<p>The mixing homogeneity of granular materials plays an important role in the manufacturing and construction of various products. The geometry of particles considerably affects the mixing performance of the granular materials during mixing processes. This investigation explores the mixing mechanism of non-spherical particles in an industrial-scale double U-shaped ribbon mixer using the discrete element method. The grid size is selected to be approximately 4.2 times the average equivalent volume diameter of the particles for the calculation of the Lacey index, which is used to evaluate the mixing homogeneity of non-spherical particles. Subsequently, the effects of the particle aspect ratio, volume, and sliding friction coefficient on the mixing performance of non-spherical particles in the ribbon mixer are investigated numerically. The numerical results indicate that the particle volume and sliding friction coefficient significantly affect the mixing efficiency of non-spherical particles, whereas the aspect ratio of the oblate or prolate particles has a relatively small effect. Furthermore, it is found that the relative velocities between the contact points in the vertical direction at the beginning and end of contact can be used to explain the effects of the parameters mentioned above on the mixing efficiency of the non-spherical particles, and larger relative velocities at the contact points are beneficial for the mixing performance of non-spherical particles.</p>