Elaboration of Al-Mn Alloys by Aluminothermic Reduction of Mn2O3

Effect of Mg Concentration on the Aluminothermic Reduction of Mn2O3 Particles Obtained from Cathodes of Discharged Alkaline Batteries: Mathematical Modeling and Experimental Results

“…They were manually collected and disassembled, cutting the battery body to remove Mn 2 O 3 from inside, and exposing the tissue containing the zinc oxide. The Mn 2 O 3 powder was washed with deionized water in order to remove the electrolyte (KOH) [6,10]. Later, it was filtered and calcined at 1223 K for 3 h, to eliminate the graphite contained in the cathode [11].…”

“…One of the most commonly employed metal according to its properties is aluminum, which is used in a process called aluminothermic reduction [5,6]. The nature of the solid-liquid interface that is in contact is determined in order to achieve the wettability that is required for a reaction to occur between them, either a dissolution or a chemical reaction.…”

“…Thus, it could be established that when adding magnesium to a bath of molten aluminium, the surface tension will be decreased, leading to an improvement in wettability between the solid particles and the molten fraction, thus increasing the kinetics of the reactions that are carried out at the solid-liquid interface. The wettability of molten metals by solid particles strongly influences the kinetics and dissolution mechanisms [6]. The chemical reaction that takes place during the aluminothermic reduction reaction of particles of Mn 2 O 3 is given as follows: From the beginning, it is established that the aluminothermic reduction process can be used for the reduction of Mn 2 O 3 powders that are obtained from the cathodes of discharged alkaline batteries, using aluminum obtained from the melting of beverage cans, as presented and discussed in this paper.…”

“…According to the thermodynamics, the first to be formed is Al 2 O 3 because it has a high affinity for oxygen [12]; however, the possibility of simultaneously forming MnO is not ruled out, because the magnesium is present at concentrations up to a maximum of 4 wt % in the alloy. The formation of spinel is only possible by the chemical reactions (5), (6), or (7). In turn, after the formation of the compounds MgAl 2 O 4 , MgO, and Al 2 O 3 , due to their low density, they will float to the surface of the molten bath [13].…”

“…In turn, after the formation of the compounds MgAl 2 O 4 , MgO, and Al 2 O 3 , due to their low density, they will float to the surface of the molten bath [13]. The reactions, as given by Equations (6) and 7, were considered according to the sequence of deoxidation of Mn 2 O 3 , because the Mn 2 O 3 particles have to go through a series of manganese compounds of lesser degree of oxidation, up to metallic manganese, which, once released, pass directly in solution within molten aluminium.…”