column

1

2

3

4

5

6

Factor

name

Size/mesh

Concentration¹⁾

soaking time/min²⁾

heating

temperature/˚C

heating time/min

pH value

Results/ppm

experiment 1

1

1

1

1

1

1

0.035

experiment 2

1

2

2

2

2

2

0.022

experiment 3

1

3

3

3

3

3

0.038

experiment 4

1

4

4

4

4

4

0.036

experiment 5

1

5

5

5

5

5

0.014

experiment 6

2

1

2

3

4

5

0.031

experiment 7

2

2

3

4

5

1

0.023

experiment 8

2

3

4

5

1

2

0.026

experiment 9

2

4

5

1

2

3

0.027

experiment 10

2

5

1

2

3

4

0.025

experiment 11

3

1

3

5

2

4

0.022

experiment 12

3

2

4

1

3

5

0.019

experiment 13

3

3

5

2

4

1

0.021

experiment 14

3

4

1

3

5

2

0.019

experiment 15

3

5

2

4

1

3

0.015

experiment 16

4

1

4

2

5

3

0.027

experiment 17

4

2

5

3

1

4

0.024

experiment 18

4

3

1

4

2

5

0.022

experiment 19

4

4

2

5

3

1

0.029

experiment 20

4

5

3

1

4

3

0.027

experiment 21

5

1

5

4

3

2

0.023

experiment 22

5

2

1

5

4

3

0.026

experiment 23

5

3

2

1

5

4

0.017

experiment 24

5

4

3

2

1

5

0.038

experiment 25

5

5

4

3

2

1

0.029

mean value 1

0.029

0.028

0.025

0.025

0.028

0.027

mean value 2

0.026

0.023

0.023

0.027

0.024

0.018

mean value 3

0.019

0.025

0.030

0.028

0.027

0.032

mean value 4

0.026

0.030

0.027

0.024

0.027

0.025

mean value 5

0.027

0.022

0.022

0.023

0.020

0.025

range

0.010

0.008

0.008

0.005

0.008

0.014