Interaction Between Anode Aggregate and Binder in the Sessile Drop Wetting Test

Coal Tar Pitch (CTP), recycled butts and Calcined Petroleum Coke (CPC) are the main raw materials used for anode fabrication. Over the last decades, considerable changes in CTP and CPC quality have been observed. Changes in metallurgical coke production technology have affected coal tar quality, and crude oil qualities have changed causing severe changes of CPC properties. This can have consequences for the mixing step during anode production, and the final anode performance. Hydro Aluminium has systematically followed these raw material changes and studied the effect on the interaction between coke and binders by applying a sessile drop measurement wetting test. The results are reviewed in terms of relevance for the anode production process. This article focuses on equipment, routines and sample preparation as they are crucial factors for obtaining reliable and repeatable results during these experiments. Wetting dependence on particle size and butt impurity level was found. Additionally, a method where hot pitch is added to a hot coke substrate is demonstrated.