Sampling a heterogeneous powder using a spinning riffler

Particles of different sizes or physical properties cannot be mixed up to the homogeneous state. Samples taken at random from a mixture usually do not permit the estimation of its composition with a sufficient degree of reliability. A sampler whose results are independent of the mixing state of the material must be chosen. The accuracy and performances of a spinning riffler were statistically estimated by sampling Al₂O₃-UO₂ heterogeneous mixtures under different conditions. The influence of the main parameters, such as the powder feeding rate to the splitter, the feeding model of the mixture and the particle size distribution of the components was theoretically determined using a PDP-8 computer. The validity of the mathematical model was confirmed by a large-scale sampling experiment.