Sample

The concentration of valuable metals (wt%)

Zn

Cu

Pb

Sb

K

Fly ash A

1.58

0.36

0.36

0.18

2.01

Fly ash B

5.09

0.40

1.11

0.95

5.28

Washed ash A

3.61

0.72

0.34

0.49

0.53

Washed ash B

7.75

0.60

1.61

1.45

0.52

Cut-off grade

1.5 - 2.0^a

0.5^a

0.5 - 1.0^a

0.5 - 0.7^b

0.5^c

Minimum industrial grade

3.0 - 6.0^a

0.7^a

1.5 - 2.0^a

1.0 - 1.5^b

2.0^c