WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Article Citation - WoS: 2Citation - Scopus: 2A Novel Biomass-Derived Reductant for Nitric Acid Dissolution of Manganiferous Iron Ore: Comparative Assessment of Organic Reductants(MDPI, 2025-12-31) Top, Soner; Altiner, Mahmut; Vapur, Huseyin; Kursunoglu, Sait; Stopic, SreckoThis study investigates the selective dissolution of manganese from a manganiferous iron ore using nitric acid (HNO3) in the presence of various organic reductants. A series of leaching experiments was performed to evaluate the effects of temperature, reductant type, and leaching time on Mn recovery, with particular emphasis on biomass (horse dung) and tartaric acid as novel reducing agents. The dissolution behaviour of Fe, Mn, Mg, Ca, and Al was systematically examined, revealing that Mn extraction was strongly enhanced in the presence of reductants, while Fe dissolution remained below 10% under all conditions. The maximum Mn dissolution exceeded 90% at 90 degrees C using biomass and reached nearly 85%-90% with tartaric acid at elevated temperatures. Kinetic studies were conducted by applying reaction order models and the shrinking core model. The results indicated that Mn dissolution in HNO3 medium is predominantly controlled by surface chemical reaction, with Arrhenius analysis yielding activation energies of 27.74 kJ/mol for biomass and 21.26 kJ/mol for tartaric acid. These relatively low values confirm the efficiency of organic reductants in facilitating Mn reduction and dissolution. To sum up, comparison of reductant efficiency revealed that, at the lowest concentrations, the dissolution of Mn followed the sequence glucose > sucrose > oxalic acid > tartaric acid > maleic acid > biomass > citric acid > acetic acid. At the highest concentrations, the trend shifted, with citric acid emerging as the most effective, followed by tartaric acid > oxalic acid > glucose > sucrose > maleic acid > biomass > acetic acid.Article Citation - WoS: 6Citation - Scopus: 6Concentration Study of a Specularite Ore via Shaking Table, Reverse Flotation, and Microwave-Assisted Magnetic Separation(Taylor & Francis inc, 2022-11-03) Al-Dhubaibi, Ammar Mahdi Ahmed; Vapur, Huseyin; Top, Soner; Sivrikaya, OsmanDespite the difficulties in pelletizing specularite-type refractory iron ores, the utilization of these resources is indispensable for the steel industry due to the increasing need for iron. This study investigated Fe recovery from a refractory iron ore using gravity separation, reverse flotation, and two-stage magnetic separation. Tilt angle and particle size had a significant effect on the grade and recovery of concentrates in shaking table tests. Gravity concentration at optimum conditions resulted in an iron concentrate with 64.47% Fe grade and 90.73% Fe recovery. In the reverse flotation tests, the frother and depressant substantially affected the Fe grade of concentrates while the collector influenced the Fe recovery. A 90% Fe recovery with 64.69% Fe grade was obtained within optimum flotation conditions. The Fe grades were raised to >67.5% in products after the first magnetic separation. The tailings of the first magnetic separation were subjected to the second magnetic separation after microwave-assisted roasting to increase the magnetic susceptibility. In the second magnetic separation, a concentrate containing 66.06% Fe was separated from the microwave-roasted non-magnetic material with 82.23% Fe recovery. To the best of our knowledge, the microwave-roasting method has been applied to a specularite-type refractory iron ore for the first time.Article A Distinctive Determination of Circular Nozzles in Downcomer for Column Flotation(Taylor & Francis inc, 2023-01-07) Vapur, Huseyin; Top, Soner; Altiner, MahmutThis study aims to recover clean coal from valuable hard coal tailings (HCT), which have been used as solid fuels in a thermal power plant, through convenient conditions. The effective diameters of circular nozzles on the recovery of HCT were investigated by using the Jameson cell (JC) as the main purpose. Preliminary tests were conducted to determine the type and dosages of the collector and frother. The JC test results were evaluated by Yates and Box Behnken based on ANOVA analysis, statistically. It was observed that 3,000 g/ton of diesel oil, 300 g/ton of MIBC, 100 g/ton of Na2SiO3, and 60 cm of downcomer depth were found applicable levels of parameters. The decrease of the diameter increased the venturi effect of downcomer which provided the best recovery ratio of 97.79%. Besides, the results of kinetic models were obtained with desired efficiencies (CR infinity = 94.77%, k(coal) = 1.20, R-2 = 0.98 and SI = 2.40). The best diameter was 5 cm supplied a short time and high carrying capacity (CC) for concentrate.