Items Standard Industry grade Industry grade Food grade Regent grade Total acid content(HCL)% 31% 32% 31% 36% Iron(FE) % 0.008% 0.002% 0.001% 0.00005% Ignition residue % 0.10% 0.05% --- 0.00009% Free chlorine(CL)% 0.008% 0.004% --- 0.0001% As% 0.0001% 0.0001% --- 0.000005% Sulfate(SO42-)% 0.03% 0.005% 0.007% 0.0002%
