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Conference Object Effect of Electroplating Parameters on "her" Current Density in Ni-Mos2 Composite Plating(Minerals, Metals and Materials Society, 2012) Güler,E.S.; Karakaya,I.; Konca,E.Nickel composites with co-deposited insoluble, solid lubricant particles such as MoS2 have been reported to reduce friction. It is known that hydrogen evolution reaction (HER), competes with nickel deposition. The influence of the electroplating parameters and their interaction effects on the peak current density for HER were studied by fractional factorial design. The parameters and their ranges were; MoS2 concentration (0-30 g/l), temperature (30-50°C), pH (2-4) and surfactants (0-1 g/l). Electrodeposition processes were carried out from a typical Watts bath containing leveler, wetting agent and brightener by using a potentiostat. The peak currents (I p) were extended to higher values and the peaks on linear sweep voltammograms became noticeable by increasing the scan rate from 20 mV/s to 100 mV/s over the range 0 to 2.5 V. The peak current densities (ip) for each experimental route were determined by fractional factorial design for three types of mineral processing surfactants; sodiumlignosulfonate (SLS), depramin-C (DC) and ammoniumlignosulfonate (ALS) using Minitab program [1]. Adding MoS2, decreasing temperature and increasing pH has decreasing effect on peak current density for all surfactants. ALS and DC have increasing effect whereas SLS has descending effect on peak current.Conference Object Citation - Scopus: 4Calcination Behavior of Sivrihisar Laterite Ores of Turkey(Minerals, Metals and Materials Society, 2011) Keskinkilic,E.; Pournaderi,S.; Geveci,A.; Topkaya,Y.A.This study investigated calcination behavior of one of the Turkish laterite deposits, which was recently found in Sivrihisar region. Representative limonitic laterite samples (1.26% Ni) taken from Yunusemre Karasivritepe and Kucuksivritepe location were first subjected to drying. Removal of chemically bound water and other volatiles were then studied, in detail. In the calcination experiments, temperature and time were the main experimental variables. Thermal treatment was conducted at the specific temperatures in 250 °C-800 °C range. The weight losses due to elimination of chemically bound water and other volatiles were reported to be approximately 10 per cent of the weight of the ore. For the particle size used in the current work, 700 °C and 40 minutes were determined to be the optimum calcination temperature and time, respectively.Conference Object Citation - Scopus: 2Production of Crude Ferronickel From Sivrihisar Laterite Ores of Turkey(Minerals, Metals and Materials Society, 2013) Keskinkilic,E.; Pournaderi,S.; Geveci,A.; Topkaya,Y.A.In the current work, laboratory-scale smelting experiments were conducted using Sivrihisar laterites (1.26% Ni). The ore samples previously subjected to drying, calcination and prereduction stages were smelted in alumina crucibles in a horizontal tube furnace under argon atmosphere. For the smelting system used in the present work, 1550°C and 40 minutes were determined to be the optimum smelting temperature and time, respectively. 25% excess coal addition in prereduction stage was reported to be crucial to obtain the desired Ni content in the final product. Colemanite in calcined form has long been known as a flux used in pyrometallurgical systems such as steelmaking and copper matte-smelting. To investigate the effects of calcined colemanite addition on the ferronickel metal-slag system, calcined colemanite of 2% and 4% of the total metal and slag weight was charged as a flux and smelted under the optimum conditions described above.Conference Object Citation - Scopus: 3Study of Certain Parameters in Laboratory-Scale Smelting of Sivrihisar Laterite Ores of Turkey(Minerals, Metals and Materials Society, 2012) Keskinkilic,E.; Pournaderi,S.; Geveci,A.; Topkaya,Y.A.Conventional ferronickel smelting has five main steps: Drying, calcination, prereduction, smelting and refining. In the scope of the current work, smelting experiments were conducted using Sivrihisar laterite ores (1.26% Ni) of Turkey. The ore samples previously subjected to drying, calcination and prereduction stages were smelted in alumina crucibles in a laboratory-scale horizontal tube furnace under argon atmosphere. Smelting experiments were performed at 1500, 1550 and 1600°C. The amount of excess coal used in prereduction step was another variable. Sivrihisar laterite ore is a limonitic one with low MgO composition. Therefore, MgO was added to the smelting charge as a flux. The effects of experimental variables on metal Ni content and slag composition were investigated.Conference Object Citation - Scopus: 1A Study on the Characterization of Nickel Laterites of Central Anatolia(Minerals, Metals and Materials Society, 2016) Keskinkilic,E.; Pournaderi,S.; Geveci,A.; Topkaya,Y.A.There are mainly three commercial nickel laterites in Turkey: Gordes, Caldag and Sivrihisar. The first two appear in Western Anatolia. The third one, Sivrihisar (Yunusemre) laterites have been found in the first decade of the millennium, in the Central Anatolia region of Turkey. Since then, mining facilities have been continued in Yunusemre. Calcination, prereduction and smelting of Sivrihisar laterites have been extensively studied and published. In the current work, some results of the studies related to characterization of Sivrihisar laterites will be presented.
