© Springer International Publishing Switzerland 2013 A gas cyclone separator represents a classic field of application where turbulent particle-laden flows play a major role. In order to evaluate the performance of a recently developed Euler–Lagrange simulation tool based on the large-eddy simulation (LES) technique and the point-particle approach, this practically relevant flow problem is considered in the present study. As a first step towards a full simulation taking all interactions between the two phases (fluid–particle, particle–fluid and particle–particle) into account, a one-way coupled prediction is carried out. Nevertheless, the entire simulation methodology is described in detail including a sandgrain roughness model and a deterministic collision model. For the latter a performance analysis was carried out demonstrating that even for a high mass loading the computational effort for the collision detection remains below 10 % of the entire CPU-time. The predicted LES results for the cyclone flow are compared with corresponding measurements and a reasonable agreement is found.