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Article Citation - WoS: 2Citation - Scopus: 2Use of Colemanite in Ferronickel Smelting(Technical Faculty, Bor-serbia, 2019) Keskinkilic, E.; Pournaderi, S.; Geveci, A.; Topkaya, Y. A.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.Article Citation - WoS: 4Citation - Scopus: 5Reduction Behavior of Iron in the Red Mud(Technical Faculty, Bor-serbia, 2021) Eray, S.; Keskinkilic, E.; Topkaya, Y. A.; Geveci, A.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.
