Browsing by Author "Kocan, F"
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Item Investigation of Leaching Kinetics of Ulexite Waste in Oxalic Acid SolutionsBayca, SU; Kocan, F; Abali, YThe dissolution of ulexite waste in oxalic acid solutions was studied in a batch reactor after characterization of the waste by X-ray diffiaction (XRD) analysis and X-ray fluorescence (XRF) analysis. The dissolution parameters in this study were acid concentration, stirring rate, and reaction temperature. The experimental data were examined using homogeneous and heterogeneous kinetic models, and the dissolution kinetics of the waste was determined to be a first-order reaction control model. The activation energy of ulexite waste in oxalic acid solution was also calculated. It was observed that the dissolution rate increased with increasing reaction temperature, stirring rate and acid concentration. The kinetic model of the dissolution process was determined to be a first-order reaction control model. The activation energy was found to be 41.09 kJ mol(-1).Item Leaching of Celestite in Sodium Hydroxide Solutions and Kinetic ModellingKocan, F; Hicsonmez, UIn this study, the dissolution kinetics of celestite in solutions of sodium hydroxide was investigated by batch process. The results showed that the parameters which had the greatest effect on the dissolution of celestite in sodium hydroxide solutions were reaction temperature, the concentration of sodium hydroxide and stirring speed. It was determined that the dissolution rate increased with increased stirring speed, sodium hydroxide concentration, reaction time and temperature and decreased with increasing particle size and solid-liquid ratio. The leaching process fitted the shrinking core model with diffusion through the product layer model as the rate-determining step. The activation energy of the dissolution of celestite was calculated as 62.24 kJ/mol. A semi-empirical kinetic model was obtained for dissolution of celestite in sodium hydroxide solution.Item Preparation and Magnetic Properties of NiFe2O4 Plate NanoparticlesKocan, FThe aim of this study was to investigate nickel ferrite (NiFe2O4) plate nanoparticles synthesized by the co-precipitation method. The effects of parameters such as solution pH and Fe3+/Ni2+ mole ratio of nickel ferrite nanoparticles were analyzed. The nanoparticles synthesized by the co-precipitation method were calcined at 650 degrees C. The samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDAX), and Fourier-transform infrared spectroscopy (FTIR). The remanent magnetization, saturated magnetism, and coercivity properties of the samples were measured with a vibrating sample magnetometer (VSM). In a synthesis process with Fe3+/Ni2+ = 1 mole ratio, a Ni1.43Fe1.7O4 compound was formed where NiFe2O4 was expected to form. NiFe2O4 plate nanoparticles with 108-nm particle size were successfully synthesized using the Fe3+/Ni2+ = 2 mole ratio.Item Leaching kinetics of celestite in nitric acid solutionsKocan, F; Hicsonmez, UIn this study, strontium nitrate extraction from celestite in nitric acid solutions was investigated using the leaching method. The influences of acid concentration, solid-to-liquid ratio, stirring speed, and reaction temperature on the leaching of strontium from celestite concentrate were studied. The results showed that the leaching rate increased with increasing acid concentration, stirring speed, and temperature and decreased with increasing solid-to-liquid ratio. The particle size was fixed in all of the dissolution experiments. The results showed that the stirring speed and the temperature were the most influential parameters with respect to the leaching process. The kinetic model best fit control by diffusion through the product layer. The activation energy of the dissolution celestite in nitric acid solutions was calculated to be 42.22 kJ/mol.Item Low-temperature synthesis of SrCrO4 nanorod particles from strontium sulfateKocan, F; Hicsonmez, UStrontium chromate (SrCrO4) nanorod particles were successfully prepared at low temperature using the chemical precipitation method. In this synthesis process, sodium dichromate and celestite mineral, which is a water-insoluble mineral, were used as starting materials. The morphology and size of the particles obtained were determined by SEM-EDAX analysis. XRD analysis of the synthesized particles revealed an SrCrO4 phase and other phases. The effects of different molar ratios on SrCrO4 formation were investigated. The addition of NaCl has been found to play a significant role in the formation of strontium chromate nanorods, in particle size, particle shape and product composition. [GRAPHICS] .Item Dissolution of Colemanite Process Waste in Oxalic Acid SolutionsBayca, SU; Kocan, F; Abali, YThe dissolution of colemanite waste in oxalic acid solutions was studied in a batch reactor, and the characterization of colemanite waste was determined by X-ray diffraction analysis and X-ray Fluorescence analysis. The dissolution parameters in this study were acid concentration, stirring speed, and reaction temperature, and it was observed that the dissolution rate increased with increasing reaction temperature. The experimental data were examined by using homogeneous and heterogeneous kinetic models, and the dissolution kinetics of the waste was determined to be a pseudo-first-order homogeneous reaction control model. The activation energy of colemanite waste in oxalic acid solution was calculated to be 27.80 kJ/mol. Thus, pure boric acid crystals can be produced using of colemanite waste, and this can benefit the environment and the economy. (c) 2013 American Institute of Chemical Engineers Environ Prog, 33: 1111-1116, 2014