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• MakaleYalnız künye2025Scopus SJRQ1/r/munzur/1099
  The Extraction of Rare-Earth Elements (REEs) from Spent Nickel–Metal Hydride (Ni–MH) Batteries by Bifunctional Ionic Liquids (Bif-ILs): Process Optimization and Kinetics Modeling

  Erust, Ceren

  The cathode material of nickel–metal hydride (Ni–MH) batteries includes nickel, cobalt, and rare-earth elements (REEs) such as La, Ce, Nd, and Pr, which are among the critical raw materials (CRMs). Ionic liquids as the environmentally friendly approaches are proposed by various investigations for the extraction of critical metals from spent Ni–MH batteries. In this study, three different Bifunctional Ionic Liquids (Bif-ILs) were designed for comparative studies, namely Aliquat 336–Cyanex 272 (AL–CY), Aliquat 336–PC88A (AL–PC), and Aliquat 336–D2EHPA (AL–D2). The extraction results indicated that temperature has a direct effect on the extraction of critical metals in the presence of all Bif-ILs. Among three types of Bif-ILs, AL–D2 has an optimal extraction power (La: 98.8%, Ce: 94.2%, Nd: 99.2%, and Pr: 98.4%) after precipitation of 99.99% of Ni and Co. Furthermore, kinetics modeling is used for reaction mechanisms investigation. Results indicated that the mixed controlled model by shrinking core model (diffusion controlled and chemical reaction controlled) was the best model fitted to all data (coefficient of determination (R2) > 0.90). according to the Arrhenius equation, activation energies for all REEs in the presence of all Bif-ILs are between 13 and 42 kJ/mol that reflects a mixed controlled reaction.

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  AtıfScopus2·OpenAlex2

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• MakaleAçık Erişim2024Scopus SJRQ1/r/munzur/1775
  Optimization and Kinetic Study of Manganese Leaching from Pyrolusite Ore in Hydrochloric Acid Solutions with Oxalic Acid

  Karacahan, Mehmet Kayra

  The leaching behavior of pyrolusite minerals was examined in hydrochloric acid solutions, including oxalic acid, to evaluate the influence of various experimental conditions. The optimum parameters for the leaching process were found in the first stage, and the process's kinetics were assessed in the second. The concentrations of oxalic acid, hydrochloric acid, and temperature were chosen as independent variables in the optimization experiments, with the central composite design used to analyze the experimental data. The optimum concentrations for oxalic acid, hydrochloric acid, and temperature were determined to be 0.75 mol/L, 1.2 mol/L, and 60 °C, respectively. The leaching rate was determined to be 97.4% for 120 min of response time in optimum situations. The kinetic assessment experiments studied the effects of solid/liquid ratio, particle size, stirring speed, and temperature on the manganese leaching rate from pyrolusite. In the studies, the leaching rate was shown to rise with increasing temperature and stirring speed, as well as with decreasing particle size and solid/liquid ratio. The kinetic analysis revealed that the leaching kinetics matched the mixed kinetic model, and a mathematical model for the leaching process was developed. This process's activation energy was determined to be 29.05 kJ/mol. Graphical Abstract: (Figure presented.)

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  AtıfScopus17·WoS15·OpenAlex18

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• MakaleYalnız künye2023Scopus SJRQ2/r/munzur/2158
  Investigation of Leaching Kinetics of Molybdenum from MoO3 Concentrate in Ammonia–Ammonium Nitrate Solutions

  Karacahan, Mehmet Kayra

  MoO3 is a widely accessible foundation material and the primary compound used to produce numerous molybdenum products. The ore was first roasted, and the leaching behavior of concentrated molybdenite mineral was assessed. The optimal conditions for the leaching process were identified in the second step, and in a subsequent stage, the process' kinetics were assessed. Ammonia and ammonium nitrate concentration were used as independent variables in the trials, and the central composite design approach was used to analyze the results. At the conclusion of the tests, the optimum concentrations of ammonia and ammonium nitrate were found to be 2.42 mol/L and 1.86 mol/L, respectively. On the rate at which molybdenum leached from MoO3, the influences of temperature, stirring speed, solid-to-liquid ratio, and particle size were investigated. It was found that the leaching rate increased when temperature and stirring speed increased, along with decreasing the solid-to-liquid ratio and particle size. Leaching efficiency of molybdenum (93%) such as temperature 20 °C, 1.859 mol/L ammonium nitrate concentration, 2.419 mol/L ammonia concentration, solid/liquid ratio 6/100 g/mL, stirring speed 400 rpm, and average particle size 0.115 mm optimum conditions have been achieved. The kinetic study proposed a mathematical model for the leaching process, which revealed that the leaching kinetics matched the Avrami model. This process' activation energy was determined to be 22.66 kJ/mol. Calcium molybdate is used in various fields, such as construction, transportation, anti-corrosion pigments, and flame retardants. Graphical Abstract: [Figure not available: see fulltext.]

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  AtıfScopus8·WoS7·OpenAlex9

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• MakaleYalnız künye2021Scopus SJRQ2/r/munzur/3005
  Determination of Optimum Process Conditions by Central Composite Design Method and Examination of Leaching Kinetics of Smithsonite Ore Using Nitric Acid Solution

  Tanaydın, Mehmet Kayra; Bakıcı Tanaydın, Zümra; Demirkıran, Nizamettin

  The leaching behavior of Tunceli smithsonite ore in nitric acid was evaluated in two study steps including optimization of leaching process and kinetics modeling. The individual and synergistic effects of effective parameters such as nitric acid concentration, solid-to-liquid ratio, stirring speed, and temperature on the dissolution rate of zinc were investigated using central composite design. Four factors including temperature (30–50 °C), nitric acid concentration (0.2–0.5 mol/L), stirring speed (350–600 rpm), and solid-to-liquid ratio (0.004–0.01 g/L) were investigated. The dissolution percent of zinc (97%) was obtained in 120 min of leaching time: acid concentration 0.5 mol/L, temperature 50 °C, stirring speed 500 rpm, and solid–liquid ratio 2/500 g/mL at the optimum conditions obtained using the central composite design. The dissolution kinetics of smithsonite was examined according to heterogenous models and it was found that the dissolution rate was controlled by ash layer diffusion process. It was found that the leaching rate increased with increasing temperature, stirring speed, and acid concentration as well as decrescent particle size and solid/liquid ratio. The trial data were analyzed by statistical and graphical methods and the activation energy of this leaching process was determined to be 28.63 kJ·mol−1. Graphical Abstract: [Figure not available: see fulltext.].

  AtıfScopus9·WoS9·OpenAlex10

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• MakaleYalnız künye2021Scopus SJRQ2/r/munzur/2926
  Recovery of Cu(II) by Acorga M5640 After Leaching of Malachite Ore in Perchloric Acid Solutions

  Demirkıran, Nizamettin; Tanaydın, Mehmet Kayra

  Abstract: In the present study, the recovery of Cu2+ from the resulting actual leach solution after the leaching of malachite ore in perchloric acid solutions was examined by applying the solvent extraction method. The organic phase was prepared using Acorga M5640 and kerosene. The effects of the initial pH of solution, extractant concentration, Cu2+ concentration, temperature, and stirring speed on the extraction process were investigated. It was determined that the extraction yield increased with an increase in the extractant concentration, initial pH of aqueous solution, stirring speed, and temperature, and with a decrease in the concentration of Cu2+. To prevent or minimize Zn2+ transfer to the organic phase and to ensure maximum Cu2+ extraction from the aqueous phase, the optimal values for the initial pH of the aqueous phase, initial concentration of Cu2+, extractant concentration, temperature, and stirring speed were selected to be 1, 0.152 g/L, 4% (v/v), 25 °C, and 400 rpm, respectively. The stoichiometry and mechanism of the extraction process were determined applying the equilibrium slope method. The changes in the Gibbs free energy, enthalpy, and entropy were determined. The changes in these thermodynamic parameters were calculated to be − 3.87 kJ/mol, 64.67 kJ/mol, and 0.23 kJ/(mol K), respectively. Graphical Abstract: The extraction percentage of Cu2+ increases substantially when the initial pH of the leach solution increases from 0.1 to 1. The further increase in the initial pH above 1 does not create an increase in the extraction extent of Cu2+. When the initial pH of the leach solution is higher than 1, the amount of Zn2+ transferred from the aqueous phase to the organic phase increases significantly.[Figure not available: see fulltext.].

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  AtıfScopus7·WoS5·OpenAlex9

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