Method for preparing sodium polyacrylate dispersant

The invention provides a method for preparing a sodium polyacrylate dispersant. The method comprises the following steps of mixing first acrylic waste liquid and a chain transfer agent, heating, dropwise adding an initiator and second acrylic waste liquid, and reacting for obtaining a reaction product; adjusting the pH value of the reaction product by adopting solid sodium hydroxide, thereby obtaining the sodium polyacrylate dispersant. According to the method, during the preparation of the sodium polyacrylate dispersant, the first acrylic waste liquid and the chain transfer agent serve as a base solution, the second acrylic waste liquid and the initiator are dropwise added to the base solution, and a manner that acrylic acid is dropwise added to part of the acrylic waste liquid is adopted, so that the phenomenon that molecular weights are unequal due to violent reaction is avoided; moreover, sodium polyacrylate is prepared from the acrylic waste liquid, so that the waste is recycled, and meanwhile, the production cost of the acrylic waste liquid is reduced.