This paper studies the effects of reducer and slag concentrations on size distribution in iron-carbon nuggets. For this, it was used mixtures and self-reducing pellets composed of low and high grade hematite, petroleum coke, graphite and slag elements. The process was developed in a rotary kiln at 1773 K for 10 minutes. In each resulting product was determined its size distribution with a set of meshes (ASTM B 214-76). Results revealed different percent of iron-carbon nuggets with diameter higher than 7.93 mm sizes. Increasing the amount of reducer by 10% in self-reducing mixtures, resulted in an 80% drop of nuggets content, however, in self-reducing pellets was only a 15% drop. And increasing slag by 10% was generated a 67.6% nuggets drop in self-reducing mixture. In both cases, the increase of distance between particles, and the creation of a physical barrier between them caused a decrease of coalescence efficiency. Copyright © 2014 by The Minerals, Metals & Materials Society.