Use of Heavy Oil Fly Ash as a Color Ingredient in Cement Mortar

International Journal of Concrete Structures and Materials

Table 4 Results of batch experiments.

Heavy metals	Detection limit (mg/l)	Peak concentration levels (mg/l) rounded to 3 digits
Heavy metals	Detection limit (mg/l)	HOFA	OC₂	OC₅	OC₁₀	OC₂₀	Permissible limit^a
As	0.001	0.041	ND	ND	0.001	0.001	0.01
Cd	0.001	0.004	ND	ND	0.001	0.001	0.001
Co	0	0.05	ND	ND	0	0	–
Cr	0.005	0.283	ND	ND	ND	0.006	0.05
Cu	0	0.6	ND	0	0	0.002	0.02
Hg	0	ND	ND	ND	ND	ND	0.002
Ni	0	77.91	ND	0.001	0.07	0.091	0.05
Pb	0	0.116	ND	0.001	0.003	0.003	0.05
Se	0.027	0.031	ND	0.001	0.001	0.001	–
V	0.001	303.912	ND	0.005	0.086	0.195	–
Zn	0.002	0.894	ND	0.001	0.003	0.006	5.00^b