Browsing by Author "Geveci, A."

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Citation - WoS: 17
Citation - Scopus: 17
Calcination Characteristics of Laterite Ores From the Central Region of Anatolia
(Southern African inst Mining Metallurgy, 2012) Keskinkilic, E.; Pournaderi, S.; Geveci, A.; Topkaya, Y. A.; Metallurgical and Materials Engineering; Metallurgical and Materials Engineering; 06. School Of Engineering; 01. Atılım University
Drying, calcination, prereduction, and smelting are the main steps in conventional crude ferronickel production. Industrially, these steps are conducted using the rotary kiln-electric arc furnace (RKEF) process. In this paper, calcination characteristics of Sivrihisar laterite ores from the Central Anatolia region are investigated. The extent of elimination of chemically bound water and other volatiles was studied by experiments conducted at various temperatures in the 250-800 degrees C range. Phase changes were examined using X-ray diffractometry. For the particle size used in the study, 300 degrees C was determined to be almost sufficient for complete transformation of goethite to haematite, and 700 degrees C was required for effective elimination of all volatiles in the ore.
Citation - WoS: 1
Citation - Scopus: 2
Laboratory-Scale Smelting of Limonitic Laterite Ore From Central Anatolia
(Southern African inst Mining Metallurgy, 2017) Pournaderi, S.; Keskinkilic, E.; Geveci, A.; Topkaya, Y. A.; Metallurgical and Materials Engineering; 06. School Of Engineering; 01. Atılım University
The feasibility of ferronickel production from a low-grade limonitic laterite ore was investigated. The ore was first calcined and then prereduced in the solid state. The reduced ore was then smelted to produce ferronickel. The effects of coal addition, smelting temperature, and retention time on the process were investigated. Chemical and physical losses in the slag were separately quantified. Coal addition was the main parameter that controlled the ferronickel grade and losses in the slag. The melting point of the slag was well below that of the ferronickel, which enhanced metal-slag separation and minimized physical losses in the slag. A microstructural study of an industrial slag revealed that Cr-rich particulates, which were suspended in the slag, were mainly responsible for the physical losses in the slag.
Citation - WoS: 9
Citation - Scopus: 11
Reducibility of Nickeliferous Limonitic Laterite Ore From Central Anatolia
(Taylor & Francis Ltd, 2014) Pournaderi, S.; Keskinkilic, E.; Geveci, A.; Topkaya, Y. A.; Metallurgical and Materials Engineering; 06. School Of Engineering; 01. Atılım University
Limonitic nickel laterite from Sivrihisar reserve in Turkey was reduced at 700-1100 degrees C by the addition of 5.74, 8.61 and 11.48 wt-% coal under an argon atmosphere. The run-of-mine ore and the reduced samples were studied using X-ray diffraction. The metallisation of Fe was found to be limited up to 900 degrees C, but increased rapidly at higher temperatures. The metallisation of Ni and Co increased when the temperature was increased from 700 to 800 degrees C, almost levelled off up to 900 degrees C and then increased up to 1100 degrees C. The results also showed that increased coal additions did not affect Fe metallisation up to 900 degrees C. At 1000 degrees C the metallisation of Fe became slightly better, but its effect was more pronounced at 1100 degrees C. The increased coal addition affected the nickel reduction equally at all temperatures, while it had no effect on the metallisation of Co.
Citation - WoS: 4
Citation - Scopus: 5
Reduction Behavior of Iron in the Red Mud
(Technical Faculty, Bor-serbia, 2021) Eray, S.; Keskinkilic, E.; Topkaya, Y. A.; Geveci, A.; Metallurgical and Materials Engineering; 06. School Of Engineering; 01. Atılım University
Red mud or bauxite residue contains significant quantities of industrial metals such as Fe, Al, and Ti, as well as rare earth elements such as Sc, Ce, and La. The authors performed a laboratory-scale project dealing with stepwise recovery of valuable elements from two bauxite residues, namely Iranian red mud (IRM) and Turkish red mud (TRM). The first stage involved the recovery of iron which was present in large quantities in red mud. Two different methods were investigated for this purpose: 1) solid state reduction followed by wet magnetic separation and 2) smelting. In the scope of this paper, some results of pyrometallurgical part of this project are presented. According to solid-state reduction experiments, it was found that more excess coal was needed for IRM (35%) than for TRM (15%) to maximize iron reduction. Temperature had significant effect on the reduction process and metallization increased from about 70% to about 95% when the temperature was raised from 1000 to 1200 degrees C. Metallization degree was reported to be slightly higher for IRM (96.2%) than for TRM (94.1%). The results demonstrated that a high degree of iron metallization can be achieved regardless of the chemical and mineralogical composition of the bauxite residue sample.
Citation - WoS: 2
Citation - Scopus: 2
Use of Colemanite in Ferronickel Smelting
(Technical Faculty, Bor-serbia, 2019) Keskinkilic, E.; Pournaderi, S.; Geveci, A.; Topkaya, Y. A.; Metallurgical and Materials Engineering; 06. School Of Engineering; 01. Atılım University
Use of colemanite in metal-slag systems aims primarily to decrease the viscosity of slag and, therefore, achieve better metal-slag separation. Enhanced metal-slag separation is helpful to decrease the number of suspended metal/alloy droplets in slag, i.e. the physical losses. In the literature, successful use of colemanite was reported both in steelmaking and copper matte smelting processes. Ferronickel smelting slags contain nickel in the range of 0.1-0.2% and correspondingly, metal-slag distribution ratio values of nickel are reported even above 200. On the contrary, nickel recoveries are hard to exceed 95%. This can be mostly attributed to the physical losses of nickel due to very high slag volume in ferronickel smelters; for 1 ton of ferronickel, 10-15 tonnes of slag are generated regardless of the type of the laterite, which contains significant quantity of ,gangue components. The authors thought that use of colemanite could be a solution to decrease physical losses. Therefore, the use of colemanite in ferronickel smelting was investigated in the present work. Laboratory-scale smelting experiments were conducted using calcined and prereduced laterites in a vertical tube furnace under different gas atmospheres. The amount of colemanite added was in the range of 0 - 2.5% of the total charge. The experiments were also performed using ferronickel and slag samples obtained from a ferronickel smelter.