Aground silicon powder was chemically characterized at multiple scales to quantify and localize the impurities of metallurgical-grade silicon. These impurities play a major role in the Rochow synthesis used to convert silicon into the primary monomer for silicone polymers. Characterizations were conducted before and after grinding to investigate the impact of the comminution step on the distribution of the impurities within the powder. At the macroscopic level, inductively coupled plasma showed that the concentration of the main impurities, Al, Ca, Fe and Ti, first increases with decreasing particle size but then drops drastically for the finest fractions (<30 mu m). At the microscopic level, energy dispersive X-ray spectroscopy indicated that these impurities are concentrated in the grain boundary as intermetallic precipitates. At the atomic level, atom probe tomography on several particles, including micro-size fines, shows that there is no significant amount of metallic impurities inside the grains for both coarse and fine particles. (C) 2014 Elsevier B.V. All rights reserved.