The content of magnetic impurities in the cathode slurry is removed, and finally the K value of the cell is improved; The utility model is connected in series with the slurry pipe, and the slurry flows through the iron separator when in use; Most of the magnetic impurities in the slurry are removed by high-strength magnetic rod adsorption; The whole magnetic rod is quickly lifted and lowered by the air cylinder to facilitate the cleaning of the magnetic rod and reduce the cleaning time.