The ever-present threat of biological weapons has encouraged the development of novel pyrotechnic formulations that release gaseous iodine upon combustion, which acts as a potent active agent capable of countering bio-agents (e. g. anthrax). These formulations typically contain a fuel (Al, B, Al/B4C) and an iodate serving as an oxidizer. However, the percentage of free iodine generated is relatively low and aging of these formulations remains an issue. In this work, the role of particle size on the combustion velocities, iodine output, and combustion products are detailed for a boron carbide/sodium periodate formulation. Formulations are studied with and without the addition of binder (protectant) and the role of particle size on achieving 3-D printable energetics is detailed. It is found that altering the fuel particle size (boron carbide) had little effect on the combustion velocity and iodine recovery. However, by reducing the particle size of the oxidizer, NaIO4, drastic improvements in iodine recovery are achieved. A reduction in mean particle size from 215 to 3 mu m resulted in a 47 % increase in observed iodine recovery for powder formulations. Combustion velocities appear to be unaffected and were 1.4-1.6 mm/s. An in-depth discussion of the decomposition pathway of pure NaIO4 as well as when paired with a B4C fuel source is also discussed.