Preparation Of Ammonium Paramolybdate Microspheres By Spray Drying And Their Calcination Reduction Process

Hollow ammonium paramolybdate precursor microspheres were prepared from ammonium paramolybdate solution by spray drying, and they were calcined and reduced to square or spherical molybdenum. The morphology of the ammonium paramolybdate precursor microspheres, and the morphology and composition were studied after calcination and reduction of ammonium paramolybdate precursor microspheres. The effects of reduction temperature, heating process and atmosphere on the reduction of ammonium paramolybdate precursor microspheres were also investigated. Results show that as the concentration of solution increases, the particle size of microspheres becomes bigger, pit number in the surface increases, and the agglomeration phenomenon becomes more obvious; with the increase of feed rate, the particle size of microspheres decreases a little, and the number of pits in the surface decreases; with the increase of spray drying temperature, the particle size first increases and then decreases, while pits in the surface increase evidently in number; at the temperature of 800 degrees C, the square or near spherical molybdenum can be obtained by hydrogen -argon mixer reduction, while the spherical molybdenum can be obtained by pure hydrogen reduction.