This paper proposes a mechanism of carbon species formation and transport in the gas phase and silicon carbide particle formation and engulfment in the liquid phase. A numerical model considering various forces acting on silicon carbide particles is developed to quantify particle transport and particle engulfment. Numerical simulations are conducted to study fluid flow and temperature distribution in an industrial directional solidification system and particle distribution in the solidified silicon. Strategies to reduce carbon contamination and improve ingot quality are proposed. (C) 2010 Elsevier B.V. All rights reserved.