Gördes Lateritinin CO Atmosferinde İzotermal Olmayan İndirgenme Kinetiği

Abstract

The growing demand for nickel metal and the depletion of high-grade sulfide ore reserves have turned the direction of industry towards laterites which are not desirable as the primary source due to their low Ni content and more energy-intensive processing. Thus, alternative routes are essential for effectively processing these ores while reducing the costs and greenhouse gas emissions. Solid-state reduction followed by magnetic separation is an attractive option for recovering the nickel in laterites. Hereby, this study analyzed the non-isothermal reduction kinetics of nickel laterite from Gördes (Manisa, Turkey) by CO at different heating rates of 20, 25, 30, 35, and 45 ºC/min. The activation energies were determined by Friedman (FR), Kissinger-Akahira-Sunose (KAS), and Flynn-Wall-Ozawa (FWO) methods, and the controlling mechanisms were determined by the Malek interpretation of the Sestak-Berggren Equation. The reduction process was divided into three stages which take place between "0 to 0.16", "0.16 to 0.45", and "0.45 to 0.7" reduction degrees respectively according to the kinetic analysis results. The first stage was determined to be interface reaction controlled (with "Ea" of 53 kJ/mol), while the second and third were determined to be mixed controlled (with "Ea" of 126 kJ/mol and 379 kJ/mol, respectively).