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Elemental tellurium and tellurium dioxide are related to the hydrometallurgy of precious metal tellurides in two ways: (1) both species are products of precious metals tellurides cyanidation; and (2) tellurium dioxide is a by-product of the roasting of tellurides to produce metallic gold/silver prior to cyanidation. An investigation to elucidate the dissolution behavior of elemental tellurium and tellurium dioxide at 1250 mg/L CN−, pH 10.9, and 25 °C was carried out. For this purpose, batch test, thermodynamic simulation, and voltametric techniques were employed. The results showed that 8% of elemental tellurium was dissolved due to the inability of dissolved atmospheric oxygen to oxidize it. However, according to the potential-pH diagram, tellurium dissolution should continue to produce TeO2(OH)22−. Cyclic voltammetry for tellurium showed an oxidation pathway to form TeO32− and TeO42− at 240 and 982 mV, although an oxidation process indicating the slight dissolution of elemental tellurium was observed at −75 mV. Tellurium dissolution form tellurium dioxide reached 82% but it could be enhanced by increasing the pH beyond 11.5. The tellurium dioxide hydrolysis in alkaline media produced TeO2(OH)22− but the pH of the system tends to decrease; if pH in not adjusted, H2TeO3 will form, hindering the tellurium dissolution.
A.A. González-Ibarra; F. Nava-Alonso; G.I. Dávila-Pulido; F.R. Carrillo-Pedroza; A.M. Rodríguez-Flores. Dissolution behavior of elemental tellurium and tellurium dioxide in alkaline cyanide solutions. Hydrometallurgy 2021, 203, 105702 .
AMA StyleA.A. González-Ibarra, F. Nava-Alonso, G.I. Dávila-Pulido, F.R. Carrillo-Pedroza, A.M. Rodríguez-Flores. Dissolution behavior of elemental tellurium and tellurium dioxide in alkaline cyanide solutions. Hydrometallurgy. 2021; 203 ():105702.
Chicago/Turabian StyleA.A. González-Ibarra; F. Nava-Alonso; G.I. Dávila-Pulido; F.R. Carrillo-Pedroza; A.M. Rodríguez-Flores. 2021. "Dissolution behavior of elemental tellurium and tellurium dioxide in alkaline cyanide solutions." Hydrometallurgy 203, no. : 105702.
Electronic waste (e‐waste) contains metallic values that can be recovered by hydrometallurgical methods. This investigation addresses the leaching kinetics of e‐waste for the recovery of copper in H2SO4‐H2O2 media with the objective of determining the rate‐controlling step in monosize particle systems. The results are then used to develop a kinetic model for copper dissolution in multisize particle systems. It is shown that in a monosize particle system, Cu dissolves completely in 150 min at 2 M H2SO4 and 0.2 M H2O2. The rate‐controlling step for this process is chemical reaction with an activation energy of 47.8 kJ/mol. The kinetic model for Cu dissolution in multisize particle systems is developed by applying an optimization method that considers the size distribution and the copper content of each of the size fractions. The results show that the model predicts satisfactorily the Cu dissolution kinetics and reveals that Cu particles with mean sizes of 79, 141, 237, 398.5, and 605 μm react completely in times varying from 15 to 120 min. Coarser Cu particles do not react completely in a time interval of up to 120 min. E‐waste losses 57.6% of its initial weight when subjected to the leaching process and solid residue has gold and silver grades of 2 402.35 and 9 035.29 g/ton, respectively.
Gloria I. Dávila‐Pulido; Armando Salinas‐Rodríguez; Francisco R. Carrillo‐Pedroza; Adrián A. González‐Ibarra; Juan Méndez‐Nonell; Mitzué Garza‐García. Leaching kinetics of electronic waste for the recovery of copper: Rate‐controlling step and rate process in a multisize particle system. International Journal of Chemical Kinetics 2020, 53, 379 -389.
AMA StyleGloria I. Dávila‐Pulido, Armando Salinas‐Rodríguez, Francisco R. Carrillo‐Pedroza, Adrián A. González‐Ibarra, Juan Méndez‐Nonell, Mitzué Garza‐García. Leaching kinetics of electronic waste for the recovery of copper: Rate‐controlling step and rate process in a multisize particle system. International Journal of Chemical Kinetics. 2020; 53 (3):379-389.
Chicago/Turabian StyleGloria I. Dávila‐Pulido; Armando Salinas‐Rodríguez; Francisco R. Carrillo‐Pedroza; Adrián A. González‐Ibarra; Juan Méndez‐Nonell; Mitzué Garza‐García. 2020. "Leaching kinetics of electronic waste for the recovery of copper: Rate‐controlling step and rate process in a multisize particle system." International Journal of Chemical Kinetics 53, no. 3: 379-389.
The sludge from a wet-off gas cleaning system of the iron blast furnace (BF) contains significant amounts of iron; however, they cannot be recycled due to their high content of zinc and alkalis. These compounds are detrimental to the optimal performance of iron and steelmaking furnaces. In this work, a comparative laboratory study to reduce zinc and alkali contained in the blast furnace sludge (BFS) is presented. The effect of leaching parameters such as oxidant (i.e., ferric ion, oxygen or ozone), aqueous solution media (i.e., 0.2 M NH4Cl, 0.2 M HCl and 0.1 M H2SO4) and temperature (i.e., 27 and 80 °C) on Zn and alkalis (Na2O and K2O) removal were studied by applying an experimental design. The results obtained show that Zn and K2O removal of 85% and 75% were achieved under the following conditions: Ozone as an oxidant agent and 0.1 M H2SO4 as an aqueous medium, temperature had no significant effect. The results are supported by thermodynamic diagrams and the possible chemical reactions are mentioned. Although the results also indicate that leaching under the above conditions dissolves up to 9% of iron, this loss is much less than leaching without the oxidizing conditions generated by the ozone. The BFS obtained from this treatment could be recirculated to the iron or steelmaking processes to recover iron values.
Ma. De Jesus Soria-Aguilar; Gloria Ivone Davila-Pulido; Francisco Raul Carrillo-Pedroza; Adrian Amilcare Gonzalez-Ibarra; Nallely Picazo-Rodriguez; Felipe López; Juan Ramos-Cano. Oxidative Leaching of Zinc and Alkalis from Iron Blast Furnace Sludge. Metals 2019, 9, 1015 .
AMA StyleMa. De Jesus Soria-Aguilar, Gloria Ivone Davila-Pulido, Francisco Raul Carrillo-Pedroza, Adrian Amilcare Gonzalez-Ibarra, Nallely Picazo-Rodriguez, Felipe López, Juan Ramos-Cano. Oxidative Leaching of Zinc and Alkalis from Iron Blast Furnace Sludge. Metals. 2019; 9 (9):1015.
Chicago/Turabian StyleMa. De Jesus Soria-Aguilar; Gloria Ivone Davila-Pulido; Francisco Raul Carrillo-Pedroza; Adrian Amilcare Gonzalez-Ibarra; Nallely Picazo-Rodriguez; Felipe López; Juan Ramos-Cano. 2019. "Oxidative Leaching of Zinc and Alkalis from Iron Blast Furnace Sludge." Metals 9, no. 9: 1015.
Although electrochemical characterization has been used to elucidate the species formed during hydrometallurgical processes, it has not been commonly applied to the cyanidation of precious metal tellurides. In this study, voltammetric characterization of the silver telluride (Ag2Te) reaction system in alkaline cyanide solutions (pH 10.9 and 1250 mg/L CN−) was carried out making use of carbon paste electrodes. For this purpose, the electrochemical reactions system of elemental silver and elemental tellurium were first studied by cyclic voltammetry in two aqueous media (i.e., aqueous solution at pH 10.9, and 1250 mg/L CN− at pH 10.9) and, by comparing the cyclic voltammograms obtained with those for Ag2Te, the electrochemical reaction system was elucidated. The results obtained showed that the anodic oxidation of Ag2Te in alkaline cyanide solutions occurred by at least two consecutive steps according to: Step 1 (fast reaction): Ag2Te + 4CN− ↔ Te + 2Ag(CN)2− + 2e−. Step 2 (slow reaction): Te + 3H2O ↔ TeO32− + 6H+ + 4e− while the cathodic reduction of Ag2Te in alkaline cyanide solutions occurred according to:Ag2Te+2e−↔2Ag+Te2−
A.A. González-Ibarra; F. Nava-Alonso; A. Uribe-Salas. Electrochemical study of silver telluride (Ag2Te): anodic and cathodic potential dependent-reactions in alkaline cyanide solutions. Hydrometallurgy 2018, 183, 230 -239.
AMA StyleA.A. González-Ibarra, F. Nava-Alonso, A. Uribe-Salas. Electrochemical study of silver telluride (Ag2Te): anodic and cathodic potential dependent-reactions in alkaline cyanide solutions. Hydrometallurgy. 2018; 183 ():230-239.
Chicago/Turabian StyleA.A. González-Ibarra; F. Nava-Alonso; A. Uribe-Salas. 2018. "Electrochemical study of silver telluride (Ag2Te): anodic and cathodic potential dependent-reactions in alkaline cyanide solutions." Hydrometallurgy 183, no. : 230-239.
The extraction of precious metals from tellurides by cyanidation is more difficult than when they are in their native form, nevertheless the reason for their refractory nature has not been adequately supported. In this study, the mechanism of the cyanidation kinetics of silver telluride (Ag2Te) was investigated. For this purpose, cyanidation experiments were carried out to: (1) study the difference between the cyanidation kinetics of elemental silver and silver telluride; (2) study the effect of temperature (i.e. 20, 25, 27, 30, 35 and 40°C) on silver telluride dissolution; and (3) elucidate the kinetic mechanism of the silver telluride cyanidation. The results obtained showed that: (1) while 83.5% of elemental silver was dissolved in 8 h, only 13.2% of silver from silver telluride was dissolved in the same time; (2) temperature has an important effect on silver extraction from silver telluride, but a minor effect on tellurium dissolution; and (3) at temperatures between 20 and 27°C, the process was controlled by the chemical reaction with an apparent activation energy of 191.9 kJ mol−1, whereas at temperatures between 30 and 40°C, the process was controlled by diffusion through a Ag5Te3 layer of products with an apparent activation energy of 25.2 kJ mol−1.
A. A. González-Ibarra; F. Nava-Alonso; A. Uribe-Salas. Cyanidation kinetics of silver telluride (Ag 2 Te). Canadian Metallurgical Quarterly 2017, 56, 272 -280.
AMA StyleA. A. González-Ibarra, F. Nava-Alonso, A. Uribe-Salas. Cyanidation kinetics of silver telluride (Ag 2 Te). Canadian Metallurgical Quarterly. 2017; 56 (3):272-280.
Chicago/Turabian StyleA. A. González-Ibarra; F. Nava-Alonso; A. Uribe-Salas. 2017. "Cyanidation kinetics of silver telluride (Ag 2 Te)." Canadian Metallurgical Quarterly 56, no. 3: 272-280.
A. A. González-Ibarra; F. Nava-Alonso; A. Uribe-Salas; E. N. Castillo-Ventureño. Decomposition kinetics of industrial jarosite in alkaline media for the recovery of precious metals by cyanidation. Canadian Metallurgical Quarterly 2016, 55, 448 -454.
AMA StyleA. A. González-Ibarra, F. Nava-Alonso, A. Uribe-Salas, E. N. Castillo-Ventureño. Decomposition kinetics of industrial jarosite in alkaline media for the recovery of precious metals by cyanidation. Canadian Metallurgical Quarterly. 2016; 55 (4):448-454.
Chicago/Turabian StyleA. A. González-Ibarra; F. Nava-Alonso; A. Uribe-Salas; E. N. Castillo-Ventureño. 2016. "Decomposition kinetics of industrial jarosite in alkaline media for the recovery of precious metals by cyanidation." Canadian Metallurgical Quarterly 55, no. 4: 448-454.
This work examines the role of NaOH and Ca(OH)2 on the hydrothermal decomposition of industrial jarosite deposited by a Mexican company in a tailings dam. The industrial jarosite is mainly composed by natrojarosite and contains 150 g Ag/t, showing a narrow particle size distribution, as revealed by XRD, fire assay, SEM-EDS and laser-diffraction analysis. The effect of the pH, when using NaOH or Ca(OH)2 as alkalinizing agent was studied by carrying out decomposition experiments at different pH values and 60?C in a homogeneous size particle system (pH = 8, 9, 10 and 11) and in a heterogeneous size particle system (pH = 11). Also, the kinetic study of the process and the controlling step of the decomposition reaction when NaOH and Ca(OH)2 are used was determined by fitting the data obtained to the shrinking core model for spherical particles of constant size. These results, supported by chemical (EDS), morphological (SEM) and mapping of elements (EDS) analysis of a partially reacted jarosite particle allowed to conclude that when NaOH is used, the process kinetics is controlled by the chemical reaction and when Ca(OH)2 is used, the rate determining step is changed to a diffusion control through a layer of solid products.
A.A. González-Ibarra; F. Nava-Alonso; J.C. Fuentes-Aceituno; A. Uribe-Salas. Hydrothermal decomposition of industrial jarosite in alkaline media: The rate determining step of the process kinetics. Journal of Mining and Metallurgy, Section B: Metallurgy 2016, 52, 135 -142.
AMA StyleA.A. González-Ibarra, F. Nava-Alonso, J.C. Fuentes-Aceituno, A. Uribe-Salas. Hydrothermal decomposition of industrial jarosite in alkaline media: The rate determining step of the process kinetics. Journal of Mining and Metallurgy, Section B: Metallurgy. 2016; 52 (2):135-142.
Chicago/Turabian StyleA.A. González-Ibarra; F. Nava-Alonso; J.C. Fuentes-Aceituno; A. Uribe-Salas. 2016. "Hydrothermal decomposition of industrial jarosite in alkaline media: The rate determining step of the process kinetics." Journal of Mining and Metallurgy, Section B: Metallurgy 52, no. 2: 135-142.