Reducing Agglomeration of Ammonium Perchlorate Using Activated Charcoal

Abstract

Ammonium perchlorate is the most widely employed oxidizer for composite solid propellants. When exposed to atmosphere, it absorbs moisture and agglomerates. It is usually vacuum dried in order to avoid this agglomeration. When ammonium perchlorate that has been exposed to atmosphere for a certain period of time, is used in making a composite solid propellant, the burning rate is different because of the change in particle size distribution due to its agglomeration. This change in burning rate will change the thrust‐time profile from that of what it is designed for. As one goes to a finer ammonium perchlorate particle size this problem becomes more evident. Experimental studies aimed at reducing the agglomeration of ammonium perchlorate by coating it with activated charcoal. Ammonium perchlorate coated with 1 % activated charcoal showed almost no agglomeration, even when the particle size of ammonium perchlorate is approx. 1 μm. The burning rates also remained unchanged when ammonium perchlorate coated with 1 % activated charcoal was employed in propellant composition, after it has been exposed to the atmosphere for a period of 1 h.

Preventing Agglomeration and Enhancing the Energetic Performance of Fine Ammonium Perchlorate through Surface Modification with Hydrophobic Reduced Graphene Oxide

“…[7][8][9] However, fine AP is hygroscopic and tends to agglomerate, altering the combustion rate and thrust-time pattern of the ensuing ECPs, and rendering the SRMs ineffective. [10] Modification of the AP surface is a crucial method for addressing the issue of AP hygroscopicity. In recent decades, the physical coating of AP particles has attracted considerable attention.…”

“…As a result, the combustion rate of the resulting ECP remains unaffected by AP@AC's exposure to the ambient environment. [10] Furthermore, AP was efficiently coated with hydrophobic chemicals, namely copper and cobalt stearates. The results demonstrate that the hydrophobic coating decreases AP's hygroscopicity and enhances its thermal decomposition behavior.…”

“…Notably, decreasing the granular size of AP accelerates the combustion rate of the resulting ECPs [7–9] . However, fine AP is hygroscopic and tends to agglomerate, altering the combustion rate and thrust‐time pattern of the ensuing ECPs, and rendering the SRMs ineffective [10] …”

“…Activated charcoal (AC) was used as a coating agent to lessen the agglomeration of AP. As a result, the combustion rate of the resulting ECP remains unaffected by AP@AC′s exposure to the ambient environment [10] . Furthermore, AP was efficiently coated with hydrophobic chemicals, namely copper and cobalt stearates.…”