Reduction kinetics of Fe2MoO4 fine powder by hydrogen in a fluidized bed

Abstract

Iron molybdate (Fe 2 MoO 4 ) powders with an average particle size of 100 m were reduced by hydrogen using a fluidized-bed batch reactor in the temperature range of 923 to 1173 K. The extent of the reaction was followed as a function of time by gas chromatography. The fluidizing-gas velocity was set at about 1.5 times the minimum fluidization velocity. The ratio of the height of the static bed to its diameter is about 1. Under the prevailing experimental conditions, it was found that the chemical reaction was the rate-controlling factor. The activation energy for this process was 158 Ϯ 17 kJ/mol. The crystal size of the Fe 2 Mo powder produced at lower temperatures was in the nanometer range, indicating the possibility of mass production of alloys and intermetallics in the nanorange, using a fluidized bed.

The Influence of Reduction Process on the Iron-Molybdenum Nanoparticles in Modified MCM-41 Silica

“…(7) Finally, the mixture of metallic iron, molybdenum and intermetalic compounds Fe 2 Mo are formed [7]. In the case of silica supported systems, the high reduction temperature may also facilitate the formation of dierent iron silicalites of low reducibility.…”

Reduction Kinetics of the Nanocluster [HxPMo12O40⊂H4Mo72Fe30(O2CMe)15O254(H2O)98-y(EtOH)y]

“…The reduction of iron-molybdenum oxides has been previously studied; however, the literature reports varied kinetic results, indicating the importance of analysis methods and experimental conditions [44][45][46][47][48]. Table 3 shows the apparent activation energies (E a ) reported in literature with the corresponding temperature range, experimental conditions, kinetic analysis methods, and proposed reaction mechanisms.…”

Reduction Kinetics of FeO-CoO Solid Solution by Hydrogen Gas

“…Details of the fluidized bed apparatus used in this study have been reported elsewhere. [3] The schematic diagram of the fluidized bed unit employed is shown in Figure 2. In the present study, the main reactor was made of quartz tube with 18-mm o.d.…”

“…For the chemical reaction controlling reduction process, assuming that the hydrogen gas has easy access to all particles, the ''shrinking-core'' model can be applied to [5] obtain the rate constants. According to Smith, [3] if Reaction [1] is of first order with respect to hydrogen and irreversible, the relationship between the reaction time, t, and the fraction of reduction, X, for chemical reaction control is expressed as…”

“…The method has been employed in the present laboratory to synthesize a number of unique alloys over the past decade. [3] In the present work, this process is employed to produce Fe-Co alloys by the reduction of the solid solutions of the corresponding oxides. The kinetics of the reduction of the oxide solid solutions was investigated by the thermogravimetry technique.…”