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BINDER MATRIX REACTIVITY UNDER CO2 GASIFICATION: A POSSIBLE EXPLANATION OF THE ANODE DISINTEGRATION IN THE ELETROLYSIS BATH IN HALL-HEROULT PROCESS F. Chevarin1,2, M. Kavand1,2, D. Ziegler3, M. Fafard2, H. Alamdari1,2* Department of Mining, Metallurgical and Materials Engineering, Université Laval, 1065 avenue de la Médecine , Québec, QC, G1V 0A6, Canada 1 NSERC/Alcoa Industrial Research Chair MACE3 and Aluminum Research Centre – REGAL Université Laval, 1065 avenue de la Médecine, Québec, QC, G1V 0A6, Canada 2 (*[email protected]) 3 Alcoa Primary Metals, Alcoa Technical Center, 100 Technical Drive, Alcoa Center, PA, 15069-0001, USA ABSTRACT Carbon anodes, used in the Hall-Heroult process, are essentially consumed by the electrochemical reaction to produce metallic aluminum. It is also consumed by parasitic reactions with air and CO2. The carbon anode is made of petroleum coke with different particle sizes, butts (recycled anodes) and coal tar pitch. The mixture of fines particles (fewer than 150 µm) of coke together with the pitch material form a matrix, binding the large coke particles together. It is generally though that the binder matrix is more reactive than the other anode constituents. This conjecture was not clearly proved in the literature. The present study is focused on the CO2 reactivity of binder matrix and anode constituents at 960 °C, both under chemical regime (100% of CO2) and under a concentration gradient (diffusion). The apparent reaction rates of these materials were measured. The role of the binder matrix in anode consumption and its disintegration (dusting phenomenon) was discussed. KEYWORDS Binder matrix, CO2 reactivity, anode, coke, pitch, chemical regime, diffusion