Abstract
Cake washing of freely mobile ions was described by an
advection–dispersion equation combined with the Donnan equilibrium and
an overall ion transfer model between the external liquid phase and the
fiber phase of kraft pulp. The ion exchange rate coefficients between
the phases were determined from the earlier published leaching test
results for an oxygen delignified Scandinavian hardwood kraft pulp. The
time constant of the first order process model was about 19 s for calcium and manganese and about 6 s
for sodium and magnesium. The calculated results for various elements
during the acid displacement were compared with the published
displacement experiments. Calculated concentrations and pH profiles in
wash effluent and cake were shown. Moreover, changes in pH values and
redistribution of ions between the external phase and the fiber phase in
the cake during the acid displacement were also demonstrated.
| Original language | English |
|---|---|
| Pages (from-to) | 6899-6908 |
| Journal | Chemical Engineering Science |
| Volume | 60 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - 2005 |
| MoE publication type | A1 Journal article-refereed |
Keywords
- dispersion
- ion exchange
- leaching
- mass transfer
- packed bed
- filter cake washing
- kraft pulp