Number

Clay dosage

Contact time

Colour reduction

FFA

Desirability

1

3.00

30.00

35.40

2.22

0.986

Selected

2

3.00

29.90

35.39

2.22

0.984

3

2.98

30.00

35.30

2.23

0.983

4

2.96

30.00

35.16

2.23

0.979

5

2.94

30.00

35.03

2.24

0.975

6

3.00

28.31

35.00

2.29

0.945

7

2.77

30.00

33.83

2.29

0.944

8

3.00

26.83

34.43

2.35

0.909