Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ3Optimized bioleaching of spent FCC catalysts for the recovery of critical metals
Erust, Ceren; Altındaş, Mediha Demet Okudan
Spent fluid catalytic cracking (FCC) catalysts, generated in large volumes by petroleum refining, represent a promising secondary source of critical metals such as lanthanum, cerium, titanium, and vanadium. In this study, a biohydrometallurgical approach was applied to recover these metals using Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans. The spent FCC catalyst, supplied by petroleum refinery, was characterized through WD-XRF, XRD, SEM-EDS, and ICP-OES analyses, confirming significant concentrations of La2O3 (1.44%), TiO2 (1.43%), and CeO2 (0.23%). Bioleaching experiments were conducted under varying initial ferrous ion concentrations (1–9 g/L) and pulp densities (5–20% w/v) at 35°C over 14 days. Results revealed that the optimal conditions for maximum recovery occurred at 5 g/L Fe2+ and 10% pulp density, achieving leaching efficiencies of 95.5% for La, 90.5% for Ce, 92.5% for Ti, and 60.8% for V within seven days. Beyond this period, efficiency decreased due to jarosite formation and microbial activity constraints. The findings confirm that bioleaching is a cost-effective and sustainable route that aligns with circular economy principles by reducing reliance on virgin rare earth mining while mitigating the environmental impact of catalyst disposal.
- MakaleYalnız künye2026Scopus SJRQ2Kinetic investigation on the recovery of copper and cobalt from sulphuric acid plant electrofilter dust
Erust, Ceren
Several waste dusts collecting equipment options are available for air pollution control in plants, the most commonly used being the electrofilter. Industrial wastes such as electrofilter dust are evaluated as a secondary resource owing to their critical metal contents. In this work, the results of studies on the extraction of cobalt and copper from electrofilter dust generated in sulphuric acid production plants are presented. The chemical and mineralogical compositions of the dust were investigated using instrumental analytical methods. The electrofilter dust consists of the main phases of haematite, quartz, and anhydrite. Also, electrofilter dust contains 1.43% copper and 0.28% cobalt. It was found that the process of copper and cobalt dissolution is characterized by chemical kinetics. When the acid leaching was applied in 1 M sulphuric acid in the presence of 0.05 M hydrogen peroxide, with the temperature 80°C and 2 h of leaching time, stirring rate of 200 rpm and liquid to solid ratio 20/1 v/w, cobalt and copper extraction achieved 88% and 98% respectively. As a result of studying the kinetics of acid leaching with sulphuric acid in the presence of oxidant hydrogen peroxide, activation energy and the type of reaction to chemical controlled model were determined.
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İncele - MakaleAçık Erişim2026Scopus SJRQ2Solvent extraction of rare earth elements and α-alumina production from pregnant leaching solution obtained from Turkish bauxite-related ore
Erust, Ceren; Uysal, Turan
The use of bauxite-related shales as a secondary source for the extraction of rare earth elements (REEs) is very important to meet the raw material supply, which is the keystone of advanced technology applications. This study presents the investigation into the recovery of REEs from Kızıldağ shale ore and the potential utilization of its leach residue as a silica source. Mineralogical analysis revealed that the ore predominantly consists of paragonite, muscovite, quartz, pyrophyllite, and calcite. Calcined ore was subjected to acid leaching, and the resulting pregnant solution was purified using solvent extraction to separate from aluminum the ∑REEs with a content of 1887.35 ppm. Optimal solvent extraction conditions 1.5 M D2EHPA, 50% O/A ratio, pH 1.5, and 15-minute mixing time achieved 95% total REE extraction, with efficiency in the order Pr > La > Nd > Ce > Dy > Y > Sc. To purify Al from the Fe- and K-rich solution post-SX, electrolysis was performed, resulting in 97.16% precipitation efficiency of Al as Al(OH)3 at pH 5. The precipitate was subsequently roasted at 1100°C to produce α-alumina with 75.2% Al2O3 content. These findings confirm the technical feasibility of recovering REEs and producing coarse-purity alumina from Kızıldağ shale ore.
AtıfScopus1WoS3OpenAlex1İncele - MakaleYalnız künye2025Scopus SJRQ1The Extraction of Rare-Earth Elements (REEs) from Spent Nickel–Metal Hydride (Ni–MH) Batteries by Bifunctional Ionic Liquids (Bif-ILs): Process Optimization and Kinetics Modeling
Erust, Ceren
The cathode material of nickel–metal hydride (Ni–MH) batteries includes nickel, cobalt, and rare-earth elements (REEs) such as La, Ce, Nd, and Pr, which are among the critical raw materials (CRMs). Ionic liquids as the environmentally friendly approaches are proposed by various investigations for the extraction of critical metals from spent Ni–MH batteries. In this study, three different Bifunctional Ionic Liquids (Bif-ILs) were designed for comparative studies, namely Aliquat 336–Cyanex 272 (AL–CY), Aliquat 336–PC88A (AL–PC), and Aliquat 336–D2EHPA (AL–D2). The extraction results indicated that temperature has a direct effect on the extraction of critical metals in the presence of all Bif-ILs. Among three types of Bif-ILs, AL–D2 has an optimal extraction power (La: 98.8%, Ce: 94.2%, Nd: 99.2%, and Pr: 98.4%) after precipitation of 99.99% of Ni and Co. Furthermore, kinetics modeling is used for reaction mechanisms investigation. Results indicated that the mixed controlled model by shrinking core model (diffusion controlled and chemical reaction controlled) was the best model fitted to all data (coefficient of determination (R2) > 0.90). according to the Arrhenius equation, activation energies for all REEs in the presence of all Bif-ILs are between 13 and 42 kJ/mol that reflects a mixed controlled reaction.
AtıfScopus2OpenAlex2İncele - Derleme MakaleAçık Erişim2022Scopus SJRQ4Kritik Hammaddelerin Geri Dönüşüm ile Döngüsel Ekonomiye Kazandırılması
Okudan, Mediha Demet; Akcil, Ata; Erust, Ceren
Endüstri 4.0 devrimi ve Nesnelerin İnterneti (IoT) gibi teknolojilerle dijitalleşme, kaynaklarımızın ve ekonomilerimizin döngüsel olmasını gerektirmektedir. Başta Avrupa Birliği olmak üzere tüm ülkeler, kritik hammaddelerin sorumlu tüketiminin, üretiminin ve geri dönüşümünün sürdürülebilir kalkınma hedeflerine ulaşmanın bir yolu olarak çok önemli olduğu konusunda hemfikirdir. Ömrünü tamamlamış ürünlerden kritik hammaddelerin geri kazanılması için uygun maliyetli bir geri dönüşüm yöntemi, madencilikten çok daha az çevresel etkiye sahiptir. Biyo & hidrometalurjik yöntemler, kritik hammaddelerin, özellikle nadir toprak elementlerinin (NTE) çıkarılması için hızlı gelişen, seçici, çevre dostu ve uygun maliyetli teknolojilerdir. Bu makale, ikincil kaynaklara genel bir bakış sağlamakta ve kritik hammaddelerin kazanımı için ekonomik bir yol olarak hizmet edebilecek bazı umut verici yöntemlerin kullanımına ilişkin yürütülen çalışmaların senaryosunu özetlemektedir.
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