Studies of robustness of industrial aciniform aggregates and agglomerates--carbon black and amorphous silicas: a review amplified by new data

Abstract

Objective: The objective of this study was to demonstrate that severe mechanical processing of industrial aciniform aggregates results in some fracture of large aggregates and minimal liberation of "primary particles."

Methods: Carbon black and amorphous silica were subjected to uniaxial compression, mixing into rubbers, and intense ultrasonication. Initial and processed states were compared by TEM/AIA.

Results: Severe treatment caused moderate breakage of the largest aggregates with some reduction in mean aggregate diameter. Breakage was at weak weldments between nodules. The breakdown is asymptotic in energy input with a constant aggregate complexity being achieved. Liberation of nodules was minimal to absent.

Conclusions: For industrial aciniform aggregates, breakdown of aggregates with liberation of nodules is not an issue in severe mechanical treatment. Given the much smaller energy inputs in biologic systems, it is extremely unlikely it is an issue there. For welding fume and soot, no assurances are possible.