Intrinsic reduction kinetics of cobalt- and nickel-titanates by hydrogen

Abstract

The isothermal reduction of synthetic CoTiO 3 and NiTiO 3 in hydrogen (1 atm) was investigated using thermogravimetric analysis technique in the temperature range, 928-1287 K (CoTiO 3 ) and 884-1387 K (NiTiO 3 ). Shallow beds of fine titanate powders were reduced by hydrogen at a high flow rate. Quenched samples were analyzed by scanning electron microscopy. The rates of the reaction of the titanates with H 2 were very fast during the reduction of Co 2+ , Ni 2+ , or Fe 2+ ions into metals. The reduction of the remaining titanium oxide was very slow. The activation energy for the reduction of CoTiO 3 by hydrogen to Co and TiO 2 was evaluated to be 151 ± 1 kJ/mol, and the activation energy for the reduction of NiTiO 3 by hydrogen to Ni and TiO 2 was evaluated to be 153 ± 1 kJ/mol. The study was complemented by hydrogen reduction of synthetic TiO 2 (rutile). The results were also compared with the hydrogen reduction of FeTiO 3 .

Hydrogen reduction of complex oxides—a novel route toward the production of nanograined alloys and intermetallics

“…The reduction kinetics of titanates containing Co 2+ , or Ni 2+ ions were investigated [11] to compare the effect of cobalt and nickel on the reduction. It was found that the reduction of CoTiO 3 and NiTiO 3 are similar as in the case of FeTiO 3 , i.e.…”

Effect of copper doping on CoTiO3 ilmenite type nanoparticles for removal of congo red from aqueous solution

“…These composite oxides are important inorganic metalloid materials and are widely used in different fields [19,20]. Cobalt titanate (CoTiO 3 ) belong to an important group of ilmenite-type transition metal manner phases with a number of interesting magnetic and electric properties [21]. They are also important for technical applications due to their catalytic properties [22].…”

New thermodynamic data for CoTiO3, NiTiO3 and CoCO3 based on low-temperature calorimetric measurements

“…They are also important for technical applications due to their catalytic properties [6-8]. CoCO 3 is a phase with interesting magnetic properties, which has not been studied in detail [9-12].…”