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Öğe Combustion Synthesis of B4C-TiB2 Nanocomposite Powder: Effect of Mg Particle Size on SHS and Optimization of Acid Leaching Process(Pleiades Publishing Inc, 2023) Coban, Ozan; Bugdayci, Mehmet; Baslayici, Serkan; Acma, M. ErcanIn this study, composite nanoparticles of B4C-TiB2 were produced by combustion synthesis. Production was carried out by self-propagating high-temperature synthesis (SHS) method in atmospheric conditions by using oxide raw materials (B2O3, TiO2), carbon black and magnesium as a reducing agent. The effect of Mg particle size on SHS efficiency was investigated. Single-stage and 2-stage leaching processes were carried out to remove undesired phases in the SHS product. In the 1st HCl acid leaching process, the leaching temperature and leaching duration were optimized. As a result of the 2nd leaching process with the addition of carbonic acid and H2O2, commercial quality nanoparticle synthesis was performed. Results revealed that the increase in Mg particle size decreased the SHS efficiency, however very fine particle sized Mg usage decreased the SHS efficiency due to the evaporation and scatter of Mg. The optimum Mg particle size was determined as 75-150 mu m. Since it has a significant effect on the removal of Mg-borate phases, 90 degrees C was determined as the optimum leaching temperature. The optimum leaching duration was determined to be 60 min. As a result of optimized leaching processes, 99.11% purity B4C-TiB2 nanoparticle with 193.5 nm particle size and 30.65 m(2)/g surface area was synthesized.Öğe Effect of Mg stoichiometry on self-propagating high temperature synthesis (SHS) of ZrC nanoparticles in ZrO2-Mg-C system(Taylor & Francis Ltd, 2023) Bugdayci, Mehmet; Coban, Ozan; Baslayici, SerkanIt is significant to develop the production processes of Zirconium Carbide (ZrC) nanoparticles due to its superior properties. In this study, self-propagating high-temperature synthesis (SHS) followed by an acid leaching route was used to produce ZrC powder. ZrO2 was used as the zirconium source, C black as the carbon source and Mg as reductant. After modelling thermodynamically with the FactSage 7.1 software in terms of adiabatic temperature and possible phases, SHS processes were carried out with varying reductant stoichiometry (90%, 100%, 110%, 120%) and applying chemical treatment with HCl leaching for purification. The obtained products were characterised by XRD and SEM-EDS analysis. The optimum reductant stoichiometry for the production of ZrC was determined as 110%. As a result of the leaching processes, it was revealed that ZrC powders with an average particle size of 320 nm and containing a small amount of oxide residues could be synthesised. Compared to carbothermal reduction, which is the main production method of the material, the desired compounds were synthesised with much lower energy consumption and in much finer particles.Öğe HYDROMETALLURGICAL NICKEL AND COBALT PRODUCTION FROM LATERITIC ORES: OPTIMIZATION AND COMPARISON OF ATMOSPHERIC PRESSURE LEACHING AND PUG-ROAST-LEACHING PROCESSES(Scicell Sro, 2021) Coban, Ozan; Baslayici, Serkan; Bugdayci, Mehmet; Acma, Mahmut ErcanCorresponding to the technological developments, production and consumption of nickel have increased greatly over time due to its unique mechanical and chemical properties. Therefore, the production of nickel will always keep its importance. The availability of laterite ores, which are oxide type ores, is 86% of the nickel reserves on the Earth, and the processes used in the production of nickel from sulphide type ores have negative environmental effects. Therefore, recovery of nickel from lateritic ores has become increasingly important in recent years. In this study, the aim was to determine the optimum parameters of nickel and cobalt production from limonite type lateritic nickel ores, which were taken from Manisa Caldag region of Turkey, using atmospheric pressure sulfuric acid leaching and pug-roast-leach process. When the results obtained in these processes were compared, it was found that the Ni leaching efficiency is nearly 8% higher and iron leaching efficiency (contamination) is nearly 4% lower in the pug-roastleach process. Furthermore, the pug-roast-leach process was completed in 33% lower time compared to the atmospheric pressure sulfuric acid leaching process.Öğe Production of B4C-TiB2 composite powder by self-propagating high-temperature synthesis(Springer, 2022) Coban, Ozan; Bugdayci, Mehmet; Acma, M. ErcanAdvanced ceramics find significant application areas due to their superior mechanical, electrical, magnetic chemical and thermal properties. By combining these materials, significant properties can be obtained as a result of production of the composites of hard metal compounds in nanoscale dimensions. Self-propagated high-temperature synthesis (SHS) is one of the prominent methods for the production of such nanoparticles. SHS is a combustion synthesis method. In this study, nanocomposite powders of B4C-TiB2 were synthesized by SHS method. FactSage software was used for thermochemical simulation and computational stoichiometric optimization. In the experimental step, 2 different SHS sets were prepared. In the first stage, B4C and TiB2 powders were synthesized. The B4C-TiB2 composite was produced in the final set of experiments. Then, production parameters of B4C-TiB2 composite powders, from B2O3, TiO2, and carbon black, were investigated. Magnesium powder was used as reductant agent. Afterwards, HCl leaching process was performed, and acid concentration was optimized. The effect of carbonic acid and H2O2 addition on dissolution of undesired phases was also been investigated as a new method. Products were characterized by XRD, SEM and BET analysis. B4C-TiB2 composite powder with quite high surface area, fine particle size and high porosity could be synthesized with reasonable purity. According to the results, the optimum molar ratios were determined as TiO2:B2O3:Mg:C = 1:3:12:1.6. Optimum acid concentration was found to be 10.5 M for leaching process, and carbonic acid addition on leaching step found to be effective on TiO2 removal. The highest purity could be obtained with 50%-50% stoichiometry. It has also been determined that the synthesis of B4C-TiB2 composite powder has a positive effect on both the chemical content and the morphology that will increase the sintering ability.