Fly ash was used to prepare poly aluminum ferric chloride and white carbon black. The 4 stages of the process are as follows: acid leaching, alkali dissolution, roasting and secondary acid leaching. The optimum conditions are as follows; 100 t for first acid leaching stage, m(NaOH) : m(activated high content silica residue) =0. 6 for alkali dissolution stage, m(Na_2CO_3) : m( clinker A) =0.8 and 20% of HCl mass fraction for the secondary acid leaching stage. Under these conditions, the total leaching efficiencies of Fe~(2+) and Al~(3+) are 96.54% and 86.67% , respectively. The quality of the main product poly aluminum ferric chloride and white carbon black can meet the national standards of GB15892 -2003 and GB10517 -89, respectively.
