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Öğe Determination of Optimum Process Conditions by Central Composite Design Method and Examination of Leaching Kinetics of Smithsonite Ore Using Nitric Acid Solution(Springer, 2021) Tanaydin, Mehmet Kayra; Tanaydin, Zumra Bakici; Demirkiran, NizamettinThe 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 degrees 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 degrees 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). [GRAPHICS] .Öğe Dissolution kinetics of calcined ulexite in ammonium sulfate solutions(Cenim, 2018) Demirkiran, Nizamettin; Tanaydin, Mehmet Kayra; Ozdemir, G. Deniz TurhanUlexite is one of the boron minerals, which include a respectable amount of hydration water. It can be used as a raw material in the production of boron compounds. Some part of water in the composition of ulexite can be removed from the solid matrix applying dehydration treatment, and a porous structure can be obtained to increase the reaction rate. In the present study, the effect of dehydration temperature on dissolution kinetics of ulexite in ammonium sulfate solutions was researched in a batch reactor utilizing the parameters of solution concentration, solid-to-liquid ratio, stirring speed and reaction temperature. It was determined that the dissolution rate of calcined material increased with increasing solution concentration and reaction temperature and with decreasing solid-to-liquid ratio. The highest dissolution rate was attained with the sample calcined at 150 degrees C. It was found that the dissolution rate fit to the first order pseudo-homogeneous model. The activation energy of the dissolution process was estimated to be 42 kJ.mol(-1).Öğe Effect of waste textile dye adsorbed almond shell on self compacting mortar(Elsevier Sci Ltd, 2021) Cemalgil, Selim; Onat, Onur; Tanaydin, Mehmet Kayra; Etli, SerkanThe aim of the current experimental study is to investigate the effect of waste textile dye absorbed almond shell on fresh and mechanical characteristics of self-compacting mortar (SCMs). In this context, eight SCMs were designed by substituting Violet Dye Solution adsorbed Almond shell (VDSA) at the rate of 0%, 2.5%, 5.0%, 7.5%, 10.0%, 12.5%, 15.0% and 17.5% as a cement on weight basis including the control mix. To measure the rheological properties of SCMs, mini slump and V-Funnel tests were conducted. A total of 72 beams of 40x40x160 mm(3) dimension specimens were casted and immersed in water curing at the end of the 7, 28 and 56 days to determine the mechanical parameters. 48 cubes of 50x50x50 mm(3) dimensions were casted and kept in the curing tank to determine durability characteristics such as porosity, sorptivity and specific gravity. Quantitative analyses are also performed by using Scanning Electron Microscopes (SEM), X-ray Diffraction Analysis (XRD), Energy-Dispersive X-ray Spectroscopy (EDS) and Fourier Transform Infrared (FTIR). The experimental results indicated that as the content of VDSA enchases, a remarkable enhancement in flexural strength at early days age and 28 days age strength. Whereas, increasing the content of VDSA resulted in a considerable decrease in compressive strength higher than 5%. (C) 2021 Elsevier Ltd. All rights reserved.Öğe Investigation of selective leaching and kinetics of copper from malachite ore in aqueous perchloric acid solutions(Taylor & Francis Inc, 2019) Tanaydin, Mehmet Kayra; Demirkiran, NizamettinIn this study, the leaching kinetics of malachite in perchloric acid solutions was investigated. The dissolution behaviors of copper, zinc, and iron in the ore matrix were determined at different acid concentrations and reaction temperatures. It was observed that the concentration of perchloric acid had a major effect on the dissolution of copper, zinc, and iron. It was determined that the effect of temperature on the dissolution of these species was not as significant as concentration impact. The results obtained shown that copper in the ore matrix was completely leached while zinc and iron were partially dissolved in perchloric acid solutions. In addition, the effects of the acid concentration, reaction temperature, stirring speed, particle size, and solid-to-liquid ratio on the leaching of malachite were researched. In these experiments, it was observed that the leaching rate of copper increased with increasing solution concentration, stirring speed, and reaction temperature, and with decreasing solid-to-liquid ratio and particle size. A kinetic analysis was performed, and it was found that the rate of leaching reaction obeyed the mixed kinetic control model in the unsteady state. The activation energy of the leaching process was calculated to be 34.69 kJ/mol.Öğe Kinetic models for the extraction of copper by Acorga M5640 after leaching of malachite ore in perchloric acid solutions and the stripping of copper from loaded organic phase(Springer Heidelberg, 2020) Tanaydin, Mehmet Kayra; Demirkiran, NizamettinIn the present work, the extraction kinetics of copper using the resulting actual leach solution obtained from the leaching of malachite ore in perchloric acid solutions and the stripping kinetics of copper from the loaded organic phase were examined. The organic phase was prepared by using Acorga M5640 and kerosene. In the extraction process, the effects of the initial pH of aqueous solution, initial concentration of copper, extractant concentration, temperature, and stirring speed on the extraction rate were investigated. In the stripping process, the effects of the concentration of perchloric acid, temperature, stirring speed, and extractant concentration on the stripping rate were examined. It was determined that the extraction rate increased with increasing the initial pH of aqueous solution, stirring speed, extractant concentration and temperature, and with decreasing the initial concentration of copper ions. In the stripping process, it was observed that the stripping rate increased with increasing the concentration of perchloric acid, temperature and stirring speed, and with decreasing the extractant concentration. It was determined that both the solvent extraction and stripping processes could be described by the first order pseudo homogenous reaction model. The activation energy for the extraction and stripping processes was calculated to be 50.04 kJ/mol and 32.42 kJ/mol, respectively.Öğe Optimization of process parameters and kinetic modelling for leaching of copper from oxidized copper ore in nitric acid solutions(Elsevier, 2022) Tanaydin, Mehmet Kayra; Tanaydin, Zumra Bakici; Demirkiran, NizamettinThe leaching behavior of Tunceli malachite mineral was investigated in nitric acid solutions by two steps to evaluate the effect of various experimental parameters. In the first step, the optimal conditions for the leaching process were determined, while in the second step, a kinetic evaluation for the process was performed. In the optimization experiments, the concentration of nitric acid, temperature, stirring speed, and solid-to-liquid ratio were selected as the independent variables, and the central composite design method (CCD) was applied to the experimental data. At the end of the experiments, the optimal values for the concentration of nitric acid, temperature, solid-to-liquid ratio and stirring speed were determined to be 0.5 mol/L, 50 degrees C, 0.004 g/mL and 500 r/min, respectively. Under the optimal conditions, the leaching rate was found to be 99% for 120 min of reaction time. In the kinetic evaluation tests, the effects of the concentration of nitric acid, temperature, stirring speed, solid-to-liquid ratio and particle size on the leaching rate of copper from malachite were investigated. In these tests, it was determined that the leaching rate increased with the increase in the temperature, acid concentration and stirring speed, and with the decrease in the particle size and solid-to-liquid ratio. In consequence of the kinetic analysis, it was observed that the leaching kinetics followed the mixed kinetic model, and a mathematical model for the leaching process was introduced. The activation energy for this process was calculated to be 36.23 kJ/mol.Öğe Preparation of cupric oxide by isothermal oxidation of metallic copper powder produced by electroless deposition(Pleiades Publishing Inc, 2014) Demirkiran, Nizamettin; Tanaydin, Mehmet KayraIn this study, cupric oxide powder was prepared from copper powder using a thermal oxidation method. The copper powder was produced by electroless deposition method using ascorbic acid as a chemical reducing agent. The oxide powder product was synthesized at 500A degrees C for 5 h. The metallic copper and oxide powder were characterized using X-ray diffraction and scanning electron microscopy. Based on results from these analytical techniques, it was determined that cupric oxide was successfully synthesized from the thermal treatment of copper powder and was in agglomerated state.Öğe Recovery of Cu(II) by Acorga M5640 After Leaching of Malachite Ore in Perchloric Acid Solutions(Springer, 2021) Demirkiran, Nizamettin; Tanaydin, Mehmet KayraIn 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 degrees 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.Öğe Removal of Copper from Aqueous Solution Using Perlite(Amer Inst Physics, 2017) Tanaydin, Mehmet Kayra; Bakici Tanaydin, Zumra; Ince, Muharrem; Demirkiran, NizamettinThe wastewaters containing organic and inorganic pollutants after many industrial processes such as metal plating, mining, textile, alloy, battery and industrial chemicals, are often discharged to environment. Heavy metals among these pollutants have highly stable, toxic, non-degradable and carcinogenic characters. They affect not only ecological system, but also human health and many life forms. Therefore, these contaminants should be eliminated or reduced to allowable levels before releasing to environment. Most of heavy metals have toxic character even at low concentrations of about 0.1-0.3 ppm. Treatment technologies such as filtration, ion exchange, precipitation, electrodeposition, reverse osmosis, sedimentation, and adsorption have been applied for removal of heavy metals from aqueous solutions. Adsorption is one of the most common and widely applied methods to eliminate the metal ions from waste solutions because of its simplicity and cost effectiveness. Activated carbon, clay minerals, ion exchange resins and various agricultural residues can be used as adsorbent materials in this process [1-3].
