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AKTAŞ, SERDAR

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AKTAŞ

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Start date: 2012 × Subject: EXTRACTION ×

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Now showing 1 - 3 of 3
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    Investigation of Alkaline Leaching Parameters on Stibnite Concentrate
    (SPRINGER HEIDELBERG, 2020) ÇETİNER, BURCU NİLGÜN; Aktas, Serdar; Cetiner, Burcu Nilgun
    According to critical statistical studies, antimony is one of the rarest elements in the world, and global resources could be exhausted by 2050. In light of these observations, its extraction will be costly due to poor-quality ore, deep mining, remote locations, and high energy consumption. In the present study, an alkaline leaching process was carried out on stibnite concentrate to evaluate the effect of reaction parameters on the percentage of antimony extraction. The leaching efficiencies of different sulfur and hydroxide sources were studied and compared to one another to create a better understanding of the reaction process. Kinetic models were investigated to identify the reaction pathway and calculate the activation energy. The activation energy of the stibnite dissolution was assessed as 19.13 kJ/mol using a two-dimensional diffusion-reaction model. The value of activation energy indicates the quantity of energy necessary for a reaction to proceed. As expected, potassium hydroxide leaching was significantly more successful than was sodium hydroxide; however, in terms of economics, the use of sodium hydroxide was found to be more cost-efficient. Interestingly, this finding indicated that caustic leaching is still the most effective method for stibnite extraction.
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    Recovery of Ruthenium Via Zinc in the Presence of Accelerator
    (SPRINGER INDIA, 2018) AKTAŞ, SERDAR; Aktas, Serdar; Morcali, Mehmet Hakan; Aksu, Kemal; Aksoy, Burak
    In this study, the recovery of ruthenium from spent bath solutions via cementation reaction with zinc powder was investigated. Studied parameters included the quantity of zinc, reaction temperature, reaction time and sodium chloride additions to understand their effects on the reaction. Tests were performed in a temperature controlled water-bath with temperatures between 20 and 70 A degrees C at atmospheric pressure. Furthermore, in order to determine activation energy of cementation reaction, several mathematical kinetic models were used and the activation energy, which was calculated from best fit, was found to be 12.48 kJ/mol. Addition of sodium chloride to the solution greatly accelerated the cementation reaction, in that, more the addition of sodium chloride, the better was the precipitation efficiency. In the absence of sodium chloride at 25 A degrees C a percentage of ruthenium recovery was below 75% whereas 1000 mg sodium chloride addition at 65 A degrees C ensured a percentage of ruthenium recovery more than 95%. This corresponded to more than about 28% increase.
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    Studies of Gold Adsorption from Chloride Media
    (UNIV FED SAO CARLOS, DEPT ENGENHARIA MATERIALS, 2015-06) AKTAŞ, SERDAR; Morcali, Mehmet Hakan; Zeytuncu, Bihter; Ozlem, Eda; Aktas, Serdar
    In this paper, adsorption of gold from chloride media using commercial sorbent (Lewatit TP 214 (L-214)) and biomass residue (rice hull (RH)) were investigated. The different adsorption parameters, sorbent dosage, contact time, temperature and pH of solution on adsorption (%) were studied in detail on a batch sorption. Before the RH was activated, adsorption (%) was poor compared with L-214. However, after the RH was activated at 1000 degrees C under an argon atmosphere, the gold adsorption (%) increased four-fold. X-ray fluorescence (XRF) was used to explore the feasibility this material as an adsorbent for the removal of gold from aqueous solutions. The adsorption equilibrium data were best fitted with the Langmuir isotherm model. The maximum adsorption capacities, Q(max), at 25 degrees C were found to be 93.46 and 108.70 mg/g for the activated rice hull (ARH) and L-214, respectively. Thermodynamic calculations using Delta H degrees, Delta S degrees, Delta G degrees and E-a values indicate that the adsorption process was spontaneous and endothermic.