the effect of binder pitch quinoline insolubles content - Coke Oven ...

Conclusions
COKE OVEN MANAGERS’ YEAR BOOK
Despite all of the contradictions in the literature studied, we can
draw some conclusions:
Good quality anode carbon requires a balanced optical texture in the
binder coke bridges that bond filler particles together – it should be
sufficiently isotropic (i.e. disordered) to give the anode the required
mechanical properties, most notably sufficient strength; but with
enough anisotropy (order) to give acceptable levels of reactivity and
electrical conductivity.
Quite fortuitously, the presence of normal QI in pitch delivers such a
heterogeneous structure. Normal QI physically inhibits the
coalescence of mesophase by absorbing on to their surface during
anode baking. As the mesophase grows, they push the normal QI
into pockets – these pockets of isotropy in the baked anode impart
the necessary strength to the binder coke bridges. The remaining
matrix of binder coke, which is still relatively anisotropic, gives the
binder coke bridges the desired reactivity and electrical resistivity
properties.
Since anodes made from 0% normal QI pitch have been found to
have unacceptable anode properties [28], it is reasonable to assume
that there will be a minimum normal QI level, below which the
concentration of normal QI will be too low to deliver this desirable
heterogeneous anode structure.
The results of the studies reviewed suggest that this minimum
normal QI level is less than 2% and may be as low as 1%. This needs
to be confirmed experimentally.
In several of the studies, reducing normal QI levels from >10% to