Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
Browse
28 results
Search Results
Article Rare Earth Elements in the Global Economy: Usage, Recovery, and the Quest for Supply Security – A Review(Springer Heidelberg, 2026) Top, Soner; Ayten, Asim Mustafa; Altiner, Mahmut; Demir, Idris; Kursunoglu, SaitOften described as the vitamins of modern industry, rare earth elements (REEs) are indispensable for the deployment of low-carbon and clean energy technologies. However, ensuring a secure and sustainable REE supply remains a major challenge due to the strong interdependence between application-driven demand, extraction and processing technologies, and the geopolitical concentration of resources. This review adopts an integrated analytical framework in which these three dimensions are treated as interconnected components shaping the resilience of global REE supply chains. First, the major application sectors of REEs are examined to clarify how emerging energy and advanced manufacturing technologies drive demand for specific elements and amplify their strategic importance. Second, extraction and processing technologies are reviewed in relation to both primary and secondary resources, highlighting how technological maturity, process selection, and material characteristics constrain or enable supply expansion. Finally, geopolitical and strategic aspects of the REE supply chain are analyzed to demonstrate how resource concentration, policy instruments, and international dependencies directly influence technological deployment and industrial competitiveness. By explicitly linking application-driven demand, technological pathways for extraction and processing, and geopolitical supply structures within a unified framework, this review provides a coherent understanding of the systemic challenges facing the REE sector and identifies key leverage points for improving the robustness and sustainability of REE supply chains in the context of the global clean energy transition.Article Recent Progress in the Beneficiation of Iron-Manganese Ores: An Overview(Pleiades Publishing Ltd, 2025) Top, SonerIron-manganese (Fe-Mn) ores are essential for steelmaking, ferroalloy production, and emerging energy technologies, yet their beneficiation is challenging due to the close association of Fe and Mn oxides and their overlapping physicochemical properties. This review assesses key processing strategies, including gravity separation, magnetic methods, flotation, reduction roasting, and selective reductive leaching. Physical beneficiation offers limited upgrades, being constrained by mineral liberation and ore texture. Reduction roasting with carbonaceous or hydrogen reductants exploits the different reduction stabilities of Fe and Mn oxides, creating magnetic contrasts for effective separation. Hydrometallurgical techniques based on reductive leaching also show strong potential, particularly with biomass-derived or organic reductants, achieving manganese recoveries often above 90-99%. A central focus is the use of Ellingham and Eh-pH diagrams as predictive tools for selective separation. Ellingham diagrams outline the thermodynamic stabilities of Fe and Mn oxides, guiding roasting design, while Eh-pH diagrams describe dissolution behavior under varying acidity and redox conditions, enabling leaching optimization. Integrating these frameworks with experimental evidence demonstrates how thermodynamic and electrochemical principles can improve process selectivity. No single technique universally addresses Fe-Mn beneficiation challenges; instead, hybrid flowsheets combining physical, thermal, and hydrometallurgical routes tailored to ore characteristics are most effective. Future research should prioritize low-carbon and sustainable approaches such as hydrogen roasting, bio-reductant leaching, and zero-waste systems. This review thus provides both a synthesis of current advances and a roadmap for sustainable Fe and Mn resource recovery.Article Production of Waste-Based Lightweight Geopolymer Concretes Using Calcined Bentonite, Fly Ash, Slag, and Expanded Polystyrene Granules(Taylor & Francis Inc, 2026-03-19) Top, Soner; Nussrat Shukur Shukur, Yasir; Vapur, HüseyinThis study investigates the production of environmentally friendly lightweight geopolymer concretes utilizing fly ash (FA) as the primary precursor with calcined calcium bentonite (CCB), ferrochrome slag (SG), and expanded polystyrene (EPS) as supplementary components. A Box-Behnken design was employed to investigate the combined effects of CCB and SG additions, along with the solid-to-liquid ratio, on the compressive strength. Moderate CCB incorporation, particularly around 10%, improved mechanical performance, achieving strengths above 48 MPa, with a maximum of 51.33 MPa at 90 degrees C for a mix containing 5% CCB and 5% SG. Higher CCB dosages (>20%) reduced strength due to matrix dilution, while SG showed limited contribution at elevated levels. Incorporation of EPS granules reduced density to as low as 1292 kg/m & sup3;, yet compressive strengths between 25 and 30 MPa were maintained in mixes with 10% CCB and 0.3% EPS. SEM-EDX analysis confirmed dense geopolymer matrices in FA-CCB composites, whereas SG particles appeared less integrated. These results confirm the potential for producing high-strength, lightweight geopolymer concretes through the effective valorization of waste. The combined use of FA, CCB, SG, and EPS offers a sustainable pathway for resource-efficient construction that supports circular resource utilization.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: 1Citation - Scopus: 1A Comprehensive Review on the Extraction and Recovery of Lithium from Primary and Secondary Sources: Advances Toward Battery-Grade Materials(Wiley, 2025-10-20) Top, Soner; Kursunoglu, Sait; Altiner, MahmutLithium-ion battery (LIB) technologies have become indispensable to modern energy systems, driving global demand for high-purity lithium compounds. This review focuses on lithium recovery and purification strategies for battery-grade lithium carbonate (Li2CO3) and lithium hydroxide (LiOH), addressing both primary sources (brines and minerals) and secondary sources (waste materials). Industrially established processes, such as evaporation-based brine treatment and conventional metallurgical methods, are discussed alongside emerging techniques, including membrane separation, solvent extraction, and CO2-assisted precipitation. Particular attention is given to lithium precipitation mechanisms, the behaviour of co-existing ions during extraction, and the specific quality requirements for cathode material synthesis. By evaluating process scalability, environmental impact, and product purity, this review provides a comprehensive understanding of current practices and future directions. Additionally, it highlights the growing importance of lithium in the context of accelerating electric vehicle (EV) adoption, underscoring the bright and expanding future of the lithium industry.Article Citation - WoS: 16Citation - Scopus: 22Ultrasonic-Assisted Production of Precipitated Calcium Carbonate Particles From Desulfurization Gypsum(Elsevier, 2021-04) Altiner, Mahmut; Top, Soner; Kaymakoglu, BurcinThis study aimed to investigate the effect of ultrasonic application on the production of precipitated calcium carbonate (PCC) particles from desulfurization gypsum via direct mineral carbonation method using conventional and venturi tube reactors in the presence of different alkali sources (NaOH, KOH and NH4OH). The venturi tube was designed to determine the effect of ultrasonication on PCC production. Ultrasonic application was performed three times (before, during, and after PCC production) to evaluate its exact effect on the properties of the PCC particles. Scanning electron microscope (SEM), X-ray diffraction (XRD), Atomic force microscope (AFM), specific surface area (SSA), Fourier transform infrared spectrometry (FTIR), and particle size analyses were performed. Results revealed the strong influence of the reactor types on the nucleation rate of PCC particles. The presence of Na+ or K+ ions in the production resulted in producing PCC particles containing only calcite crystals, while a mixture of vaterite and calcite crystals was observed if NH4+ ions were present. The use of ultrasonic power during PCC production resulted in producing cubic calcite rather than vaterite crystals in the presence of all ions. It was determined that ultrasonic power should be conducted in the venturi tube before PCC production to obtain PCC particles with superior properties (uniform particle size, nanosized crystals, and high SSA value). The resulting PCC particles in this study can be suitably used in paint, paper, and plastic industries according to the ASTM standards.Article Citation - WoS: 30Citation - Scopus: 37Testing of 17-Different Leaching Agents for the Recovery of Zinc From a Carbonate-Type Pb-Zn Ore Flotation Tailing(Pergamon-Elsevier Science Ltd, 2021-07) Hussaini, Shokrullah; Kursunoglu, Sait; Top, Soner; Ichlas, Zela Tanlega; Kaya, MuammerThe recovery of zinc from a flotation tailing using 17-different leaching agents, including inorganic and organic acids, alkaline solutions and chelating agents, was investigated. The effects of the lixiviant type, acid concentration, leaching temperature, leaching time, and solid-to-liquid ratio on the metals dissolution were studied. The use of sulfuric acid resulted in 91% of zinc extraction with a high selectivity against lead. The major impurities of lead, iron, calcium and arsenic precipitated during the leaching process as a segnisite, beudantite, gypsum, and goethite in this lixiviant. It was seen that the addition of oxidants in sulfuric acid solution slightly increased zinc dissolution. The citric acid dissolved 90.1% of zinc along with 9.1% lead. 90% of zinc dissolution was achieved by using malic acid, and high selectivity between zinc and lead dissolutions was also observed. The citric and malic acid leach residues contained a substantial amount of segnitite, beudantite, and quartz as the major phases. In term of zinc and lead dissolution selectivity, the best inorganic agents were determined in the following order: sulfuric acid > hydrochloric acid > perchloric acid > nitric acid. With organic agents, the best zinc and lead selectivity was achieved in the following order: sulfosalicylic acid > citric acid > malic acid > formic acid > tartaric acid > ascorbic acid. The best simultaneous zinc and lead dissolutions were achieved using sodium hydroxide agent. Using 5 M sodium hydroxide at 80 degrees C and 1/10 solid-to-liquid ratio for 180 min. leaching time, 81.4% of zinc and 47.4% of lead were dissolved while leaving a considerable amount of iron in the residue. When the ammonium chloride was used as a lixiviant, the silver and zinc were taken into the leach solution. 61.3% of zinc dissolution was obtained by using 50% ammonia as lixiviant, whereas no iron and lead dissolutions were observed. Using 0.37 M EDTA at 80 degrees C, 1/10 solid-to-liquid ratio for 180 min. leaching time, more than 90% of zinc dissolved along with a substantial amount of iron, arsenic and lead co-dissolutions. 47.4% of zinc dissolution was obtained at 80 degrees C and 1/10 solid-to-liquid ratio for 180 min. leaching time when sodium citrate was used as lixiviant, whereas less than 20% of zinc dissolved using ammonium oxalate at similar leaching condition. 39% zinc was dissolved using 3 M ammonium acetate at 80 degrees C, 1/10 solid-to-liquid ratio for 180 min., while 23.1% of zinc dissolution was achieved when the ammonium acetate was tested under similar experimental conditions. As a result, sulfuric, citric, malic, sulfosalicylic and formic acids were deemed to be the most promising leaching agents for the selective recovery of zinc from the lead-zinc flotation tailing.Article Citation - WoS: 7Citation - Scopus: 7Separation of Mn and Fe From a Manganiferous Iron Ore Using Horse Dung as Reductant: A Zero Waste Approach(Springer, 2022-01-13) Top, Soner; Altiner, Mahmut; Kursunoglu, SaitThe separation of manganese and iron from a manganiferous iron ore using horse dung (biomass) as reductant was investigated in a sulfuric acid solution, and 99.80% Mn and 17.76% Fe were extracted into the solution under these leaching conditions: 1 M sulphuric acid concentration, 120 g/L biomass, 1/10 solid to liquid ratio, 300 rev/min stirring speed, 90 degrees C leaching temperature, and 3 h leaching time. In the first precipitation step, the iron and aluminum were first rejected from the solution at pH 5.04. Thereafter, 98.58% Mn was precipitated at pH 10 in the second step. The precipitate was identified as a pyrochroite mineral. After the leaching, the residue was subjected to a carbothermal reduction process conducted at 700 degrees C for 10 min in the presence of no extra reductant. The residue was converted to magnetite mineral, which can be easily recovered by magnetic separation. Based on the experimental results, a flowsheet has been proposed.Article Citation - WoS: 5Citation - Scopus: 5Selective Leaching of a Mixed Nickel-Cobalt Hydroxide Precipitate in Sulphuric Acid Solution With Potassium Permanganate as Oxidant(Taylor & Francis inc, 2020-10-12) Hussaini, Shokrullah; Ichlas, Zela Tanlega; Top, Soner; Kursunoglu, Sait; Kaya, MuammerSelective leaching of a mixed nickel-cobalt hydroxide precipitate was investigated using potassium permanganate as oxidant in sulfuric acid solution. 94.9% Ni, 50% Co and 0.6% Mn were dissolved under the following conditions: sulfuric acid concentration of 0.75 M, potassium permanganate of 5 g/L, temperature of 30 degrees C, leaching duration of 60 min, solid-to-liquid ratio of 1/10, and stirring speed of 400rpm. The pregnant leach solution was subjected to a solvent extraction process. 98% Co and 99% Mn were extracted at pH 4.84 with 30% (v/v) Cyanex 272, leaving essentially all nickel in the raffinate. Based on the experimental results, a flowsheet is proposed.Article Citation - WoS: 6Citation - Scopus: 8Removal of Heavy Metals from Wastewater Solution Using a Mechanically Activated Novel Zeolitic Material(Pleiades Publishing Ltd, 2020-11) Uckun, Sukru; Sarikaya, Musa; Top, Soner; Timur, Irfan; Şükrü, Uçkun; Musa, Sarıkaya; Soner, Top; İrfan, TimürThe removal of heavy metals from the wastewater solution using a novel zeolitic material was conceived and experimentally probed. The natural zeolite was ground in a planetary ball mill to increase negative surface charge and amorphization of the material as well as a conventional ball mill. The ground materials were used for the removal of heavy metals from the wastewater solution. The maximum removals were found to be 78% for Pb, 67% for Ni and 54% for Cd by using the conventional milled natural zeolitic material at pH 11. However, 93% of Pb, 72% of Ni and 57% of Cd were removed at pH 9 with the novel zeolitic material milled by a planetary ball mill. It was revealed that the novel zeolitic material produced by a planetary ball mill increased the absorption capacity of the heavy metals and reduced the alkali requirement for pH adjustment. The removal order of heavy metals with the novel zeolitic material is determined as follows: Pb> Ni>Cd.
- «
- 1 (current)
- 2
- 3
- »