Abstract: A technology for preparing high efficient flocculant—polymeric aluminum ferric chloride (PAFC) with the modified bayer red mud as raw material was studied.The technology adopted hydrochloric acid to lixiviate aluminum and iron in the bayer red mud to prepare the aluminum hydroxide and iron hydroxide by gel method.Then,PAFC could be prepared through polymerization.Process parameters of acid leaching for the PAFC preparation were mainly studied,and PAFC was prepared with the optimized parameters.Flocculating experiment was also carried out to test the performances of prepared products.Results showed that the product′s flocculant effect was good.This technology developed a new way for comprehensive utilization of bayer red mud.