A shape correction factor for flake-like particles is applied to six different previously reported models (Leith and Licht model, ideal laminar cyclonic flow model, ideal turbulent cyclonic flow model, mixed flow model, Zhang and Basu model, and Avci and Karagoz model) to calculate cyclone collection efficiency. The correction factor was obtained using an equivalent diameter concept based on particle volume and particle geometry. The results obtained after using this correction were compared to experimental data and it was found that the above mentioned models describe better the experimental collection efficiency data for particle diameters smaller than 20 mu m in five of the six used models. Values for the D-50 were also calculated as well as their error compared to the experimental data. Error values for the D-50 calculation went from 77.8% to 7.7% for the Ideal laminar cyclonic flow model; from 92.9% to 70.3% for the Leith and Licht model, from 74.8% to 4.9% for the Mixed flow model; from 91% to 62.5% for the Avci and Karagoz model; from 87.7% to 48.6% for the Zhang and Basu model, and from 33.7% to 176% for the Ideal turbulent cyclonic flow model. These are promising results to predict collection efficiency more accurately for industrial processes that use cyclones. (C) 2011 Elsevier B.V. All rights reserved.