Browsing by Author "Keskinkilic, E."
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Article Citation Count: 1Laboratory-scale smelting of limonitic laterite ore from Central Anatolia(Southern African inst Mining Metallurgy, 2017) Keskinkılıç, Ender; Keskinkilic, E.; Geveci, A.; Topkaya, Y. A.; Metallurgical and Materials EngineeringThe 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.Article Citation Count: 0Liquid processing of silicon steels using the converter-ladle furnace-circulation degasser route(Southern African inst Mining Metallurgy, 2019) Keskinkılıç, Ender; Metallurgical and Materials EngineeringElectrical steels are used in motors, power generators, and transformers for electrical applications owing to their superior magnetic properties. These properties are attributed to the presence of a significant amount of silicon in the steel composition. Silicon steels are mainly grouped into two categories: grain-oriented (GO) and non-grain-oriented (NGO). The Si content of silicon steels is generally between about 0.50% and 6.5%. Therefore, silicon steels are further classified as low-, medium-, and high-Si steels. In this paper, liquid steel processing practices for certain silicon steel grades are outlined by considering a steelmaking company that integrates a basic oxygen furnace (BOF), a ladle furnace (LF), and an RH-type degassing unit (RH). Possible problems are identified, suggestions are discussed, and conclusions are drawn on the basis of real plant data.Article Citation Count: 4NEW TRENDS IN BASIC OXYGEN FURNACE DEPHOSPHORIZATION(Technical Faculty, Bor-serbia, 2020) Keskinkılıç, Ender; Metallurgical and Materials EngineeringExcept for special grades of steel where it is used as an alloying element, phosphorus is regarded as an impurity that must be removed. Considering the conventional integrated iron and steelmaking, there are primarily two processes for phosphorus removal. The first is a hot metal dephosphorization (DeP) process that is applied to a blast furnace for hot metal before the steelmaking process. The second is the basic oxygen furnace steelmaking (BOS), a unique method primarily used for steelmaking, with the exception of stainless steels. Hot metal phosphorus content has a direct impact on BOS. An increase of phosphorus in hot metal is mainly related to the use of high P2O5 containing iron ores. In the current literature review, new trends of phosphorus removal in converter steelmaking are outlined. The double-slag practice was reported to be successful when hot metal P content was larger than 0.100%. It was indicated that the tapping temperature was critical for the production of low-phosphorus grades for which maximum allowable P content was 0.007% and that high tapping temperatures should be avoided. The tap-to-tap time for the double-slag process was slightly longer than the conventional converter steelmaking. It was further reported that the double-slag practice would be more economical than an establishment of a separate hot metal dephosphorization unit, if low-phosphorus grades did not have a significant share in the product mix of a steelmaking company. Endpoint phosphorus prediction was one of the important recent trends of converter steelmaking. A mixed injection of CO2-O-2 to a basic oxygen furnace was applied to enhance dephosphorization, and promising results were reported. Unfortunately, a successful process for recycling of BOS dephosphorization slag has not been reported yet.Article Citation Count: 11Reducibility of nickeliferous limonitic laterite ore from Central Anatolia(Taylor & Francis Ltd, 2014) Keskinkılıç, Ender; Keskinkilic, E.; Geveci, A.; Topkaya, Y. A.; Metallurgical and Materials EngineeringLimonitic 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.Article Citation Count: 4REDUCTION BEHAVIOR OF IRON IN THE RED MUD(Technical Faculty, Bor-serbia, 2021) Keskinkılıç, Ender; Keskinkilic, E.; Topkaya, Y. A.; Geveci, A.; Metallurgical and Materials EngineeringRed 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.Article Citation Count: 2USE OF COLEMANITE IN FERRONICKEL SMELTING(Technical Faculty, Bor-serbia, 2019) Keskinkılıç, Ender; Pournaderi, S.; Geveci, A.; Topkaya, Y. A.; Metallurgical and Materials EngineeringUse 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.Article Citation Count: 0VARIATIONS IN CHEMICAL COMPOSITION OF SOME STEELS DURING CONTINUOUS CASTING(Springer, 2012) Keskinkılıç, Ender; Metallurgical and Materials EngineeringIn this study, chemical composition variations of some steels during continuous casting were investigated in Eregli Iron and Steel Works Co. (ERDEMIR), Turkey. Final chemical analysis of a heat is determined in the continuous casting stage. Three steel specimens are regularly taken from the mould at certain meters of slab strand for each heat. The aim of this work was to evaluate the extent of changes in chemical analysis along the slab strand. Consequently, the leading aim of this study was to determine whether the number of specimens taken for each heat could be decreased without compromising quality control of the continuous casting. This was accomplished for some low-carbon, ultra-low carbon, and structural steels, which constitute the majority part of the ERDEMIR product range. The results revealed that the number of specimens could only be decreased for a limited number of steels and under certain circumstances.