Application of Mixture Design for Optimization of Smoke Signal Formulation: A Comparative Study of KClO3 and KNO3 as Oxidizers

Abstract

Smoke signals are traditionally used in military contexts, but in recent times, they have gained popularity among civilians. The M18 smoke grenade was designed with a highly reactive oxidizer, KClO₃, and substituting it with a safer oxidizer, notably KNO₃, is one way that helps provide a safer choice for civilian use. However, providing optimal formulations for both formulations helps in deciding whether KNO₃ can be substituted for the traditional KClO₃ oxidizer. One of the techniques for enhancing smoke formulation is the Design of Experiments (DOE). Many researchers these days are focusing on substituting the smoke chemicals for a safer option using a trial-and-error process. However, from the standpoint of environmental contamination, numerical testing to identify the most significant output causes air pollution and chemical waste, which is not only costly but also endangers sea life if not properly disposed of. Therefore, it is crucial to optimize the smoke formulation in order to decrease waste and air pollution as well as enable future mass production of the product for both military and civilian use. The purpose of this paper is to implement the mixture design tool of the DOE approach to determine the optimal formulation of smoke signals using KClO₃-based formulations, as well as to provide a comparative analysis of substituting KNO₃ to optimize KClO₃-based formulations in terms of time and smoke emission. From the KClO₃-based formulation (28.68 wt.% KClO₃, 23.47 wt.% C₁₂H₂₂O₁₁, 34.39 wt.% dye, and 13.46 wt.% MgCO₃) with an average time of 73.43 seconds, an acceptable formulation with a data means of 73.43, substituting with KNO₃ oxidizer gave an average of 80.18 seconds, in which the smoke emission was slightly thinner compared to KClO₃. As a result, KNO₃ can be used as an alternative oxidizer to KClO₃, and the KClO₃-optimized formulation can be considered a baseline for smoke formulation for future research.