Method for producing sewage flocculating agent by utilizing dead catalyst

The invention provides a method for producing a sewage flocculating agent by utilizing a dead catalyst. The method comprises the following steps of: 1) pre-treatment: crushing the dead catalyst into particles of 40 -60 meshes, roasting and activating the particles for 6 -12 hours at a temperature of 600 -800 DEG C for later use; 2) polymerization reaction: adding strong acid and water into a reaction kettle, starting stirring and heating up, when the temperature reaches a predetermined value, feeding the dead catalyst and bauxite according to a certain proportion into the reaction kettle to react for 3 hours; 3) adjustment reaction: unloading reactants in the reaction kettle into an adjusting reaction tank from an unloading opening, adding a calcium aluminate powder and water according to a certain proportion to continue the reaction for 2 -2.5 hours; and 4) post-treatment: cooling the solution subjected to the adjustment reaction to the temperature of 40 DEG C, and filter-pressing the solution to obtain a li