Study on the Centrifugal Spray Granulator Process for Tungsten Heavy Alloy Powder

For the development of ready to press powder of tungsten heavy alloy, the influences of process parameters of centrifugal spray granulation were investigated. The results showed that the bulk density, flow rate, particle size distribution and morphology of granulated powder were significantly influenced by the solid loading and dynamic viscosity of slurry, inlet and outlet temperature, feed rate and rotational speed of atomizer disk. A set of process parameters were obtained included the solid loading of 70%(volume percentage is 9.7%) and dynamic viscosity of 2.5 Pa?s for the slurry, the inlet and outlet temperatures of 300 ℃ and 120 ℃ respectively, the feeding rate 90 mL?min-1 of peristaltic pump , and the rotational speed 9800 r?min-1 of atomizer disk. The proper granulated powder with good flowability and narrow particle size distribution can be obtained by using these parameters, the D50 and D90 of granulation powder are 52 μm and 91 μm respectively, and the flow rate is 14.4 s?(50g)-1.