Experiments Model G U NS10 L10 L20 NS20 First order model             kR/10-3s-1 89 57 44 34 30 21 Active surface model             a/% 4.0 4.0 5.4 5.7 5.1 4.0 z=h/r0 0.38 0.027 0.50 3.6 3.6 0.97 Gel layer model             e/% 19.2 100 26.9 32.3 30.3 12.9 D0/μm 96 530 170 222 222 141

Table 4: Estimated model parameters. G=Grinded KCl; U=Ungrinded KCl; NS10=Native Starch 10%; L10=Lignin 10%; L20=Lignin 20%; NS20=Native Starch 20%.