Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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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.Conference Object Citation - Scopus: 2Leaching of Yahyali Non-Sulphide Pb-Zn Flotation Tailing Using Organic Acids(Baski, 2019) Hussaini, Shokrullah; Kursunoglu, Sait; Kaya, MuammerThe laboratory scale leaching of Kayseri-Yahyali non-sulphide lead (Pb)-zinc (Zn) flotation tailing using two organic acids was experimentally investigated. The effect of citric and oxalic acid on the dissolution of Zn, Pb, iron (Fe) and arsenic (As) was individually investigated under the following conditions: citric or oxalic acid concentration of 0.5-1.0M, temperature of 60-80°C and leaching time of 30-180 min. at 1/10 solid-to-liquid (S/L) ratio. 90.1% Zn dissolution was achieved using 0.5 M citric acid at 80°C leaching temperature for 180 min leaching time. The Fe, Pb and As dissolutions were determined as less than 20% under the conditions tested. 95.5% Fe and 68.8% As were removed from the flotation tailing along with less than 5% of Zn and Pb using 1.0 M oxalic acid for 180 min. leaching time at 60°C leaching temperature. It was found that citric acid is more prominent than oxalic acid for the selective leaching of zinc from the flotation tailing whereas a substantial amount of iron and arsenic removal can be achived by oxalic acid leaching. The use of NaCl along with citric acid was not useful for higher Zn dissolution. Based on the experimental results, an appropriate process will be improved for the selective leaching of valuable metals from the Pb-Zn non-sulphide flotation tailing in the near future. © 2020 Elsevier B.V., All rights reserved.Article Citation - WoS: 34Citation - Scopus: 35An Atomistic Study on the Help Mechanism of Hydrogen Embrittlement in Pure Metal Fe(Pergamon-Elsevier Science Ltd, 2024-02) Hasan, Md Shahrier; Kapci, Mehmet Fazil; Bal, Burak; Koyama, Motomichi; Bayat, Hadia; Xu, WenwuThe Hydrogen Enhanced Localized Plasticity (HELP) mechanism is one of the most important theories explaining Hydrogen Embrittlement in metallic materials. While much research has focused on hydrogen's impact on dislocation core structure and dislocation mobility, its effect on local dislocation density and plasticity remains less explored. This study examines both aspects using two distinct atomistic simulations: one for a single edge dislocation under shear and another for a bulk model under cyclic loading, both across varying hydrogen concentrations. We find that hydrogen stabilizes the edge dislocation and exhibits a dual impact on dislocation mobility. Specifically, mobility increases below a shear load of 900 MPa but progressively decreases above this threshold. Furthermore, dislocation accumulation is notably suppressed at around 1 % hydrogen concentration. These findings offer key insights for future research on Hydrogen Embrittlement, particularly in fatigue scenarios.Article Manganzı Demir Cevherinden Manganın Çözündürülmesinde Farklı İndirgeme Maddelerinin Etkisi(Chamber of Mining Engineers of Turkey, 2022-06-26) Top, S.; Altiner, Mahmut; Kursunoglu, SaitIIn this paper, the manganese extraction from a manganiferous iron ore was investigated using reductive leaching. Various chemicals were used as a reducing agent to leach manganese selectively from the ore in the presence of sulfuric acid (H2SO4) solution. Firstly, optimum dissolution values were determined for selective manganese dissolution without using a reducing agent. As it was aimed at the selective extraction of manganese from the ore, the reductive leaching tests were conducted by adding the reducing agents under the following optimal parameters: a leaching time of 1 h, a stirring speed of 300 rpm, a temperature of 70°C, a sulfuric acid concentration of 1 M where the ore was leached with an extraction ratio of 11.54% Mn and 2.16% Fe. Manganese was dissolved with high efficiencies (up to 97.46%) from the ore by using different organic compounds (tartaric acid (C<inf>4</inf>H<inf>6</inf>O<inf>6</inf>), oxalic acid (C<inf>2</inf>H<inf>2</inf>O<inf>4</inf>), citric acid (C<inf>6</inf>H<inf>8</inf>O<inf>7</inf>), glucose (C<inf>6</inf>H<inf>12</inf>O<inf>6</inf>), sucrose (C<inf>12</inf>H<inf>22</inf>O<inf>11</inf>), and maleic acid (C<inf>4</inf>H<inf>4</inf>O<inf>4</inf>)) as the reducing agents. © 2022 Elsevier B.V., All rights reserved.