal solubility in seawater. Here we measure the solubility of aluminum (Al), cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) from natural aerosol samples in seawater over a 7 days period to (1) evaluate the role of extraction time in trace metal dissolution behavior and (2) explore how the individual dissolution patterns could influence biota. Dissolution behavior occurs over a continuum ranging from rapid dissolution, in which the majority of soluble metal dissolved immediately upon seawater exposure (Cd and Co in our samples), to gradual dissolution, where metals dissolved slowly over time (Zn, Mn, Cu, and Al in our samples). Additionally, dissolution affected by interactions with particles was observed in which a decline in soluble metal concentration over time occurred (Fe and Pb in our samples). Natural variability in aerosol chemistry between samples can cause metals to display different dissolution kinetics in different samples, and this was particularly evident for Ni, for which samples showed a broad range of dissolution rates. The elemental molar ratio of metals in the bulk aerosols was 23,189Fe: 22,651Al: 445Mn: 348Zn: 71Cu: 48Ni: 23Pb: 9Co: 1Cd, whereas the seawater soluble molar ratio after 7 days of leaching was 11Fe: 620Al: 205Mn: 240Zn: 20Cu: 14Ni: 9Pb: 2Co: 1Cd. The different kinetics and ratios of aerosol metal dissolution have implications for phytoplankton nutrition, and highlight the need for unified extraction protocols that simulate aerosol metal dissolution in the surface ocean.

The influence of different conducting salts on the metal dissolution and capacity fading of NCM cathode material

LiNi1/3Co1/3Mn1/3O2 (NCM) cathode material can be charged to different potentials. When using the standard salt LiPF6, elevated cut-off potentials during charge lead to increased capacity and energy density during discharge, but reduce the cycle life dramatically. Metal dissolution is promoted by acids, like HF, derived from deterioration of the electrolyte salt. To exclude the influence of HF, as alternative to LiPF6, the less hydrolysis sensitive LiBF4 and the fluorine-free conducting salt LiClO4 were investigated. To determine the metal dissolution behavior, NCM electrodes were stored in 1M EC/DMC (1/1, by wt.) electrolyte containing different salts for 28 days at different states of charge. The measurement of the metal ion content in the electrolyte was carried out by the inductively coupled plasma/optical emission spectrometry (ICP-OES) technique. Constant current cycling experiments were performed with different charge cut-off potentials. In contrast to LiPF6, LiBF4 showed suppressed metal dissolution and superior cycling performance with low capacity fading even at high cut-off potentials (4.6V vs. Li/Li+). At lower cut-off potentials, metal dissolution, as well as capacity fading, is rather low for LiClO4 but escalates at potentials above 4.4V vs. Li/Li+.

Improvements on Capacity Retention and Metal Dissolution of NCM Cathode Material By the Use of Alternative Conducting Salts

Ni1/3Co1/3Mn1/3O2 (NCM) cathode material can be charged to different potentials. When using the standard salt LiPF6, elevated cutoff potentials lead to increased energy densities and better energy quality, but reduce the cycle life dramatically. Metal dissolution is catalyzed by acids, like HF, derived from deterioration of the salt. To exclude the influence of HF, next to LiPF6 the less hydrolysis sensitive LiBF4 and the fluorine-free conducting salt LiClO4 were investigated. To determine the metal dissolution behavior of NCM, these electrodes were stored in 1 M EC/DMC (1/1, by wt.) electrolyte containing different salts for 28 days at different states of charge. The measurement of metal ion content was carried out by inductively coupled plasma/optical emission spectrometry (ICP-OES) technique. Constant current cycling experiments were performed with different charge potential limits. In contrast to LiPF6, LiBF4 showed suppressed metal dissolution and superior cycling performance with low capacity fading even at high cutoff-potentials (4.6 V vs. Li/Li+). At low potentials, metal dissolution, as well as capacity fading, is rather low for LiClO4 but escalates at potentials above 4.4 V vs. Li/Li+.

Recovery of valuable metals and regeneration of acid from the leaching solution of spent HDS catalysts by solvent extraction

Leaching and solvent extraction experiments have been performed to recover Mo and Co from spent HDS catalysts. The dissolution behavior of metals in spent catalysts was investigated with respect to HCl concentration, time and S/L ratio. Particle size had negligible effect, whereas reaction temperature had created a great effect. Under the optimum leaching condition viz: 3mol/L HCl, 90°C, 250μm particle size, 5% (w/v) solid to liquid ratio and 60min reaction time, it was possible to dissolve 97% and 94% of Mo and Co, respectively. Solvent extraction was conducted for recovery of Mo using TBP and Mo was stripped from the loaded TBP with dilute HCl solution. The Mo free raffinate was processed for the recovery of Co by Alamine 308 in three counter current extraction stages and Co was quantitatively stripped with acidified distilled water. Furthermore, a complete extraction and stripping of HCl was achieved with TEHA in counter current extraction and stripping experiments. Using the process developed in this study, it was possible to recover 99% of Mo and Co and 90% of HCl with their purity higher than 99%. Finally, a conceptual process flow sheet was presented.

Dissolution behavior of metals from particulate matter emissions*

Exposure to air particulate matter (PM) is linked to numerous health effects. In order to improve the understanding of the role of its metallic components, their solubility was examined by using serial short-contact dissolutions totalling 1 h and additional sequential contact periods of 1, 4, and 8 days. The dissolution experiments were performed in solutions containing the main biological electrolytes. ICPMS determinations were used to quantify the dissolved metals. The total compositions were determined after closed vessel microwave digestion. Large variations in the rate and completeness of the dissolutions were observed. Fast and extensive dissolutions within the short-contact time (e.g., Zn, Cd) as well as slow dissolutions persisting during the last contact period (e.g., Ni, Cu, Sb, Pb) were found for smelting emissions. The multi-element determinations also made it possible to identify relationships between dissolution of different metals and define gradual composition changes of residual PM. When comparing with dissolutions performed in de-ionized water, similar major fractions were observed at short-contact time for minor components of smelting or combustion emissions (e.g., V, Ni, Cd), suggesting a preponderance of easily available forms at the surface of the relatively inert particle cores. The use of these time sequential methods may help in (1) modeling metal partitioning in biological media and (2) investigating the causes of adverse effects attributed to air PM. This work was presented in part at the 2006 Winter Conference on Plasma Spectrochemistry, January 8–14, 2006, Tucson, USA.

Dissolution behavior of metals from binary alloys

The strategy of recovering metals from scrap is, in general, much different from primary sources. One of the main differences between the treatment of scrap and that of primary sources is the fact that metals are frequently associated with other metals to form alloys in scrap, while metals occur in primary sources as oxides or sulfides. In this paper, factors affecting the dissolution behavior of metals from various alloy systems are reviewed and discussed. Specific examples are drawn from Au/Ag, Au/Cu, and Ag/Cu systems. The results of the dissolution of various metals from these alloys are reviewed and compared to the dissolution behavior of single metal systems in various lixiviants such as acids, cyanide and ammonia. It has been observed that the presence of other metals in alloys significantly affects the dissolution rate of the metal in question. The leaching behavior of metals from homogeneous alloys relies on the chemical interaction between atoms in the lattice of the alloys, while that from heterogeneous alloys is affected by galvanic interaction established in the solution. The manner in which the dissolution of a certain metal is influenced by surrounding metals is discussed in terms of the passive and noble nature of the metal in relation to the neighboring metals.

The dissolution behavior of metals from silver/copper alloys in ammoniacal solutions

The dissolution behavior of silver and copper from silver/copper alloys in ammoniacal solutions was investigated using a rotating disc. Oxygen was used as an oxidant. The effects of the alloy composition, concentration of lixiviants, stirring speed and temperature on the overall dissolution kinetics were studied. Three silver/copper alloys (containing 76.7, 46.9 and 24.1% silver) were used in this study. The rates of dissolution for these alloys were compared to that of pure silver and copper under the same testing conditions. Emphasis was given to the galvanic effect on the overall dissolution rates.

Influence of loading frequency on transient current behavior of Fe26Cr1Mo during low cycle corrosion fatigue in 1M H2SO4 and 0.6M NaCl solutions

To understand the corrosion fatigue (CF) mechanism, in recent years many studies have been done on the transient current behavior of cyclic straining electrode for mild steel although there have been some studies on the transient current evolution under cyclic deformation, detailed information concerning the effect of loading frequency in corrosive solutions with different passivation characteristics is lacking. Crack initiation mechanisms are generally analyzed from the effect of surface dissolution, which is related to competition between the kinetics of depassivation by film rupture and repassivation by refilming of new metal surface. Two important factors should affect this surface reaction process: (1) surface dissolution behavior of metals which is dependent on the strain rate in the case of Fe-26Cr-1Mo stainless steel and gives a distribution of passive film damage; (2) repassivation kinetics, which are determined by the refilming ability of the corrosive medium. In the condition of CF, frequency is therefore an important factor which simultaneously determines both the material plastic deformation rate and the new surface repassivation time. On the other hand, the surface refilming process will be controlled by the characteristics of the selective medium. The main purpose of this paper is to study the effect of loading frequencymore » on the transient current behavior for Fe-26Cr-1Mo stainless steel under a low cycle CF condition, and to compare the difference of current response in 1M H[sub 2]SO[sub 4] solution.« less

The dissolution behavior of metals from Ag/Cu and Ag/Au alloys in acidic and cyanide solutions

The dissolution behavior of silver, copper, and gold from silver/copper and silver/gold alloys in acid and cyanide solutions has been investigated using a rotating disc. Oxygen or ferric ion was used as an oxidant. The effect of composition of alloys, rotation speed, concentration of lixiviants, and temperature on the overall dissolution kinetics of these metals has been studied. The dissolution rate of silver was reduced due to galvanic effect, when it was leached from a silver/copper alloy disc in acidic media at relatively low oxidation potentials. On the other hand, when the oxidation potential was high, the galvanic effect of the dissolution rate became less pronounced. In the case of the silver/gold system in cyanide solutions, the effect of alloy composition on the dissolution rate of gold and silver was not as much as in the case of silver/ copper alloy systems. This may be attributed to the fact that both gold and silver are noble, and therefore, the electromotive forces of these two metals are not significantly different.

Modeling of base metal dissolution behavior during transient liquid-phase brazing

Detailed finite difference modeling of dissolution during transient liquid-phase (TLP) brazing of nickel using Ni-11 wt pct P and Ni-14 wt pct Cr-10 wt pct P filler metals is carried out assuminginfinite andfinite heating rates between the filler melting temperature (T m) and the brazing temperature (T b). Two conditions are modeled during brazing, namely, where the liquid width due to base metal dissolution isunrestrained (variable) and where the liquid width is keptconstant due to expulsion of excess liquid during the brazing process. The time required for completion of dissolution is proportional to the square of the filler metal thickness when an infinite heating rate betweenT m andT b is assumed. This occurs for both for constant and unrestrained liquid width situations. Also, the advance of the solid-liquid interface is approximately related to the reciprocal of the square root of the solute diffusivity in the liquid, except in the final stages of the dissolution process. When a multicomponent filler metal composition (Ni14 wt pct Cr-10 wt pct P) is used, the time for completion of dissolution exceeds that when using a simple binary filler metal composition. The phosphorous concentration in the liquid approaches that of the liquidus line when the heating rate betweenT m andT b decreases and thin filler metals are used. This tendency can be estimated using a homogenizing index (z) which combines the effects of filler metal thickness, diffusivity in the liquid, brazing temperature and heating rate, and a distribution index(a). When thick filler metals are used, lower heating rates produce more dissolution at temperatures betweenT m andT b and less dissolution at the final brazing temperature. Conversely, heating slowly when using thin filler metals produces less base metal dissolution (at any temperature) and negligible dissolution at the final brazing temperature. At very low heating rates, solidification can occur while heating fromT m toT b.

“Fast” diffusion in alloys

Abstract It is now recognized that the transport of noble metal and late transition metal impurities in metallic hosts with relatively large atomic volumes is affected predominantly by an interstitial mechanism. This means that the transport is very rapid at relatively low temperatures and that, contrary to the widely accepted empirical rules of metal dissolution behavior, a substantial proportion of these impurities occupy interstitial positions in the alloys. This behavior and its implications for alloy theory will be surveyed.