Abstract: Using AlCl₃ as raw materials, Polyaluminum chloride(PAC)with high Al₁₃ content was prepared by electrolysis with exchanging electrodes. The synthesis mechanism of Al₁₃ in the process of electrolysis was discussed, the effects of electrolysis voltage, the original concentration of Al ³⁺, the circulation mixing rate of the electrolyte and the exchanging frequency of the electrodes on the synthesis velocity of Al₁₃, ratio of Al₁₃ in total Al(Al_T) and the electrolysis time were studied. The optimum conditions are determined: the exchanging frequency of the electrodes is once per minute, the original concentration of Al³⁺ is 0.5000mol·L^-1, the electrolysis voltage is 12V, and the circulation mixing rate of the electrolyte is 0.5L·min^-1. Under the optimal conditions, the liquid product with basicity of 82.0% and Al₁₃ polymer accounted for 91.2% of total Al is successfully prepared.

Key words: Al₁₃ polymer, synthesis speed, electroanalysis prepraration, exchanging frequency of the electrodes