Method for preparing polycarboxylic slump-retaining agent by tail liquid in production for acrolein

The invention provides a method for preparing a polycarboxylic slump-retaining agent by a tail liquid in production for acrolein, wherein the polycarboxylic slump-retaining agent is formed by performing copolymerization on the tail liquid in production for acrolein, unsaturated polyether (macromonomer A) and acrylic acid derivative (micromonomer B); and the method relates to the fields of waste recycling and concrete admixture. The dispersity and slump-retaining capacity of the slump-retaining agent prepared by the method provided by the invention for cement achieve the effects of normal product on the market; and the method provided by the invention can omit the expense of incineration treatment for the tail liquid of acrolein, as well as decreases the production cost of the polycarboxylic slump-retaining agent, and has positive significance for environmental protection and waste recycling.