Abstract
Pilot test anodes were designed by Hydro Aluminium
for laboratory studies using controlled blends of <2
mm aggregate from two single source cokes. Spa-
tial and imaging methods were used to characterise
anode surfaces with respect to consumption, density,
pore distribution and real active area before and after
electrolysis. The methods include X-ray computed
tomography (CT), confocal microscopy, scanning elec-
tron microscopy (SEM) and energy-dispersive X-ray
spectroscopy (EDS). It was found that during electro-
lysis, the electrolyte does not completely wet the
carbon inside large pores on the surface. Hence, even
large pores do not contribute to the electrochemically
active surface area. Large grains of isotropic cokes
and anisotropic sponge cokes are consumed at approxi-
mately the same rate, and bubble coke in anisotropic
sponge cokes are consumed at a slower rate than
the bulk material. This is due to higher resistivity
through the bubble coke.
for laboratory studies using controlled blends of <2
mm aggregate from two single source cokes. Spa-
tial and imaging methods were used to characterise
anode surfaces with respect to consumption, density,
pore distribution and real active area before and after
electrolysis. The methods include X-ray computed
tomography (CT), confocal microscopy, scanning elec-
tron microscopy (SEM) and energy-dispersive X-ray
spectroscopy (EDS). It was found that during electro-
lysis, the electrolyte does not completely wet the
carbon inside large pores on the surface. Hence, even
large pores do not contribute to the electrochemically
active surface area. Large grains of isotropic cokes
and anisotropic sponge cokes are consumed at approxi-
mately the same rate, and bubble coke in anisotropic
sponge cokes are consumed at a slower rate than
the bulk material. This is due to higher resistivity
through the bubble coke.