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Conference Object Maghemite - a Source of Heavy Medium for Coal Washeries(2010) Arol,A.; Ozbayoglu,G.; Anaç,S.; Bulut,M.Use of magnetite as heavy medium in coal preparation plants has been increasing steadily in recent years. It might be in short supply in some areas or excessively costly in certain times. In Turkey, the cost of heavy medium magnetite has almost tripled since 2003. As a result, alternative sources of heavy medium material have been evaluated. A maghemite ore from Elbistan-Kahramanmaras was found to be an interesting source. Tests showed that the maghemite ore can be enriched via magnetic separation at 1556 gauss to obtain a heavy medium material with 4.93 g/cm3 density and 97.22 per cent magnetic recovery. Further tests were conducted to determine the optimum fi eld strength for magnetic separation, friability and regeneration recovery.Conference Object Citation - WoS: 2Citation - Scopus: 2A Study on Recovery of Iron from Red Mud by Solid State Reduction Followed by Magnetic Separation(Springer international Publishing Ag, 2020) Eray, Said; Keskinkilic, Ender; Varol, Mustafa; Topkaya, Yavuz A.; Geveci, AhmetRed mud is a waste material of the Bayer process for alumina production from bauxite ore. Red mud is generally pumped to disposal in an artificial pond which is accompanied by great land occupation and environmental issues. Many researches in different fields have been carried out to evaluate the red mud. Of these, researches on recovering valuable metals from red mud are the most successful. In this study, recovery of iron, which is the most abundant metal in red mud, was investigated. A red mud sample with 34% Fe2O3 was used. Solid state carbothermic reduction followed by wet magnetic separation was performed to recover iron. Reduction was carried out at temperatures 1000-1200 degrees C. Reduced samples were ground and subjected to wet magnetic separation. The effect of reduction temperature and grinding time were investigated on the metallization of iron and the iron content of the final concentrate.Article Citation - WoS: 46Citation - Scopus: 51Ruthenium(0) Nanoparticles Supported on Magnetic Silica Coated Cobalt Ferrite: Reusable Catalyst in Hydrogen Generation From the Hydrolysis of Ammonia-Borane(Elsevier Science Bv, 2014) Akbayrak, Serdar; Kaya, Murat; Volkan, Murvet; Ozkar, SaimRuthenium(0) nanoparticles supported on magnetic silica-coated cobalt ferrite (Ru(0)/SiO2-CoFe2O4) were in situ generated from the reduction of Ru3+/SiO2-CoFe2O4 during the catalytic hydrolysis of ammonia-borane (AB). Ruthenium(III) ions were impregnated on SiO2-CoFe2O4 from the aqueous solution of ruthenium(III) chloride and then reduced by AB at room temperature yielding Ru(0)/SiO2-CoFe2O4 which were isolated from the reaction solution by using a permanent magnet and characterized by ICP-OES, XRD, TEM, TEM-EDX and XPS techniques. The resulting magnetically isolable Ru(0)/SiO2-CoFe2O4 were found to be highly reusable catalyst in hydrolysis of AB retaining 94% of their initial catalytic activity even after tenth run. Ru(0)/SiO2-CoFe2O4 provide the highest catalytic activity after the tenth use in hydrolysis of AB as compared to the other ruthenium catalysts. The work reported here also includes the formation kinetics of ruthenium(0) nanoparticles. The evaluation of rate constants for the nucleation and autocatalytic surface growth of ruthenium(0) nanoparticles at various temperatures provides the estimation of activation energy for both reactions; E-a = 116 +/- 7 kJ/mol for the nucleation and E-a = 51 +/- 2 kJ/mol for the autocatalytic surface growth of ruthenium(0) nanoparticles. The report also includes the activation energy of the catalytic hydrogen generation from the hydrolysis of AB (E-a = 45 +/- 2 kJ/mol) determined from the evaluation of temperature dependent kinetic data and the effect of catalyst concentration on the rate of hydrolysis of AB. (C) 2014 Elsevier B.V. All rights reserved.Article Citation - WoS: 35Citation - Scopus: 32Preparation of Silica Coated Cobalt Ferrite Magnetic Nanoparticles for the Purification of Histidine-Tagged Proteins(Pergamon-elsevier Science Ltd, 2015) Aygar, Gulfem; Kaya, Murat; Ozkan, Necati; Kocabiyik, Semra; Volkan, MurvetSurface modified cobalt ferrite (CoFe2O4) nanoparticles containing Ni-NTA affinity group were synthesized and used for the separation of histidine tag proteins from the complex matrices through the use of imidazole side chains of histidine molecules. Firstly, CoFe2O4 nanoparticles with a narrow size distribution were prepared in an aqueous solution using the controlled co-precipitation method. In order to obtain small CoFe2O4 agglomerates, oleic acid and sodium chloride were used as dispersants. The CoFe2O4 particles were coated with silica and subsequently the surface of these silica coated particles (SiO2-CoFe2O4) was modified by amine (NH2) groups in order to add further functional groups on the silica shell. Then, carboxyl (-COOH) functional groups were added to the SiO2-CoFe2O4 magnetic nanoparticles through the NH2 groups. After that N alpha,N alpha-Bis(carboxymethyl)-L-lysine hydrate (NTA) was attached to carboxyl ends of the structure. Finally, the surface modified nanoparticles were labeled with nickel (Ni) (II) ions. Furthermore, the modified SiO2-CoFe2O4 magnetic nanoparticles were utilized as a new system that allows purification of the N-terminal His-tagged recombinant small heat shock protein, Tpv-sHSP 14.3. (C) 2015 Elsevier Ltd. All rights reserved.
